modernc.org/knuth@v0.0.4/mf/internal/trap/mf.go

// Code generated by '[/tmp/go-build1429805405/b001/exe/generate]', DO NOT EDIT.

// % This program is copyright (C) 1984 by D. E. Knuth; all rights are reserved.
// % Unlimited copying and redistribution of this file are permitted as long
// % as this file is not modified. Modifications are permitted, but only if
// % the resulting file is not named mf.web. (The WEB system provides
// % for alterations via an auxiliary file; the master file should stay intact.)
// % In other words, METAFONT is under essentially the same ground rules as TeX.
//
// % TeX is a trademark of the American Mathematical Society.
// % METAFONT is a trademark of Addison-Wesley Publishing Company.
//
// % Version 0 was completed on July 28, 1984.
// % Version 1 was completed on January 4, 1986; it corresponds to "Volume D".
// % Version 1.1 trivially corrected the punctuation in one message (June 1986).
// % Version 1.2 corrected an arithmetic overflow problem (July 1986).
// % Version 1.3 improved rounding when elliptical pens are made (November 1986).
// % Version 1.4 corrected scan_declared_variable timing (May 1988).
// % Version 1.5 fixed negative halving in allocator when mem_min<0 (June 1988).
// % Version 1.6 kept open_log_file from calling fatal_error (November 1988).
// % Version 1.7 solved that problem a better way (December 1988).
// % Version 1.8 introduced major changes for 8-bit extensions (September 1989).
// % Version 1.9 improved skimping and was edited for style (December 1989).
// % Version 2.0 fixed bug in addto; released with TeX version 3.0 (March 1990).
// % Version 2.7 made consistent with TeX version 3.1 (September 1990).
// % Version 2.71 fixed bug in draw, allowed unprintable filenames (March 1992).
// % Version 2.718 fixed bug in <Choose a dependent...> (March 1995).
// % Version 2.7182 fixed bugs related to "<unprintable char>" (August 1996).
// % Version 2.71828 suppressed autorounding in dangerous cases (June 2003).
// % Version 2.718281 was a general cleanup with minor fixes (February 2008).
// % Version 2.7182818 was similar (January 2014).
// % Version 2.71828182 was similar (January 2021).
//
// % A reward of $327.68 will be paid to the first finder of any remaining bug.
//
// % Although considerable effort has been expended to make the METAFONT program
// % correct and reliable, no warranty is implied; the author disclaims any
// % obligation or liability for damages, including but not limited to
// % special, indirect, or consequential damages arising out of or in
// % connection with the use or performance of this software. This work has
// % been a ``labor of love'' and the author hopes that users enjoy it.
//
// % Here is TeX material that gets inserted after \input webmac
// \def\hang[\hangindent 3em\noindent\ignorespaces]
// \def\textindent#1[\hangindent2.5em\noindent\hbox to2.5em[\hss#1 ]\ignorespaces]
// \font\ninerm=cmr9
// \let\mc=\ninerm % medium caps for names like SAIL
// \def\PASCAL[Pascal]
// \def\ph[\hbox[Pascal-H]]
// \def\psqrt#1[\sqrt[\mathstrut#1]]
// \def\k[_[k+1]]
// \def\pct![[\char`\%]] % percent sign in ordinary text
// \font\tenlogo=logo10 % font used for the METAFONT logo
// \font\logos=logosl10
// \font\eightlogo=logo8
// \def\MF[[\tenlogo META]\-[\tenlogo FONT]]
// \def\<#1>[$\langle#1\rangle$]
// \def\section[\mathhexbox278]
// \let\swap=\leftrightarrow
// \def\round[\mathop[\rm round]\nolimits]
//
// \def\(#1)[] % this is used to make section names sort themselves better
// \def\9#1[] % this is used for sort keys in the index via @:sort key][entry@>
//
// \outer\def\N#1. \[#2]#3.[\MN#1.\vfil\eject % begin starred section
//   \def\rhead[PART #2:\uppercase[#3]] % define running headline
//   \message[*\modno] % progress report
//   \edef\next[\write\cont[\Z[\?#2]#3][\modno][\the\pageno]]]\next
//   \ifon\startsection[\bf\ignorespaces#3.\quad]\ignorespaces]
// \let\?=\relax % we want to be able to \write a \?
//
// \def\title[[\eightlogo METAFONT]]
// \def\topofcontents[\hsize 5.5in
//   \vglue -30pt plus 1fil minus 1.5in
//   \def\?##1][\hbox to 1in[\hfil##1.\ ]]
//   ]
// \def\botofcontents[\vskip 0pt plus 1fil minus 1.5in]
// \pageno=3
// \def\glob[13] % this should be the section number of "<Global...>"
// \def\gglob[20, 26] % this should be the next two sections of "<Global...>"
//
//

// 1. \[1] Introduction

// tangle:pos ../../mf.web:80:22:

// This is \MF, a font compiler intended to produce typefaces of high quality.
// The \PASCAL\ program that follows is the definition of \MF84, a standard
// \xref[PASCAL][\PASCAL]
//  \xref[METAFONT84][\MF84]
// version of \MF\ that is designed to be highly portable so that identical output
// will be obtainable on a great variety of computers. The conventions
// of \MF84 are the same as those of \TeX82.
//
// The main purpose of the following program is to explain the algorithms of \MF\
// as clearly as possible. As a result, the program will not necessarily be very
// efficient when a particular \PASCAL\ compiler has translated it into a
// particular machine language. However, the program has been written so that it
// can be tuned to run efficiently in a wide variety of operating environments
// by making comparatively few changes. Such flexibility is possible because
// the documentation that follows is written in the \.[WEB] language, which is
// at a higher level than \PASCAL; the preprocessing step that converts \.[WEB]
// to \PASCAL\ is able to introduce most of the necessary refinements.
// Semi-automatic translation to other languages is also feasible, because the
// program below does not make extensive use of features that are peculiar to
// \PASCAL.
//
// A large piece of software like \MF\ has inherent complexity that cannot
// be reduced below a certain level of difficulty, although each individual
// part is fairly simple by itself. The \.[WEB] language is intended to make
// the algorithms as readable as possible, by reflecting the way the
// individual program pieces fit together and by providing the
// cross-references that connect different parts. Detailed comments about
// what is going on, and about why things were done in certain ways, have
// been liberally sprinkled throughout the program.  These comments explain
// features of the implementation, but they rarely attempt to explain the
// \MF\ language itself, since the reader is supposed to be familiar with
// [\sl The [\logos METAFONT\/]book].
// \xref[WEB]
// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]

// 2.

// tangle:pos ../../mf.web:116:3:

// The present implementation has a long ancestry, beginning in the spring
// of~1977, when its author wrote a prototype set of subroutines and macros
// \xref[Knuth, Donald Ervin]
// that were used to develop the first Computer Modern fonts.
// This original proto-\MF\ required the user to recompile a [\mc SAIL] program
// whenever any character was changed, because it was not a ``language'' for
// font design; the language was [\mc SAIL]. After several hundred characters
// had been designed in that way, the author developed an interpretable language
// called \MF, in which it was possible to express the Computer Modern programs
// less cryptically. A complete \MF\ processor was designed and coded by the
// author in 1979. This program, written in [\mc SAIL], was adapted for use
// with a variety of typesetting equipment and display terminals by Leo Guibas,
// Lyle Ramshaw, and David Fuchs.
// \xref[Guibas, Leonidas Ioannis]
// \xref[Ramshaw, Lyle Harold]
// \xref[Fuchs, David Raymond]
// Major improvements to the design of Computer Modern fonts were made in the
// spring of 1982, after which it became clear that a new language would
// better express the needs of letterform designers. Therefore an entirely
// new \MF\ language and system were developed in 1984; the present system
// retains the name and some of the spirit of \MF79, but all of the details
// have changed.
//
// No doubt there still is plenty of room for improvement, but the author
// is firmly committed to keeping \MF84 ``frozen'' from now on; stability
// and reliability are to be its main virtues.
//
// On the other hand, the \.[WEB] description can be extended without changing
// the core of \MF84 itself, and the program has been designed so that such
// extensions are not extremely difficult to make.
// The |banner| string defined here should be changed whenever \MF\
// undergoes any modifications, so that it will be clear which version of
// \MF\ might be the guilty party when a problem arises.
// \xref[extensions to \MF]
// \xref[system dependencies]
//
// If this program is changed, the resulting system should not be called
// `\MF\kern.5pt'; the official name `\MF\kern.5pt' by itself is reserved
// for software systems that are fully compatible with each other.
// A special test suite called the ``\.[TRAP] test'' is available for
// helping to determine whether an implementation deserves to be
// known as `\MF\kern.5pt' [cf.~Stanford Computer Science report CS1095,
// January 1986].

// 3.

// tangle:pos ../../mf.web:162:3:

// Different \PASCAL s have slightly different conventions, and the present
//  \xref[PASCAL H][\ph]
// program expresses \MF\ in terms of the \PASCAL\ that was
// available to the author in 1984. Constructions that apply to
// this particular compiler, which we shall call \ph, should help the
// reader see how to make an appropriate interface for other systems
// if necessary. (\ph\ is Charles Hedrick's modification of a compiler
// \xref[Hedrick, Charles Locke]
// for the DECsystem-10 that was originally developed at the University of
// Hamburg; cf.\ [\sl Software---Practice and Experience \bf6] (1976),
// 29--42. The \MF\ program below is intended to be adaptable, without
// extensive changes, to most other versions of \PASCAL, so it does not fully
// use the admirable features of \ph. Indeed, a conscious effort has been
// made here to avoid using several idiosyncratic features of standard
// \PASCAL\ itself, so that most of the code can be translated mechanically
// into other high-level languages. For example, the `\&[with]' and `\\[new]'
// features are not used, nor are pointer types, set types, or enumerated
// scalar types; there are no `\&[var]' parameters, except in the case of files
// or in the system-dependent |paint_row| procedure;
// there are no tag fields on variant records; there are no |real| variables;
// no procedures are declared local to other procedures.)
//
// The portions of this program that involve system-dependent code, where
// changes might be necessary because of differences between \PASCAL\ compilers
// and/or differences between
// operating systems, can be identified by looking at the sections whose
// numbers are listed under `system dependencies' in the index. Furthermore,
// the index entries for `dirty \PASCAL' list all places where the restrictions
// of \PASCAL\ have not been followed perfectly, for one reason or another.
//  \xref[system dependencies]
//  \xref[dirty \PASCAL]

// 4.

// tangle:pos ../../mf.web:194:3:

// The program begins with a normal \PASCAL\ program heading, whose
// components will be filled in later, using the conventions of \.[WEB].
// \xref[WEB]
// For example, the portion of the program called `\X\glob:Global
// variables\X' below will be replaced by a sequence of variable declarations
// that starts in $\section\glob$ of this documentation. In this way, we are able
// to define each individual global variable when we are prepared to
// understand what it means; we do not have to define all of the globals at
// once.  Cross references in $\section\glob$, where it says ``See also
// sections \gglob, \dots,'' also make it possible to look at the set of
// all global variables, if desired.  Similar remarks apply to the other
// portions of the program heading.
//
// Actually the heading shown here is not quite normal: The |program| line
// does not mention any |output| file, because \ph\ would ask the \MF\ user
// to specify a file name if |output| were specified here.
// \xref[PASCAL H][\ph]
// \xref[system dependencies]
// \4
// Compiler directives
// $C-,A+,D-
// no range check, catch arithmetic overflow, no debug overhead
//  [$C+,D+]  [  ]
// but turn everything on when debugging

package trap

import (
	"math"
	"unsafe"

	"modernc.org/knuth"
)

var (
	_ = math.MaxInt32
	_ unsafe.Pointer
)

type (
	char   = byte
	signal int
)

func strcopy(dst []char, src string) {
	for i := 0; i < len(dst) && i < len(src); i++ {
		dst[i] = src[i]
	}
}

func arraystr(a []char) string {
	b := make([]byte, len(a))
	for i, c := range a {
		b[i] = c
	}
	return string(b)
}

func abs(n int32) int32 {
	if n >= 0 {
		return n
	}

	return -n
}

func fabs(f float64) float64 {
	if f >= 0 {
		return f
	}

	return -f
}

func round(f float64) int32 {
	if f >= 0 {
		return int32(f + 0.5)
	}

	return int32(f - 0.5)
}

// key control points

const (
	startOfMf = 1    /* go here when \MF's variables are initialized */
	endOfMf   = 9998 /* go here to close files and terminate gracefully */
	finalEnd  = 9999 /* this label marks the ending of the program */
	memMin    = 0    // smallest index in the |mem| array, must not be less
	//   than |min_halfword|

	hashSize = 2100 // maximum number of symbolic tokens,
	//   must be less than |max_halfword-3*param_size|

	hashPrime = 1777 /* a prime number equal to about 85\pct! of |hash_size| */
	maxInOpen = 6    // maximum number of input files and error insertions that
	//   can be going on simultaneously

	paramSize = 150 // maximum number of simultaneous macro parameters
	// \xref[system dependencies]

	exit                    = 10  /* go here to leave a procedure */
	restart                 = 20  /* go here to start a procedure again */
	reswitch                = 21  /* go here to start a case statement again */
	continue1               = 22  /* go here to resume a loop */
	done                    = 30  /* go here to exit a loop */
	done1                   = 31  /* like |done|, when there is more than one loop */
	done2                   = 32  /* for exiting the second loop in a long block */
	done3                   = 33  /* for exiting the third loop in a very long block */
	done4                   = 34  /* for exiting the fourth loop in an extremely long block */
	done5                   = 35  /* for exiting the fifth loop in an immense block */
	done6                   = 36  /* for exiting the sixth loop in a block */
	found                   = 40  /* go here when you've found it */
	found1                  = 41  /* like |found|, when there's more than one per routine */
	found2                  = 42  /* like |found|, when there's more than two per routine */
	notFound                = 45  /* go here when you've found nothing */
	commonEnding            = 50  /* go here when you want to merge with another branch */
	firstTextChar           = 0   /* ordinal number of the smallest element of |text_char| */
	lastTextChar            = 255 /* ordinal number of the largest element of |text_char| */
	maxStrRef               = 127 /* ``infinite'' number of references */
	noPrint                 = 0   /* |selector| setting that makes data disappear */
	termOnly                = 1   /* printing is destined for the terminal only */
	logOnly                 = 2   /* printing is destined for the transcript file only */
	termAndLog              = 3   /* normal |selector| setting */
	pseudo                  = 4   /* special |selector| setting for |show_context| */
	newString               = 5   /* printing is deflected to the string pool */
	maxSelector             = 5   /* highest selector setting */
	batchMode               = 0   /* omits all stops and omits terminal output */
	nonstopMode             = 1   /* omits all stops */
	scrollMode              = 2   /* omits error stops */
	errorStopMode           = 3   /* stops at every opportunity to interact */
	spotless                = 0   /* |history| value when nothing has been amiss yet */
	warningIssued           = 1   /* |history| value when |begin_diagnostic| has been called */
	errorMessageIssued      = 2   /* |history| value when |error| has been called */
	fatalErrorStop          = 3   /* |history| value when termination was premature */
	negateX                 = 1
	negateY                 = 2
	switchXAndY             = 4
	firstOctant             = 1
	secondOctant            = firstOctant + switchXAndY
	thirdOctant             = firstOctant + switchXAndY + negateX
	fourthOctant            = firstOctant + negateX
	fifthOctant             = firstOctant + negateX + negateY
	sixthOctant             = firstOctant + switchXAndY + negateX + negateY
	seventhOctant           = firstOctant + switchXAndY + negateY
	eighthOctant            = firstOctant + negateY
	minQuarterword          = 0   /* smallest allowable value in a |quarterword| */
	maxQuarterword          = 255 /* largest allowable value in a |quarterword| */
	ifTest                  = 1   /* conditional text (\&[if]) */
	fiOrElse                = 2   /* delimiters for conditionals (\&[elseif], \&[else], \&[fi]) */
	input                   = 3   /* input a source file (\&[input], \&[endinput]) */
	iteration               = 4   /* iterate (\&[for], \&[forsuffixes], \&[forever], \&[endfor]) */
	repeatLoop              = 5   /* special command substituted for \&[endfor] */
	exitTest                = 6   /* premature exit from a loop (\&[exitif]) */
	relax                   = 7   /* do nothing (\.[\char`\\]) */
	scanTokens              = 8   /* put a string into the input buffer */
	expandAfter             = 9   /* look ahead one token */
	definedMacro            = 10  /* a macro defined by the user */
	minCommand              = definedMacro + 1
	displayCommand          = 11 /* online graphic output (\&[display]) */
	saveCommand             = 12 /* save a list of tokens (\&[save]) */
	interimCommand          = 13 /* save an internal quantity (\&[interim]) */
	letCommand              = 14 /* redefine a symbolic token (\&[let]) */
	newInternal             = 15 /* define a new internal quantity (\&[newinternal]) */
	macroDef                = 16 /* define a macro (\&[def], \&[vardef], etc.) */
	shipOutCommand          = 17 /* output a character (\&[shipout]) */
	addToCommand            = 18 /* add to edges (\&[addto]) */
	cullCommand             = 19 /* cull and normalize edges (\&[cull]) */
	tfmCommand              = 20 /* command for font metric info (\&[ligtable], etc.) */
	protectionCommand       = 21 /* set protection flag (\&[outer], \&[inner]) */
	showCommand             = 22 /* diagnostic output (\&[show], \&[showvariable], etc.) */
	modeCommand             = 23 /* set interaction level (\&[batchmode], etc.) */
	randomSeed              = 24 /* initialize random number generator (\&[randomseed]) */
	messageCommand          = 25 /* communicate to user (\&[message], \&[errmessage]) */
	everyJobCommand         = 26 /* designate a starting token (\&[everyjob]) */
	delimiters              = 27 /* define a pair of delimiters (\&[delimiters]) */
	openWindow              = 28 /* define a window on the screen (\&[openwindow]) */
	specialCommand          = 29 /* output special info (\&[special], \&[numspecial]) */
	typeName                = 30 /* declare a type (\&[numeric], \&[pair], etc.) */
	maxStatementCommand     = typeName
	minPrimaryCommand       = typeName
	leftDelimiter           = 31 /* the left delimiter of a matching pair */
	beginGroup              = 32 /* beginning of a group (\&[begingroup]) */
	nullary                 = 33 /* an operator without arguments (e.g., \&[normaldeviate]) */
	unary                   = 34 /* an operator with one argument (e.g., \&[sqrt]) */
	strOp                   = 35 /* convert a suffix to a string (\&[str]) */
	cycle                   = 36 /* close a cyclic path (\&[cycle]) */
	primaryBinary           = 37 /* binary operation taking `\&[of]' (e.g., \&[point]) */
	capsuleToken            = 38 /* a value that has been put into a token list */
	stringToken             = 39 /* a string constant (e.g., |"hello"|) */
	internalQuantity        = 40 /* internal numeric parameter (e.g., \&[pausing]) */
	minSuffixToken          = internalQuantity
	tagToken                = 41 /* a symbolic token without a primitive meaning */
	numericToken            = 42 /* a numeric constant (e.g., \.[3.14159]) */
	maxSuffixToken          = numericToken
	plusOrMinus             = 43          /* either `\.+' or `\.-' */
	maxPrimaryCommand       = plusOrMinus /* should also be |numeric_token+1| */
	minTertiaryCommand      = plusOrMinus
	tertiarySecondaryMacro  = 44 /* a macro defined by \&[secondarydef] */
	tertiaryBinary          = 45 /* an operator at the tertiary level (e.g., `\.[++]') */
	maxTertiaryCommand      = tertiaryBinary
	leftBrace               = 46 /* the operator `\.[\char`\[]' */
	minExpressionCommand    = leftBrace
	pathJoin                = 47 /* the operator `\.[..]' */
	ampersand               = 48 /* the operator `\.\&' */
	expressionTertiaryMacro = 49 /* a macro defined by \&[tertiarydef] */
	expressionBinary        = 50 /* an operator at the expression level (e.g., `\.<') */
	equals                  = 51 /* the operator `\.=' */
	maxExpressionCommand    = equals
	andCommand              = 52 /* the operator `\&[and]' */
	minSecondaryCommand     = andCommand
	secondaryPrimaryMacro   = 53 /* a macro defined by \&[primarydef] */
	slash                   = 54 /* the operator `\./' */
	secondaryBinary         = 55 /* an operator at the binary level (e.g., \&[shifted]) */
	maxSecondaryCommand     = secondaryBinary
	paramType               = 56 /* type of parameter (\&[primary], \&[expr], \&[suffix], etc.) */
	controls                = 57 /* specify control points explicitly (\&[controls]) */
	tension                 = 58 /* specify tension between knots (\&[tension]) */
	atLeast                 = 59 /* bounded tension value (\&[atleast]) */
	curlCommand             = 60 /* specify curl at an end knot (\&[curl]) */
	macroSpecial            = 61 /* special macro operators (\&[quote], \.[\#\AT!], etc.) */
	rightDelimiter          = 62 /* the right delimiter of a matching pair */
	leftBracket             = 63 /* the operator `\.[' */
	rightBracket            = 64 /* the operator `\.]' */
	rightBrace              = 65 /* the operator `\.[\char`\]]' */
	withOption              = 66 /* option for filling (\&[withpen], \&[withweight]) */
	cullOp                  = 67 /* the operator `\&[keeping]' or `\&[dropping]' */
	thingToAdd              = 68
	/* variant of \&[addto] (\&[contour], \&[doublepath], \&[also]) */
	ofToken      = 69 /* the operator `\&[of]' */
	fromToken    = 70 /* the operator `\&[from]' */
	toToken      = 71 /* the operator `\&[to]' */
	atToken      = 72 /* the operator `\&[at]' */
	inWindow     = 73 /* the operator `\&[inwindow]' */
	stepToken    = 74 /* the operator `\&[step]' */
	untilToken   = 75 /* the operator `\&[until]' */
	ligKernToken = 76
	/* the operators `\&[kern]' and `\.[=:]' and `\.[=:\char'174]', etc. */
	assignment        = 77 /* the operator `\.[:=]' */
	skipTo            = 78 /* the operation `\&[skipto]' */
	bcharLabel        = 79 /* the operator `\.[\char'174\char'174:]' */
	doubleColon       = 80 /* the operator `\.[::]' */
	colon             = 81 /* the operator `\.:' */
	comma             = 82 /* the operator `\.,', must be |colon+1| */
	semicolon         = 83 /* the operator `\.;', must be |comma+1| */
	endGroup          = 84 /* end a group (\&[endgroup]), must be |semicolon+1| */
	stop              = 85 /* end a job (\&[end], \&[dump]), must be |end_group+1| */
	maxCommandCode    = stop
	outerTag          = maxCommandCode + 1 /* protection code added to command code */
	undefined         = 0                  /* no type has been declared */
	unknownTag        = 1                  /* this constant is added to certain type codes below */
	vacuous           = 1                  /* no expression was present */
	booleanType       = 2                  /* \&[boolean] with a known value */
	unknownBoolean    = booleanType + unknownTag
	stringType        = 4 /* \&[string] with a known value */
	unknownString     = stringType + unknownTag
	penType           = 6 /* \&[pen] with a known value */
	unknownPen        = penType + unknownTag
	futurePen         = 8 /* subexpression that will become a \&[pen] at a higher level */
	pathType          = 9 /* \&[path] with a known value */
	unknownPath       = pathType + unknownTag
	pictureType       = 11 /* \&[picture] with a known value */
	unknownPicture    = pictureType + unknownTag
	transformType     = 13 /* \&[transform] variable or capsule */
	pairType          = 14 /* \&[pair] variable or capsule */
	numericType       = 15 /* variable that has been declared \&[numeric] but not used */
	known             = 16 /* \&[numeric] with a known value */
	dependent         = 17 /* a linear combination with |fraction| coefficients */
	protoDependent    = 18 /* a linear combination with |scaled| coefficients */
	independent       = 19 /* \&[numeric] with unknown value */
	tokenList         = 20 /* variable name or suffix argument or text argument */
	structured        = 21 /* variable with subscripts and attributes */
	unsuffixedMacro   = 22 /* variable defined with \&[vardef] but no \.[\AT!\#] */
	suffixedMacro     = 23 /* variable defined with \&[vardef] and \.[\AT!\#] */
	root              = 0  /* |name_type| at the top level of a variable */
	savedRoot         = 1  /* same, when the variable has been saved */
	structuredRoot    = 2  /* |name_type| where a |structured| branch occurs */
	subscr            = 3  /* |name_type| in a subscript node */
	attr              = 4  /* |name_type| in an attribute node */
	xPartSector       = 5  /* |name_type| in the \&[xpart] of a node */
	yPartSector       = 6  /* |name_type| in the \&[ypart] of a node */
	xxPartSector      = 7  /* |name_type| in the \&[xxpart] of a node */
	xyPartSector      = 8  /* |name_type| in the \&[xypart] of a node */
	yxPartSector      = 9  /* |name_type| in the \&[yxpart] of a node */
	yyPartSector      = 10 /* |name_type| in the \&[yypart] of a node */
	capsule           = 11 /* |name_type| in stashed-away subexpressions */
	token             = 12 /* |name_type| in a numeric token or string token */
	trueCode          = 30 /* operation code for \.[true] */
	falseCode         = 31 /* operation code for \.[false] */
	nullPictureCode   = 32 /* operation code for \.[nullpicture] */
	nullPenCode       = 33 /* operation code for \.[nullpen] */
	jobNameOp         = 34 /* operation code for \.[jobname] */
	readStringOp      = 35 /* operation code for \.[readstring] */
	penCircle         = 36 /* operation code for \.[pencircle] */
	normalDeviate     = 37 /* operation code for \.[normaldeviate] */
	oddOp             = 38 /* operation code for \.[odd] */
	knownOp           = 39 /* operation code for \.[known] */
	unknownOp         = 40 /* operation code for \.[unknown] */
	notOp             = 41 /* operation code for \.[not] */
	decimal           = 42 /* operation code for \.[decimal] */
	reverse           = 43 /* operation code for \.[reverse] */
	makePathOp        = 44 /* operation code for \.[makepath] */
	makePenOp         = 45 /* operation code for \.[makepen] */
	totalWeightOp     = 46 /* operation code for \.[totalweight] */
	octOp             = 47 /* operation code for \.[oct] */
	hexOp             = 48 /* operation code for \.[hex] */
	asciiOp           = 49 /* operation code for \.[ASCII] */
	charOp            = 50 /* operation code for \.[char] */
	lengthOp          = 51 /* operation code for \.[length] */
	turningOp         = 52 /* operation code for \.[turningnumber] */
	xPart             = 53 /* operation code for \.[xpart] */
	yPart             = 54 /* operation code for \.[ypart] */
	xxPart            = 55 /* operation code for \.[xxpart] */
	xyPart            = 56 /* operation code for \.[xypart] */
	yxPart            = 57 /* operation code for \.[yxpart] */
	yyPart            = 58 /* operation code for \.[yypart] */
	sqrtOp            = 59 /* operation code for \.[sqrt] */
	mExpOp            = 60 /* operation code for \.[mexp] */
	mLogOp            = 61 /* operation code for \.[mlog] */
	sinDOp            = 62 /* operation code for \.[sind] */
	cosDOp            = 63 /* operation code for \.[cosd] */
	floorOp           = 64 /* operation code for \.[floor] */
	uniformDeviate    = 65 /* operation code for \.[uniformdeviate] */
	charExistsOp      = 66 /* operation code for \.[charexists] */
	angleOp           = 67 /* operation code for \.[angle] */
	cycleOp           = 68 /* operation code for \.[cycle] */
	plus              = 69 /* operation code for \.+ */
	minus             = 70 /* operation code for \.- */
	times             = 71 /* operation code for \.* */
	over              = 72 /* operation code for \./ */
	pythagAdd         = 73 /* operation code for \.[++] */
	pythagSub         = 74 /* operation code for \.[+-+] */
	orOp              = 75 /* operation code for \.[or] */
	andOp             = 76 /* operation code for \.[and] */
	lessThan          = 77 /* operation code for \.< */
	lessOrEqual       = 78 /* operation code for \.[<=] */
	greaterThan       = 79 /* operation code for \.> */
	greaterOrEqual    = 80 /* operation code for \.[>=] */
	equalTo           = 81 /* operation code for \.= */
	unequalTo         = 82 /* operation code for \.[<>] */
	concatenate       = 83 /* operation code for \.\& */
	rotatedBy         = 84 /* operation code for \.[rotated] */
	slantedBy         = 85 /* operation code for \.[slanted] */
	scaledBy          = 86 /* operation code for \.[scaled] */
	shiftedBy         = 87 /* operation code for \.[shifted] */
	transformedBy     = 88 /* operation code for \.[transformed] */
	xScaled           = 89 /* operation code for \.[xscaled] */
	yScaled           = 90 /* operation code for \.[yscaled] */
	zScaled           = 91 /* operation code for \.[zscaled] */
	intersect         = 92 /* operation code for \.[intersectiontimes] */
	doubleDot         = 93 /* operation code for improper \.[..] */
	substringOf       = 94 /* operation code for \.[substring] */
	minOf             = substringOf
	subpathOf         = 95  /* operation code for \.[subpath] */
	directionTimeOf   = 96  /* operation code for \.[directiontime] */
	pointOf           = 97  /* operation code for \.[point] */
	precontrolOf      = 98  /* operation code for \.[precontrol] */
	postcontrolOf     = 99  /* operation code for \.[postcontrol] */
	penOffsetOf       = 100 /* operation code for \.[penoffset] */
	tracingTitles     = 1   /* show titles online when they appear */
	tracingEquations  = 2   /* show each variable when it becomes known */
	tracingCapsules   = 3   /* show capsules too */
	tracingChoices    = 4   /* show the control points chosen for paths */
	tracingSpecs      = 5   /* show subdivision of paths into octants before digitizing */
	tracingPens       = 6   /* show details of pens that are made */
	tracingCommands   = 7   /* show commands and operations before they are performed */
	tracingRestores   = 8   /* show when a variable or internal is restored */
	tracingMacros     = 9   /* show macros before they are expanded */
	tracingEdges      = 10  /* show digitized edges as they are computed */
	tracingOutput     = 11  /* show digitized edges as they are output */
	tracingStats      = 12  /* show memory usage at end of job */
	tracingOnline     = 13  /* show long diagnostics on terminal and in the log file */
	year              = 14  /* the current year (e.g., 1984) */
	month             = 15  /* the current month (e.g., 3 $\equiv$ March) */
	day               = 16  /* the current day of the month */
	time              = 17  /* the number of minutes past midnight when this job started */
	charCode          = 18  /* the number of the next character to be output */
	charExt           = 19  /* the extension code of the next character to be output */
	charWd            = 20  /* the width of the next character to be output */
	charHt            = 21  /* the height of the next character to be output */
	charDp            = 22  /* the depth of the next character to be output */
	charIc            = 23  /* the italic correction of the next character to be output */
	charDx            = 24  /* the device's $x$ movement for the next character, in pixels */
	charDy            = 25  /* the device's $y$ movement for the next character, in pixels */
	designSize        = 26  /* the unit of measure used for |char_wd..char_ic|, in points */
	hppp              = 27  /* the number of horizontal pixels per point */
	vppp              = 28  /* the number of vertical pixels per point */
	xOffset           = 29  /* horizontal displacement of shipped-out characters */
	yOffset           = 30  /* vertical displacement of shipped-out characters */
	pausing           = 31  /* positive to display lines on the terminal before they are read */
	showstopping      = 32  /* positive to stop after each \&[show] command */
	fontmaking        = 33  /* positive if font metric output is to be produced */
	proofing          = 34  /* positive for proof mode, negative to suppress output */
	smoothing         = 35  /* positive if moves are to be ``smoothed'' */
	autorounding      = 36  /* controls path modification to ``good'' points */
	granularity       = 37  /* autorounding uses this pixel size */
	fillin            = 38  /* extra darkness of diagonal lines */
	turningCheck      = 39  /* controls reorientation of clockwise paths */
	warningCheck      = 40  /* controls error message when variable value is large */
	boundaryChar      = 41  /* the boundary character for ligatures */
	maxGivenInternal  = 41
	digitClass        = 0   /* the class number of \.[0123456789] */
	periodClass       = 1   /* the class number of `\..' */
	spaceClass        = 2   /* the class number of spaces and nonstandard characters */
	percentClass      = 3   /* the class number of `\.\%' */
	stringClass       = 4   /* the class number of `\."' */
	rightParenClass   = 8   /* the class number of `\.)' */
	letterClass       = 9   /* letters and the underline character */
	leftBracketClass  = 17  /* `\.[' */
	rightBracketClass = 18  /* `\.]' */
	invalidClass      = 20  /* bad character in the input */
	maxClass          = 20  /* the largest class number */
	hashBase          = 257 /* hashing actually starts here */
	tokenNodeSize     = 2   /* the number of words in a large token node */
	generalMacro      = 0   /* preface to a macro defined with a parameter list */
	primaryMacro      = 1   /* preface to a macro with a \&[primary] parameter */
	secondaryMacro    = 2   /* preface to a macro with a \&[secondary] parameter */
	tertiaryMacro     = 3   /* preface to a macro with a \&[tertiary] parameter */
	exprMacro         = 4   /* preface to a macro with an undelimited \&[expr] parameter */
	ofMacro           = 5   // preface to a macro with
	//   undelimited `\&[expr] |x| \&[of]~|y|' parameters

	suffixMacro           = 6  /* preface to a macro with an undelimited \&[suffix] parameter */
	textMacro             = 7  /* preface to a macro with an undelimited \&[text] parameter */
	valueNodeSize         = 2  /* the number of words in a value node */
	attrNodeSize          = 3  /* the number of words in an attribute node */
	subscrNodeSize        = 3  /* the number of words in a subscript node */
	collectiveSubscript   = 0  /* code for the attribute `\.[[]]' */
	pairNodeSize          = 4  /* the number of words in a pair node */
	transformNodeSize     = 12 /* the number of words in a transform node */
	saveNodeSize          = 2  /* number of words per non-boundary save-stack node */
	endpoint              = 0  /* |left_type| at path beginning and |right_type| at path end */
	knotNodeSize          = 7  /* number of words in a knot node */
	explicit              = 1  /* |left_type| or |right_type| when control points are known */
	given                 = 2  /* |left_type| or |right_type| when a direction is given */
	curl                  = 3  /* |left_type| or |right_type| when a curl is desired */
	open                  = 4  /* |left_type| or |right_type| when \MF\ should choose the direction */
	endCycle              = open + 1
	moveIncrement         = 11 /* number of items pushed by |make_moves| */
	zeroW                 = 4
	rowNodeSize           = 2    /* number of words in a row header node */
	zeroField             = 4096 /* amount added to coordinates to make them positive */
	edgeHeaderSize        = 6    /* number of words in an edge-structure header */
	fastCaseUp            = 60   /* for octants 1 and 4 */
	fastCaseDown          = 61   /* for octants 5 and 8 */
	slowCaseUp            = 62   /* for octants 2 and 3 */
	slowCaseDown          = 63   /* for octants 6 and 7 */
	axis                  = 0    /* a transition across the $x'$- or $y'$-axis */
	diagonal              = 1    /* a transition where $y'=\pm x'$ */
	doublePathCode        = 0    /* command modifier for `\&[doublepath]' */
	contourCode           = 1    /* command modifier for `\&[contour]' */
	alsoCode              = 2    /* command modifier for `\&[also]' */
	penNodeSize           = 10
	coordNodeSize         = 3
	intPackets            = 20                          /* number of words to represent $U_k$, $V_k$, $X_k$, and $Y_k$ */
	intIncrement          = intPackets + intPackets + 5 /* number of stack words per level */
	maxPatience           = 5000
	white                 = 0  /* background pixels */
	black                 = 1  /* visible pixels */
	sScale                = 64 /* the serial numbers are multiplied by this factor */
	depNodeSize           = 2  /* the number of words per dependency node */
	independentNeedingFix = 0
	fractionThreshold     = 2685          /* a |fraction| coefficient less than this is zeroed */
	halfFractionThreshold = 1342          /* half of |fraction_threshold| */
	scaledThreshold       = 8             /* a |scaled| coefficient less than this is zeroed */
	halfScaledThreshold   = 4             /* half of |scaled_threshold| */
	independentBeingFixed = 1             /* this variable already appears in |s| */
	foreverText           = maxInOpen + 1 /* |token_type| code for loop texts */
	loopText              = maxInOpen + 2 /* |token_type| code for loop texts */
	parameter             = maxInOpen + 3 /* |token_type| code for parameter texts */
	backedUp              = maxInOpen + 4 /* |token_type| code for texts to be reread */
	inserted              = maxInOpen + 5 /* |token_type| code for inserted texts */
	macro                 = maxInOpen + 6 /* |token_type| code for macro replacement texts */
	normal                = 0             /* |scanner_status| at ``quiet times'' */
	skipping              = 1             /* |scanner_status| when false conditional text is being skipped */
	flushing              = 2             /* |scanner_status| when junk after a statement is being ignored */
	absorbing             = 3             /* |scanner_status| when a \&[text] parameter is being scanned */
	varDefining           = 4             /* |scanner_status| when a \&[vardef] is being scanned */
	opDefining            = 5             /* |scanner_status| when a macro \&[def] is being scanned */
	loopDefining          = 6             /* |scanner_status| when a \&[for] loop is being scanned */
	switch1               = 25            /* a label in |get_next| */
	startNumericToken     = 85            /* another */
	startDecimalToken     = 86            /* and another */
	finNumericToken       = 87
	/* and still another, although |goto| is considered harmful */
	startDef             = 1                 /* command modifier for \&[def] */
	varDef               = 2                 /* command modifier for \&[vardef] */
	endDef               = 0                 /* command modifier for \&[enddef] */
	startForever         = 1                 /* command modifier for \&[forever] */
	endFor               = 0                 /* command modifier for \&[endfor] */
	quote                = 0                 /* |macro_special| modifier for \&[quote] */
	macroPrefix          = 1                 /* |macro_special| modifier for \.[\#\AT!] */
	macroAt              = 2                 /* |macro_special| modifier for \.[\AT!] */
	macroSuffix          = 3                 /* |macro_special| modifier for \.[\AT!\#] */
	ifNodeSize           = 2                 /* number of words in stack entry for conditionals */
	ifCode               = 1                 /* code for \&[if] being evaluated */
	fiCode               = 2                 /* code for \&[fi] */
	elseCode             = 3                 /* code for \&[else] */
	elseIfCode           = 4                 /* code for \&[elseif] */
	loopNodeSize         = 2                 /* the number of words in a loop control node */
	progressionNodeSize  = 4                 /* the number of words in a progression node */
	baseDefaultLength    = 18                /* length of the |MF_base_default| string */
	baseAreaLength       = 8                 /* length of its area part */
	baseExtLength        = 5                 /* length of its `\.[.base]' part */
	baseExtension        = /* ".base" */ 742 /* the extension, as a \.[WEB] constant */
	continuePath         = 25                /* a label inside of |scan_expression| */
	finishPath           = 26                /* another */
	showTokenCode        = 0                 /* show the meaning of a single token */
	showStatsCode        = 1                 /* show current memory and string usage */
	showCode             = 2                 /* show a list of expressions */
	showVarCode          = 3                 /* show a variable and its descendents */
	showDependenciesCode = 4                 /* show dependent variables in terms of independents */
	dropCode             = 0                 /* command modifier for `\&[dropping]' */
	keepCode             = 1                 /* command modifier for `\&[keeping]' */
	messageCode          = 0
	errMessageCode       = 1
	errHelpCode          = 2
	noTag                = 0 /* vanilla character */
	ligTag               = 1 /* character has a ligature/kerning program */
	listTag              = 2 /* character has a successor in a charlist */
	extTag               = 3 /* character is extensible */
	stopFlag             = 128 + minQuarterword
	/* value indicating `\.[STOP]' in a lig/kern program */
	kernFlag         = 128 + minQuarterword /* op code for a kern step */
	slantCode        = 1
	spaceCode        = 2
	spaceStretchCode = 3
	spaceShrinkCode  = 4
	xHeightCode      = 5
	quadCode         = 6
	extraSpaceCode   = 7
	charListCode     = 0
	ligTableCode     = 1
	extensibleCode   = 2
	headerByteCode   = 3
	fontDimenCode    = 4
	gfIdByte         = 131 /* identifies the kind of \.[GF] files described here */
	paint0           = 0   /* beginning of the \\[paint] commands */
	paint1           = 64  // move right a given number of columns, then
	//   black$[]\swap[]$white

	boc        = 67   /* beginning of a character */
	boc1       = 68   /* short form of |boc| */
	eoc        = 69   /* end of a character */
	skip0      = 70   /* skip no blank rows */
	skip1      = 71   /* skip over blank rows */
	newRow0    = 74   /* move down one row and then right */
	maxNewRow  = 164  /* the largest \\[new\_row] command is |new_row_164| */
	xxx1       = 239  /* for \&[special] strings */
	xxx3       = 241  /* for long \&[special] strings */
	yyy        = 243  /* for \&[numspecial] numbers */
	charLoc    = 245  /* character locators in the postamble */
	pre        = 247  /* preamble */
	post       = 248  /* postamble beginning */
	postPost   = 249  /* postamble ending */
	offBase    = 6666 /* go here if the base file is unacceptable */
	breakpoint = 888  /* place where a breakpoint is desirable */

	// Constants in the outer block
	memMax = 3000 // greatest index in \MF's internal |mem| array;
	//   must be strictly less than |max_halfword|;
	//   must be equal to |mem_top| in \.[INIMF], otherwise |>=mem_top|

	maxInternal = 100 // maximum number of internal quantities
	bufSize     = 500 // maximum number of characters simultaneously present in
	//   current lines of open files; must not exceed |max_halfword|

	errorLine     = 64 // width of context lines on terminal error messages
	halfErrorLine = 32 // width of first lines of contexts in terminal
	//   error messages; should be between 30 and |error_line-15|

	maxPrintLine    = 72   // width of longest text lines output; should be at least 60
	screenWidth     = 100  // number of pixels in each row of screen display
	screenDepth     = 200  // number of pixels in each column of screen display
	stackSize       = 30   // maximum number of simultaneous input sources
	maxStrings      = 2000 // maximum number of strings; must not exceed |max_halfword|
	stringVacancies = 8000 // the minimum number of characters that should be
	//   available for the user's identifier names and strings,
	//   after \MF's own error messages are stored

	poolSize = 32000 // maximum number of characters in strings, including all
	//   error messages and help texts, and the names of all identifiers;
	//   must exceed |string_vacancies| by the total
	//   length of \MF's own strings, which is currently about 22000

	moveSize     = 5000 // space for storing moves in a single octant
	maxWiggle    = 300  // number of autorounded points per cycle
	gfBufSize    = 8    // size of the output buffer, must be a multiple of 8
	fileNameSize = 40   // file names shouldn't be longer than this
	poolName     = "MFbases:MF.POOL                         "
	// string of length |file_name_size|; tells where the string pool appears
	// \xref[MFbases]
	pathSize    = 300 // maximum number of knots between breakpoints of a path
	bistackSize = 785 // size of stack for bisection algorithms;
	//   should probably be left at this value

	headerSize   = 100  // maximum number of \.[TFM] header words, times~4
	ligTableSize = 5000 // maximum number of ligature/kern steps, must be
	//   at least 255 and at most 32510

	maxKerns     = 500 // maximum number of distinct kern amounts
	maxFontDimen = 50  // maximum number of \&[fontdimen] parameters
)

type (
	// Types in the outer block
	asciiCode = /* 0..255 */ byte // eight-bit numbers

	eightBits = /* 0..255 */ byte // unsigned one-byte quantity
	alphaFile = knuth.File        // files that contain textual data
	byteFile  = knuth.File        // files that contain binary data

	poolPointer     = /* 0..poolSize */ uint16   // for variables that point into |str_pool|
	strNumber       = /* 0..maxStrings */ uint16 // for variables that point into |str_start|
	packedAsciiCode = /* 0..255 */ byte          // elements of |str_pool| array

	scaled      = int32            // this type is used for scaled integers
	smallNumber = /* 0..63 */ byte // this type is self-explanatory

	fraction = int32 // this type is used for scaled fractions

	angle = int32 // this type is used for scaled angles

	quarterword  = /* minQuarterword..maxQuarterword */ byte // 1/4 of a word
	halfword     = /* 0..65535 */ uint16                     // 1/2 of a word
	twoChoices   = /* 1..2 */ byte                           // used when there are two variants in a record
	threeChoices = /* 1..3 */ byte                           // used when there are three variants in a record
	twoHalves    struct{ data uint32 }
	fourQuarters = struct {
		b0 quarterword
		b1 quarterword
		b2 quarterword
		b3 quarterword
	}
	memoryWord struct{ data uint32 }
	wordFile   = knuth.File

	commandCode = /* 1..maxCommandCode */ byte

	screenRow  = /* 0..screenDepth */ byte // a row number on the screen
	screenCol  = /* 0..screenWidth */ byte // a column number on the screen
	transSpec  [101]screenCol              // a transition spec, see below
	pixelColor = /* white..black */ byte   // specifies one of the two pixel values

	windowNumber = /* 0..15 */ byte

	inStateRecord = struct {
		indexField                                  quarterword
		startField, locField, limitField, nameField halfword
	}

	gfIndex = /* 0..gfBufSize */ byte // an index into the output buffer
)

func (r *memoryWord) hh() *twoHalves {
	return (*twoHalves)(unsafe.Add(unsafe.Pointer(&r.data), 0))
}

func (r *memoryWord) int() *int32 {
	return (*int32)(unsafe.Add(unsafe.Pointer(&r.data), 0))
}

func (r *memoryWord) qqqq() *fourQuarters {
	return (*fourQuarters)(unsafe.Add(unsafe.Pointer(&r.data), 0))
}

func (r *twoHalves) b0() *quarterword {
	return (*quarterword)(unsafe.Add(unsafe.Pointer(&r.data), 2))
}

func (r *twoHalves) b1() *quarterword {
	return (*quarterword)(unsafe.Add(unsafe.Pointer(&r.data), 3))
}

func (r *twoHalves) lh() *halfword {
	return (*halfword)(unsafe.Add(unsafe.Pointer(&r.data), 2))
}

func (r *twoHalves) rh() *halfword {
	return (*halfword)(unsafe.Add(unsafe.Pointer(&r.data), 0))
}

type prg struct {
	stdin, stdout, stderr knuth.File
	// Global variables
	bad int32 // is some ``constant'' wrong?

	xord [256]asciiCode
	// specifies conversion of input characters
	xchr [256]char
	// specifies conversion of output characters

	nameOfFile [40]char

	// on some systems this may be a \&[record] variable
	nameLength/* 0..fileNameSize */ byte
	// this many characters are actually
	//   relevant in |name_of_file| (the rest are blank)

	buffer                             [501]asciiCode // lines of characters being read
	first/* 0..bufSize */ uint16       // the first unused position in |buffer|
	last/* 0..bufSize */ uint16        // end of the line just input to |buffer|
	maxBufStack/* 0..bufSize */ uint16 // largest index used in |buffer|

	termIn  alphaFile // the terminal as an input file
	termOut alphaFile // the terminal as an output file

	strPool     [32001]packedAsciiCode // the characters
	strStart    [2001]poolPointer      // the starting pointers
	poolPtr     poolPointer            // first unused position in |str_pool|
	strPtr      strNumber              // number of the current string being created
	initPoolPtr poolPointer            // the starting value of |pool_ptr|
	initStrPtr  strNumber              // the starting value of |str_ptr|
	maxPoolPtr  poolPointer            // the maximum so far of |pool_ptr|
	maxStrPtr   strNumber              // the maximum so far of |str_ptr|

	strRef [2001] /* 0..maxStrRef */ byte

	poolFile alphaFile // the string-pool file output by \.[TANGLE]

	logFile                           alphaFile // transcript of \MF\ session
	selector/* 0..maxSelector */ byte // where to print a message
	dig                               [23] /* 0..15 */ byte // digits in a number being output
	tally                             int32                 // the number of characters recently printed
	termOffset/* 0..maxPrintLine */ byte
	// the number of characters on the current terminal line
	fileOffset/* 0..maxPrintLine */ byte
	// the number of characters on the current file line
	trickBuf [65]asciiCode // circular buffer for
	//   pseudoprinting

	trickCount int32 // threshold for pseudoprinting, explained later
	firstCount int32 // another variable for pseudoprinting

	interaction/* batchMode..errorStopMode */ byte // current level of interaction

	deletionsAllowed                           bool // is it safe for |error| to call |get_next|?
	history/* spotless..fatalErrorStop */ byte // has the source input been clean so far?
	errorCount/*  -1..100 */ int8              // the number of scrolled errors since the
	//   last statement ended

	helpLine               [6]strNumber // helps for the next |error|
	helpPtr/* 0..6 */ byte // the number of help lines present
	useErrHelp             bool      // should the |err_help| string be shown?
	errHelp                strNumber // a string set up by \&[errhelp]

	interrupt     int32 // should \MF\ pause for instructions?
	okToInterrupt bool  // should interrupts be observed?

	arithError bool // has arithmetic overflow occurred recently?

	twoToThe [31]int32 // powers of two
	specLog  [28]int32 // special logarithms

	specAtan [26]angle // $\arctan2^[-k]$ times $2^[20]\cdot180/\pi$

	nSin, nCos fraction // results computed by |n_sin_cos|

	randoms                 [55]fraction // the last 55 random values generated
	jRandom/* 0..54 */ byte // the number of unused |randoms|

	mem      [3001]memoryWord // the big dynamic storage area
	loMemMax halfword         // the largest location of variable-size memory in use
	hiMemMin halfword         // the smallest location of one-word memory in use

	varUsed, dynUsed int32 // how much memory is in use

	avail  halfword // head of the list of available one-word nodes
	memEnd halfword // the last one-word node used in |mem|

	rover halfword // points to some node in the list of empties

	//   free: packed array [mem_min..mem_max] of boolean; [free cells]
	// [ \hskip1em ] was_free: packed array [mem_min..mem_max] of boolean;
	//   [previously free cells]
	// [ \hskip1em ] was_mem_end, was_lo_max, was_hi_min: halfword ;
	//   [previous |mem_end|, |lo_mem_max|, and |hi_mem_min|]
	// [ \hskip1em ] panicking:boolean; [do we want to check memory constantly?]
	// [  ]

	internal [100]scaled
	// the values of internal quantities
	intName [100]strNumber
	// their names
	intPtr/* maxGivenInternal..maxInternal */ byte
	// the maximum internal quantity defined so far

	oldSetting/* 0..maxSelector */ byte
	sysTime, sysDay, sysMonth, sysYear int32
	// date and time supplied by external system

	charClass [256] /* 0..maxClass */ byte // the class numbers

	hashUsed halfword // allocation pointer for |hash|
	stCount  int32    // total number of known identifiers

	hash [2369]twoHalves // the hash table
	eqtb [2369]twoHalves // the equivalents

	gPointer halfword // (global) parameter to the |forward| procedures

	bigNodeSize [2]smallNumber

	savePtr halfword // the most recently saved item

	pathTail halfword // the node that links to the beginning of a path

	deltaX, deltaY, delta [301]scaled // knot differences
	psi                   [300]angle  // turning angles

	theta [301]angle    // values of $\theta_k$
	uu    [301]fraction // values of $u_k$
	vv    [301]angle    // values of $v_k$
	ww    [301]fraction // values of $w_k$

	st, ct, sf, cf fraction // sines and cosines

	move                            [5001]int32 // the recorded moves
	movePtr/* 0..moveSize */ uint16 // the number of items in the |move| list

	bisectStack [786]int32
	bisectPtr/* 0..bistackSize */ uint16

	curEdges halfword // the edge structure of current interest
	curWt    int32    // the edge weight of current interest

	traceX  int32 // $x$~coordinate most recently shown in a trace
	traceY  int32 // $y$~coordinate most recently shown in a trace
	traceYy int32 // $y$~coordinate most recently encountered

	octant/* firstOctant..sixthOctant */ byte // the current octant of interest

	curX, curY scaled
	// outputs of |skew|, |unskew|, and a few other routines

	octantDir [8]strNumber

	curSpec                                           halfword // the principal output of |make_spec|
	turningNumber                                     int32    // another output of |make_spec|
	curPen                                            halfword // an implicit input of |make_spec|, used in autorounding
	curPathType/* doublePathCode..contourCode */ byte // likewise
	maxAllowed                                        scaled // coordinates must be at most this big

	before, after                           [301]scaled   // data for |make_safe|
	nodeToRound                             [301]halfword // reference back to the path
	curRoundingPtr/* 0..maxWiggle */ uint16 // how many are being used
	maxRoundingPtr/* 0..maxWiggle */ uint16 // how many have been used

	curGran scaled // the current granularity (which normally is |unity|)

	octantNumber [8] /* 1..8 */ byte
	octantCode   [8] /* firstOctant..sixthOctant */ byte

	revTurns bool // should we make U-turns in the English manner?

	yCorr, xyCorr, zCorr [8] /* 0..1 */ byte
	xCorr                [8] /*  -1..1 */ int8

	m0, n0, m1, n1        int32 // lattice point coordinates
	d0, d1/* 0..1 */ byte // displacement corrections

	envMove [5001]int32

	tolStep/* 0..6 */ byte // either 0 or 3, usually

	curT, curTt int32 // controls and results of |cubic_intersection|
	timeToGo    int32 // this many backtracks before giving up
	maxT        int32 // maximum of $2^[l+1]$ so far achieved

	delx, dely                        int32 // the components of $\Delta=2^l(w_0-z_0)$
	tol                               int32 // bound on the uncertainty in the overlap test
	uv, xy/* 0..bistackSize */ uint16 // pointers to the current packets of interest
	threeL                            int32 // |tol_step| times the bisection level
	apprT, apprTt                     int32 // best approximations known to the answers

	//  screen_pixel:array[screen_row,screen_col] of pixel_color[ ;  ]

	screenStarted bool // have the screen primitives been initialized?
	screenOk      bool // is it legitimate to call |blank_rectangle|,
	//   |paint_row|, and |update_screen|?

	windowOpen [16]bool
	// has this window been opened?
	leftCol [16]screenCol
	// leftmost column position on screen
	rightCol [16]screenCol
	// rightmost column position, plus~1
	topRow [16]screenRow
	// topmost row position on screen
	botRow [16]screenRow
	// bottommost row position, plus~1
	mWindow [16]int32
	// offset between user and screen columns
	nWindow [16]int32
	// offset between user and screen rows
	windowTime [16]int32
	// it has been updated this often

	rowTransition transSpec // an array of |black|/|white| transitions

	serialNo int32 // the most recent serial number, times |s_scale|

	fixNeeded  bool     // does at least one |independent| variable need scaling?
	watchCoefs bool     // should we scale coefficients that exceed |coef_bound|?
	depFinal   halfword // location of the constant term and final link

	curCmd eightBits // current command set by |get_next|
	curMod int32     // operand of current command
	curSym halfword  // hash address of current symbol

	inputStack                        [31]inStateRecord
	inputPtr/* 0..stackSize */ byte   // first unused location of |input_stack|
	maxInStack/* 0..stackSize */ byte // largest value of |input_ptr| when pushing
	curInput                          inStateRecord // the ``top'' input state

	inOpen/* 0..maxInOpen */ byte     // the number of lines in the buffer, less one
	openParens/* 0..maxInOpen */ byte // the number of open text files
	inputFile                         [6]alphaFile
	line                              int32 // current line number in the current source file
	lineStack                         [6]int32

	paramStack [151]halfword
	// token list pointers for parameters
	paramPtr/* 0..paramSize */ byte // first unused entry in |param_stack|
	maxParamStack                   int32
	// largest value of |param_ptr|

	filePtr/* 0..stackSize */ byte // shallowest level shown by |show_context|

	scannerStatus/* normal..loopDefining */ byte // are we scanning at high speed?
	warningInfo                                  int32 // if so, what else do we need to know,
	//     in case an error occurs?

	forceEof bool // should the next \&[input] be aborted early?

	bgLoc, egLoc/* 1..hashBase+2112 */ uint16
	// hash addresses of `\.[begingroup]' and `\.[endgroup]'

	condPtr                              halfword // top of the condition stack
	ifLimit/* normal..elseIfCode */ byte // upper bound on |fi_or_else| codes
	curIf                                smallNumber // type of conditional being worked on
	ifLine                               int32       // line where that conditional began

	loopPtr halfword // top of the loop-control-node stack

	curName strNumber // name of file just scanned
	curArea strNumber // file area just scanned, or \.[""]
	curExt  strNumber // file extension just scanned, or \.[""]

	areaDelimiter poolPointer // the most recent `\.>' or `\.:', if any
	extDelimiter  poolPointer // the relevant `\..', if any

	mfBaseDefault [18]char

	jobName   strNumber // principal file name
	logOpened bool      // has the transcript file been opened?
	logName   strNumber // full name of the log file

	gfExt strNumber // default extension for the output file

	gfFile         byteFile  // the generic font output goes here
	outputFileName strNumber // full name of the output file

	curType smallNumber // the type of the expression just found
	curExp  int32       // the value of the expression just found

	maxC [2]int32
	// max coefficient magnitude
	maxPtr [2]halfword
	// where |p| occurs with |max_c|
	maxLink [2]halfword
	// other occurrences of |p|

	varFlag/* 0..maxCommandCode */ byte // command that wants a variable

	txx, txy, tyx, tyy, tx, ty scaled // current transform coefficients

	startSym halfword // a symbolic token to insert at beginning of job

	longHelpSeen bool // has the long \&[errmessage] help been used?

	tfmFile        byteFile  // the font metric output goes here
	metricFileName strNumber // full name of the font metric file

	bc, ec        eightBits                          // smallest and largest character codes shipped out
	tfmWidth      [256]scaled                        // \&[charwd] values
	tfmHeight     [256]scaled                        // \&[charht] values
	tfmDepth      [256]scaled                        // \&[chardp] values
	tfmItalCorr   [256]scaled                        // \&[charic] values
	charExists    [256]bool                          // has this code been shipped out?
	charTag       [256] /* noTag..extTag */ byte     // |remainder| category
	charRemainder [256] /* 0..ligTableSize */ uint16 // the |remainder| byte
	headerByte    [100] /*  -1..255 */ int16
	// bytes of the \.[TFM] header, or $-1$ if unset
	ligKern                              [5001]fourQuarters // the ligature/kern table
	nl/* 0..32767-256 */ uint16          // the number of ligature/kern steps so far
	kern                                 [501]scaled // distinct kerning amounts
	nk/* 0..maxKerns */ uint16           // the number of distinct kerns so far
	exten                                [256]fourQuarters // extensible character recipes
	ne/* 0..256 */ uint16                // the number of extensible characters so far
	param                                [50]scaled // \&[fontdimen] parameters
	np/* 0..maxFontDimen */ byte         // the largest \&[fontdimen] parameter specified so far
	nw, nh, nd, ni/* 0..256 */ uint16    // sizes of \.[TFM] subtables
	skipTable                            [256] /* 0..ligTableSize */ uint16 // local label status
	lkStarted                            bool                               // has there been a lig/kern step in this command yet?
	bchar                                int32                              // right boundary character
	bchLabel/* 0..ligTableSize */ uint16 // left boundary starting location
	ll, lll/* 0..ligTableSize */ uint16  // registers used for lig/kern processing
	labelLoc                             [257] /*  -1..ligTableSize */ int16 // lig/kern starting addresses
	labelChar                            [256]eightBits                      // characters for |label_loc|
	labelPtr/* 0..256 */ uint16          // highest position occupied in |label_loc|

	perturbation scaled // quantity related to \.[TFM] rounding
	excess       int32  // the list is this much too long

	dimenHead [4]halfword // lists of \.[TFM] dimensions

	maxTfmDimen scaled // bound on widths, heights, kerns, etc.
	tfmChanged  int32  // the number of data entries that were out of bounds

	gfMinM, gfMaxM, gfMinN, gfMaxN int32      // bounding rectangle
	gfPrevPtr                      int32      // where the present/next character started/starts
	totalChars                     int32      // the number of characters output so far
	charPtr                        [256]int32 // where individual characters started
	gfDx, gfDy                     [256]int32 // device escapements

	gfBuf    [9]eightBits // buffer for \.[GF] output
	halfBuf  gfIndex      // half of |gf_buf_size|
	gfLimit  gfIndex      // end of the current half buffer
	gfPtr    gfIndex      // the next available buffer address
	gfOffset int32        // |gf_buf_size| times the number of times the
	//   output buffer has been fully emptied

	bocC, bocP int32 // parameters of the next |boc| command

	baseIdent strNumber

	baseFile wordFile // for input or output of base information

	readyAlready int32 // a sacrifice of purity for economy
}

func (prg *prg) initialize() { // this procedure gets things started properly
	var (
		// Local variables for initialization
		i int32

		k int32 // all-purpose loop index
	)
	prg.xchr[040] = ' '
	prg.xchr[041] = '!'
	prg.xchr[042] = '"'
	prg.xchr[043] = '#'
	prg.xchr[044] = '$'
	prg.xchr[045] = '%'
	prg.xchr[046] = '&'
	prg.xchr[047] = '\''

	prg.xchr[050] = '('
	prg.xchr[051] = ')'
	prg.xchr[052] = '*'
	prg.xchr[053] = '+'
	prg.xchr[054] = ','
	prg.xchr[055] = '-'
	prg.xchr[056] = '.'
	prg.xchr[057] = '/'

	prg.xchr[060] = '0'
	prg.xchr[061] = '1'
	prg.xchr[062] = '2'
	prg.xchr[063] = '3'
	prg.xchr[064] = '4'
	prg.xchr[065] = '5'
	prg.xchr[066] = '6'
	prg.xchr[067] = '7'

	prg.xchr[070] = '8'
	prg.xchr[071] = '9'
	prg.xchr[072] = ':'
	prg.xchr[073] = ';'
	prg.xchr[074] = '<'
	prg.xchr[075] = '='
	prg.xchr[076] = '>'
	prg.xchr[077] = '?'

	prg.xchr[0100] = '@'
	prg.xchr[0101] = 'A'
	prg.xchr[0102] = 'B'
	prg.xchr[0103] = 'C'
	prg.xchr[0104] = 'D'
	prg.xchr[0105] = 'E'
	prg.xchr[0106] = 'F'
	prg.xchr[0107] = 'G'

	prg.xchr[0110] = 'H'
	prg.xchr[0111] = 'I'
	prg.xchr[0112] = 'J'
	prg.xchr[0113] = 'K'
	prg.xchr[0114] = 'L'
	prg.xchr[0115] = 'M'
	prg.xchr[0116] = 'N'
	prg.xchr[0117] = 'O'

	prg.xchr[0120] = 'P'
	prg.xchr[0121] = 'Q'
	prg.xchr[0122] = 'R'
	prg.xchr[0123] = 'S'
	prg.xchr[0124] = 'T'
	prg.xchr[0125] = 'U'
	prg.xchr[0126] = 'V'
	prg.xchr[0127] = 'W'

	prg.xchr[0130] = 'X'
	prg.xchr[0131] = 'Y'
	prg.xchr[0132] = 'Z'
	prg.xchr[0133] = '['
	prg.xchr[0134] = '\\'
	prg.xchr[0135] = ']'
	prg.xchr[0136] = '^'
	prg.xchr[0137] = '_'

	prg.xchr[0140] = '`'
	prg.xchr[0141] = 'a'
	prg.xchr[0142] = 'b'
	prg.xchr[0143] = 'c'
	prg.xchr[0144] = 'd'
	prg.xchr[0145] = 'e'
	prg.xchr[0146] = 'f'
	prg.xchr[0147] = 'g'

	prg.xchr[0150] = 'h'
	prg.xchr[0151] = 'i'
	prg.xchr[0152] = 'j'
	prg.xchr[0153] = 'k'
	prg.xchr[0154] = 'l'
	prg.xchr[0155] = 'm'
	prg.xchr[0156] = 'n'
	prg.xchr[0157] = 'o'

	prg.xchr[0160] = 'p'
	prg.xchr[0161] = 'q'
	prg.xchr[0162] = 'r'
	prg.xchr[0163] = 's'
	prg.xchr[0164] = 't'
	prg.xchr[0165] = 'u'
	prg.xchr[0166] = 'v'
	prg.xchr[0167] = 'w'

	prg.xchr[0170] = 'x'
	prg.xchr[0171] = 'y'
	prg.xchr[0172] = 'z'
	prg.xchr[0173] = '{'
	prg.xchr[0174] = '|'
	prg.xchr[0175] = '}'
	prg.xchr[0176] = '~'

	for ii := int32(0); ii <= 037; ii++ {
		i = ii
		_ = i
		prg.xchr[i] = ' '
	}
	for ii := int32(0177); ii <= 0377; ii++ {
		i = ii
		_ = i
		prg.xchr[i] = ' '
	}

	for ii := int32(firstTextChar); ii <= lastTextChar; ii++ {
		i = ii
		_ = i
		prg.xord[char(i)] = 0177
	}
	for ii := int32(0200); ii <= 0377; ii++ {
		i = ii
		_ = i
		prg.xord[prg.xchr[i]] = byte(i)
	}
	for ii := int32(0); ii <= 0176; ii++ {
		i = ii
		_ = i
		prg.xord[prg.xchr[i]] = byte(i)
	}

	prg.interaction = byte(errorStopMode)

	prg.deletionsAllowed = true
	prg.errorCount = 0 // |history| is initialized elsewhere

	prg.helpPtr = 0
	prg.useErrHelp = false
	prg.errHelp = 0

	prg.interrupt = 0
	prg.okToInterrupt = true

	prg.arithError = false

	prg.twoToThe[0] = 1
	for ii := int32(1); ii <= 30; ii++ {
		k = ii
		_ = k
		prg.twoToThe[k] = 2 * prg.twoToThe[k-1]
	}
	prg.specLog[1-1] = 93032640
	prg.specLog[2-1] = 38612034
	prg.specLog[3-1] = 17922280
	prg.specLog[4-1] = 8662214
	prg.specLog[5-1] = 4261238
	prg.specLog[6-1] = 2113709
	prg.specLog[7-1] = 1052693
	prg.specLog[8-1] = 525315
	prg.specLog[9-1] = 262400
	prg.specLog[10-1] = 131136
	prg.specLog[11-1] = 65552
	prg.specLog[12-1] = 32772
	prg.specLog[13-1] = 16385
	for ii := int32(14); ii <= 27; ii++ {
		k = ii
		_ = k
		prg.specLog[k-1] = prg.twoToThe[27-k]
	}
	prg.specLog[28-1] = 1

	prg.specAtan[1-1] = 27855475
	prg.specAtan[2-1] = 14718068
	prg.specAtan[3-1] = 7471121
	prg.specAtan[4-1] = 3750058
	prg.specAtan[5-1] = 1876857
	prg.specAtan[6-1] = 938658
	prg.specAtan[7-1] = 469357
	prg.specAtan[8-1] = 234682
	prg.specAtan[9-1] = 117342
	prg.specAtan[10-1] = 58671
	prg.specAtan[11-1] = 29335
	prg.specAtan[12-1] = 14668
	prg.specAtan[13-1] = 7334
	prg.specAtan[14-1] = 3667
	prg.specAtan[15-1] = 1833
	prg.specAtan[16-1] = 917
	prg.specAtan[17-1] = 458
	prg.specAtan[18-1] = 229
	prg.specAtan[19-1] = 115
	prg.specAtan[20-1] = 57
	prg.specAtan[21-1] = 29
	prg.specAtan[22-1] = 14
	prg.specAtan[23-1] = 7
	prg.specAtan[24-1] = 4
	prg.specAtan[25-1] = 2
	prg.specAtan[26-1] = 1

	//  was_mem_end:=mem_min; [indicate that everything was previously free]
	// was_lo_max:=mem_min; was_hi_min:=mem_max;
	// panicking:=false;
	// [  ]

	for ii := int32(1); ii <= maxGivenInternal; ii++ {
		k = ii
		_ = k
		prg.internal[k-1] = 0
	}
	prg.intPtr = byte(maxGivenInternal)

	for ii := int32('0'); ii <= '9'; ii++ {
		k = ii
		_ = k
		prg.charClass[k] = byte(digitClass)
	}
	prg.charClass['.'] = byte(periodClass)
	prg.charClass[' '] = byte(spaceClass)
	prg.charClass['%'] = byte(percentClass)
	prg.charClass['"'] = byte(stringClass)

	prg.charClass[','] = 5
	prg.charClass[';'] = 6
	prg.charClass['('] = 7
	prg.charClass[')'] = byte(rightParenClass)
	for ii := int32('A'); ii <= 'Z'; ii++ {
		k = ii
		_ = k
		prg.charClass[k] = byte(letterClass)
	}
	for ii := int32('a'); ii <= 'z'; ii++ {
		k = ii
		_ = k
		prg.charClass[k] = byte(letterClass)
	}
	prg.charClass['_'] = byte(letterClass)

	prg.charClass['<'] = 10
	prg.charClass['='] = 10
	prg.charClass['>'] = 10
	prg.charClass[':'] = 10
	prg.charClass['|'] = 10

	prg.charClass['`'] = 11
	prg.charClass['\''] = 11

	prg.charClass['+'] = 12
	prg.charClass['-'] = 12

	prg.charClass['/'] = 13
	prg.charClass['*'] = 13
	prg.charClass['\\'] = 13

	prg.charClass['!'] = 14
	prg.charClass['?'] = 14

	prg.charClass['#'] = 15
	prg.charClass['&'] = 15
	prg.charClass['@'] = 15
	prg.charClass['$'] = 15

	prg.charClass['^'] = 16
	prg.charClass['~'] = 16

	prg.charClass['['] = byte(leftBracketClass)
	prg.charClass[']'] = byte(rightBracketClass)

	prg.charClass['{'] = 19
	prg.charClass['}'] = 19

	for ii := int32(0); ii <= ' '-1; ii++ {
		k = ii
		_ = k
		prg.charClass[k] = byte(invalidClass)
	}
	for ii := int32(127); ii <= 255; ii++ {
		k = ii
		_ = k
		prg.charClass[k] = byte(invalidClass)
	}

	*prg.hash[1-1].lh() = 0
	*prg.hash[1-1].rh() = 0
	*prg.eqtb[1-1].lh() = uint16(tagToken)
	*prg.eqtb[1-1].rh() = uint16(memMin)
	for ii := int32(2); ii <= hashBase+hashSize+12; ii++ {
		k = ii
		_ = k
		prg.hash[k-1] = prg.hash[1-1]
		prg.eqtb[k-1] = prg.eqtb[1-1]
	}

	prg.bigNodeSize[transformType-13] = byte(transformNodeSize)
	prg.bigNodeSize[pairType-13] = byte(pairNodeSize)

	prg.savePtr = uint16(memMin)

	prg.octantDir[firstOctant-1] = /* "ENE" */ 548
	prg.octantDir[secondOctant-1] = /* "NNE" */ 549
	prg.octantDir[thirdOctant-1] = /* "NNW" */ 550
	prg.octantDir[fourthOctant-1] = /* "WNW" */ 551
	prg.octantDir[fifthOctant-1] = /* "WSW" */ 552
	prg.octantDir[sixthOctant-1] = /* "SSW" */ 553
	prg.octantDir[seventhOctant-1] = /* "SSE" */ 554
	prg.octantDir[eighthOctant-1] = /* "ESE" */ 555

	prg.maxRoundingPtr = 0

	prg.octantCode[1-1] = byte(firstOctant)
	prg.octantCode[2-1] = byte(secondOctant)
	prg.octantCode[3-1] = byte(thirdOctant)
	prg.octantCode[4-1] = byte(fourthOctant)
	prg.octantCode[5-1] = byte(fifthOctant)
	prg.octantCode[6-1] = byte(sixthOctant)
	prg.octantCode[7-1] = byte(seventhOctant)
	prg.octantCode[8-1] = byte(eighthOctant)
	for ii := int32(1); ii <= 8; ii++ {
		k = ii
		_ = k
		prg.octantNumber[prg.octantCode[k-1]-1] = byte(k)
	}

	prg.revTurns = false

	prg.xCorr[firstOctant-1] = 0
	prg.yCorr[firstOctant-1] = 0
	prg.xyCorr[firstOctant-1] = 0

	prg.xCorr[secondOctant-1] = 0
	prg.yCorr[secondOctant-1] = 0
	prg.xyCorr[secondOctant-1] = 1

	prg.xCorr[thirdOctant-1] = int8(-1)
	prg.yCorr[thirdOctant-1] = 1
	prg.xyCorr[thirdOctant-1] = 0

	prg.xCorr[fourthOctant-1] = 1
	prg.yCorr[fourthOctant-1] = 0
	prg.xyCorr[fourthOctant-1] = 1

	prg.xCorr[fifthOctant-1] = 0
	prg.yCorr[fifthOctant-1] = 1
	prg.xyCorr[fifthOctant-1] = 1

	prg.xCorr[sixthOctant-1] = 0
	prg.yCorr[sixthOctant-1] = 1
	prg.xyCorr[sixthOctant-1] = 0

	prg.xCorr[seventhOctant-1] = 1
	prg.yCorr[seventhOctant-1] = 0
	prg.xyCorr[seventhOctant-1] = 1

	prg.xCorr[eighthOctant-1] = int8(-1)
	prg.yCorr[eighthOctant-1] = 1
	prg.xyCorr[eighthOctant-1] = 0

	for ii := int32(1); ii <= 8; ii++ {
		k = ii
		_ = k
		prg.zCorr[k-1] = byte(int32(prg.xyCorr[k-1]) - int32(prg.xCorr[k-1]))
	}

	prg.screenStarted = false
	prg.screenOk = false

	for ii := int32(0); ii <= 15; ii++ {
		k = ii
		_ = k
		prg.windowOpen[k] = false
		prg.windowTime[k] = 0
	}

	prg.fixNeeded = false
	prg.watchCoefs = true

	prg.condPtr = uint16(memMin)
	prg.ifLimit = byte(normal)
	prg.curIf = 0
	prg.ifLine = 0

	prg.loopPtr = uint16(memMin)

	strcopy(prg.mfBaseDefault[:], "MFbases:plain.base")
	// \xref[MFbases]
	// \xref[plain]
	// \xref[system dependencies]

	prg.curExp = 0

	prg.varFlag = 0

	prg.startSym = 0

	prg.longHelpSeen = false

	for ii := int32(0); ii <= 255; ii++ {
		k = ii
		_ = k
		prg.tfmWidth[k] = 0
		prg.tfmHeight[k] = 0
		prg.tfmDepth[k] = 0
		prg.tfmItalCorr[k] = 0
		prg.charExists[k] = false
		prg.charTag[k] = byte(noTag)
		prg.charRemainder[k] = 0
		prg.skipTable[k] = uint16(ligTableSize)
	}
	for ii := int32(1); ii <= headerSize; ii++ {
		k = ii
		_ = k
		prg.headerByte[k-1] = int16(-1)
	}
	prg.bc = 255
	prg.ec = 0
	prg.nl = 0
	prg.nk = 0
	prg.ne = 0
	prg.np = 0

	prg.internal[boundaryChar-1] = -0200000
	prg.bchLabel = uint16(ligTableSize)

	prg.labelLoc[0] = int16(-1)
	prg.labelPtr = 0

	prg.gfPrevPtr = 0
	prg.totalChars = 0

	prg.halfBuf = byte(gfBufSize / 2)
	prg.gfLimit = byte(gfBufSize)
	prg.gfPtr = 0
	prg.gfOffset = 0

	prg.baseIdent = 0

}

// \4
// Basic printing procedures
func (prg *prg) printLn() {
	switch prg.selector {
	case termAndLog:
		prg.termOut.Writeln()
		prg.logFile.Writeln()
		prg.termOffset = 0
		prg.fileOffset = 0

	case logOnly:
		prg.logFile.Writeln()
		prg.fileOffset = 0

	case termOnly:
		prg.termOut.Writeln()
		prg.termOffset = 0

	case noPrint, pseudo, newString:
	} // there are no other cases
} // note that |tally| is not affected

func (prg *prg) printChar(s asciiCode) {
	switch prg.selector {
	case termAndLog:
		prg.termOut.Write(string(rune(prg.xchr[s])))
		prg.logFile.Write(string(rune(prg.xchr[s])))
		prg.termOffset = byte(int32(prg.termOffset) + 1)
		prg.fileOffset = byte(int32(prg.fileOffset) + 1)
		if int32(prg.termOffset) == maxPrintLine {
			prg.termOut.Writeln()
			prg.termOffset = 0
		}
		if int32(prg.fileOffset) == maxPrintLine {
			prg.logFile.Writeln()
			prg.fileOffset = 0
		}

	case logOnly:
		prg.logFile.Write(string(rune(prg.xchr[s])))
		prg.fileOffset = byte(int32(prg.fileOffset) + 1)
		if int32(prg.fileOffset) == maxPrintLine {
			prg.printLn()
		}

	case termOnly:
		prg.termOut.Write(string(rune(prg.xchr[s])))
		prg.termOffset = byte(int32(prg.termOffset) + 1)
		if int32(prg.termOffset) == maxPrintLine {
			prg.printLn()
		}

	case noPrint:
	case pseudo:
		if prg.tally < prg.trickCount {
			prg.trickBuf[prg.tally%errorLine] = s
		}
	case newString:
		if int32(prg.poolPtr) < poolSize {
			prg.strPool[prg.poolPtr] = s
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
		// we drop characters if the string space is full
	} // there are no other cases
	prg.tally = prg.tally + 1
}

func (prg *prg) print(s int32) { // prints string |s|
	var (
		j poolPointer // current character code position
	)
	if s < 0 || s >= int32(prg.strPtr) {
		s = /* "???" */ 259
	} // this can't happen
	// \xref[???]
	if s < 256 && int32(prg.selector) > pseudo {
		prg.printChar(asciiCode(s))
	} else {
		j = prg.strStart[s]
		for int32(j) < int32(prg.strStart[s+1]) {
			prg.printChar(prg.strPool[j])
			j = uint16(int32(j) + 1)
		}
	}
}

func (prg *prg) slowPrint(s int32) { // prints string |s|
	var (
		j poolPointer // current character code position
	)
	if s < 0 || s >= int32(prg.strPtr) {
		s = /* "???" */ 259
	} // this can't happen
	// \xref[???]
	if s < 256 && int32(prg.selector) > pseudo {
		prg.printChar(asciiCode(s))
	} else {
		j = prg.strStart[s]
		for int32(j) < int32(prg.strStart[s+1]) {
			prg.print(int32(prg.strPool[j]))
			j = uint16(int32(j) + 1)
		}
	}
}

func (prg *prg) printNl(s strNumber) {
	if int32(prg.termOffset) > 0 && prg.selector&1 != 0 || int32(prg.fileOffset) > 0 && int32(prg.selector) >= logOnly {
		prg.printLn()
	}
	prg.print(int32(s))
}

func (prg *prg) printTheDigs(k eightBits) {
	for int32(k) > 0 {
		k = byte(int32(k) - 1)
		prg.printChar(asciiCode('0' + int32(prg.dig[k])))
	}
}

func (prg *prg) printInt(n int32) { // prints an integer in decimal form
	var (
		k/* 0..23 */ byte       // index to current digit; we assume that $\vert n\vert<10^[23]$
		m                 int32 // used to negate |n| in possibly dangerous cases
	)
	k = 0
	if n < 0 {
		prg.printChar(asciiCode('-'))
		if n > -100000000 {
			n = -n
		} else {
			m = -1 - n
			n = m / 10
			m = m%10 + 1
			k = 1
			if m < 10 {
				prg.dig[0] = byte(m)
			} else {
				prg.dig[0] = 0
				n = n + 1
			}
		}
	}
	for {
		prg.dig[k] = byte(n % 10)
		n = n / 10
		k = byte(int32(k) + 1)
		if n == 0 {
			break
		}
	}
	prg.printTheDigs(k)
}

func (prg *prg) printScaled(s scaled) { // prints scaled real, rounded to five
	//   digits

	var (
		delta scaled // amount of allowable inaccuracy
	)
	if s < 0 {
		prg.printChar(asciiCode('-'))
		s = -s // print the sign, if negative
	}
	prg.printInt(s / 0200000) // print the integer part
	s = 10*(s%0200000) + 5
	if s != 5 {
		delta = 10
		prg.printChar(asciiCode('.'))
		for {
			if delta > 0200000 {
				s = s + 0100000 - delta/2
			} // round the final digit
			prg.printChar(asciiCode('0' + s/0200000))
			s = 10 * (s % 0200000)
			delta = delta * 10
			if s <= delta {
				break
			}
		}
	}
}

func (prg *prg) printTwo(x, y scaled) {
	prg.printChar(asciiCode('('))
	prg.printScaled(x)
	prg.printChar(asciiCode(','))
	prg.printScaled(y)
	prg.printChar(asciiCode(')'))
}

func (prg *prg) printType(t smallNumber) {
	switch t {
	case vacuous:
		prg.print( /* "vacuous" */ 324)
	case booleanType:
		prg.print( /* "boolean" */ 325)
	case unknownBoolean:
		prg.print( /* "unknown boolean" */ 326)
	case stringType:
		prg.print( /* "string" */ 327)
	case unknownString:
		prg.print( /* "unknown string" */ 328)
	case penType:
		prg.print( /* "pen" */ 329)
	case unknownPen:
		prg.print( /* "unknown pen" */ 330)
	case futurePen:
		prg.print( /* "future pen" */ 331)
	case pathType:
		prg.print( /* "path" */ 332)
	case unknownPath:
		prg.print( /* "unknown path" */ 333)
	case pictureType:
		prg.print( /* "picture" */ 334)
	case unknownPicture:
		prg.print( /* "unknown picture" */ 335)
	case transformType:
		prg.print( /* "transform" */ 336)
	case pairType:
		prg.print( /* "pair" */ 337)
	case known:
		prg.print( /* "known numeric" */ 338)
	case dependent:
		prg.print( /* "dependent" */ 339)
	case protoDependent:
		prg.print( /* "proto-dependent" */ 340)
	case numericType:
		prg.print( /* "numeric" */ 341)
	case independent:
		prg.print( /* "independent" */ 342)
	case tokenList:
		prg.print( /* "token list" */ 343)
	case structured:
		prg.print( /* "structured" */ 344)
	case unsuffixedMacro:
		prg.print( /* "unsuffixed macro" */ 345)
	case suffixedMacro:
		prg.print( /* "suffixed macro" */ 346)

	default:
		prg.print( /* "undefined" */ 347)
	}
}

func (prg *prg) beginDiagnostic() {
	prg.oldSetting = prg.selector
	if prg.internal[tracingOnline-1] <= 0 && int32(prg.selector) == termAndLog {
		prg.selector = byte(int32(prg.selector) - 1)
		if int32(prg.history) == spotless {
			prg.history = byte(warningIssued)
		}
	}
}

func (prg *prg) endDiagnostic(blankLine bool) {
	prg.printNl(strNumber( /* "" */ 285))
	if blankLine {
		prg.printLn()
	}
	prg.selector = prg.oldSetting
}

func (prg *prg) printDiagnostic(s, t strNumber, nuline bool) {
	prg.beginDiagnostic()
	if nuline {
		prg.printNl(s)
	} else {
		prg.print(int32(s))
	}
	prg.print( /* " at line " */ 265)
	prg.printInt(prg.line)
	prg.print(int32(t))
	prg.printChar(asciiCode(':'))
}

func (prg *prg) printFileName(n, a, e int32) {
	prg.slowPrint(a)
	prg.slowPrint(n)
	prg.slowPrint(e)
} // \2

// \4\hskip-\fontdimen2\font
//  procedure debug_help;
//   forward;  [  ]

// \4
// Declare the procedure called |flush_string|
func (prg *prg) flushString(s strNumber) {
	if int32(s) < int32(prg.strPtr)-1 {
		prg.strRef[s] = 0
	} else {
		for {
			prg.strPtr = uint16(int32(prg.strPtr) - 1)
			if int32(prg.strRef[int32(prg.strPtr)-1]) != 0 {
				break
			}
		}
	}
	prg.poolPtr = prg.strStart[prg.strPtr]
}

func (prg *prg) jumpOut() {
	panic(signal(endOfMf))
}

func (prg *prg) error1() {
	var (
		c          asciiCode   // what the user types
		s1, s2, s3 int32       // used to save global variables when deleting tokens
		j          poolPointer // character position being printed
	)
	if int32(prg.history) < errorMessageIssued {
		prg.history = byte(errorMessageIssued)
	}
	prg.printChar(asciiCode('.'))
	prg.showContext()
	if int32(prg.interaction) == errorStopMode {
		for true {
		continue1:
			if int32(prg.interaction) != errorStopMode {
				goto exit
			}
			prg.clearForErrorPrompt()
			{
				prg.print( /* "? " */ 263)
				prg.termInput()
			}
			// \xref[?\relax]
			if int32(prg.last) == int32(prg.first) {
				goto exit
			}
			c = prg.buffer[prg.first]
			if int32(c) >= 'a' {
				c = byte(int32(c) + 'A' - 'a')
			} // convert to uppercase

			// Interpret code |c| and |return| if done
			switch c {
			case '0', '1', '2', '3',
				'4', '5', '6', '7',
				'8', '9':
				if prg.deletionsAllowed {
					s1 = int32(prg.curCmd)
					s2 = prg.curMod
					s3 = int32(prg.curSym)
					prg.okToInterrupt = false
					if int32(prg.last) > int32(prg.first)+1 && int32(prg.buffer[int32(prg.first)+1]) >= '0' && int32(prg.buffer[int32(prg.first)+1]) <= '9' {
						c = byte(int32(c)*10 + int32(prg.buffer[int32(prg.first)+1]) - '0'*11)
					} else {
						c = byte(int32(c) - '0')
					}
					for int32(c) > 0 {
						prg.getNext() // one-level recursive call of |error| is possible

						// Decrease the string reference count, if the current token is a string
						if int32(prg.curCmd) == stringToken {
							if int32(prg.strRef[prg.curMod]) < maxStrRef {
								if int32(prg.strRef[prg.curMod]) > 1 {
									prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
								} else {
									prg.flushString(strNumber(prg.curMod))
								}
							}
						}
						c = byte(int32(c) - 1)
					}
					prg.curCmd = byte(s1)
					prg.curMod = s2
					prg.curSym = uint16(s3)
					prg.okToInterrupt = true
					{
						prg.helpPtr = 2
						prg.helpLine[1] = /* "I have just deleted some text, as you asked." */ 278
						prg.helpLine[0] = /* "You can now delete more, or insert, or whatever." */ 279
					}
					prg.showContext()
					goto continue1
				}

			// \4\4
			//  ["D"=]68:begin debug_help;goto continue; end; [  ]

			// "E"=
			case 'E':
				if int32(prg.filePtr) > 0 {
					if int32(prg.inputStack[prg.filePtr].nameField) >= 256 {
						prg.printNl(strNumber( /* "You want to edit file " */ 264))
						// \xref[You want to edit file x]
						prg.slowPrint(int32(prg.inputStack[prg.filePtr].nameField))
						prg.print( /* " at line " */ 265)
						prg.printInt(prg.line)

						prg.interaction = byte(scrollMode)
						prg.jumpOut()
					}
				}
			// "H"=
			case 'H':
				// Print the help information and |goto continue|
				if prg.useErrHelp {
					j = prg.strStart[prg.errHelp]
					for int32(j) < int32(prg.strStart[int32(prg.errHelp)+1]) {
						if int32(prg.strPool[j]) != '%' {
							prg.print(int32(prg.strPool[j]))
						} else if int32(j)+1 == int32(prg.strStart[int32(prg.errHelp)+1]) {
							prg.printLn()
						} else if int32(prg.strPool[int32(j)+1]) != '%' {
							prg.printLn()
						} else {
							j = uint16(int32(j) + 1)
							prg.printChar(asciiCode('%'))
						}
						j = uint16(int32(j) + 1)
					}
					prg.useErrHelp = false
				} else {
					if int32(prg.helpPtr) == 0 {
						prg.helpPtr = 2
						prg.helpLine[1] = /* "Sorry, I don't know how to help in this situation." */ 280
						prg.helpLine[0] = /* "Maybe you should try asking a human?" */ 281
					}
					for {
						prg.helpPtr = byte(int32(prg.helpPtr) - 1)
						prg.print(int32(prg.helpLine[prg.helpPtr]))
						prg.printLn()
						if int32(prg.helpPtr) == 0 {
							break
						}
					}
				}
				{
					prg.helpPtr = 4
					prg.helpLine[3] = /* "Sorry, I already gave what help I could..." */ 282
					prg.helpLine[2] = /* "Maybe you should try asking a human?" */ 281
					prg.helpLine[1] = /* "An error might have occurred before I noticed any problems." */ 283
					prg.helpLine[0] = /* "``If all else fails, read the instructions.''" */ 284
				}

				goto continue1

			// "I"=
			case 'I':
				// Introduce new material from the terminal and |return|
				prg.beginFileReading() // enter a new syntactic level for terminal input
				if int32(prg.last) > int32(prg.first)+1 {
					prg.curInput.locField = uint16(int32(prg.first) + 1)
					prg.buffer[prg.first] = ' '
				} else {
					{
						prg.print( /* "insert>" */ 277)
						prg.termInput()
					}
					prg.curInput.locField = prg.first
					// \xref[insert>]
				}
				prg.first = uint16(int32(prg.last) + 1)
				prg.curInput.limitField = prg.last
				goto exit

			// "Q"=
			case 'Q', 'R', 'S':
				// Change the interaction level and |return|
				prg.errorCount = 0
				prg.interaction = byte(batchMode + int32(c) - 'Q')
				prg.print( /* "OK, entering " */ 272)
				switch c {
				case 'Q':
					prg.print( /* "batchmode" */ 273)
					prg.selector = byte(int32(prg.selector) - 1)

				// "R"=
				case 'R':
					prg.print( /* "nonstopmode" */ 274)
				// "S"=
				case 'S':
					prg.print( /* "scrollmode" */ 275)
				} // there are no other cases
				prg.print( /* "..." */ 276)
				prg.printLn()
				goto exit

			// "X"=
			case 'X':
				prg.interaction = byte(scrollMode)
				prg.jumpOut()

			default:
			}

			// Print the menu of available options
			{
				prg.print( /* "Type <return> to proceed, S to scroll future error messages," */ 266)

				// \xref[Type <return> to proceed...]
				prg.printNl(strNumber( /* "R to run without stopping, Q to run quietly," */ 267))

				prg.printNl(strNumber( /* "I to insert something, " */ 268))
				if int32(prg.filePtr) > 0 {
					if int32(prg.inputStack[prg.filePtr].nameField) >= 256 {
						prg.print( /* "E to edit your file," */ 269)
					}
				}
				if prg.deletionsAllowed {
					prg.printNl(strNumber( /* "1 or ... or 9 to ignore the next 1 to 9 tokens of input," */ 270))
				}
				prg.printNl(strNumber( /* "H for help, X to quit." */ 271))
			}
		}
	}
	prg.errorCount = int8(int32(prg.errorCount) + 1)
	if int32(prg.errorCount) == 100 {
		prg.printNl(strNumber( /* "(That makes 100 errors; please try again.)" */ 262))
		// \xref[That makes 100 errors...]
		prg.history = byte(fatalErrorStop)
		prg.jumpOut()
	}

	// Put help message on the transcript file
	if int32(prg.interaction) > batchMode {
		prg.selector = byte(int32(prg.selector) - 1)
	} // avoid terminal output
	if prg.useErrHelp {
		prg.printNl(strNumber( /* "" */ 285))

		// Print the string |err_help|, possibly on several lines
		j = prg.strStart[prg.errHelp]
		for int32(j) < int32(prg.strStart[int32(prg.errHelp)+1]) {
			if int32(prg.strPool[j]) != '%' {
				prg.print(int32(prg.strPool[j]))
			} else if int32(j)+1 == int32(prg.strStart[int32(prg.errHelp)+1]) {
				prg.printLn()
			} else if int32(prg.strPool[int32(j)+1]) != '%' {
				prg.printLn()
			} else {
				j = uint16(int32(j) + 1)
				prg.printChar(asciiCode('%'))
			}
			j = uint16(int32(j) + 1)
		}
	} else {
		for int32(prg.helpPtr) > 0 {
			prg.helpPtr = byte(int32(prg.helpPtr) - 1)
			prg.printNl(prg.helpLine[prg.helpPtr])
		}
	}
	prg.printLn()
	if int32(prg.interaction) > batchMode {
		prg.selector = byte(int32(prg.selector) + 1)
	} // re-enable terminal output
	prg.printLn()

exit:
}

func (prg *prg) fatalError(s strNumber) {
	prg.normalizeSelector()

	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "Emergency stop" */ 286) /* \xref[!\relax]  */
	}
	{
		prg.helpPtr = 1
		prg.helpLine[0] = s
	}
	{
		if int32(prg.interaction) == errorStopMode {
			prg.interaction = byte(scrollMode)
		}
		if prg.logOpened {
			prg.error1()
		} /*  if interaction>batch_mode then debug_help; [  ] */
		prg.history = byte(fatalErrorStop)
		prg.jumpOut()
	}
	// \xref[Emergency stop]
}

func (prg *prg) overflow(s strNumber, n int32) {
	prg.normalizeSelector()
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "METAFONT capacity exceeded, sorry [" */ 287) /* \xref[!\relax]  */
	}
	// \xref[METAFONT capacity exceeded ...]
	prg.print(int32(s))
	prg.printChar(asciiCode('='))
	prg.printInt(n)
	prg.printChar(asciiCode(']'))
	{
		prg.helpPtr = 2
		prg.helpLine[1] = /* "If you really absolutely need more capacity," */ 288
		prg.helpLine[0] = /* "you can ask a wizard to enlarge me." */ 289
	}
	{
		if int32(prg.interaction) == errorStopMode {
			prg.interaction = byte(scrollMode)
		}
		if prg.logOpened {
			prg.error1()
		} /*  if interaction>batch_mode then debug_help; [  ] */
		prg.history = byte(fatalErrorStop)
		prg.jumpOut()
	}
}

func (prg *prg) confusion(s strNumber) {
	prg.normalizeSelector()
	if int32(prg.history) < errorMessageIssued {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "This can't happen (" */ 290) /* \xref[!\relax]  */
		}
		prg.print(int32(s))
		prg.printChar(asciiCode(')'))
		// \xref[This can't happen]
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "I'm broken. Please show this to someone who can fix can fix" */ 291
		}
	} else {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "I can't go on meeting you like this" */ 292) /* \xref[!\relax]  */
		}
		// \xref[I can't go on...]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "One of your faux pas seems to have wounded me deeply..." */ 293
			prg.helpLine[0] = /* "in fact, I'm barely conscious. Please fix it and try again." */ 294
		}
	}
	{
		if int32(prg.interaction) == errorStopMode {
			prg.interaction = byte(scrollMode)
		}
		if prg.logOpened {
			prg.error1()
		} /*  if interaction>batch_mode then debug_help; [  ] */
		prg.history = byte(fatalErrorStop)
		prg.jumpOut()
	}
}

// 5.

// tangle:pos ../../mf.web:231:3:

// The overall \MF\ program begins with the heading just shown, after which
// comes a bunch of procedure declarations and function declarations.
// Finally we will get to the main program, which begins with the
// comment `|start_here|'. If you want to skip down to the
// main program now, you can look up `|start_here|' in the index.
// But the author suggests that the best way to understand this program
// is to follow pretty much the order of \MF's components as they appear in the
// \.[WEB] description you are now reading, since the present ordering is
// intended to combine the advantages of the ``bottom up'' and ``top down''
// approaches to the problem of understanding a somewhat complicated system.

// 7.

// tangle:pos ../../mf.web:253:3:

// Some of the code below is intended to be used only when diagnosing the
// strange behavior that sometimes occurs when \MF\ is being installed or
// when system wizards are fooling around with \MF\ without quite knowing
// what they are doing. Such code will not normally be compiled; it is
// delimited by the codewords `$|debug|\ldots|gubed|$', with apologies
// to people who wish to preserve the purity of English.
//
// Similarly, there is some conditional code delimited by
// `$|stat|\ldots|tats|$' that is intended for use when statistics are to be
// kept about \MF's memory usage.  The |stat| $\ldots$ |tats| code also
// implements special diagnostic information that is printed when
// $\\[tracingedges]>1$.
// \xref[debugging]

// 8.

// tangle:pos ../../mf.web:279:3:

// This program has two important variations: (1) There is a long and slow
// version called \.[INIMF], which does the extra calculations needed to
// \xref[INIMF]
// initialize \MF's internal tables; and (2)~there is a shorter and faster
// production version, which cuts the initialization to a bare minimum.
// Parts of the program that are needed in (1) but not in (2) are delimited by
// the codewords `$|init|\ldots|tini|$'.

// 10.

// tangle:pos ../../mf.web:307:3:

// This \MF\ implementation conforms to the rules of the [\sl Pascal User
// \xref[PASCAL][\PASCAL]
// \xref[system dependencies]
// Manual] published by Jensen and Wirth in 1975, except where system-dependent
// \xref[Wirth, Niklaus]
// \xref[Jensen, Kathleen]
// code is necessary to make a useful system program, and except in another
// respect where such conformity would unnecessarily obscure the meaning
// and clutter up the code: We assume that |case| statements may include a
// default case that applies if no matching label is found. Thus, we shall use
// constructions like
// $$\vbox[\halign[\ignorespaces#\hfil\cr
// |case x of|\cr
// 1: $\langle\,$code for $x=1\,\rangle$;\cr
// 3: $\langle\,$code for $x=3\,\rangle$;\cr
// |othercases| $\langle\,$code for |x<>1| and |x<>3|$\,\rangle$\cr
// |endcases|\cr]]$$
// since most \PASCAL\ compilers have plugged this hole in the language by
// incorporating some sort of default mechanism. For example, the \ph\
// compiler allows `|others|:' as a default label, and other \PASCAL s allow
// syntaxes like `\&[else]' or `\&[otherwise]' or `\\[otherwise]:', etc. The
// definitions of |othercases| and |endcases| should be changed to agree with
// local conventions.  Note that no semicolon appears before |endcases| in
// this program, so the definition of |endcases| should include a semicolon
// if the compiler wants one. (Of course, if no default mechanism is
// available, the |case| statements of \MF\ will have to be laboriously
// extended by listing all remaining cases. People who are stuck with such
// \PASCAL s have, in fact, done this, successfully but not happily!)
// \xref[PASCAL H][\ph]

// 12.

// tangle:pos ../../mf.web:386:3:

// Like the preceding parameters, the following quantities can be changed
// at compile time to extend or reduce \MF's capacity. But if they are changed,
// it is necessary to rerun the initialization program \.[INIMF]
// \xref[INIMF]
// to generate new tables for the production \MF\ program.
// One can't simply make helter-skelter changes to the following constants,
// since certain rather complex initialization
// numbers are computed from them. They are defined here using
// \.[WEB] macros, instead of being put into \PASCAL's |const| list, in order to
// emphasize this distinction.

// 15.

// tangle:pos ../../mf.web:432:3:

// Labels are given symbolic names by the following definitions, so that
// occasional |goto| statements will be meaningful. We insert the label
// `|exit|' just before the `\ignorespaces|end|\unskip' of a procedure in
// which we have used the `|return|' statement defined below; the label
// `|restart|' is occasionally used at the very beginning of a procedure; and
// the label `|reswitch|' is occasionally used just prior to a |case|
// statement in which some cases change the conditions and we wish to branch
// to the newly applicable case.  Loops that are set up with the |loop|
// construction defined below are commonly exited by going to `|done|' or to
// `|found|' or to `|not_found|', and they are sometimes repeated by going to
// `|continue|'.  If two or more parts of a subroutine start differently but
// end up the same, the shared code may be gathered together at
// `|common_ending|'.
//
// Incidentally, this program never declares a label that isn't actually used,
// because some fussy \PASCAL\ compilers will complain about redundant labels.

// 16.

// tangle:pos ../../mf.web:466:3:

// Here are some macros for common programming idioms.

// 17. \[2] The character set

// tangle:pos ../../mf.web:479:27:

// In order to make \MF\ readily portable to a wide variety of
// computers, all of its input text is converted to an internal eight-bit
// code that includes standard ASCII, the ``American Standard Code for
// Information Interchange.''  This conversion is done immediately when each
// character is read in. Conversely, characters are converted from ASCII to
// the user's external representation just before they are output to a
// text file.
// \xref[ASCII code]
//
// Such an internal code is relevant to users of \MF\ only with respect to
// the \&[char] and \&[ASCII] operations, and the comparison of strings.

// 26.

// tangle:pos ../../mf.web:742:3:

// The \ph\ compiler with which the present version of \MF\ was prepared has
// extended the rules of \PASCAL\ in a very convenient way. To open file~|f|,
// we can write
// $$\vbox[\halign[#\hfil\qquad&#\hfil\cr
// |reset(f,\\[name],'/O')|&for input;\cr
// |rewrite(f,\\[name],'/O')|&for output.\cr]]$$
// The `\\[name]' parameter, which is of type `\ignorespaces|packed
// array[\<\\[any]>] of text_char|', stands for the name of
// the external file that is being opened for input or output.
// Blank spaces that might appear in \\[name] are ignored.
//
// The `\.[/O]' parameter tells the operating system not to issue its own
// error messages if something goes wrong. If a file of the specified name
// cannot be found, or if such a file cannot be opened for some other reason
// (e.g., someone may already be trying to write the same file), we will have
// | erstat(f)<>0| after an unsuccessful |reset| or |rewrite|.  This allows
// \MF\ to undertake appropriate corrective action.
// \xref[PASCAL H][\ph]
// \xref[system dependencies]
//
// \MF's file-opening procedures return |false| if no file identified by
// |name_of_file| could be opened.
func (prg *prg) aOpenIn(f alphaFile) (r bool) {
	f.Reset(arraystr(prg.nameOfFile[:]), "/O")
	r = f.ErStat() == 0
	return r
}

func (prg *prg) aOpenOut(f alphaFile) (r bool) {
	f.Rewrite(arraystr(prg.nameOfFile[:]), "/O")
	r = f.ErStat() == 0
	return r
}

func (prg *prg) bOpenOut(f byteFile) (r bool) {
	f.Rewrite(arraystr(prg.nameOfFile[:]), "/O")
	r = f.ErStat() == 0
	return r
}

func (prg *prg) wOpenIn(f wordFile) (r bool) {
	f.Reset(arraystr(prg.nameOfFile[:]), "/O")
	r = f.ErStat() == 0
	return r
}

func (prg *prg) wOpenOut(f wordFile) (r bool) {
	f.Rewrite(arraystr(prg.nameOfFile[:]), "/O")
	r = f.ErStat() == 0
	return r
}

// 27.

// tangle:pos ../../mf.web:793:3:

// Files can be closed with the \ph\ routine `|close(f)|', which
// \xref[PASCAL H][\ph]
// \xref[system dependencies]
// should be used when all input or output with respect to |f| has been completed.
// This makes |f| available to be opened again, if desired; and if |f| was used for
// output, the |close| operation makes the corresponding external file appear
// on the user's area, ready to be read.
func (prg *prg) aClose(f alphaFile) {
	f.Close()
}

func (prg *prg) bClose(f byteFile) {
	f.Close()
}

func (prg *prg) wClose(f wordFile) {
	f.Close()
}

// 28.

// tangle:pos ../../mf.web:813:3:

// Binary input and output are done with \PASCAL's ordinary |get| and |put|
// procedures, so we don't have to make any other special arrangements for
// binary~I/O. Text output is also easy to do with standard \PASCAL\ routines.
// The treatment of text input is more difficult, however, because
// of the necessary translation to |ASCII_code| values.
// \MF's conventions should be efficient, and they should
// blend nicely with the user's operating environment.

// 30.

// tangle:pos ../../mf.web:834:3:

// The |input_ln| function brings the next line of input from the specified
// file into available positions of the buffer array and returns the value
// |true|, unless the file has already been entirely read, in which case it
// returns |false| and sets |last:=first|.  In general, the |ASCII_code|
// numbers that represent the next line of the file are input into
// |buffer[first]|, |buffer[first+1]|, \dots, |buffer[last-1]|; and the
// global variable |last| is set equal to |first| plus the length of the
// line. Trailing blanks are removed from the line; thus, either |last=first|
// (in which case the line was entirely blank) or |buffer[last-1]<>" "|.
// \xref[inner loop]
//
// An overflow error is given, however, if the normal actions of |input_ln|
// would make |last>=buf_size|; this is done so that other parts of \MF\
// can safely look at the contents of |buffer[last+1]| without overstepping
// the bounds of the |buffer| array. Upon entry to |input_ln|, the condition
// |first<buf_size| will always hold, so that there is always room for an
// ``empty'' line.
//
// The variable |max_buf_stack|, which is used to keep track of how large
// the |buf_size| parameter must be to accommodate the present job, is
// also kept up to date by |input_ln|.
//
// If the |bypass_eoln| parameter is |true|, |input_ln| will do a |get|
// before looking at the first character of the line; this skips over
// an |eoln| that was in |f^|. The procedure does not do a |get| when it
// reaches the end of the line; therefore it can be used to acquire input
// from the user's terminal as well as from ordinary text files.
//
// Standard \PASCAL\ says that a file should have |eoln| immediately
// before |eof|, but \MF\ needs only a weaker restriction: If |eof|
// occurs in the middle of a line, the system function |eoln| should return
// a |true| result (even though |f^| will be undefined).
func (prg *prg) inputLn(f alphaFile, bypassEoln bool) (r bool) {
	// inputs the next line or returns |false|
	var (
		lastNonblank /* 0..bufSize */ uint16 // |last| with trailing blanks removed
	)
	if bypassEoln {
		if !f.EOF() {
			f.Get()
		}
	}
	// input the first character of the line into |f^|
	prg.last = prg.first // cf.\ Matthew 19\thinspace:\thinspace30
	if f.EOF() {
		r = false
	} else {
		lastNonblank = prg.first
		for !f.EOLN() {
			if int32(prg.last) >= int32(prg.maxBufStack) {
				prg.maxBufStack = uint16(int32(prg.last) + 1)
				if int32(prg.maxBufStack) == bufSize {
					if int32(prg.baseIdent) == 0 {
						prg.termOut.Writeln("Buffer size exceeded!")
						panic(signal(finalEnd))
						// \xref[Buffer size exceeded]
					} else {
						prg.curInput.locField = prg.first
						prg.curInput.limitField = uint16(int32(prg.last) - 1)
						prg.overflow(strNumber( /* "buffer size" */ 256), bufSize)
						// \xref[METAFONT capacity exceeded buffer size][\quad buffer size]
					}
				}
			}
			prg.buffer[prg.last] = prg.xord[*f.ByteP()]
			f.Get()
			prg.last = uint16(int32(prg.last) + 1)
			if int32(prg.buffer[int32(prg.last)-1]) != ' ' {
				lastNonblank = prg.last
			}
		}
		prg.last = lastNonblank
		r = true
	}
	return r
}

// 32.

// tangle:pos ../../mf.web:898:3:

// Here is how to open the terminal files
// in \ph. The `\.[/I]' switch suppresses the first |get|.
// \xref[PASCAL H][\ph]
// \xref[system dependencies]

// 33.

// tangle:pos ../../mf.web:907:3:

// Sometimes it is necessary to synchronize the input/output mixture that
// happens on the user's terminal, and three system-dependent
// procedures are used for this
// purpose. The first of these, |update_terminal|, is called when we want
// to make sure that everything we have output to the terminal so far has
// actually left the computer's internal buffers and been sent.
// The second, |clear_terminal|, is called when we wish to cancel any
// input that the user may have typed ahead (since we are about to
// issue an unexpected error message). The third, |wake_up_terminal|,
// is supposed to revive the terminal if the user has disabled it by
// some instruction to the operating system.  The following macros show how
// these operations can be specified in \ph:
// \xref[PASCAL H][\ph]
// \xref[system dependencies]

// 35.

// tangle:pos ../../mf.web:963:3:

// Different systems have different ways to get started. But regardless of
// what conventions are adopted, the routine that initializes the terminal
// should satisfy the following specifications:
//
// \yskip\textindent[1)]It should open file |term_in| for input from the
//   terminal. (The file |term_out| will already be open for output to the
//   terminal.)
//
// \textindent[2)]If the user has given a command line, this line should be
//   considered the first line of terminal input. Otherwise the
//   user should be prompted with `\.[**]', and the first line of input
//   should be whatever is typed in response.
//
// \textindent[3)]The first line of input, which might or might not be a
//   command line, should appear in locations |first| to |last-1| of the
//   |buffer| array.
//
// \textindent[4)]The global variable |loc| should be set so that the
//   character to be read next by \MF\ is in |buffer[loc]|. This
//   character should not be blank, and we should have |loc<last|.
//
// \yskip\noindent(It may be necessary to prompt the user several times
// before a non-blank line comes in. The prompt is `\.[**]' instead of the
// later `\.*' because the meaning is slightly different: `\.[input]' need
// not be typed immediately after~`\.[**]'.)

// 36.

// tangle:pos ../../mf.web:991:3:

// The following program does the required initialization
// without retrieving a possible command line.
// It should be clear how to modify this routine to deal with command lines,
// if the system permits them.
// \xref[system dependencies]
func (prg *prg) initTerminal() (r bool) {
	prg.termIn.Reset("TTY:", "/O/I")
	for true {
		prg.termOut.Write("**")
		// \xref[**]
		if !prg.inputLn(prg.termIn, false) {
			prg.termOut.Writeln()
			prg.termOut.Write("! End of file on the terminal... why?")
			// \xref[End of file on the terminal]
			r = false
			goto exit
		}
		prg.curInput.locField = prg.first
		for int32(prg.curInput.locField) < int32(prg.last) && int32(prg.buffer[prg.curInput.locField]) == ' ' {
			prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
		}
		if int32(prg.curInput.locField) < int32(prg.last) {
			r = true

			goto exit // return unless the line was all blank
		}
		prg.termOut.Writeln("Please type the name of your input file.")
	}

exit:
	;
	return r
}

// 39.

// tangle:pos ../../mf.web:1077:3:

// Several of the elementary string operations are performed using \.[WEB]
// macros instead of \PASCAL\ procedures, because many of the
// operations are done quite frequently and we want to avoid the
// overhead of procedure calls. For example, here is
// a simple macro that computes the length of a string.
// \xref[WEB]

// 40.

// tangle:pos ../../mf.web:1087:3:

// The length of the current string is called |cur_length|:

// 41.

// tangle:pos ../../mf.web:1091:3:

// Strings are created by appending character codes to |str_pool|.
// The |append_char| macro, defined here, does not check to see if the
// value of |pool_ptr| has gotten too high; this test is supposed to be
// made before |append_char| is used.
//
// To test if there is room to append |l| more characters to |str_pool|,
// we shall write |str_room(l)|, which aborts \MF\ and gives an
// apologetic error message if there isn't enough room.

// 44.

// tangle:pos ../../mf.web:1153:3:

// Once a sequence of characters has been appended to |str_pool|, it
// officially becomes a string when the function |make_string| is called.
// This function returns the identification number of the new string as its
// value.
func (prg *prg) makeString() (r strNumber) {
	if int32(prg.strPtr) == int32(prg.maxStrPtr) {
		if int32(prg.strPtr) == maxStrings {
			prg.overflow(strNumber( /* "number of strings" */ 258), maxStrings-int32(prg.initStrPtr))
		}
		// \xref[METAFONT capacity exceeded number of strings][\quad number of strings]
		prg.maxStrPtr = uint16(int32(prg.maxStrPtr) + 1)
	}
	prg.strRef[prg.strPtr] = 1
	prg.strPtr = uint16(int32(prg.strPtr) + 1)
	prg.strStart[prg.strPtr] = prg.poolPtr
	r = uint16(int32(prg.strPtr) - 1)
	return r
}

// 45.

// tangle:pos ../../mf.web:1169:3:

// The following subroutine compares string |s| with another string of the
// same length that appears in |buffer| starting at position |k|;
// the result is |true| if and only if the strings are equal.
func (prg *prg) strEqBuf(s strNumber, k int32) (r bool) { // loop exit
	var (
		j      poolPointer // running index
		result bool        // result of comparison
	)
	j = prg.strStart[s]
	for int32(j) < int32(prg.strStart[int32(s)+1]) {
		if int32(prg.strPool[j]) != int32(prg.buffer[k]) {
			result = false
			goto notFound
		}
		j = uint16(int32(j) + 1)
		k = k + 1
	}
	result = true

notFound:
	r = result
	return r
}

// 46.

// tangle:pos ../../mf.web:1189:3:

// Here is a similar routine, but it compares two strings in the string pool,
// and it does not assume that they have the same length. If the first string
// is lexicographically greater than, less than, or equal to the second,
// the result is respectively positive, negative, or zero.
func (prg *prg) strVsStr(s, t strNumber) (r int32) {
	var (
		j, k   poolPointer // running indices
		ls, lt int32       // lengths
		l      int32       // length remaining to test
	)
	ls = int32(prg.strStart[int32(s)+1]) - int32(prg.strStart[s])
	lt = int32(prg.strStart[int32(t)+1]) - int32(prg.strStart[t])
	if ls <= lt {
		l = ls
	} else {
		l = lt
	}
	j = prg.strStart[s]
	k = prg.strStart[t]
	for l > 0 {
		if int32(prg.strPool[j]) != int32(prg.strPool[k]) {
			r = int32(prg.strPool[j]) - int32(prg.strPool[k])
			goto exit
		}
		j = uint16(int32(j) + 1)
		k = uint16(int32(k) + 1)
		l = l - 1
	}
	r = ls - lt

exit:
	;
	return r
}

// 47.

// tangle:pos ../../mf.web:1212:3:

// The initial values of |str_pool|, |str_start|, |pool_ptr|,
// and |str_ptr| are computed by the \.[INIMF] program, based in part
// on the information that \.[WEB] has output while processing \MF.
// \xref[INIMF]
// \xref[string pool]
func (prg *prg) getStringsStarted() (r bool) {
	var (
		k, l/* 0..255 */ byte           // small indices or counters
		m, n                  char      // characters input from |pool_file|
		g                     strNumber // the string just created
		a                     int32     // accumulator for check sum
		c                     bool      // check sum has been checked
	)
	prg.poolPtr = 0
	prg.strPtr = 0
	prg.maxPoolPtr = 0
	prg.maxStrPtr = 0
	prg.strStart[0] = 0

	// Make the first 256 strings
	for ii := int32(0); ii <= 255; ii++ {
		k = byte(ii)
		_ = k
		if int32(k) < ' ' || int32(k) > '~' {
			{
				prg.strPool[prg.poolPtr] = '^'
				prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
			}
			{
				prg.strPool[prg.poolPtr] = '^'
				prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
			}
			if int32(k) < 0100 {
				prg.strPool[prg.poolPtr] = byte(int32(k) + 0100)
				prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
			} else if int32(k) < 0200 {
				prg.strPool[prg.poolPtr] = byte(int32(k) - 0100)
				prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
			} else {
				l = byte(int32(k) / 16)
				if int32(l) < 10 {
					prg.strPool[prg.poolPtr] = byte(int32(l) + '0')
					prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
				} else {
					prg.strPool[prg.poolPtr] = byte(int32(l) - 10 + 'a')
					prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
				}
				l = byte(int32(k) % 16)
				if int32(l) < 10 {
					prg.strPool[prg.poolPtr] = byte(int32(l) + '0')
					prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
				} else {
					prg.strPool[prg.poolPtr] = byte(int32(l) - 10 + 'a')
					prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
				}
			}
		} else {
			prg.strPool[prg.poolPtr] = k
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
		g = prg.makeString()
		prg.strRef[g] = byte(maxStrRef)
	}

	// Read the other strings from the \.[MF.POOL] file and return |true|, or give an error message and return |false|
	strcopy(prg.nameOfFile[:], "MFbases:MF.POOL                         ") // we needn't set |name_length|
	if prg.aOpenIn(prg.poolFile) {
		c = false
		for {
			// Read one string, but return |false| if the string memory space is getting too tight for comfort
			{
				if prg.poolFile.EOF() {
					prg.termOut.Writeln("! MF.POOL has no check sum.")
					prg.aClose(prg.poolFile)
					r = false
					goto exit
				}
				// \xref[MF.POOL has no check sum]
				prg.poolFile.Read(&m, &n) // read two digits of string length
				if int32(m) == '*' {
					a = 0
					k = 1
					for true {
						if int32(prg.xord[n]) < '0' || int32(prg.xord[n]) > '9' {
							prg.termOut.Writeln("! MF.POOL check sum doesn't have nine digits.")
							prg.aClose(prg.poolFile)
							r = false
							goto exit
						}
						// \xref[MF.POOL check sum...]
						a = 10*a + int32(prg.xord[n]) - '0'
						if int32(k) == 9 {
							goto done
						}
						k = byte(int32(k) + 1)
						prg.poolFile.Read(&n)
					}

				done:
					if a != 461259239 {
						prg.termOut.Writeln("! MF.POOL doesn't match; TANGLE me again.")
						prg.aClose(prg.poolFile)
						r = false
						goto exit
					}
					// \xref[MF.POOL doesn't match]
					c = true
				} else {
					if int32(prg.xord[m]) < '0' || int32(prg.xord[m]) > '9' || int32(prg.xord[n]) < '0' || int32(prg.xord[n]) > '9' {
						prg.termOut.Writeln("! MF.POOL line doesn't begin with two digits.")
						prg.aClose(prg.poolFile)
						r = false
						goto exit
					}
					// \xref[MF.POOL line doesn't...]
					l = byte(int32(prg.xord[m])*10 + int32(prg.xord[n]) - '0'*11) // compute the length
					if int32(prg.poolPtr)+int32(l)+stringVacancies > poolSize {
						prg.termOut.Writeln("! You have to increase POOLSIZE.")
						prg.aClose(prg.poolFile)
						r = false
						goto exit
					}
					// \xref[You have to increase POOLSIZE]
					for ii := int32(1); ii <= int32(l); ii++ {
						k = byte(ii)
						_ = k
						if prg.poolFile.EOLN() {
							m = ' '
						} else {
							prg.poolFile.Read(&m)
						}
						{
							prg.strPool[prg.poolPtr] = prg.xord[m]
							prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
						}
					}
					prg.poolFile.Readln()
					g = prg.makeString()
					prg.strRef[g] = byte(maxStrRef)
				}
			}
			if c {
				break
			}
		}
		prg.aClose(prg.poolFile)
		r = true
	} else {
		prg.termOut.Writeln("! I can't read MF.POOL.")
		prg.aClose(prg.poolFile)
		r = false
		goto exit
	}

exit:
	;
	return r
}

// 56.

// tangle:pos ../../mf.web:1406:3:

// Macro abbreviations for output to the terminal and to the log file are
// defined here for convenience. Some systems need special conventions
// for terminal output, and it is possible to adhere to those conventions
// by changing |wterm|, |wterm_ln|, and |wterm_cr| here.
// \xref[system dependencies]

// 65.

// tangle:pos ../../mf.web:1560:3:

// \MF\ also makes use of a trivial procedure to print two digits. The
// following subroutine is usually called with a parameter in the range |0<=n<=99|.
func (prg *prg) printDd(n int32) {
	n = abs(n) % 100
	prg.printChar(asciiCode('0' + n/10))
	prg.printChar(asciiCode('0' + n%10))
} // \2

func (prg *prg) termInput() { // gets a line from the terminal
	var (
		k /* 0..bufSize */ uint16 // index into |buffer|
	) // now the user sees the prompt for sure
	if !prg.inputLn(prg.termIn, true) {
		prg.fatalError(strNumber( /* "End of file on the terminal!" */ 260))
	}
	// \xref[End of file on the terminal]
	prg.termOffset = 0                           // the user's line ended with \<\rm return>
	prg.selector = byte(int32(prg.selector) - 1) // prepare to echo the input
	if int32(prg.last) != int32(prg.first) {
		for ii := int32(prg.first); ii <= int32(prg.last)-1; ii++ {
			k = uint16(ii)
			_ = k
			prg.print(int32(prg.buffer[k]))
		}
	}
	prg.printLn()
	prg.buffer[prg.last] = '%'
	prg.selector = byte(int32(prg.selector) + 1) // restore previous status
}

// \4
// Error handling procedures
func (prg *prg) normalizeSelector() {
	if prg.logOpened {
		prg.selector = byte(termAndLog)
	} else {
		prg.selector = byte(termOnly)
	}
	if int32(prg.jobName) == 0 {
		prg.openLogFile()
	}
	if int32(prg.interaction) == batchMode {
		prg.selector = byte(int32(prg.selector) - 1)
	}
}

// 93.

// tangle:pos ../../mf.web:1993:3:

// When an interrupt has been detected, the program goes into its
// highest interaction level and lets the user have the full flexibility of
// the |error| routine.  \MF\ checks for interrupts only at times when it is
// safe to do this.
func (prg *prg) pauseForInstructions() {
	if prg.okToInterrupt {
		prg.interaction = byte(errorStopMode)
		if int32(prg.selector) == logOnly || int32(prg.selector) == noPrint {
			prg.selector = byte(int32(prg.selector) + 1)
		}
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Interruption" */ 295) /* \xref[!\relax]  */
		}
		// \xref[Interruption]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "You rang?" */ 296
			prg.helpLine[1] = /* "Try to insert an instruction for me (e.g., `I show x;')," */ 297
			prg.helpLine[0] = /* "unless you just want to quit by typing `X'." */ 298
		}
		prg.deletionsAllowed = false
		prg.error1()
		prg.deletionsAllowed = true
		prg.interrupt = 0
	}
}

// 94.

// tangle:pos ../../mf.web:2013:3:

// Many of \MF's error messages state that a missing token has been
// inserted behind the scenes. We can save string space and program space
// by putting this common code into a subroutine.
func (prg *prg) missingErr(s strNumber) {
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "Missing `" */ 299) /* \xref[!\relax]  */
	}
	prg.print(int32(s))
	prg.print( /* "' has been inserted" */ 300)
	// \xref[Missing...inserted]
}

// 95. \[7] Arithmetic with scaled numbers

// tangle:pos ../../mf.web:2022:40:

// The principal computations performed by \MF\ are done entirely in terms of
// integers less than $2^[31]$ in magnitude; thus, the arithmetic specified in this
// program can be carried out in exactly the same way on a wide variety of
// computers, including some small ones.
// \xref[small computers]
//
// But \PASCAL\ does not define the  |div|
// operation in the case of negative dividends; for example, the result of
// |(-2*n-1) div 2| is |-(n+1)| on some computers and |-n| on others.
// There are two principal types of arithmetic: ``translation-preserving,''
// in which the identity |(a+q*b)div b=(a div b)+q| is valid; and
// ``negation-preserving,'' in which |(-a)div b=-(a div b)|. This leads to
// two \MF s, which can produce different results, although the differences
// should be negligible when the language is being used properly.
// The \TeX\ processor has been defined carefully so that both varieties
// of arithmetic will produce identical output, but it would be too
// inefficient to constrain \MF\ in a similar way.

// 96.

// tangle:pos ../../mf.web:2043:3:

// One of \MF's most common operations is the calculation of
// $\lfloor[a+b\over2]\rfloor$,
// the midpoint of two given integers |a| and~|b|. The only decent way to do
// this in \PASCAL\ is to write `|(a+b) div 2|'; but on most machines it is
// far more efficient to calculate `|(a+b)| right shifted one bit'.
//
// Therefore the midpoint operation will always be denoted by `|half(a+b)|'
// in this program. If \MF\ is being implemented with languages that permit
// binary shifting, the |half| macro should be changed to make this operation
// as efficient as possible.

// 99.

// tangle:pos ../../mf.web:2068:3:

// At crucial points the program will say |check_arith|, to test if
// an arithmetic error has been detected.
func (prg *prg) clearArith() {
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "Arithmetic overflow" */ 301) /* \xref[!\relax]  */
	}
	// \xref[Arithmetic overflow]
	{
		prg.helpPtr = 4
		prg.helpLine[3] = /* "Uh, oh. A little while ago one of the quantities that I was" */ 302
		prg.helpLine[2] = /* "computing got too large, so I'm afraid your answers will be" */ 303
		prg.helpLine[1] = /* "somewhat askew. You'll probably have to adopt different" */ 304
		prg.helpLine[0] = /* "tactics next time. But I shall try to carry on anyway." */ 305
	}
	prg.error1()
	prg.arithError = false
}

// 100.

// tangle:pos ../../mf.web:2083:3:

// Addition is not always checked to make sure that it doesn't overflow,
// but in places where overflow isn't too unlikely the |slow_add| routine
// is used.
func (prg *prg) slowAdd(x, y int32) (r int32) {
	if x >= 0 {
		if y <= 017777777777-x {
			r = x + y
		} else {
			prg.arithError = true
			r = 017777777777
		}
	} else if -y <= 017777777777+x {
		r = x + y
	} else {
		prg.arithError = true
		r = -017777777777
	}
	return r
}

// 102.

// tangle:pos ../../mf.web:2112:3:

// The following function is used to create a scaled integer from a given decimal
// fraction $(.d_0d_1\ldots d_[k-1])$, where |0<=k<=17|. The digit $d_i$ is
// given in |dig[i]|, and the calculation produces a correctly rounded result.
func (prg *prg) roundDecimals(k smallNumber) (r scaled) {
	// converts a decimal fraction
	var (
		a int32 // the accumulator
	)
	a = 0
	for int32(k) > 0 {
		k = byte(int32(k) - 1)
		a = (a + int32(prg.dig[k])*0400000) / 10
	}
	r = (a + 1) / 2
	return r
}

// 107.

// tangle:pos ../../mf.web:2194:3:

// The |make_fraction| routine produces the |fraction| equivalent of
// |p/q|, given integers |p| and~|q|; it computes the integer
// $f=\lfloor2^[28]p/q+[1\over2]\rfloor$, when $p$ and $q$ are
// positive. If |p| and |q| are both of the same scaled type |t|,
// the ``type relation'' |make_fraction(t,t)=fraction| is valid;
// and it's also possible to use the subroutine ``backwards,'' using
// the relation |make_fraction(t,fraction)=t| between scaled types.
//
// If the result would have magnitude $2^[31]$ or more, |make_fraction|
// sets |arith_error:=true|. Most of \MF's internal computations have
// been designed to avoid this sort of error.
//
// Notice that if 64-bit integer arithmetic were available,
// we could simply compute |$(2^[29]$*p+q)div (2*q)|.
// But when we are restricted to \PASCAL's 32-bit arithmetic we
// must either resort to multiple-precision maneuvering
// or use a simple but slow iteration. The multiple-precision technique
// would be about three times faster than the code adopted here, but it
// would be comparatively long and tricky, involving about sixteen
// additional multiplications and divisions.
//
// This operation is part of \MF's ``inner loop''; indeed, it will
// consume nearly 10\pct! of the running time (exclusive of input and output)
// if the code below is left unchanged. A machine-dependent recoding
// will therefore make \MF\ run faster. The present implementation
// is highly portable, but slow; it avoids multiplication and division
// except in the initial stage. System wizards should be careful to
// replace it with a routine that is guaranteed to produce identical
// results in all cases.
// \xref[system dependencies]
//
// As noted below, a few more routines should also be replaced by machine-dependent
// code, for efficiency. But when a procedure is not part of the ``inner loop,''
// such changes aren't advisable; simplicity and robustness are
// preferable to trickery, unless the cost is too high.
// \xref[inner loop]
func (prg *prg) makeFraction(p, q int32) (r fraction) {
	var (
		f         int32 // the fraction bits, with a leading 1 bit
		n         int32 // the integer part of $\vert p/q\vert$
		negative  bool  // should the result be negated?
		beCareful int32 // disables certain compiler optimizations
	)
	if p >= 0 {
		negative = false
	} else {
		p = -p
		negative = true
	}
	if q <= 0 {
		q = -q
		negative = !negative
	}
	n = p / q
	p = p % q
	if n >= 8 {
		prg.arithError = true
		if negative {
			r = -017777777777
		} else {
			r = 017777777777
		}
	} else {
		n = (n - 1) * 02000000000

		// Compute $f=\lfloor 2^[28](1+p/q)+[1\over2]\rfloor$
		f = 1
		for {
			beCareful = p - q
			p = beCareful + p
			if p >= 0 {
				f = f + f + 1
			} else {
				f = f + f
				p = p + q
			}
			if f >= 02000000000 {
				break
			}
		}
		beCareful = p - q
		if beCareful+p >= 0 {
			f = f + 1
		}
		if negative {
			r = -(f + n)
		} else {
			r = f + n
		}
	}
	return r
}

// 109.

// tangle:pos ../../mf.web:2278:3:

// The dual of |make_fraction| is |take_fraction|, which multiplies a
// given integer~|q| by a fraction~|f|. When the operands are positive, it
// computes $p=\lfloor qf/2^[28]+[1\over2]\rfloor$, a symmetric function
// of |q| and~|f|.
//
// This routine is even more ``inner loopy'' than |make_fraction|;
// the present implementation consumes almost 20\pct! of \MF's computation
// time during typical jobs, so a machine-language or 64-bit
// substitute is advisable.
// \xref[inner loop] \xref[system dependencies]
func (prg *prg) takeFraction(q int32, f fraction) (r int32) {
	var (
		p         int32 // the fraction so far
		negative  bool  // should the result be negated?
		n         int32 // additional multiple of $q$
		beCareful int32 // disables certain compiler optimizations
	)
	if f >= 0 {
		negative = false
	} else {
		f = -f
		negative = true
	}
	if q < 0 {
		q = -q
		negative = !negative
	}

	if f < 02000000000 {
		n = 0
	} else {
		n = f / 02000000000
		f = f % 02000000000
		if q <= 017777777777/n {
			n = n * q
		} else {
			prg.arithError = true
			n = 017777777777
		}
	}
	f = f + 02000000000

	// Compute $p=\lfloor qf/2^[28]+[1\over2]\rfloor-q$
	p = 01000000000 // that's $2^[27]$; the invariants hold now with $k=28$
	if q < 010000000000 {
		for {
			if f&1 != 0 {
				p = (p + q) / 2
			} else {
				p = p / 2
			}
			f = f / 2
			if f == 1 {
				break
			}
		}
	} else {
		for {
			if f&1 != 0 {
				p = p + (q-p)/2
			} else {
				p = p / 2
			}
			f = f / 2
			if f == 1 {
				break
			}
		}
	}
	beCareful = n - 017777777777
	if beCareful+p > 0 {
		prg.arithError = true
		n = 017777777777 - p
	}
	if negative {
		r = -(n + p)
	} else {
		r = n + p
	}
	return r
}

// 112.

// tangle:pos ../../mf.web:2335:3:

// When we want to multiply something by a |scaled| quantity, we use a scheme
// analogous to |take_fraction| but with a different scaling.
// Given positive operands, |take_scaled|
// computes the quantity $p=\lfloor qf/2^[16]+[1\over2]\rfloor$.
//
// Once again it is a good idea to use 64-bit arithmetic if
// possible; otherwise |take_scaled| will use more than 2\pct! of the running time
// when the Computer Modern fonts are being generated.
// \xref[inner loop]
func (prg *prg) takeScaled(q int32, f scaled) (r int32) {
	var (
		p         int32 // the fraction so far
		negative  bool  // should the result be negated?
		n         int32 // additional multiple of $q$
		beCareful int32 // disables certain compiler optimizations
	)
	if f >= 0 {
		negative = false
	} else {
		f = -f
		negative = true
	}
	if q < 0 {
		q = -q
		negative = !negative
	}

	if f < 0200000 {
		n = 0
	} else {
		n = f / 0200000
		f = f % 0200000
		if q <= 017777777777/n {
			n = n * q
		} else {
			prg.arithError = true
			n = 017777777777
		}
	}
	f = f + 0200000

	// Compute $p=\lfloor qf/2^[16]+[1\over2]\rfloor-q$
	p = 0100000 // that's $2^[15]$; the invariants hold now with $k=16$
	// \xref[inner loop]
	if q < 010000000000 {
		for {
			if f&1 != 0 {
				p = (p + q) / 2
			} else {
				p = p / 2
			}
			f = f / 2
			if f == 1 {
				break
			}
		}
	} else {
		for {
			if f&1 != 0 {
				p = p + (q-p)/2
			} else {
				p = p / 2
			}
			f = f / 2
			if f == 1 {
				break
			}
		}
	}
	beCareful = n - 017777777777
	if beCareful+p > 0 {
		prg.arithError = true
		n = 017777777777 - p
	}
	if negative {
		r = -(n + p)
	} else {
		r = n + p
	}
	return r
}

// 114.

// tangle:pos ../../mf.web:2378:3:

// For completeness, there's also |make_scaled|, which computes a
// quotient as a |scaled| number instead of as a |fraction|.
// In other words, the result is $\lfloor2^[16]p/q+[1\over2]\rfloor$, if the
// operands are positive. \ (This procedure is not used especially often,
// so it is not part of \MF's inner loop.)
func (prg *prg) makeScaled(p, q int32) (r scaled) {
	var (
		f         int32 // the fraction bits, with a leading 1 bit
		n         int32 // the integer part of $\vert p/q\vert$
		negative  bool  // should the result be negated?
		beCareful int32 // disables certain compiler optimizations
	)
	if p >= 0 {
		negative = false
	} else {
		p = -p
		negative = true
	}
	if q <= 0 {
		q = -q
		negative = !negative
	}
	n = p / q
	p = p % q
	if n >= 0100000 {
		prg.arithError = true
		if negative {
			r = -017777777777
		} else {
			r = 017777777777
		}
	} else {
		n = (n - 1) * 0200000

		// Compute $f=\lfloor 2^[16](1+p/q)+[1\over2]\rfloor$
		f = 1
		for {
			beCareful = p - q
			p = beCareful + p
			if p >= 0 {
				f = f + f + 1
			} else {
				f = f + f
				p = p + q
			}
			if f >= 0200000 {
				break
			}
		}
		beCareful = p - q
		if beCareful+p >= 0 {
			f = f + 1
		}
		if negative {
			r = -(f + n)
		} else {
			r = f + n
		}
	}
	return r
}

// 116.

// tangle:pos ../../mf.web:2418:3:

// Here is a typical example of how the routines above can be used.
// It computes the function
// $$[1\over3\tau]f(\theta,\phi)=
// [\tau^[-1]\bigl(2+\sqrt2\,(\sin\theta-[1\over16]\sin\phi)
//  (\sin\phi-[1\over16]\sin\theta)(\cos\theta-\cos\phi)\bigr)\over
// 3\,\bigl(1+[1\over2](\sqrt5-1)\cos\theta+[1\over2](3-\sqrt5\,)\cos\phi\bigr)],$$
// where $\tau$ is a |scaled| ``tension'' parameter. This is \MF's magic
// fudge factor for placing the first control point of a curve that starts
// at an angle $\theta$ and ends at an angle $\phi$ from the straight path.
// (Actually, if the stated quantity exceeds 4, \MF\ reduces it to~4.)
//
// The trigonometric quantity to be multiplied by $\sqrt2$ is less than $\sqrt2$.
// (It's a sum of eight terms whose absolute values can be bounded using
// relations such as $\sin\theta\cos\theta\L[1\over2]$.) Thus the numerator
// is positive; and since the tension $\tau$ is constrained to be at least
// $3\over4$, the numerator is less than $16\over3$. The denominator is
// nonnegative and at most~6.  Hence the fixed-point calculations below
// are guaranteed to stay within the bounds of a 32-bit computer word.
//
// The angles $\theta$ and $\phi$ are given implicitly in terms of |fraction|
// arguments |st|, |ct|, |sf|, and |cf|, representing $\sin\theta$, $\cos\theta$,
// $\sin\phi$, and $\cos\phi$, respectively.
func (prg *prg) velocity(st, ct, sf, cf fraction, t scaled) (r fraction) {
	var (
		acc, num, denom int32 // registers for intermediate calculations
	)
	acc = prg.takeFraction(st-sf/16, sf-st/16)
	acc = prg.takeFraction(acc, ct-cf)
	num = 04000000000 + prg.takeFraction(acc, fraction(379625062))
	// $2^[28]\sqrt2\approx379625062.497$
	denom = 06000000000 + prg.takeFraction(ct, fraction(497706707)) + prg.takeFraction(cf, fraction(307599661))
	// $3\cdot2^[27]\cdot(\sqrt5-1)\approx497706706.78$ and
	//     $3\cdot2^[27]\cdot(3-\sqrt5\,)\approx307599661.22$

	if t != 0200000 {
		num = prg.makeScaled(num, t)
	}
	// |make_scaled(fraction,scaled)=fraction|
	if num/4 >= denom {
		r = 010000000000
	} else {
		r = prg.makeFraction(num, denom)
	}
	return r
}

// 117.

// tangle:pos ../../mf.web:2456:3:

// The following somewhat different subroutine tests rigorously if $ab$ is
// greater than, equal to, or less than~$cd$,
// given integers $(a,b,c,d)$. In most cases a quick decision is reached.
// The result is $+1$, 0, or~$-1$ in the three respective cases.
func (prg *prg) abVsCd(a, b, c, d int32) (r int32) {
	var (
		q, r1 int32 // temporary registers
	)
	if a < 0 {
		a = -a
		b = -b
	}
	if c < 0 {
		c = -c
		d = -d
	}
	if d <= 0 {
		if b >= 0 {
			if (a == 0 || b == 0) && (c == 0 || d == 0) {
				r = 0
				goto exit
			} else {
				r = 1
				goto exit
			}
		}
		if d == 0 {
			if a == 0 {
				r = 0
				goto exit
			} else {
				r = -1
				goto exit
			}
		}
		q = a
		a = c
		c = q
		q = -b
		b = -d
		d = q
	} else if b <= 0 {
		if b < 0 {
			if a > 0 {
				r = -1
				goto exit
			}
		}
		if c == 0 {
			r = 0
			goto exit
		} else {
			r = -1
			goto exit
		}
	}
	for true {
		q = a / d
		r1 = c / b
		if q != r1 {
			if q > r1 {
				r = 1
				goto exit
			} else {
				r = -1
				goto exit
			}
		}
		q = a % d
		r1 = c % b
		if r1 == 0 {
			if q == 0 {
				r = 0
				goto exit
			} else {
				r = 1
				goto exit
			}
		}
		if q == 0 {
			r = -1
			goto exit
		}
		a = b
		b = q
		c = d
		d = r1
	} // now |a>d>0| and |c>b>0|
	// now |a>d>0| and |c>b>0|
exit:
	;
	return r
}

// 119.

// tangle:pos ../../mf.web:2499:3:

// We conclude this set of elementary routines with some simple rounding
// and truncation operations that are coded in a machine-independent fashion.
// The routines are slightly complicated because we want them to work
// without overflow whenever $-2^[31]\L x<2^[31]$.
func (prg *prg) floorScaled(x scaled) (r scaled) {
	// $2^[16]\lfloor x/2^[16]\rfloor$
	var (
		beCareful int32 // temporary register
	)
	if x >= 0 {
		r = x - x%0200000
	} else {
		beCareful = x + 1
		r = x + -beCareful%0200000 + 1 - 0200000
	}
	return r
}

func (prg *prg) floorUnscaled(x scaled) (r int32) {
	// $\lfloor x/2^[16]\rfloor$
	var (
		beCareful int32 // temporary register
	)
	if x >= 0 {
		r = x / 0200000
	} else {
		beCareful = x + 1
		r = -(1 + -beCareful/0200000)
	}
	return r
}

func (prg *prg) roundUnscaled(x scaled) (r int32) {
	// $\lfloor x/2^[16]+.5\rfloor$
	var (
		beCareful int32 // temporary register
	)
	if x >= 0100000 {
		r = 1 + (x-0100000)/0200000
	} else if x >= -0100000 {
		r = 0
	} else {
		beCareful = x + 1
		r = -(1 + (-beCareful-0100000)/0200000)
	}
	return r
}

func (prg *prg) roundFraction(x fraction) (r scaled) {
	// $\lfloor x/2^[12]+.5\rfloor$
	var (
		beCareful int32 // temporary register
	)
	if x >= 2048 {
		r = 1 + (x-2048)/4096
	} else if x >= -2048 {
		r = 0
	} else {
		beCareful = x + 1
		r = -(1 + (-beCareful-2048)/4096)
	}
	return r
}

// 120. \[8] Algebraic and transcendental functions

// tangle:pos ../../mf.web:2541:48:

// \MF\ computes all of the necessary special functions from scratch, without
// relying on |real| arithmetic or system subroutines for sines, cosines, etc.

// 121.

// tangle:pos ../../mf.web:2545:3:

// To get the square root of a |scaled| number |x|, we want to calculate
// $s=\lfloor 2^8\!\sqrt x +[1\over2]\rfloor$. If $x>0$, this is the unique
// integer such that $2^[16]x-s\L s^2<2^[16]x+s$. The following subroutine
// determines $s$ by an iterative method that maintains the invariant
// relations $x=2^[46-2k]x_0\bmod 2^[30]$, $0<y=\lfloor 2^[16-2k]x_0\rfloor
// -s^2+s\L q=2s$, where $x_0$ is the initial value of $x$. The value of~$y$
// might, however, be zero at the start of the first iteration.
func (prg *prg) squareRt(x scaled) (r scaled) {
	var (
		k    smallNumber // iteration control counter
		y, q int32       // registers for intermediate calculations
	)
	if x <= 0 {
		if x < 0 {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Square root of " */ 306) /* \xref[!\relax]  */
			}
			// \xref[Square root...replaced by 0]
			prg.printScaled(x)
			prg.print( /* " has been replaced by 0" */ 307)
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "Since I don't take square roots of negative numbers," */ 308
				prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
			}
			prg.error1()
		}
		r = 0
	} else {
		k = 23
		q = 2
		for x < 04000000000 { // i.e., |while x<$2^[29]$|\unskip
			k = byte(int32(k) - 1)
			x = x + x + x + x
		}
		if x < 010000000000 {
			y = 0
		} else {
			x = x - 010000000000
			y = 1
		}
		for {
			// Decrease |k| by 1, maintaining the invariant relations between |x|, |y|, and~|q|
			x = x + x
			y = y + y
			if x >= 010000000000 {
				x = x - 010000000000
				y = y + 1
			}
			x = x + x
			y = y + y - q
			q = q + q
			if x >= 010000000000 {
				x = x - 010000000000
				y = y + 1
			}
			if y > q {
				y = y - q
				q = q + 2
			} else if y <= 0 {
				q = q - 2
				y = y + q
			}
			k = byte(int32(k) - 1)
			if int32(k) == 0 {
				break
			}
		}
		r = q / 2
	}
	return r
}

// 124.

// tangle:pos ../../mf.web:2600:3:

// Pythagorean addition $\psqrt[a^2+b^2]$ is implemented by an elegant
// iterative scheme due to Cleve Moler and Donald Morrison [[\sl IBM Journal
// \xref[Moler, Cleve Barry]
// \xref[Morrison, Donald Ross]
// of Research and Development\/ \bf27] (1983), 577--581]. It modifies |a| and~|b|
// in such a way that their Pythagorean sum remains invariant, while the
// smaller argument decreases.
func (prg *prg) pythAdd(a, b int32) (r int32) {
	var (
		r1  fraction // register used to transform |a| and |b|
		big bool     // is the result dangerously near $2^[31]$?
	)
	a = abs(a)
	b = abs(b)
	if a < b {
		r1 = b
		b = a
		a = r1
	} // now |0<=b<=a|
	if b > 0 {
		if a < 04000000000 {
			big = false
		} else {
			a = a / 4
			b = b / 4
			big = true
		} // we reduced the precision to avoid arithmetic overflow

		// Replace |a| by an approximation to $\psqrt[a^2+b^2]$
		for true {
			r1 = prg.makeFraction(b, a)
			r1 = prg.takeFraction(r1, r1) // now $r\approx b^2/a^2$
			if r1 == 0 {
				goto done
			}
			r1 = prg.makeFraction(r1, 010000000000+r1)
			a = a + prg.takeFraction(a+a, r1)
			b = prg.takeFraction(b, r1)
		}

	done:
		;
		if big {
			if a < 04000000000 {
				a = a + a + a + a
			} else {
				prg.arithError = true
				a = 017777777777
			}
		}
	}
	r = a
	return r
}

// 126.

// tangle:pos ../../mf.web:2641:3:

// Here is a similar algorithm for $\psqrt[a^2-b^2]$.
// It converges slowly when $b$ is near $a$, but otherwise it works fine.
func (prg *prg) pythSub(a, b int32) (r int32) {
	var (
		r1  fraction // register used to transform |a| and |b|
		big bool     // is the input dangerously near $2^[31]$?
	)
	a = abs(a)
	b = abs(b)
	if a <= b {
		if a < b {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Pythagorean subtraction " */ 310) /* \xref[!\relax]  */
			}
			prg.printScaled(a)
			prg.print( /* "+-+" */ 311)
			prg.printScaled(b)
			prg.print( /* " has been replaced by 0" */ 307)
			// \xref[Pythagorean...]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "Since I don't take square roots of negative numbers," */ 308
				prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
			}
			prg.error1()
		}
		a = 0
	} else {
		if a < 010000000000 {
			big = false
		} else {
			a = a / 2
			b = b / 2
			big = true
		}

		// Replace |a| by an approximation to $\psqrt[a^2-b^2]$
		for true {
			r1 = prg.makeFraction(b, a)
			r1 = prg.takeFraction(r1, r1) // now $r\approx b^2/a^2$
			if r1 == 0 {
				goto done
			}
			r1 = prg.makeFraction(r1, 010000000000-r1)
			a = a - prg.takeFraction(a+a, r1)
			b = prg.takeFraction(b, r1)
		}

	done:
		;
		if big {
			a = a + a
		}
	}
	r = a
	return r
}

// 132.

// tangle:pos ../../mf.web:2713:3:

// Here is the routine that calculates $2^8$ times the natural logarithm
// of a |scaled| quantity; it is an integer approximation to $2^[24]\ln(x/2^[16])$,
// when |x| is a given positive integer.
//
// The method is based on exercise 1.2.2--25 in [\sl The Art of Computer
// Programming\/]: During the main iteration we have $1\L 2^[-30]x<1/(1-2^[1-k])$,
// and the logarithm of $2^[30]x$ remains to be added to an accumulator
// register called~$y$. Three auxiliary bits of accuracy are retained in~$y$
// during the calculation, and sixteen auxiliary bits to extend |y| are
// kept in~|z| during the initial argument reduction. (We add
// $100\cdot2^[16]=6553600$ to~|z| and subtract 100 from~|y| so that |z| will
// not become negative; also, the actual amount subtracted from~|y| is~96,
// not~100, because we want to add~4 for rounding before the final division by~8.)
func (prg *prg) mLog(x scaled) (r scaled) {
	var (
		y, z int32 // auxiliary registers
		k    int32 // iteration counter
	)
	if x <= 0 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Logarithm of " */ 312) /* \xref[!\relax]  */
		}
		// \xref[Logarithm...replaced by 0]
		prg.printScaled(x)
		prg.print( /* " has been replaced by 0" */ 307)
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "Since I don't take logs of non-positive numbers," */ 313
			prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
		}
		prg.error1()
		r = 0
	} else {
		y = 1302456956 + 4 - 100 // $14\times2^[27]\ln2\approx1302456956.421063$
		z = 27595 + 6553600      // and $2^[16]\times .421063\approx 27595$
		for x < 010000000000 {
			x = x + x
			y = y - 93032639
			z = z - 48782
		} // $2^[27]\ln2\approx 93032639.74436163$
		//       and $2^[16]\times.74436163\approx 48782$

		y = y + z/0200000
		k = 2
		for x > 010000000000+4 {

			// Increase |k| until |x| can be multiplied by a factor of $2^[-k]$, and adjust $y$ accordingly
			z = (x-1)/prg.twoToThe[k] + 1 // $z=\lceil x/2^k\rceil$
			for x < 010000000000+z {
				z = (z + 1) / 2
				k = k + 1
			}
			y = y + prg.specLog[k-1]
			x = x - z
		}
		r = y / 8
	}
	return r
}

// 135.

// tangle:pos ../../mf.web:2762:3:

// Conversely, the exponential routine calculates $\exp(x/2^8)$,
// when |x| is |scaled|. The result is an integer approximation to
// $2^[16]\exp(x/2^[24])$, when |x| is regarded as an integer.
func (prg *prg) mExp(x scaled) (r scaled) {
	var (
		k    smallNumber // loop control index
		y, z int32       // auxiliary registers
	)
	if x > 174436200 {
		prg.arithError = true
		r = 017777777777
	} else if x < -197694359 {
		r = 0
	} else {
		if x <= 0 {
			z = -(8 * x)
			y = 04000000 // $y=2^[20]$
		} else {
			if x <= 127919879 {
				z = 1023359037 - 8*x
			} else {
				z = 8 * (174436200 - x)
			} // |z| is always nonnegative
			y = 017777777777
		}

		// Multiply |y| by $\exp(-z/2^[27])$
		k = 1
		for z > 0 {
			for z >= prg.specLog[k-1] {
				z = z - prg.specLog[k-1]
				y = y - 1 - (y-prg.twoToThe[int32(k)-1])/prg.twoToThe[k]
			}
			k = byte(int32(k) + 1)
		}
		if x <= 127919879 {
			r = (y + 8) / 16
		} else {
			r = y
		}
	}
	return r
}

// 139.

// tangle:pos ../../mf.web:2841:3:

// Given integers |x| and |y|, not both zero, the |n_arg| function
// returns the |angle| whose tangent points in the direction $(x,y)$.
// This subroutine first determines the correct octant, then solves the
// problem for |0<=y<=x|, then converts the result appropriately to
// return an answer in the range |-one_eighty_deg<=$\theta$<=one_eighty_deg|.
// (The answer is |+one_eighty_deg| if |y=0| and |x<0|, but an answer of
// |-one_eighty_deg| is possible if, for example, |y=-1| and $x=-2^[30]$.)
//
// The octants are represented in a ``Gray code,'' since that turns out
// to be computationally simplest.
func (prg *prg) nArg(x, y int32) (r angle) {
	var (
		z                                         angle       // auxiliary register
		t                                         int32       // temporary storage
		k                                         smallNumber // loop counter
		octant/* firstOctant..sixthOctant */ byte             // octant code
	)
	if x >= 0 {
		octant = byte(firstOctant)
	} else {
		x = -x
		octant = byte(firstOctant + negateX)
	}
	if y < 0 {
		y = -y
		octant = byte(int32(octant) + negateY)
	}
	if x < y {
		t = y
		y = x
		x = t
		octant = byte(int32(octant) + switchXAndY)
	}
	if x == 0 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "angle(0,0) is taken as zero" */ 314) /* \xref[!\relax]  */
		}
		// \xref[angle(0,0)...zero]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "The `angle' between two identical points is undefined." */ 315
			prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
		}
		prg.error1()
		r = 0
	} else {
		for x >= 04000000000 {
			x = x / 2
			y = y / 2
		}
		z = 0
		if y > 0 {
			for x < 02000000000 {
				x = x + x
				y = y + y
			}

			// Increase |z| to the arg of $(x,y)$
			k = 0
			for {
				y = y + y
				k = byte(int32(k) + 1)
				if y > x {
					z = z + prg.specAtan[k-1]
					t = x
					x = x + y/prg.twoToThe[int32(k)+int32(k)]
					y = y - t
				}
				if int32(k) == 15 {
					break
				}
			}
			for {
				y = y + y
				k = byte(int32(k) + 1)
				if y > x {
					z = z + prg.specAtan[k-1]
					y = y - x
				}
				if int32(k) == 26 {
					break
				}
			}
		}

		// Return an appropriate answer based on |z| and |octant|
		switch octant {
		case firstOctant:
			r = z
		case secondOctant:
			r = 0550000000 - z
		case thirdOctant:
			r = 0550000000 + z
		case fourthOctant:
			r = 01320000000 - z
		case fifthOctant:
			r = z - 01320000000
		case sixthOctant:
			r = -z - 0550000000
		case seventhOctant:
			r = z - 0550000000
		case eighthOctant:
			r = -z
		}
	}
	return r
}

// 145.

// tangle:pos ../../mf.web:2955:3:

// Given an integer |z| that is $2^[20]$ times an angle $\theta$ in degrees,
// the purpose of |n_sin_cos(z)| is to set
// |x=$r\cos\theta$| and |y=$r\sin\theta$| (approximately),
// for some rather large number~|r|. The maximum of |x| and |y|
// will be between $2^[28]$ and $2^[30]$, so that there will be hardly
// any loss of accuracy. Then |x| and~|y| are divided by~|r|.
func (prg *prg) nSinCos(z angle) { // computes a multiple of the sine and cosine
	var (
		k                smallNumber // loop control variable
		q/* 0..7 */ byte             // specifies the quadrant
		r1               fraction    // magnitude of |(x,y)|
		x, y, t          int32       // temporary registers
	)
	for z < 0 {
		z = z + 02640000000
	}
	z = z % 02640000000 // now |0<=z<three_sixty_deg|
	q = byte(z / 0264000000)
	z = z % 0264000000
	x = 02000000000
	y = x
	if !(q&1 != 0) {
		z = 0264000000 - z
	}

	// Subtract angle |z| from |(x,y)|
	k = 1
	for z > 0 {
		if z >= prg.specAtan[k-1] {
			z = z - prg.specAtan[k-1]
			t = x

			x = t + y/prg.twoToThe[k]
			y = y - t/prg.twoToThe[k]
		}
		k = byte(int32(k) + 1)
	}
	if y < 0 {
		y = 0
	}

	// Convert |(x,y)| to the octant determined by~|q|
	switch q {
	case 0:
	case 1:
		t = x
		x = y
		y = t

	case 2:
		t = x
		x = -y
		y = t

	case 3:
		x = -x
	case 4:
		x = -x
		y = -y

	case 5:
		t = x
		x = -y
		y = -t

	case 6:
		t = x
		x = y
		y = -t

	case 7:
		y = -y
	}
	r1 = prg.pythAdd(x, y)
	prg.nCos = prg.makeFraction(x, r1)
	prg.nSin = prg.makeFraction(y, r1)
}

// 149.

// tangle:pos ../../mf.web:3029:3:

// To consume a random fraction, the program below will say `|next_random|'
// and then it will fetch |randoms[j_random]|. The |next_random| macro
// actually accesses the numbers backwards; blocks of 55~$x$'s are
// essentially being ``flipped.'' But that doesn't make them less random.
func (prg *prg) newRandoms() {
	var (
		k/* 0..54 */ byte          // index into |randoms|
		x                 fraction // accumulator
	)
	for ii := int32(0); ii <= 23; ii++ {
		k = byte(ii)
		_ = k
		x = prg.randoms[k] - prg.randoms[int32(k)+31]
		if x < 0 {
			x = x + 02000000000
		}
		prg.randoms[k] = x
	}
	for ii := int32(24); ii <= 54; ii++ {
		k = byte(ii)
		_ = k
		x = prg.randoms[k] - prg.randoms[int32(k)-24]
		if x < 0 {
			x = x + 02000000000
		}
		prg.randoms[k] = x
	}
	prg.jRandom = 54
}

// 150.

// tangle:pos ../../mf.web:3053:3:

// To initialize the |randoms| table, we call the following routine.
func (prg *prg) initRandoms(seed scaled) {
	var (
		j, jj, k          fraction // more or less random integers
		i/* 0..54 */ byte          // index into |randoms|
	)
	j = abs(seed)
	for j >= 02000000000 {
		j = j / 2
	}
	k = 1
	for ii := int32(0); ii <= 54; ii++ {
		i = byte(ii)
		_ = i
		jj = k
		k = j - k
		j = jj
		if k < 0 {
			k = k + 02000000000
		}
		prg.randoms[int32(i)*21%55] = j
	}
	prg.newRandoms()
	prg.newRandoms()
	prg.newRandoms() // ``warm up'' the array
}

// 151.

// tangle:pos ../../mf.web:3069:3:

// To produce a uniform random number in the range |0<=u<x| or |0>=u>x|
// or |0=u=x|, given a |scaled| value~|x|, we proceed as shown here.
//
// Note that the call of |take_fraction| will produce the values 0 and~|x|
// with about half the probability that it will produce any other particular
// values between 0 and~|x|, because it rounds its answers.
func (prg *prg) unifRand(x scaled) (r scaled) {
	var (
		y scaled // trial value
	)
	if int32(prg.jRandom) == 0 {
		prg.newRandoms()
	} else {
		prg.jRandom = byte(int32(prg.jRandom) - 1)
	}
	y = prg.takeFraction(abs(x), prg.randoms[prg.jRandom])
	if y == abs(x) {
		r = 0
	} else if x > 0 {
		r = y
	} else {
		r = -y
	}
	return r
}

// 152.

// tangle:pos ../../mf.web:3084:3:

// Finally, a normal deviate with mean zero and unit standard deviation
// can readily be obtained with the ratio method (Algorithm 3.4.1R in
// [\sl The Art of Computer Programming\/]).
func (prg *prg) normRand() (r scaled) {
	var (
		x, u, l int32 // what the book would call $2^[16]X$, $2^[28]U$,
	// and $-2^[24]\ln U$
	)
	for {
		for {
			if int32(prg.jRandom) == 0 {
				prg.newRandoms()
			} else {
				prg.jRandom = byte(int32(prg.jRandom) - 1)
			}
			x = prg.takeFraction(112429, prg.randoms[prg.jRandom]-01000000000)
			// $2^[16]\sqrt[8/e]\approx 112428.82793$
			if int32(prg.jRandom) == 0 {
				prg.newRandoms()
			} else {
				prg.jRandom = byte(int32(prg.jRandom) - 1)
			}
			u = prg.randoms[prg.jRandom]
			if abs(x) < u {
				break
			}
		}
		x = prg.makeFraction(x, u)
		l = 139548960 - prg.mLog(u) // $2^[24]\cdot12\ln2\approx139548959.6165$
		if prg.abVsCd(1024, l, x, x) >= 0 {
			break
		}
	}
	r = x
	return r
} // \2

func (prg *prg) showTokenList(p, q int32, l, nullTally int32) {
	var (
		class, c smallNumber // the |char_class| of previous and new tokens
		r1, v    int32       // temporary registers
	)
	class = byte(percentClass)
	prg.tally = nullTally
	for p != memMin && prg.tally < l {
		if p == q {
			prg.firstCount = prg.tally
			prg.trickCount = prg.tally + 1 + errorLine - halfErrorLine
			if prg.trickCount < errorLine {
				prg.trickCount = errorLine
			}
		}

		// Display token |p| and set |c| to its class; but |return| if there are problems
		c = byte(letterClass) // the default
		if p < memMin || p > int32(prg.memEnd) {
			prg.print( /* " CLOBBERED" */ 493)
			goto exit
			// \xref[CLOBBERED]
		}
		if p < int32(prg.hiMemMin) {
			if int32(*(*prg.mem[p].hh()).b1()) == token {
				if int32(*(*prg.mem[p].hh()).b0()) == known {
					if int32(class) == digitClass {
						prg.printChar(asciiCode(' '))
					}
					v = *prg.mem[p+1].int()
					if v < 0 {
						if int32(class) == leftBracketClass {
							prg.printChar(asciiCode(' '))
						}
						prg.printChar(asciiCode('['))
						prg.printScaled(v)
						prg.printChar(asciiCode(']'))
						c = byte(rightBracketClass)
					} else {
						prg.printScaled(v)
						c = byte(digitClass)
					}
				} else if int32(*(*prg.mem[p].hh()).b0()) != stringType {
					prg.print( /* " BAD" */ 496)
				} else {
					prg.printChar(asciiCode('"'))
					prg.slowPrint(*prg.mem[p+1].int())
					prg.printChar(asciiCode('"'))
					c = byte(stringClass)
				}
			} else if int32(*(*prg.mem[p].hh()).b1()) != capsule || int32(*(*prg.mem[p].hh()).b0()) < vacuous || int32(*(*prg.mem[p].hh()).b0()) > independent {
				prg.print( /* " BAD" */ 496)
			} else {
				prg.gPointer = uint16(p)
				prg.printCapsule()
				c = byte(rightParenClass)
			}
		} else {
			r1 = int32(*(*prg.mem[p].hh()).lh())
			if r1 >= hashBase+hashSize+12+1 {
				if r1 < hashBase+hashSize+12+1+paramSize {
					prg.print( /* "(EXPR" */ 498)
					r1 = r1 - (hashBase + hashSize + 12 + 1)
					// \xref[EXPR]
				} else if r1 < hashBase+hashSize+12+1+paramSize+paramSize {
					prg.print( /* "(SUFFIX" */ 499)
					r1 = r1 - (hashBase + hashSize + 12 + 1 + paramSize)
					// \xref[SUFFIX]
				} else {
					prg.print( /* "(TEXT" */ 500)
					r1 = r1 - (hashBase + hashSize + 12 + 1 + paramSize + paramSize)
					// \xref[TEXT]
				}
				prg.printInt(r1)
				prg.printChar(asciiCode(')'))
				c = byte(rightParenClass)
			} else if r1 < 1 {
				if r1 == 0 {
					if int32(class) == leftBracketClass {
						prg.printChar(asciiCode(' '))
					}
					prg.print( /* "[]" */ 497)
					c = byte(rightBracketClass)
				} else {
					prg.print( /* " IMPOSSIBLE" */ 494)
				}
			} else {
				r1 = int32(*prg.hash[r1-1].rh())
				if r1 < 0 || r1 >= int32(prg.strPtr) {
					prg.print( /* " NONEXISTENT" */ 495)
				} else {
					// Print string |r| as a symbolic token and set |c| to its class
					c = prg.charClass[prg.strPool[prg.strStart[r1]]]
					if int32(c) == int32(class) {
						switch c {
						case letterClass:
							prg.printChar(asciiCode('.'))
						case 5, 6, 7, 8:

						default:
							prg.printChar(asciiCode(' '))
						}
					}
					prg.slowPrint(r1)
				}
			}
		}
		class = c
		p = int32(*(*prg.mem[p].hh()).rh())
	}
	if p != memMin {
		prg.print( /* " ETC." */ 492)
	}
	// \xref[ETC]

	// \xref[ETC]
exit:
}

// \4
// Declare the procedure called |runaway|
func (prg *prg) runaway() {
	if int32(prg.scannerStatus) > flushing {
		prg.printNl(strNumber( /* "Runaway " */ 637))
		switch prg.scannerStatus {
		case absorbing:
			prg.print( /* "text?" */ 638)
		case varDefining, opDefining:
			prg.print( /* "definition?" */ 639)
		case loopDefining:
			prg.print( /* "loop?" */ 640)
		} // there are no other cases
		prg.printLn()
		prg.showTokenList(int32(*(*prg.mem[3000-2].hh()).rh()), memMin, errorLine-10, 0)
	}
}

// 163.

// tangle:pos ../../mf.web:3304:3:

// The function |get_avail| returns a pointer to a new one-word node whose
// |link| field is null. However, \MF\ will halt if there is no more room left.
// \xref[inner loop]
func (prg *prg) getAvail() (r halfword) { // single-word node allocation
	var (
		p halfword // the new node being got
	)
	p = prg.avail // get top location in the |avail| stack
	if int32(p) != memMin {
		prg.avail = *(*prg.mem[prg.avail].hh()).rh()
	} else if int32(prg.memEnd) < memMax {
		prg.memEnd = uint16(int32(prg.memEnd) + 1)
		p = prg.memEnd
	} else {
		prg.hiMemMin = uint16(int32(prg.hiMemMin) - 1)
		p = prg.hiMemMin
		if int32(prg.hiMemMin) <= int32(prg.loMemMax) {
			prg.runaway() // if memory is exhausted, display possible runaway text
			prg.overflow(strNumber( /* "main memory size" */ 316), memMax+1-memMin)
			// quit; all one-word nodes are busy
			// \xref[METAFONT capacity exceeded main memory size][\quad main memory size]
		}
	}
	*(*prg.mem[p].hh()).rh() = uint16(memMin) // provide an oft-desired initialization of the new node
	prg.dynUsed = prg.dynUsed + 1             // maintain statistics
	r = p
	return r
}

// 164.

// tangle:pos ../../mf.web:3328:3:

// Conversely, a one-word node is recycled by calling |free_avail|.

// 165.

// tangle:pos ../../mf.web:3335:3:

// There's also a |fast_get_avail| routine, which saves the procedure-call
// overhead at the expense of extra programming. This macro is used in
// the places that would otherwise account for the most calls of |get_avail|.
// \xref[inner loop]

// 167.

// tangle:pos ../../mf.web:3373:3:

// A call to |get_node| with argument |s| returns a pointer to a new node
// of size~|s|, which must be 2~or more. The |link| field of the first word
// of this new node is set to null. An overflow stop occurs if no suitable
// space exists.
//
// If |get_node| is called with $s=2^[30]$, it simply merges adjacent free
// areas and returns the value |max_halfword|.
func (prg *prg) getNode(s int32) (r halfword) {
	var (
		p     halfword // the node currently under inspection
		q     halfword // the node physically after node |p|
		r1    int32    // the newly allocated node, or a candidate for this honor
		t, tt int32    // temporary registers
	// \xref[inner loop]
	)
restart:
	p = prg.rover // start at some free node in the ring
	for {
		// Try to allocate within node |p| and its physical successors, and |goto found| if allocation was possible
		q = uint16(int32(p) + int32(*(*prg.mem[p].hh()).lh())) // find the physical successor
		for int32(*(*prg.mem[q].hh()).rh()) == 65535 {         // merge node |p| with node |q|
			t = int32(*(*prg.mem[int32(q)+1].hh()).rh())
			tt = int32(*(*prg.mem[int32(q)+1].hh()).lh())
			// \xref[inner loop]
			if int32(q) == int32(prg.rover) {
				prg.rover = uint16(t)
			}
			*(*prg.mem[t+1].hh()).lh() = uint16(tt)
			*(*prg.mem[tt+1].hh()).rh() = uint16(t)

			q = uint16(int32(q) + int32(*(*prg.mem[q].hh()).lh()))
		}
		r1 = int32(q) - s
		if r1 > int32(p)+1 {
			*(*prg.mem[p].hh()).lh() = uint16(r1 - int32(p)) // store the remaining size
			prg.rover = p                                    // start searching here next time
			// start searching here next time
			goto found
		}
		if r1 == int32(p) {
			if int32(*(*prg.mem[int32(p)+1].hh()).rh()) != int32(p) {
				prg.rover = *(*prg.mem[int32(p)+1].hh()).rh()
				t = int32(*(*prg.mem[int32(p)+1].hh()).lh())
				*(*prg.mem[int32(prg.rover)+1].hh()).lh() = uint16(t)
				*(*prg.mem[t+1].hh()).rh() = prg.rover

				goto found
			}
		}
		*(*prg.mem[p].hh()).lh() = uint16(int32(q) - int32(p))
		p = *(*prg.mem[int32(p)+1].hh()).rh() // move to the next node in the ring
		if int32(p) == int32(prg.rover) {
			break
		}
	} // repeat until the whole list has been traversed
	if s == 010000000000 {
		r = 65535
		goto exit
	}
	if int32(prg.loMemMax)+2 < int32(prg.hiMemMin) {
		if int32(prg.loMemMax)+2 <= memMin+65535 {
			if int32(prg.hiMemMin)-int32(prg.loMemMax) >= 1998 {
				t = int32(prg.loMemMax) + 1000
			} else {
				t = int32(prg.loMemMax) + 1 + (int32(prg.hiMemMin)-int32(prg.loMemMax))/2
			}
			// |lo_mem_max+2<=t<hi_mem_min|
			if t > memMin+65535 {
				t = memMin + 65535
			}
			p = *(*prg.mem[int32(prg.rover)+1].hh()).lh()
			q = prg.loMemMax
			*(*prg.mem[int32(p)+1].hh()).rh() = q
			*(*prg.mem[int32(prg.rover)+1].hh()).lh() = q

			*(*prg.mem[int32(q)+1].hh()).rh() = prg.rover
			*(*prg.mem[int32(q)+1].hh()).lh() = p
			*(*prg.mem[q].hh()).rh() = 65535
			*(*prg.mem[q].hh()).lh() = uint16(t - int32(prg.loMemMax))

			prg.loMemMax = uint16(t)
			*(*prg.mem[prg.loMemMax].hh()).rh() = uint16(memMin)
			*(*prg.mem[prg.loMemMax].hh()).lh() = uint16(memMin)
			prg.rover = q
			goto restart
		}
	}
	prg.overflow(strNumber( /* "main memory size" */ 316), memMax+1-memMin)
	// sorry, nothing satisfactory is left
	// \xref[METAFONT capacity exceeded main memory size][\quad main memory size]

	// sorry, nothing satisfactory is left
	// \xref[METAFONT capacity exceeded main memory size][\quad main memory size]
found:
	*(*prg.mem[r1].hh()).rh() = uint16(memMin) // this node is now nonempty
	prg.varUsed = prg.varUsed + s              // maintain usage statistics

	r = uint16(r1)

exit:
	;
	return r
}

// 172.

// tangle:pos ../../mf.web:3454:3:

// Conversely, when some variable-size node |p| of size |s| is no longer needed,
// the operation |free_node(p,s)| will make its words available, by inserting
// |p| as a new empty node just before where |rover| now points.
func (prg *prg) freeNode(p halfword, s halfword) { // variable-size node
	//   liberation

	var (
		q halfword // |llink(rover)|
	)
	*(*prg.mem[p].hh()).lh() = s
	*(*prg.mem[p].hh()).rh() = 65535
	// \xref[inner loop]
	q = *(*prg.mem[int32(prg.rover)+1].hh()).lh()
	*(*prg.mem[int32(p)+1].hh()).lh() = q
	*(*prg.mem[int32(p)+1].hh()).rh() = prg.rover // set both links
	*(*prg.mem[int32(prg.rover)+1].hh()).lh() = p
	*(*prg.mem[int32(q)+1].hh()).rh() = p // insert |p| into the ring
	prg.varUsed = prg.varUsed - int32(s)  // maintain statistics
}

// 173.

// tangle:pos ../../mf.web:3468:3:

// Just before \.[INIMF] writes out the memory, it sorts the doubly linked
// available space list. The list is probably very short at such times, so a
// simple insertion sort is used. The smallest available location will be
// pointed to by |rover|, the next-smallest by |rlink(rover)|, etc.
func (prg *prg) sortAvail() { // sorts the available variable-size nodes
	//   by location

	var (
		p, q, r1 halfword // indices into |mem|
		oldRover halfword // initial |rover| setting
	)
	p = prg.getNode(010000000000) // merge adjacent free areas
	p = *(*prg.mem[int32(prg.rover)+1].hh()).rh()
	*(*prg.mem[int32(prg.rover)+1].hh()).rh() = 65535
	oldRover = prg.rover
	for int32(p) != int32(oldRover) {
		// Sort |p| into the list starting at |rover| and advance |p| to |rlink(p)|
		if int32(p) < int32(prg.rover) {
			q = p
			p = *(*prg.mem[int32(q)+1].hh()).rh()
			*(*prg.mem[int32(q)+1].hh()).rh() = prg.rover
			prg.rover = q
		} else {
			q = prg.rover
			for int32(*(*prg.mem[int32(q)+1].hh()).rh()) < int32(p) {
				q = *(*prg.mem[int32(q)+1].hh()).rh()
			}
			r1 = *(*prg.mem[int32(p)+1].hh()).rh()
			*(*prg.mem[int32(p)+1].hh()).rh() = *(*prg.mem[int32(q)+1].hh()).rh()
			*(*prg.mem[int32(q)+1].hh()).rh() = p
			p = r1
		}
	}
	p = prg.rover
	for int32(*(*prg.mem[int32(p)+1].hh()).rh()) != 65535 {
		*(*prg.mem[int32(*(*prg.mem[int32(p)+1].hh()).rh())+1].hh()).lh() = p
		p = *(*prg.mem[int32(p)+1].hh()).rh()
	}
	*(*prg.mem[int32(p)+1].hh()).rh() = prg.rover
	*(*prg.mem[int32(prg.rover)+1].hh()).lh() = p
}

// 175. \[11] Memory layout

// tangle:pos ../../mf.web:3502:24:

// Some areas of |mem| are dedicated to fixed usage, since static allocation is
// more efficient than dynamic allocation when we can get away with it. For
// example, locations |mem_min| to |mem_min+2| are always used to store the
// specification for null pen coordinates that are `$(0,0)$'. The
// following macro definitions accomplish the static allocation by giving
// symbolic names to the fixed positions. Static variable-size nodes appear
// in locations |mem_min| through |lo_mem_stat_max|, and static single-word nodes
// appear in locations |hi_mem_stat_min| through |mem_top|, inclusive.

// 177.

// tangle:pos ../../mf.web:3545:3:

// The procedure |flush_list(p)| frees an entire linked list of one-word
// nodes that starts at a given position, until coming to |sentinel| or a
// pointer that is not in the one-word region. Another procedure,
// |flush_node_list|, frees an entire linked list of one-word and two-word
// nodes, until coming to a |null| pointer.
// \xref[inner loop]
func (prg *prg) flushList(p halfword) {
	var (
		q, r1 halfword // list traversers
	)
	if int32(p) >= int32(prg.hiMemMin) {
		if int32(p) != 3000 {
			r1 = p
			for {
				q = r1
				r1 = *(*prg.mem[r1].hh()).rh()
				prg.dynUsed = prg.dynUsed - 1

				if int32(r1) < int32(prg.hiMemMin) {
					goto done
				}
				if int32(r1) == 3000 {
					break
				}
			}

		done:
			*(*prg.mem[q].hh()).rh() = prg.avail
			prg.avail = p
		}
	}
}

func (prg *prg) flushNodeList(p halfword) {
	var (
		q halfword // the node being recycled
	)
	for int32(p) != memMin {
		q = p
		p = *(*prg.mem[p].hh()).rh()
		if int32(q) < int32(prg.hiMemMin) {
			prg.freeNode(q, halfword(2))
		} else {
			*(*prg.mem[q].hh()).rh() = prg.avail
			prg.avail = q
			prg.dynUsed = prg.dynUsed - 1
		}
	}
}

// 180.

// tangle:pos ../../mf.web:3599:3:

// Procedure |check_mem| makes sure that the available space lists of
// |mem| are well formed, and it optionally prints out all locations
// that are reserved now but were free the last time this procedure was called.
//  procedure check_mem( print_locs : boolean);
// label done1,done2; [loop exits]
// var  p, q, r:halfword ; [current locations of interest in |mem|]
//  clobbered:boolean; [is something amiss?]
// begin for p:=mem_min to lo_mem_max do free[p]:=false; [you can probably
//   do this faster]
// for p:=hi_mem_min to mem_end do free[p]:=false; [ditto]
//
// [ Check single-word |avail| list ]
// p:=avail; q:=mem_min ; clobbered:=false;
// while p<>mem_min  do
//   begin if (p>mem_end)or(p<hi_mem_min) then clobbered:=true
//   else if free[p] then clobbered:=true;
//   if clobbered then
//     begin print_nl(["AVAIL list clobbered at "=]317);
// [ \xref[AVAIL list clobbered...] ]
//     print_int(q); goto done1;
//     end;
//   free[p]:=true; q:=p; p:= mem[ q].hh.rh ;
//   end;
// done1:
//
// ;
//
// [ Check variable-size |avail| list ]
// p:=rover; q:=mem_min ; clobbered:=false;
// repeat if (p>=lo_mem_max)or(p<mem_min) then clobbered:=true
//   else if (  mem[  p+ 1].hh.rh  >=lo_mem_max)or(  mem[  p+ 1].hh.rh  <mem_min) then clobbered:=true
//   else if  not( ( mem[  p].hh.rh = 65535  ) )or(  mem[ p].hh.lh <2)or
//    (p+  mem[ p].hh.lh >lo_mem_max)or  (  mem[    mem[    p+ 1].hh.rh  + 1].hh.lh  <>p) then clobbered:=true;
//   if clobbered then
//   begin print_nl(["Double-AVAIL list clobbered at "=]318);
// [ \xref[Double-AVAIL list clobbered...] ]
//   print_int(q); goto done2;
//   end;
// for q:=p to p+  mem[ p].hh.lh -1 do [mark all locations free]
//   begin if free[q] then
//     begin print_nl(["Doubly free location at "=]319);
// [ \xref[Doubly free location...] ]
//     print_int(q); goto done2;
//     end;
//   free[q]:=true;
//   end;
// q:=p; p:=  mem[  p+ 1].hh.rh  ;
// until p=rover;
// done2:
//
// ;
//
// [ Check flags of unavailable nodes ]
// p:=mem_min;
// while p<=lo_mem_max do [node |p| should not be empty]
//   begin if  ( mem[  p].hh.rh = 65535  )  then
//     begin print_nl(["Bad flag at "=]320); print_int(p);
// [ \xref[Bad flag...] ]
//     end;
//   while (p<=lo_mem_max) and not free[p] do   p:= p+1 ;
//   while (p<=lo_mem_max) and free[p] do   p:= p+1 ;
//   end
//
// ;
//
// [ Check the list of linear dependencies ]
// q:=mem_min +3 +10 ; p:= mem[ q].hh.rh ;
// while p<>mem_min +3 +10  do
//   begin if  mem[    p+1 ].hh.lh  <>q then
//     begin print_nl(["Bad PREVDEP at "=]597); print_int(p);
// [ \xref[Bad PREVDEP...] ]
//     end;
//   p:= mem[    p+1 ].hh.rh  ; r:=mem_min +3 +10 +2 +2  +2 ;
//   repeat if mem[   mem[   p].hh.lh +1 ].int >=mem[  r+1 ].int  then
//     begin print_nl(["Out of order at "=]598); print_int(p);
// [ \xref[Out of order...] ]
//     end;
//   r:= mem[ p].hh.lh ; q:=p; p:= mem[ q].hh.rh ;
//   until r=mem_min ;
//   end
//
// ;
// if print_locs then
// [ Print newly busy locations ]
// begin print_nl(["New busy locs:"=]321);
// [ \xref[New busy locs] ]
// for p:=mem_min to lo_mem_max do
//   if not free[p] and ((p>was_lo_max) or was_free[p]) then
//     begin print_char([" "=]32); print_int(p);
//     end;
// for p:=hi_mem_min to mem_end do
//   if not free[p] and
//    ((p<was_hi_min) or (p>was_mem_end) or was_free[p]) then
//     begin print_char([" "=]32); print_int(p);
//     end;
// end
//
// ;
// for p:=mem_min to lo_mem_max do was_free[p]:=free[p];
// for p:=hi_mem_min to mem_end do was_free[p]:=free[p];
//   [|was_free:=free| might be faster]
// was_mem_end:=mem_end; was_lo_max:=lo_mem_max; was_hi_min:=hi_mem_min;
// end;
// [  ]

// 185.

// tangle:pos ../../mf.web:3684:3:

// The |search_mem| procedure attempts to answer the question ``Who points
// to node~|p|?'' In doing so, it fetches |link| and |info| fields of |mem|
// that might not be of type |two_halves|. Strictly speaking, this is
// \xref[dirty \PASCAL]
// undefined in \PASCAL, and it can lead to ``false drops'' (words that seem to
// point to |p| purely by coincidence). But for debugging purposes, we want
// to rule out the places that do [\sl not\/] point to |p|, so a few false
// drops are tolerable.
//  procedure search_mem( p:halfword ); [look for pointers to |p|]
// var  q:integer; [current position being searched]
// begin for q:=mem_min to lo_mem_max do
//   begin if  mem[ q].hh.rh =p then
//     begin print_nl(["LINK("=]322); print_int(q); print_char([")"=]41);
//     end;
//   if  mem[ q].hh.lh =p then
//     begin print_nl(["INFO("=]323); print_int(q); print_char([")"=]41);
//     end;
//   end;
// for q:=hi_mem_min to mem_end do
//   begin if  mem[ q].hh.rh =p then
//     begin print_nl(["LINK("=]322); print_int(q); print_char([")"=]41);
//     end;
//   if  mem[ q].hh.lh =p then
//     begin print_nl(["INFO("=]323); print_int(q); print_char([")"=]41);
//     end;
//   end;
//
// [ Search |eqtb| for equivalents equal to |p| ]
// for q:=1 to hash_base+hash_size +12  do
//   begin if  eqtb[ q].rh =p then
//     begin print_nl(["EQUIV("=]458); print_int(q); print_char([")"=]41);
//     end;
//   end
//
// ;
// end;
// [  ]

// 188.

// tangle:pos ../../mf.web:3900:3:

// Values inside \MF\ are stored in two-word nodes that have a |name_type|
// as well as a |type|. The possibilities for |name_type| are defined
// here; they will be explained in more detail later.

// 189.

// tangle:pos ../../mf.web:3918:3:

// Primitive operations that produce values have a secondary identification
// code in addition to their command code; it's something like genera and species.
// For example, `\.*' has the command code |primary_binary|, and its
// secondary identification is |times|. The secondary codes start at 30 so that
// they don't overlap with the type codes; some type codes (e.g., |string_type|)
// are used as operators as well as type identifications.
func (prg *prg) printOp(c quarterword) {
	if int32(c) <= numericType {
		prg.printType(c)
	} else {
		switch c {
		case trueCode:
			prg.print( /* "true" */ 348)
		case falseCode:
			prg.print( /* "false" */ 349)
		case nullPictureCode:
			prg.print( /* "nullpicture" */ 350)
		case nullPenCode:
			prg.print( /* "nullpen" */ 351)
		case jobNameOp:
			prg.print( /* "jobname" */ 352)
		case readStringOp:
			prg.print( /* "readstring" */ 353)
		case penCircle:
			prg.print( /* "pencircle" */ 354)
		case normalDeviate:
			prg.print( /* "normaldeviate" */ 355)
		case oddOp:
			prg.print( /* "odd" */ 356)
		case knownOp:
			prg.print( /* "known" */ 357)
		case unknownOp:
			prg.print( /* "unknown" */ 358)
		case notOp:
			prg.print( /* "not" */ 359)
		case decimal:
			prg.print( /* "decimal" */ 360)
		case reverse:
			prg.print( /* "reverse" */ 361)
		case makePathOp:
			prg.print( /* "makepath" */ 362)
		case makePenOp:
			prg.print( /* "makepen" */ 363)
		case totalWeightOp:
			prg.print( /* "totalweight" */ 364)
		case octOp:
			prg.print( /* "oct" */ 365)
		case hexOp:
			prg.print( /* "hex" */ 366)
		case asciiOp:
			prg.print( /* "ASCII" */ 367)
		case charOp:
			prg.print( /* "char" */ 368)
		case lengthOp:
			prg.print( /* "length" */ 369)
		case turningOp:
			prg.print( /* "turningnumber" */ 370)
		case xPart:
			prg.print( /* "xpart" */ 371)
		case yPart:
			prg.print( /* "ypart" */ 372)
		case xxPart:
			prg.print( /* "xxpart" */ 373)
		case xyPart:
			prg.print( /* "xypart" */ 374)
		case yxPart:
			prg.print( /* "yxpart" */ 375)
		case yyPart:
			prg.print( /* "yypart" */ 376)
		case sqrtOp:
			prg.print( /* "sqrt" */ 377)
		case mExpOp:
			prg.print( /* "mexp" */ 378)
		case mLogOp:
			prg.print( /* "mlog" */ 379)
		case sinDOp:
			prg.print( /* "sind" */ 380)
		case cosDOp:
			prg.print( /* "cosd" */ 381)
		case floorOp:
			prg.print( /* "floor" */ 382)
		case uniformDeviate:
			prg.print( /* "uniformdeviate" */ 383)
		case charExistsOp:
			prg.print( /* "charexists" */ 384)
		case angleOp:
			prg.print( /* "angle" */ 385)
		case cycleOp:
			prg.print( /* "cycle" */ 386)
		case plus:
			prg.printChar(asciiCode('+'))
		case minus:
			prg.printChar(asciiCode('-'))
		case times:
			prg.printChar(asciiCode('*'))
		case over:
			prg.printChar(asciiCode('/'))
		case pythagAdd:
			prg.print( /* "++" */ 387)
		case pythagSub:
			prg.print( /* "+-+" */ 311)
		case orOp:
			prg.print( /* "or" */ 388)
		case andOp:
			prg.print( /* "and" */ 389)
		case lessThan:
			prg.printChar(asciiCode('<'))
		case lessOrEqual:
			prg.print( /* "<=" */ 390)
		case greaterThan:
			prg.printChar(asciiCode('>'))
		case greaterOrEqual:
			prg.print( /* ">=" */ 391)
		case equalTo:
			prg.printChar(asciiCode('='))
		case unequalTo:
			prg.print( /* "<>" */ 392)
		case concatenate:
			prg.print('&')
		case rotatedBy:
			prg.print( /* "rotated" */ 393)
		case slantedBy:
			prg.print( /* "slanted" */ 394)
		case scaledBy:
			prg.print( /* "scaled" */ 395)
		case shiftedBy:
			prg.print( /* "shifted" */ 396)
		case transformedBy:
			prg.print( /* "transformed" */ 397)
		case xScaled:
			prg.print( /* "xscaled" */ 398)
		case yScaled:
			prg.print( /* "yscaled" */ 399)
		case zScaled:
			prg.print( /* "zscaled" */ 400)
		case intersect:
			prg.print( /* "intersectiontimes" */ 401)
		case substringOf:
			prg.print( /* "substring" */ 402)
		case subpathOf:
			prg.print( /* "subpath" */ 403)
		case directionTimeOf:
			prg.print( /* "directiontime" */ 404)
		case pointOf:
			prg.print( /* "point" */ 405)
		case precontrolOf:
			prg.print( /* "precontrol" */ 406)
		case postcontrolOf:
			prg.print( /* "postcontrol" */ 407)
		case penOffsetOf:
			prg.print( /* "penoffset" */ 408)

		default:
			prg.print( /* ".." */ 409)
		}
	}
}

// 194.

// tangle:pos ../../mf.web:4268:3:

// The following procedure, which is called just before \MF\ initializes its
// input and output, establishes the initial values of the date and time.
// \xref[system dependencies]
// Since standard \PASCAL\ cannot provide such information, something special
// is needed. The program here simply assumes that suitable values appear in
// the global variables \\[sys\_time], \\[sys\_day], \\[sys\_month], and
// \\[sys\_year] (which are initialized to noon on 4 July 1776,
// in case the implementor is careless).
//
// Note that the values are |scaled| integers. Hence \MF\ can no longer
// be used after the year 32767.
func (prg *prg) fixDateAndTime() {
	prg.sysTime = 12 * 60
	prg.sysDay = 4
	prg.sysMonth = 7
	prg.sysYear = 1776                             // self-evident truths
	prg.internal[time-1] = prg.sysTime * 0200000   // minutes since midnight
	prg.internal[day-1] = prg.sysDay * 0200000     // day of the month
	prg.internal[month-1] = prg.sysMonth * 0200000 // month of the year
	prg.internal[year-1] = prg.sysYear * 0200000   // Anno Domini
}

// 205.

// tangle:pos ../../mf.web:4485:3:

// Here is the subroutine that searches the hash table for an identifier
// that matches a given string of length~|l| appearing in |buffer[j..
// (j+l-1)]|. If the identifier is not found, it is inserted; hence it
// will always be found, and the corresponding hash table address
// will be returned.
func (prg *prg) idLookup(j, l int32) (r halfword) { // go here when you've found it
	var (
		h int32    // hash code
		p halfword // index in |hash| array
		k halfword // index in |buffer| array
	)
	if l == 1 {
		p = uint16(int32(prg.buffer[j]) + 1)
		*prg.hash[p-1].rh() = uint16(int32(p) - 1)
		goto found
	}

	// Compute the hash code |h|
	h = int32(prg.buffer[j])
	for ii := j + 1; ii <= j+l-1; ii++ {
		k = halfword(ii)
		_ = k
		h = h + h + int32(prg.buffer[k])
		for h >= hashPrime {
			h = h - hashPrime
		}
	}
	p = uint16(h + hashBase) // we start searching here; note that |0<=h<hash_prime|
	for true {
		if int32(*prg.hash[p-1].rh()) > 0 {
			if int32(prg.strStart[int32(*prg.hash[p-1].rh())+1])-int32(prg.strStart[*prg.hash[p-1].rh()]) == l {
				if prg.strEqBuf(*prg.hash[p-1].rh(), j) {
					goto found
				}
			}
		}
		if int32(*prg.hash[p-1].lh()) == 0 {
			if int32(*prg.hash[p-1].rh()) > 0 {
				for {
					if int32(prg.hashUsed) == hashBase {
						prg.overflow(strNumber( /* "hash size" */ 457), hashSize)
					}
					// \xref[METAFONT capacity exceeded hash size][\quad hash size]
					prg.hashUsed = uint16(int32(prg.hashUsed) - 1)
					if int32(*prg.hash[prg.hashUsed-1].rh()) == 0 {
						break
					}
				} // search for an empty location in |hash|
				*prg.hash[p-1].lh() = prg.hashUsed
				p = prg.hashUsed
			}
			{
				if int32(prg.poolPtr)+l > int32(prg.maxPoolPtr) {
					if int32(prg.poolPtr)+l > poolSize {
						prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
					} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
					prg.maxPoolPtr = uint16(int32(prg.poolPtr) + l)
				}
			}
			for ii := j; ii <= j+l-1; ii++ {
				k = halfword(ii)
				_ = k
				prg.strPool[prg.poolPtr] = prg.buffer[k]
				prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
			}
			*prg.hash[p-1].rh() = prg.makeString()
			prg.strRef[*prg.hash[p-1].rh()] = byte(maxStrRef)
			prg.stCount = prg.stCount + 1

			goto found
		}
		p = *prg.hash[p-1].lh()
	}

found:
	r = p
	return r
}

// 210.

// tangle:pos ../../mf.web:4549:3:

// We need to put \MF's ``primitive'' symbolic tokens into the hash
// table, together with their command code (which will be the |eq_type|)
// and an operand (which will be the |equiv|). The |primitive| procedure
// does this, in a way that no \MF\ user can. The global value |cur_sym|
// contains the new |eqtb| pointer after |primitive| has acted.
func (prg *prg) primitive(s strNumber, c halfword, o halfword) {
	var (
		k poolPointer // index into |str_pool|
		j smallNumber // index into |buffer|
		l smallNumber // length of the string
	)
	k = prg.strStart[s]
	l = byte(int32(prg.strStart[int32(s)+1]) - int32(k))
	// we will move |s| into the (empty) |buffer|
	for ii := int32(0); ii <= int32(l)-1; ii++ {
		j = smallNumber(ii)
		_ = j
		prg.buffer[j] = prg.strPool[int32(k)+int32(j)]
	}
	prg.curSym = prg.idLookup(0, int32(l))

	if int32(s) >= 256 {
		prg.flushString(strNumber(int32(prg.strPtr) - 1))
		*prg.hash[prg.curSym-1].rh() = s
	}
	*prg.eqtb[prg.curSym-1].lh() = c
	*prg.eqtb[prg.curSym-1].rh() = o
}

// 213.

// tangle:pos ../../mf.web:4712:3:

// We will deal with the other primitives later, at some point in the program
// where their |eq_type| and |equiv| values are more meaningful.  For example,
// the primitives for macro definitions will be loaded when we consider the
// routines that define macros.
// It is easy to find where each particular
// primitive was treated by looking in the index at the end; for example, the
// section where |"def"| entered |eqtb| is listed under `\&[def] primitive'.

// 215.

// tangle:pos ../../mf.web:4764:3:

// A numeric token is created by the following trivial routine.
func (prg *prg) newNumTok(v scaled) (r halfword) {
	var (
		p halfword // the new node
	)
	p = prg.getNode(tokenNodeSize)
	*prg.mem[int32(p)+1].int() = v
	*(*prg.mem[p].hh()).b0() = byte(known)
	*(*prg.mem[p].hh()).b1() = byte(token)
	r = p
	return r
} // \2

func (prg *prg) flushTokenList(p halfword) {
	var (
		q halfword // the node being recycled
	)
	for int32(p) != memMin {
		q = p
		p = *(*prg.mem[p].hh()).rh()
		if int32(q) >= int32(prg.hiMemMin) {
			*(*prg.mem[q].hh()).rh() = prg.avail
			prg.avail = q
			prg.dynUsed = prg.dynUsed - 1
		} else {
			switch *(*prg.mem[q].hh()).b0() {
			case vacuous, booleanType, known:
			case stringType:
				if int32(prg.strRef[*prg.mem[int32(q)+1].int()]) < maxStrRef {
					if int32(prg.strRef[*prg.mem[int32(q)+1].int()]) > 1 {
						prg.strRef[*prg.mem[int32(q)+1].int()] = byte(int32(prg.strRef[*prg.mem[int32(q)+1].int()]) - 1)
					} else {
						prg.flushString(strNumber(*prg.mem[int32(q)+1].int()))
					}
				}
			case unknownBoolean, unknownString, unknownPen, unknownPicture,
				unknownPath, penType, pathType, futurePen,
				pictureType, pairType, transformType, dependent,
				protoDependent, independent:
				prg.gPointer = q
				prg.tokenRecycle()

			default:
				prg.confusion(strNumber( /* "token" */ 491))
				// \xref[this can't happen token][\quad token]
			}

			prg.freeNode(q, halfword(tokenNodeSize))
		}
	}
}

// 226.

// tangle:pos ../../mf.web:4940:3:

// Macro definitions are kept in \MF's memory in the form of token lists
// that have a few extra one-word nodes at the beginning.
//
// The first node contains a reference count that is used to tell when the
// list is no longer needed. To emphasize the fact that a reference count is
// present, we shall refer to the |info| field of this special node as the
// |ref_count| field.
// \xref[reference counts]
//
// The next node or nodes after the reference count serve to describe the
// formal parameters. They consist of zero or more parameter tokens followed
// by a code for the type of macro.
func (prg *prg) deleteMacRef(p halfword) {
	if int32(*(*prg.mem[p].hh()).lh()) == memMin {
		prg.flushTokenList(p)
	} else {
		*(*prg.mem[p].hh()).lh() = uint16(int32(*(*prg.mem[p].hh()).lh()) - 1)
	}
}

// 227.

// tangle:pos ../../mf.web:4972:3:

// The following subroutine displays a macro, given a pointer to its
// reference count.
// \4
// Declare the procedure called |print_cmd_mod|
func (prg *prg) printCmdMod(c, m int32) {
	switch c {
	case addToCommand:
		prg.print( /* "addto" */ 462)
	case assignment:
		prg.print( /* ":=" */ 461)
	case atLeast:
		prg.print( /* "atleast" */ 464)
	case atToken:
		prg.print( /* "at" */ 463)
	case bcharLabel:
		prg.print( /* "||:" */ 460)
	case beginGroup:
		prg.print( /* "begingroup" */ 465)
	case colon:
		prg.print(':')
	case comma:
		prg.print(',')
	case controls:
		prg.print( /* "controls" */ 466)
	case cullCommand:
		prg.print( /* "cull" */ 467)
	case curlCommand:
		prg.print( /* "curl" */ 468)
	case delimiters:
		prg.print( /* "delimiters" */ 469)
	case displayCommand:
		prg.print( /* "display" */ 470)
	case doubleColon:
		prg.print( /* "::" */ 459)
	case endGroup:
		prg.print( /* "endgroup" */ 453)
	case everyJobCommand:
		prg.print( /* "everyjob" */ 471)
	case exitTest:
		prg.print( /* "exitif" */ 472)
	case expandAfter:
		prg.print( /* "expandafter" */ 473)
	case fromToken:
		prg.print( /* "from" */ 474)
	case inWindow:
		prg.print( /* "inwindow" */ 475)
	case interimCommand:
		prg.print( /* "interim" */ 476)
	case leftBrace:
		prg.print('{')
	case leftBracket:
		prg.print('[')
	case letCommand:
		prg.print( /* "let" */ 477)
	case newInternal:
		prg.print( /* "newinternal" */ 478)
	case ofToken:
		prg.print( /* "of" */ 479)
	case openWindow:
		prg.print( /* "openwindow" */ 480)
	case pathJoin:
		prg.print( /* ".." */ 409)
	case randomSeed:
		prg.print( /* "randomseed" */ 481)
	case relax:
		prg.printChar(asciiCode('\\'))
	case rightBrace:
		prg.print('}')
	case rightBracket:
		prg.print(']')
	case saveCommand:
		prg.print( /* "save" */ 482)
	case scanTokens:
		prg.print( /* "scantokens" */ 483)
	case semicolon:
		prg.print(';')
	case shipOutCommand:
		prg.print( /* "shipout" */ 484)
	case skipTo:
		prg.print( /* "skipto" */ 485)
	case stepToken:
		prg.print( /* "step" */ 486)
	case strOp:
		prg.print( /* "str" */ 487)
	case tension:
		prg.print( /* "tension" */ 488)
	case toToken:
		prg.print( /* "to" */ 489)
	case untilToken:
		prg.print( /* "until" */ 490)

	case macroDef:
		if m <= varDef {
			if m == startDef {
				prg.print( /* "def" */ 654)
			} else if m < startDef {
				prg.print( /* "enddef" */ 454)
			} else {
				prg.print( /* "vardef" */ 655)
			}
		} else if m == secondaryPrimaryMacro {
			prg.print( /* "primarydef" */ 656)
		} else if m == tertiarySecondaryMacro {
			prg.print( /* "secondarydef" */ 657)
		} else {
			prg.print( /* "tertiarydef" */ 658)
		}
	case iteration:
		if m <= startForever {
			if m == startForever {
				prg.print( /* "forever" */ 661)
			} else {
				prg.print( /* "endfor" */ 455)
			}
		} else if m == hashBase+hashSize+12+1 {
			prg.print( /* "for" */ 659)
		} else {
			prg.print( /* "forsuffixes" */ 660)
		}

	case macroSpecial:
		switch m {
		case macroPrefix:
			prg.print( /* "#@" */ 663)
		case macroAt:
			prg.printChar(asciiCode('@'))
		case macroSuffix:
			prg.print( /* "@#" */ 664)

		default:
			prg.print( /* "quote" */ 662)
		}

	case paramType:
		if m >= hashBase+hashSize+12+1 {
			if m == hashBase+hashSize+12+1 {
				prg.print( /* "expr" */ 675)
			} else if m == hashBase+hashSize+12+1+paramSize {
				prg.print( /* "suffix" */ 676)
			} else {
				prg.print( /* "text" */ 677)
			}
		} else if m < secondaryMacro {
			prg.print( /* "primary" */ 678)
		} else if m == secondaryMacro {
			prg.print( /* "secondary" */ 679)
		} else {
			prg.print( /* "tertiary" */ 680)
		}

	case input:
		if m == 0 {
			prg.print( /* "input" */ 690)
		} else {
			prg.print( /* "endinput" */ 616)
		}

	case ifTest, fiOrElse:
		switch m {
		case ifCode:
			prg.print( /* "if" */ 717)
		case fiCode:
			prg.print( /* "fi" */ 452)
		case elseCode:
			prg.print( /* "else" */ 718)

		default:
			prg.print( /* "elseif" */ 719)
		}

	case nullary, unary, primaryBinary, secondaryBinary,
		tertiaryBinary, expressionBinary, cycle, plusOrMinus,
		slash, ampersand, equals, andCommand:
		prg.printOp(quarterword(m))

	case typeName:
		prg.printType(smallNumber(m))

	case stop:
		if m == 0 {
			prg.print( /* "end" */ 912)
		} else {
			prg.print( /* "dump" */ 913)
		}

	case modeCommand:
		switch m {
		case batchMode:
			prg.print( /* "batchmode" */ 273)
		case nonstopMode:
			prg.print( /* "nonstopmode" */ 274)
		case scrollMode:
			prg.print( /* "scrollmode" */ 275)

		default:
			prg.print( /* "errorstopmode" */ 919)
		}

	case protectionCommand:
		if m == 0 {
			prg.print( /* "inner" */ 920)
		} else {
			prg.print( /* "outer" */ 921)
		}

	case showCommand:
		switch m {
		case showTokenCode:
			prg.print( /* "showtoken" */ 935)
		case showStatsCode:
			prg.print( /* "showstats" */ 936)
		case showCode:
			prg.print( /* "show" */ 937)
		case showVarCode:
			prg.print( /* "showvariable" */ 938)

		default:
			prg.print( /* "showdependencies" */ 939)
		}

	case leftDelimiter, rightDelimiter:
		if c == leftDelimiter {
			prg.print( /* "lef" */ 942)
		} else {
			prg.print( /* "righ" */ 943)
		}
		prg.print( /* "t delimiter that matches " */ 944)
		prg.slowPrint(int32(*prg.hash[m-1].rh()))

	case tagToken:
		if m == memMin {
			prg.print( /* "tag" */ 945)
		} else {
			prg.print( /* "variable" */ 946)
		}
	case definedMacro:
		prg.print( /* "macro:" */ 947)
	case secondaryPrimaryMacro, tertiarySecondaryMacro, expressionTertiaryMacro:
		prg.printCmdMod(macroDef, c)
		prg.print( /* "'d macro:" */ 948)
		prg.printLn()
		prg.showTokenList(int32(*(*prg.mem[*(*prg.mem[m].hh()).rh()].hh()).rh()), memMin, 1000, 0)

	case repeatLoop:
		prg.print( /* "[repeat the loop]" */ 949)
	case internalQuantity:
		prg.slowPrint(int32(prg.intName[m-1]))

	case thingToAdd:
		if m == contourCode {
			prg.print( /* "contour" */ 956)
		} else if m == doublePathCode {
			prg.print( /* "doublepath" */ 957)
		} else {
			prg.print( /* "also" */ 958)
		}
	case withOption:
		if m == penType {
			prg.print( /* "withpen" */ 959)
		} else {
			prg.print( /* "withweight" */ 960)
		}
	case cullOp:
		if m == dropCode {
			prg.print( /* "dropping" */ 961)
		} else {
			prg.print( /* "keeping" */ 962)
		}

	case messageCommand:
		if m < errMessageCode {
			prg.print( /* "message" */ 992)
		} else if m == errMessageCode {
			prg.print( /* "errmessage" */ 993)
		} else {
			prg.print( /* "errhelp" */ 994)
		}

	case tfmCommand:
		switch m {
		case charListCode:
			prg.print( /* "charlist" */ 1004)
		case ligTableCode:
			prg.print( /* "ligtable" */ 1005)
		case extensibleCode:
			prg.print( /* "extensible" */ 1006)
		case headerByteCode:
			prg.print( /* "headerbyte" */ 1007)

		default:
			prg.print( /* "fontdimen" */ 1008)
		}

	case ligKernToken:
		switch m {
		case 0:
			prg.print( /* "=:" */ 1026)
		case 1:
			prg.print( /* "=:|" */ 1027)
		case 2:
			prg.print( /* "|=:" */ 1029)
		case 3:
			prg.print( /* "|=:|" */ 1031)
		case 5:
			prg.print( /* "=:|>" */ 1028)
		case 6:
			prg.print( /* "|=:>" */ 1030)
		case 7:
			prg.print( /* "|=:|>" */ 1032)
		case 11:
			prg.print( /* "|=:|>>" */ 1033)

		default:
			prg.print( /* "kern" */ 1034)
		}

	case specialCommand:
		if m == known {
			prg.print( /* "numspecial" */ 1059)
		} else {
			prg.print( /* "special" */ 1058)
		}

	default:
		prg.print( /* "[unknown command code!]" */ 602)
	}
}

func (prg *prg) showMacro(p halfword, q, l int32) {
	var (
		r1 halfword // temporary storage
	)
	p = *(*prg.mem[p].hh()).rh() // bypass the reference count
	for int32(*(*prg.mem[p].hh()).lh()) > textMacro {
		r1 = *(*prg.mem[p].hh()).rh()
		*(*prg.mem[p].hh()).rh() = uint16(memMin)
		prg.showTokenList(int32(p), memMin, l, 0)
		*(*prg.mem[p].hh()).rh() = r1
		p = r1
		if l > 0 {
			l = l - prg.tally
		} else {
			goto exit
		}
	} // control printing of `\.[ETC.]'
	// \xref[ETC]
	prg.tally = 0
	switch *(*prg.mem[p].hh()).lh() {
	case generalMacro:
		prg.print( /* "->" */ 501)
	// \xref[->]
	case primaryMacro, secondaryMacro, tertiaryMacro:
		prg.printChar(asciiCode('<'))
		prg.printCmdMod(paramType, int32(*(*prg.mem[p].hh()).lh()))
		prg.print( /* ">->" */ 502)

	case exprMacro:
		prg.print( /* "<expr>->" */ 503)
	case ofMacro:
		prg.print( /* "<expr>of<primary>->" */ 504)
	case suffixMacro:
		prg.print( /* "<suffix>->" */ 505)
	case textMacro:
		prg.print( /* "<text>->" */ 506)
	} // there are no other cases
	prg.showTokenList(int32(*(*prg.mem[p].hh()).rh()), q, l-prg.tally, 0)

exit:
}

// 228. \[15] Data structures for variables

// tangle:pos ../../mf.web:5001:40:

// The variables of \MF\ programs can be simple, like `\.x', or they can
// combine the structural properties of arrays and records, like `\.[x20a.b]'.
// A \MF\ user assigns a type to a variable like \.[x20a.b] by saying, for
// example, `\.[boolean] \.[x[]a.b]'. It's time for us to study how such
// things are represented inside of the computer.
//
// Each variable value occupies two consecutive words, either in a two-word
// node called a value node, or as a two-word subfield of a larger node.  One
// of those two words is called the |value| field; it is an integer,
// containing either a |scaled| numeric value or the representation of some
// other type of quantity. (It might also be subdivided into halfwords, in
// which case it is referred to by other names instead of |value|.) The other
// word is broken into subfields called |type|, |name_type|, and |link|.  The
// |type| field is a quarterword that specifies the variable's type, and
// |name_type| is a quarterword from which \MF\ can reconstruct the
// variable's name (sometimes by using the |link| field as well).  Thus, only
// 1.25 words are actually devoted to the value itself; the other
// three-quarters of a word are overhead, but they aren't wasted because they
// allow \MF\ to deal with sparse arrays and to provide meaningful diagnostics.
//
// In this section we shall be concerned only with the structural aspects of
// variables, not their values. Later parts of the program will change the
// |type| and |value| fields, but we shall treat those fields as black boxes
// whose contents should not be touched.
//
// However, if the |type| field is |structured|, there is no |value| field,
// and the second word is broken into two pointer fields called |attr_head|
// and |subscr_head|. Those fields point to additional nodes that
// contain structural information, as we shall see.

// 232.

// tangle:pos ../../mf.web:5177:3:

// If |type(p)=pair_type| or |transform_type| and if |value(p)=null|, the
// procedure call |init_big_node(p)| will allocate a pair or transform node
// for~|p|.  The individual parts of such nodes are initially of type
// |independent|.
func (prg *prg) initBigNode(p halfword) {
	var (
		q halfword    // the new node
		s smallNumber // its size
	)
	s = prg.bigNodeSize[*(*prg.mem[p].hh()).b0()-13]
	q = prg.getNode(int32(s))
	for {
		s = byte(int32(s) - 2)
		/* Make variable |q+s| newly independent  */ {
			if prg.serialNo > 017777777777-sScale {
				prg.overflow(strNumber( /* "independent variables" */ 587), prg.serialNo/sScale)
			} /* \xref[METAFONT capacity exceeded independent variables][\quad independent variables]  */
			*(*prg.mem[int32(q)+int32(s)].hh()).b0() = byte(independent)
			prg.serialNo = prg.serialNo + sScale
			*prg.mem[int32(q)+int32(s)+1].int() = prg.serialNo
		}
		*(*prg.mem[int32(q)+int32(s)].hh()).b1() = byte(int32(s)/2 + xPartSector)
		*(*prg.mem[int32(q)+int32(s)].hh()).rh() = uint16(memMin)
		if int32(s) == 0 {
			break
		}
	}
	*(*prg.mem[q].hh()).rh() = p
	*prg.mem[int32(p)+1].int() = int32(q)
}

// 233.

// tangle:pos ../../mf.web:5192:3:

// The |id_transform| function creates a capsule for the
// identity transformation.
func (prg *prg) idTransform() (r halfword) {
	var (
		p, q, r1 halfword // list manipulation registers
	)
	p = prg.getNode(valueNodeSize)
	*(*prg.mem[p].hh()).b0() = byte(transformType)
	*(*prg.mem[p].hh()).b1() = byte(capsule)
	*prg.mem[int32(p)+1].int() = memMin
	prg.initBigNode(p)
	q = uint16(*prg.mem[int32(p)+1].int())
	r1 = uint16(int32(q) + transformNodeSize)
	for {
		r1 = uint16(int32(r1) - 2)
		*(*prg.mem[r1].hh()).b0() = byte(known)
		*prg.mem[int32(r1)+1].int() = 0
		if int32(r1) == int32(q) {
			break
		}
	}
	*prg.mem[int32(q)+4+1].int() = 0200000
	*prg.mem[int32(q)+10+1].int() = 0200000
	r = p
	return r
}

// 234.

// tangle:pos ../../mf.web:5207:3:

// Tokens are of type |tag_token| when they first appear, but they point
// to |null| until they are first used as the root of a variable.
// The following subroutine establishes the root node on such grand occasions.
func (prg *prg) newRoot(x halfword) {
	var (
		p halfword // the new node
	)
	p = prg.getNode(valueNodeSize)
	*(*prg.mem[p].hh()).b0() = byte(undefined)
	*(*prg.mem[p].hh()).b1() = byte(root)
	*(*prg.mem[p].hh()).rh() = x
	*prg.eqtb[x-1].rh() = p
}

// 235.

// tangle:pos ../../mf.web:5217:3:

// These conventions for variable representation are illustrated by the
// |print_variable_name| routine, which displays the full name of a
// variable given only a pointer to its two-word value packet.
func (prg *prg) printVariableName(p halfword) {
	var (
		q  halfword // a token list that will name the variable's suffix
		r1 halfword // temporary for token list creation
	)
	for int32(*(*prg.mem[p].hh()).b1()) >= xPartSector {

		// Preface the output with a part specifier; |return| in the case of a capsule
		switch *(*prg.mem[p].hh()).b1() {
		case xPartSector:
			prg.printChar(asciiCode('x'))
		case yPartSector:
			prg.printChar(asciiCode('y'))
		case xxPartSector:
			prg.print( /* "xx" */ 509)
		case xyPartSector:
			prg.print( /* "xy" */ 510)
		case yxPartSector:
			prg.print( /* "yx" */ 511)
		case yyPartSector:
			prg.print( /* "yy" */ 512)
		case capsule:
			prg.print( /* "%CAPSULE" */ 513)
			prg.printInt(int32(p) - memMin)
			goto exit
			// \xref[CAPSULE]

		} // there are no other cases
		prg.print( /* "part " */ 514)
		p = *(*prg.mem[int32(p)-2*(int32(*(*prg.mem[p].hh()).b1())-xPartSector)].hh()).rh()
	}
	q = uint16(memMin)
	for int32(*(*prg.mem[p].hh()).b1()) > savedRoot {

		// Ascend one level, pushing a token onto list |q| and replacing |p| by its parent
		if int32(*(*prg.mem[p].hh()).b1()) == subscr {
			r1 = prg.newNumTok(*prg.mem[int32(p)+2].int())
			for {
				p = *(*prg.mem[p].hh()).rh()
				if int32(*(*prg.mem[p].hh()).b1()) == attr {
					break
				}
			}
		} else if int32(*(*prg.mem[p].hh()).b1()) == structuredRoot {
			p = *(*prg.mem[p].hh()).rh()
			goto found
		} else {
			if int32(*(*prg.mem[p].hh()).b1()) != attr {
				prg.confusion(strNumber( /* "var" */ 508))
			}
			// \xref[this can't happen var][\quad var]
			r1 = prg.getAvail()
			*(*prg.mem[r1].hh()).lh() = *(*prg.mem[int32(p)+2].hh()).lh()
		}
		*(*prg.mem[r1].hh()).rh() = q
		q = r1

	found:
		p = *(*prg.mem[int32(p)+2].hh()).rh()
	}
	r1 = prg.getAvail()
	*(*prg.mem[r1].hh()).lh() = *(*prg.mem[p].hh()).rh()
	*(*prg.mem[r1].hh()).rh() = q
	if int32(*(*prg.mem[p].hh()).b1()) == savedRoot {
		prg.print( /* "(SAVED)" */ 507)
	}
	// \xref[SAVED]
	prg.showTokenList(int32(r1), memMin, 017777777777, prg.tally)
	prg.flushTokenList(r1)

exit:
}

// 238.

// tangle:pos ../../mf.web:5270:3:

// The |interesting| function returns |true| if a given variable is not
// in a capsule, or if the user wants to trace capsules.
func (prg *prg) interesting(p halfword) (r bool) {
	var (
		t smallNumber // a |name_type|
	)
	if prg.internal[tracingCapsules-1] > 0 {
		r = true
	} else {
		t = *(*prg.mem[p].hh()).b1()
		if int32(t) >= xPartSector {
			if int32(t) != capsule {
				t = *(*prg.mem[*(*prg.mem[int32(p)-2*(int32(t)-xPartSector)].hh()).rh()].hh()).b1()
			}
		}
		r = int32(t) != capsule
	}
	return r
}

// 239.

// tangle:pos ../../mf.web:5283:3:

// Now here is a subroutine that converts an unstructured type into an
// equivalent structured type, by inserting a |structured| node that is
// capable of growing. This operation is done only when |name_type(p)=root|,
// |subscr|, or |attr|.
//
// The procedure returns a pointer to the new node that has taken node~|p|'s
// place in the structure. Node~|p| itself does not move, nor are its
// |value| or |type| fields changed in any way.
func (prg *prg) newStructure(p halfword) (r halfword) {
	var (
		q, r1 halfword // list manipulation registers
	)
	switch *(*prg.mem[p].hh()).b1() {
	case root:
		q = *(*prg.mem[p].hh()).rh()
		r1 = prg.getNode(valueNodeSize)
		*prg.eqtb[q-1].rh() = r1

	case subscr:
		// Link a new subscript node |r| in place of node |p|
		q = p
		for {
			q = *(*prg.mem[q].hh()).rh()
			if int32(*(*prg.mem[q].hh()).b1()) == attr {
				break
			}
		}
		q = *(*prg.mem[int32(q)+2].hh()).rh()
		r1 = uint16(int32(q) + 1) // |link(r)=subscr_head(q)|
		for {
			q = r1
			r1 = *(*prg.mem[r1].hh()).rh()
			if int32(r1) == int32(p) {
				break
			}
		}
		r1 = prg.getNode(subscrNodeSize)
		*(*prg.mem[q].hh()).rh() = r1
		*prg.mem[int32(r1)+2].int() = *prg.mem[int32(p)+2].int()

	case attr:
		// Link a new attribute node |r| in place of node |p|
		q = *(*prg.mem[int32(p)+2].hh()).rh()
		r1 = *(*prg.mem[int32(q)+1].hh()).lh()
		for {
			q = r1
			r1 = *(*prg.mem[r1].hh()).rh()
			if int32(r1) == int32(p) {
				break
			}
		}
		r1 = prg.getNode(attrNodeSize)
		*(*prg.mem[q].hh()).rh() = r1

		prg.mem[int32(r1)+2] = prg.mem[int32(p)+2] // copy |attr_loc| and |parent|
		if int32(*(*prg.mem[int32(p)+2].hh()).lh()) == collectiveSubscript {
			q = uint16(int32(*(*prg.mem[int32(p)+2].hh()).rh()) + 1)
			for int32(*(*prg.mem[q].hh()).rh()) != int32(p) {
				q = *(*prg.mem[q].hh()).rh()
			}
			*(*prg.mem[q].hh()).rh() = r1
		}

	default:
		prg.confusion(strNumber( /* "struct" */ 515))
		// \xref[this can't happen struct][\quad struct]
	}

	*(*prg.mem[r1].hh()).rh() = *(*prg.mem[p].hh()).rh()
	*(*prg.mem[r1].hh()).b0() = byte(structured)
	*(*prg.mem[r1].hh()).b1() = *(*prg.mem[p].hh()).b1()
	*(*prg.mem[int32(r1)+1].hh()).lh() = p
	*(*prg.mem[p].hh()).b1() = byte(structuredRoot)

	q = prg.getNode(attrNodeSize)
	*(*prg.mem[p].hh()).rh() = q
	*(*prg.mem[int32(r1)+1].hh()).rh() = q
	*(*prg.mem[int32(q)+2].hh()).rh() = r1
	*(*prg.mem[q].hh()).b0() = byte(undefined)
	*(*prg.mem[q].hh()).b1() = byte(attr)
	*(*prg.mem[q].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2)
	*(*prg.mem[int32(q)+2].hh()).lh() = uint16(collectiveSubscript)
	r = r1
	return r
}

// 242.

// tangle:pos ../../mf.web:5336:3:

// The |find_variable| routine is given a pointer~|t| to a nonempty token
// list of suffixes; it returns a pointer to the corresponding two-word
// value. For example, if |t| points to token \.x followed by a numeric
// token containing the value~7, |find_variable| finds where the value of
// \.[x7] is stored in memory. This may seem a simple task, and it
// usually is, except when \.[x7] has never been referenced before.
// Indeed, \.x may never have even been subscripted before; complexities
// arise with respect to updating the collective subscript information.
//
// If a macro type is detected anywhere along path~|t|, or if the first
// item on |t| isn't a |tag_token|, the value |null| is returned.
// Otherwise |p| will be a non-null pointer to a node such that
// |undefined<type(p)<structured|.
func (prg *prg) findVariable(t halfword) (r halfword) {
	var (
		p, q, r1, s    halfword   // nodes in the ``value'' line
		pp, qq, rr, ss halfword   // nodes in the ``collective'' line
		n              int32      // subscript or attribute
		saveWord       memoryWord // temporary storage for a word of |mem|
	// \xref[inner loop]
	)
	p = *(*prg.mem[t].hh()).lh()
	t = *(*prg.mem[t].hh()).rh()
	if int32(*prg.eqtb[p-1].lh())%outerTag != tagToken {
		r = uint16(memMin)
		goto exit
	}
	if int32(*prg.eqtb[p-1].rh()) == memMin {
		prg.newRoot(p)
	}
	p = *prg.eqtb[p-1].rh()
	pp = p
	for int32(t) != memMin {
		if int32(*(*prg.mem[pp].hh()).b0()) != structured {
			if int32(*(*prg.mem[pp].hh()).b0()) > structured {
				r = uint16(memMin)
				goto exit
			}
			ss = prg.newStructure(pp)
			if int32(p) == int32(pp) {
				p = ss
			}
			pp = ss
		} // now |type(pp)=structured|
		if int32(*(*prg.mem[p].hh()).b0()) != structured {
			p = prg.newStructure(p)
		}
		if int32(t) < int32(prg.hiMemMin) {
			n = *prg.mem[int32(t)+1].int()
			pp = *(*prg.mem[*(*prg.mem[int32(pp)+1].hh()).lh()].hh()).rh() // now |attr_loc(pp)=collective_subscript|
			q = *(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh()
			saveWord = prg.mem[int32(q)+2]
			*prg.mem[int32(q)+2].int() = 017777777777
			s = uint16(int32(p) + 1) // |link(s)=subscr_head(p)|
			for {
				r1 = s
				s = *(*prg.mem[s].hh()).rh()
				if n <= *prg.mem[int32(s)+2].int() {
					break
				}
			}
			if n == *prg.mem[int32(s)+2].int() {
				p = s
			} else {
				p = prg.getNode(subscrNodeSize)
				*(*prg.mem[r1].hh()).rh() = p
				*(*prg.mem[p].hh()).rh() = s
				*prg.mem[int32(p)+2].int() = n
				*(*prg.mem[p].hh()).b1() = byte(subscr)
				*(*prg.mem[p].hh()).b0() = byte(undefined)
			}
			prg.mem[int32(q)+2] = saveWord
		} else {
			// Descend one level for the attribute |info(t)|
			n = int32(*(*prg.mem[t].hh()).lh())
			ss = *(*prg.mem[int32(pp)+1].hh()).lh()
			for {
				rr = ss
				ss = *(*prg.mem[ss].hh()).rh()
				if n <= int32(*(*prg.mem[int32(ss)+2].hh()).lh()) {
					break
				}
			}
			if n < int32(*(*prg.mem[int32(ss)+2].hh()).lh()) {
				qq = prg.getNode(attrNodeSize)
				*(*prg.mem[rr].hh()).rh() = qq
				*(*prg.mem[qq].hh()).rh() = ss
				*(*prg.mem[int32(qq)+2].hh()).lh() = uint16(n)
				*(*prg.mem[qq].hh()).b1() = byte(attr)
				*(*prg.mem[qq].hh()).b0() = byte(undefined)
				*(*prg.mem[int32(qq)+2].hh()).rh() = pp
				ss = qq
			}
			if int32(p) == int32(pp) {
				p = ss
				pp = ss
			} else {
				pp = ss
				s = *(*prg.mem[int32(p)+1].hh()).lh()
				for {
					r1 = s
					s = *(*prg.mem[s].hh()).rh()
					if n <= int32(*(*prg.mem[int32(s)+2].hh()).lh()) {
						break
					}
				}
				if n == int32(*(*prg.mem[int32(s)+2].hh()).lh()) {
					p = s
				} else {
					q = prg.getNode(attrNodeSize)
					*(*prg.mem[r1].hh()).rh() = q
					*(*prg.mem[q].hh()).rh() = s
					*(*prg.mem[int32(q)+2].hh()).lh() = uint16(n)
					*(*prg.mem[q].hh()).b1() = byte(attr)
					*(*prg.mem[q].hh()).b0() = byte(undefined)
					*(*prg.mem[int32(q)+2].hh()).rh() = p
					p = q
				}
			}
		}
		t = *(*prg.mem[t].hh()).rh()
	}
	if int32(*(*prg.mem[pp].hh()).b0()) >= structured {
		if int32(*(*prg.mem[pp].hh()).b0()) == structured {
			pp = *(*prg.mem[int32(pp)+1].hh()).lh()
		} else {
			r = uint16(memMin)
			goto exit
		}
	}
	if int32(*(*prg.mem[p].hh()).b0()) == structured {
		p = *(*prg.mem[int32(p)+1].hh()).lh()
	}
	if int32(*(*prg.mem[p].hh()).b0()) == undefined {
		if int32(*(*prg.mem[pp].hh()).b0()) == undefined {
			*(*prg.mem[pp].hh()).b0() = byte(numericType)
			*prg.mem[int32(pp)+1].int() = memMin
		}
		*(*prg.mem[p].hh()).b0() = *(*prg.mem[pp].hh()).b0()
		*prg.mem[int32(p)+1].int() = memMin
	}
	r = p

exit:
	;
	return r
}

// 246.

// tangle:pos ../../mf.web:5440:3:

// Variables lose their former values when they appear in a type declaration,
// or when they are defined to be macros or \&[let] equal to something else.
// A subroutine will be defined later that recycles the storage associated
// with any particular |type| or |value|; our goal now is to study a higher
// level process called |flush_variable|, which selectively frees parts of a
// variable structure.
//
// This routine has some complexity because of examples such as
// `\hbox[\tt numeric x[]a[]b]',
// which recycles all variables of the form \.[x[i]a[j]b] (and no others), while
// `\hbox[\tt vardef x[]a[]=...]'
// discards all variables of the form \.[x[i]a[j]] followed by an arbitrary
// suffix, except for the collective node \.[x[]a[]] itself. The obvious way
// to handle such examples is to use recursion; so that's what we~do.
// \xref[recursion]
//
// Parameter |p| points to the root information of the variable;
// parameter |t| points to a list of one-word nodes that represent
// suffixes, with |info=collective_subscript| for subscripts.
// \4
// Declare subroutines for printing expressions
func (prg *prg) printPath(h halfword, s strNumber, nuline bool) {
	var (
		p, q halfword // for list traversal
	)
	prg.printDiagnostic(strNumber( /* "Path" */ 517), s, nuline)
	prg.printLn()
	// \xref[Path at line...]
	p = h
	for {
		q = *(*prg.mem[p].hh()).rh()
		if int32(p) == memMin || int32(q) == memMin {
			prg.printNl(strNumber( /* "???" */ 259))
			goto done // this won't happen
			// \xref[???]
		}

		// Print information for adjacent knots |p| and |q|
		prg.printTwo(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2].int())
		switch *(*prg.mem[p].hh()).b1() {
		case endpoint:
			if int32(*(*prg.mem[p].hh()).b0()) == open {
				prg.print( /* "[open?]" */ 518)
			} // can't happen
			// \xref[open?]
			if int32(*(*prg.mem[q].hh()).b0()) != endpoint || int32(q) != int32(h) {
				q = uint16(memMin)
			} // force an error
			// force an error
			goto done1

		case explicit:
			// Print control points between |p| and |q|, then |goto done1|
			prg.print( /* "..controls " */ 524)
			prg.printTwo(*prg.mem[int32(p)+5].int(), *prg.mem[int32(p)+6].int())
			prg.print( /* " and " */ 523)
			if int32(*(*prg.mem[q].hh()).b0()) != explicit {
				prg.print( /* "??" */ 525)
			} else {
				prg.printTwo(*prg.mem[int32(q)+3].int(), *prg.mem[int32(q)+4].int())
			}

			goto done1

		case open:
			// Print information for a curve that begins |open|
			if int32(*(*prg.mem[p].hh()).b0()) != explicit && int32(*(*prg.mem[p].hh()).b0()) != open {
				prg.print( /* "[open?]" */ 518)
			} // can't happen
		// \xref[open?]

		case curl, given:
			// Print information for a curve that begins |curl| or |given|
			if int32(*(*prg.mem[p].hh()).b0()) == open {
				prg.print( /* "??" */ 525)
			} // can't happen
			// \xref[??]
			if int32(*(*prg.mem[p].hh()).b1()) == curl {
				prg.print( /* "[curl " */ 521)
				prg.printScaled(*prg.mem[int32(p)+5].int())
			} else {
				prg.nSinCos(*prg.mem[int32(p)+5].int())
				prg.printChar(asciiCode('{'))
				prg.printScaled(prg.nCos)
				prg.printChar(asciiCode(','))
				prg.printScaled(prg.nSin)
			}
			prg.printChar(asciiCode('}'))

		default:
			prg.print( /* "???" */ 259) // can't happen
			// \xref[???]
		}

		if int32(*(*prg.mem[q].hh()).b0()) <= explicit {
			prg.print( /* "..control?" */ 519)
		} else if *prg.mem[int32(p)+6].int() != 0200000 || *prg.mem[int32(q)+4].int() != 0200000 {
			prg.print( /* "..tension " */ 522)
			if *prg.mem[int32(p)+6].int() < 0 {
				prg.print( /* "atleast" */ 464)
			}
			prg.printScaled(abs(*prg.mem[int32(p)+6].int()))
			if *prg.mem[int32(p)+6].int() != *prg.mem[int32(q)+4].int() {
				prg.print( /* " and " */ 523)
				if *prg.mem[int32(q)+4].int() < 0 {
					prg.print( /* "atleast" */ 464)
				}
				prg.printScaled(abs(*prg.mem[int32(q)+4].int()))
			}
		}

	done1:
		;
		p = q
		if int32(p) != int32(h) || int32(*(*prg.mem[h].hh()).b0()) != endpoint {
			prg.printNl(strNumber( /* " .." */ 520))
			if int32(*(*prg.mem[p].hh()).b0()) == given {
				prg.nSinCos(*prg.mem[int32(p)+3].int())
				prg.printChar(asciiCode('{'))
				prg.printScaled(prg.nCos)
				prg.printChar(asciiCode(','))
				prg.printScaled(prg.nSin)
				prg.printChar(asciiCode('}'))
			} else if int32(*(*prg.mem[p].hh()).b0()) == curl {
				prg.print( /* "[curl " */ 521)
				prg.printScaled(*prg.mem[int32(p)+3].int())
				prg.printChar(asciiCode('}'))
			}
		}
		if int32(p) == int32(h) {
			break
		}
	}
	if int32(*(*prg.mem[h].hh()).b0()) != endpoint {
		prg.print( /* "cycle" */ 386)
	}

done:
	prg.endDiagnostic(true)
}

// \4
// Declare the procedure called |print_weight|
func (prg *prg) printWeight(q halfword, xOff int32) {
	var (
		w, m int32 // unpacked weight and coordinate
		d    int32 // temporary data register
	)
	d = int32(*(*prg.mem[q].hh()).lh()) - 0
	w = d % 8
	m = d/8 - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())
	if int32(prg.fileOffset) > maxPrintLine-9 {
		prg.printNl(strNumber(' '))
	} else {
		prg.printChar(asciiCode(' '))
	}
	prg.printInt(m + xOff)
	for w > zeroW {
		prg.printChar(asciiCode('+'))
		w = w - 1
	}
	for w < zeroW {
		prg.printChar(asciiCode('-'))
		w = w + 1
	}
}

func (prg *prg) printEdges(s strNumber, nuline bool, xOff, yOff int32) {
	var (
		p, q, r1 halfword // for list traversal
		n        int32    // row number
	)
	prg.printDiagnostic(strNumber( /* "Edge structure" */ 532), s, nuline)
	p = *(*prg.mem[prg.curEdges].hh()).lh()
	n = int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) - zeroField
	for int32(p) != int32(prg.curEdges) {
		q = *(*prg.mem[int32(p)+1].hh()).lh()
		r1 = *(*prg.mem[int32(p)+1].hh()).rh()
		if int32(q) > memMin+1 || int32(r1) != 3000 {
			prg.printNl(strNumber( /* "row " */ 533))
			prg.printInt(n + yOff)
			prg.printChar(asciiCode(':'))
			for int32(q) > memMin+1 {
				prg.printWeight(q, xOff)
				q = *(*prg.mem[q].hh()).rh()
			}
			prg.print( /* " |" */ 534)
			for int32(r1) != 3000 {
				prg.printWeight(r1, xOff)
				r1 = *(*prg.mem[r1].hh()).rh()
			}
		}
		p = *(*prg.mem[p].hh()).lh()
		n = n - 1
	}
	prg.endDiagnostic(true)
}

func (prg *prg) unskew(x, y scaled, octant smallNumber) {
	switch octant {
	case firstOctant:
		prg.curX = x + y
		prg.curY = y
	case secondOctant:
		prg.curX = y
		prg.curY = x + y
	case thirdOctant:
		prg.curX = -y
		prg.curY = x + y
	case fourthOctant:
		prg.curX = -x - y
		prg.curY = y
	case fifthOctant:
		prg.curX = -x - y
		prg.curY = -y
	case sixthOctant:
		prg.curX = -y
		prg.curY = -x - y
	case seventhOctant:
		prg.curX = y
		prg.curY = -x - y
	case eighthOctant:
		prg.curX = x + y
		prg.curY = -y
	} // there are no other cases
}

func (prg *prg) printPen(p halfword, s strNumber, nuline bool) {
	var (
		nothingPrinted   bool     // has there been any action yet?
		k/* 1..8 */ byte          // octant number
		h                halfword // offset list head
		m, n             int32    // offset indices
		w, ww            halfword // pointers that traverse the offset list
	)
	prg.printDiagnostic(strNumber( /* "Pen polygon" */ 569), s, nuline)
	nothingPrinted = true
	prg.printLn()
	for ii := int32(1); ii <= 8; ii++ {
		k = byte(ii)
		_ = k
		prg.octant = prg.octantCode[k-1]
		h = uint16(int32(p) + int32(prg.octant))
		n = int32(*(*prg.mem[h].hh()).lh())
		w = *(*prg.mem[h].hh()).rh()
		if !(k&1 != 0) {
			w = *(*prg.mem[w].hh()).lh()
		} // in even octants, start at $w_[n+1]$
		for ii := int32(1); ii <= n+1; ii++ {
			m = ii
			_ = m
			if k&1 != 0 {
				ww = *(*prg.mem[w].hh()).rh()
			} else {
				ww = *(*prg.mem[w].hh()).lh()
			}
			if *prg.mem[int32(ww)+1].int() != *prg.mem[int32(w)+1].int() || *prg.mem[int32(ww)+2].int() != *prg.mem[int32(w)+2].int() {
				if nothingPrinted {
					nothingPrinted = false
				} else {
					prg.printNl(strNumber( /* " .. " */ 571))
				}
				prg.unskew(*prg.mem[int32(ww)+1].int(), *prg.mem[int32(ww)+2].int(), prg.octant)
				prg.printTwo(prg.curX, prg.curY)
			}
			w = ww
		}
	}
	if nothingPrinted {
		w = *(*prg.mem[int32(p)+firstOctant].hh()).rh()
		prg.printTwo(*prg.mem[int32(w)+1].int()+*prg.mem[int32(w)+2].int(), *prg.mem[int32(w)+2].int())
	}
	prg.printNl(strNumber( /* " .. cycle" */ 570))
	prg.endDiagnostic(true)
}

func (prg *prg) printDependency(p halfword, t smallNumber) {
	var (
		v     int32    // a coefficient
		pp, q halfword // for list manipulation
	)
	pp = p
	for true {
		v = abs(*prg.mem[int32(p)+1].int())
		q = *(*prg.mem[p].hh()).lh()
		if int32(q) == memMin {
			if v != 0 || int32(p) == int32(pp) {
				if *prg.mem[int32(p)+1].int() > 0 {
					if int32(p) != int32(pp) {
						prg.printChar(asciiCode('+'))
					}
				}
				prg.printScaled(*prg.mem[int32(p)+1].int())
			}

			goto exit
		}

		// Print the coefficient, unless it's $\pm1.0$
		if *prg.mem[int32(p)+1].int() < 0 {
			prg.printChar(asciiCode('-'))
		} else if int32(p) != int32(pp) {
			prg.printChar(asciiCode('+'))
		}
		if int32(t) == dependent {
			v = prg.roundFraction(v)
		}
		if v != 0200000 {
			prg.printScaled(v)
		}
		if int32(*(*prg.mem[q].hh()).b0()) != independent {
			prg.confusion(strNumber( /* "dep" */ 588))
		}
		// \xref[this can't happen dep][\quad dep]
		prg.printVariableName(q)
		v = *prg.mem[int32(q)+1].int() % sScale
		for v > 0 {
			prg.print( /* "*4" */ 589)
			v = v - 2
		}
		p = *(*prg.mem[p].hh()).rh()
	}

exit:
}

// \4
// Declare the procedure called |print_dp|
func (prg *prg) printDp(t smallNumber, p halfword, verbosity smallNumber) {
	var (
		q halfword // the node following |p|
	)
	q = *(*prg.mem[p].hh()).rh()
	if int32(*(*prg.mem[q].hh()).lh()) == memMin || int32(verbosity) > 0 {
		prg.printDependency(p, t)
	} else {
		prg.print( /* "linearform" */ 764)
	}
	// \xref[linearform]
}

// \4
// Declare the stashing/unstashing routines
func (prg *prg) stashCurExp() (r halfword) {
	var (
		p halfword // the capsule that will be returned
	)
	switch prg.curType {
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath, transformType, pairType, dependent,
		protoDependent, independent:
		p = uint16(prg.curExp)

	default:
		p = prg.getNode(valueNodeSize)
		*(*prg.mem[p].hh()).b1() = byte(capsule)
		*(*prg.mem[p].hh()).b0() = prg.curType
		*prg.mem[int32(p)+1].int() = prg.curExp

	}

	prg.curType = byte(vacuous)
	*(*prg.mem[p].hh()).rh() = uint16(memMin + 1)
	r = p
	return r
}

func (prg *prg) unstashCurExp(p halfword) {
	prg.curType = *(*prg.mem[p].hh()).b0()
	switch prg.curType {
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath, transformType, pairType, dependent,
		protoDependent, independent:
		prg.curExp = int32(p)

	default:
		prg.curExp = *prg.mem[int32(p)+1].int()
		prg.freeNode(p, halfword(valueNodeSize))

	}

}

func (prg *prg) printExp(p halfword, verbosity smallNumber) {
	var (
		restoreCurExp bool        // should |cur_exp| be restored?
		t             smallNumber // the type of the expression
		v             int32       // the value of the expression
		q             halfword    // a big node being displayed
	)
	if int32(p) != memMin {
		restoreCurExp = false
	} else {
		p = prg.stashCurExp()
		restoreCurExp = true
	}
	t = *(*prg.mem[p].hh()).b0()
	if int32(t) < dependent {
		v = *prg.mem[int32(p)+1].int()
	} else if int32(t) < independent {
		v = int32(*(*prg.mem[int32(p)+1].hh()).rh())
	}

	// Print an abbreviated value of |v| with format depending on |t|
	switch t {
	case vacuous:
		prg.print( /* "vacuous" */ 324)
	case booleanType:
		if v == trueCode {
			prg.print( /* "true" */ 348)
		} else {
			prg.print( /* "false" */ 349)
		}
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath, numericType:
		// Display a variable that's been declared but not defined
		prg.printType(t)
		if v != memMin {
			prg.printChar(asciiCode(' '))
			for int32(*(*prg.mem[v].hh()).b1()) == capsule && v != int32(p) {
				v = *prg.mem[v+1].int()
			}
			prg.printVariableName(halfword(v))
		}

	case stringType:
		prg.printChar(asciiCode('"'))
		prg.slowPrint(v)
		prg.printChar(asciiCode('"'))

	case penType, futurePen, pathType, pictureType:
		// Display a complex type
		if int32(verbosity) <= 1 {
			prg.printType(t)
		} else {
			if int32(prg.selector) == termAndLog {
				if prg.internal[tracingOnline-1] <= 0 {
					prg.selector = byte(termOnly)
					prg.printType(t)
					prg.print( /* " (see the transcript file)" */ 762)
					prg.selector = byte(termAndLog)
				}
			}
			switch t {
			case penType:
				prg.printPen(halfword(v), strNumber( /* "" */ 285), false)
			case futurePen:
				prg.printPath(halfword(v), strNumber( /* " (future pen)" */ 763), false)
			case pathType:
				prg.printPath(halfword(v), strNumber( /* "" */ 285), false)
			case pictureType:
				prg.curEdges = uint16(v)
				prg.printEdges(strNumber( /* "" */ 285), false, 0, 0)

			} // there are no other cases
		}

	case transformType, pairType:
		if v == memMin {
			prg.printType(t)
		} else {
			// Display a big node
			prg.printChar(asciiCode('('))
			q = uint16(v + int32(prg.bigNodeSize[t-13]))
			for {
				if int32(*(*prg.mem[v].hh()).b0()) == known {
					prg.printScaled(*prg.mem[v+1].int())
				} else if int32(*(*prg.mem[v].hh()).b0()) == independent {
					prg.printVariableName(halfword(v))
				} else {
					prg.printDp(*(*prg.mem[v].hh()).b0(), *(*prg.mem[v+1].hh()).rh(), verbosity)
				}
				v = v + 2
				if v != int32(q) {
					prg.printChar(asciiCode(','))
				}
				if v == int32(q) {
					break
				}
			}
			prg.printChar(asciiCode(')'))
		}

	case known:
		prg.printScaled(v)
	case dependent, protoDependent:
		prg.printDp(t, halfword(v), verbosity)
	case independent:
		prg.printVariableName(p)

	default:
		prg.confusion(strNumber( /* "exp" */ 761))
		// \xref[this can't happen exp][\quad exp]
	}
	if restoreCurExp {
		prg.unstashCurExp(p)
	}
}

func (prg *prg) dispErr(p halfword, s strNumber) {
	if int32(prg.interaction) == errorStopMode {
	}
	prg.printNl(strNumber( /* ">> " */ 765))
	// \xref[>>]
	prg.printExp(p, smallNumber(1)) // ``medium verbose'' printing of the expression
	if int32(s) != 285 {
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print(int32(s))
		// \xref[!\relax]
	}
}

// \4
// Declare basic dependency-list subroutines
func (prg *prg) pPlusFq(p halfword, f int32, q halfword,
	t, tt smallNumber) (r halfword) {
	var (
		pp, qq    halfword // |info(p)| and |info(q)|, respectively
		r1, s     halfword // for list manipulation
		threshold int32    // defines a neighborhood of zero
		v         int32    // temporary register
	)
	if int32(t) == dependent {
		threshold = fractionThreshold
	} else {
		threshold = scaledThreshold
	}
	r1 = uint16(3000 - 1)
	pp = *(*prg.mem[p].hh()).lh()
	qq = *(*prg.mem[q].hh()).lh()
	for true {
		if int32(pp) == int32(qq) {
			if int32(pp) == memMin {
				goto done
			} else {
				// Contribute a term from |p|, plus |f| times the corresponding term from |q|
				if int32(tt) == dependent {
					v = *prg.mem[int32(p)+1].int() + prg.takeFraction(f, *prg.mem[int32(q)+1].int())
				} else {
					v = *prg.mem[int32(p)+1].int() + prg.takeScaled(f, *prg.mem[int32(q)+1].int())
				}
				*prg.mem[int32(p)+1].int() = v
				s = p
				p = *(*prg.mem[p].hh()).rh()
				if abs(v) < threshold {
					prg.freeNode(s, halfword(depNodeSize))
				} else {
					if abs(v) >= 04525252525 {
						if prg.watchCoefs {
							*(*prg.mem[qq].hh()).b0() = byte(independentNeedingFix)
							prg.fixNeeded = true
						}
					}
					*(*prg.mem[r1].hh()).rh() = s
					r1 = s
				}
				pp = *(*prg.mem[p].hh()).lh()
				q = *(*prg.mem[q].hh()).rh()
				qq = *(*prg.mem[q].hh()).lh()
			}
		} else if *prg.mem[int32(pp)+1].int() < *prg.mem[int32(qq)+1].int() {
			if int32(tt) == dependent {
				v = prg.takeFraction(f, *prg.mem[int32(q)+1].int())
			} else {
				v = prg.takeScaled(f, *prg.mem[int32(q)+1].int())
			}
			if abs(v) > threshold/2 {
				s = prg.getNode(depNodeSize)
				*(*prg.mem[s].hh()).lh() = qq
				*prg.mem[int32(s)+1].int() = v
				if abs(v) >= 04525252525 {
					if prg.watchCoefs {
						*(*prg.mem[qq].hh()).b0() = byte(independentNeedingFix)
						prg.fixNeeded = true
					}
				}
				*(*prg.mem[r1].hh()).rh() = s
				r1 = s
			}
			q = *(*prg.mem[q].hh()).rh()
			qq = *(*prg.mem[q].hh()).lh()
		} else {
			*(*prg.mem[r1].hh()).rh() = p
			r1 = p
			p = *(*prg.mem[p].hh()).rh()
			pp = *(*prg.mem[p].hh()).lh()
		}
	}

done:
	if int32(t) == dependent {
		*prg.mem[int32(p)+1].int() = prg.slowAdd(*prg.mem[int32(p)+1].int(), prg.takeFraction(*prg.mem[int32(q)+1].int(), f))
	} else {
		*prg.mem[int32(p)+1].int() = prg.slowAdd(*prg.mem[int32(p)+1].int(), prg.takeScaled(*prg.mem[int32(q)+1].int(), f))
	}
	*(*prg.mem[r1].hh()).rh() = p
	prg.depFinal = p
	r = *(*prg.mem[3000-1].hh()).rh()
	return r
}

func (prg *prg) pOverV(p halfword, v scaled,
	t0, t1 smallNumber) (r halfword) {
	var (
		r1, s       halfword // for list manipulation
		w           int32    // tentative coefficient
		threshold   int32
		scalingDown bool
	)
	if int32(t0) != int32(t1) {
		scalingDown = true
	} else {
		scalingDown = false
	}
	if int32(t1) == dependent {
		threshold = halfFractionThreshold
	} else {
		threshold = halfScaledThreshold
	}
	r1 = uint16(3000 - 1)
	for int32(*(*prg.mem[p].hh()).lh()) != memMin {
		if scalingDown {
			if abs(v) < 02000000 {
				w = prg.makeScaled(*prg.mem[int32(p)+1].int(), v*010000)
			} else {
				w = prg.makeScaled(prg.roundFraction(*prg.mem[int32(p)+1].int()), v)
			}
		} else {
			w = prg.makeScaled(*prg.mem[int32(p)+1].int(), v)
		}
		if abs(w) <= threshold {
			s = *(*prg.mem[p].hh()).rh()
			prg.freeNode(p, halfword(depNodeSize))
			p = s
		} else {
			if abs(w) >= 04525252525 {
				prg.fixNeeded = true
				*(*prg.mem[*(*prg.mem[p].hh()).lh()].hh()).b0() = byte(independentNeedingFix)
			}
			*(*prg.mem[r1].hh()).rh() = p
			r1 = p
			*prg.mem[int32(p)+1].int() = w
			p = *(*prg.mem[p].hh()).rh()
		}
	}
	*(*prg.mem[r1].hh()).rh() = p
	*prg.mem[int32(p)+1].int() = prg.makeScaled(*prg.mem[int32(p)+1].int(), v)
	r = *(*prg.mem[3000-1].hh()).rh()
	return r
}

func (prg *prg) valTooBig(x scaled) {
	if prg.internal[warningCheck-1] > 0 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Value is too large (" */ 590) /* \xref[!\relax]  */
		}
		prg.printScaled(x)
		prg.printChar(asciiCode(')'))
		// \xref[Value is too large]
		{
			prg.helpPtr = 4
			prg.helpLine[3] = /* "The equation I just processed has given some variable" */ 591
			prg.helpLine[2] = /* "a value of 4096 or more. Continue and I'll try to cope" */ 592
			prg.helpLine[1] = /* "with that big value; but it might be dangerous." */ 593
			prg.helpLine[0] = /* "(Set warningcheck:=0 to suppress this message.)" */ 594
		}
		prg.error1()
	}
}

func (prg *prg) makeKnown(p, q halfword) {
	var (
		t /* dependent..protoDependent */ byte // the previous type
	)
	*(*prg.mem[int32(*(*prg.mem[q].hh()).rh())+1].hh()).lh() = *(*prg.mem[int32(p)+1].hh()).lh()
	*(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh() = *(*prg.mem[q].hh()).rh()
	t = *(*prg.mem[p].hh()).b0()
	*(*prg.mem[p].hh()).b0() = byte(known)
	*prg.mem[int32(p)+1].int() = *prg.mem[int32(q)+1].int()
	prg.freeNode(q, halfword(depNodeSize))
	if abs(*prg.mem[int32(p)+1].int()) >= 02000000000 {
		prg.valTooBig(*prg.mem[int32(p)+1].int())
	}
	if prg.internal[tracingEquations-1] > 0 {
		if prg.interesting(p) {
			prg.beginDiagnostic()
			prg.printNl(strNumber( /* "#### " */ 595))
			// \xref[]]]\#\#\#\#_][\.[\#\#\#\#]]
			prg.printVariableName(p)
			prg.printChar(asciiCode('='))
			prg.printScaled(*prg.mem[int32(p)+1].int())
			prg.endDiagnostic(false)
		}
	}
	if prg.curExp == int32(p) {
		if int32(prg.curType) == int32(t) {
			prg.curType = byte(known)
			prg.curExp = *prg.mem[int32(p)+1].int()
			prg.freeNode(p, halfword(valueNodeSize))
		}
	}
}

func (prg *prg) fixDependencies() {
	var (
		p, q, r1, s, t halfword // list manipulation registers
		x              halfword // an independent variable
	)
	r1 = *(*prg.mem[memMin+3+10].hh()).rh()
	s = uint16(memMin)
	for int32(r1) != memMin+3+10 {
		t = r1

		// Run through the dependency list for variable |t|, fixing all nodes, and ending with final link~|q|
		r1 = uint16(int32(t) + 1) // |link(r)=dep_list(t)|
		for true {
			q = *(*prg.mem[r1].hh()).rh()
			x = *(*prg.mem[q].hh()).lh()
			if int32(x) == memMin {
				goto done
			}
			if int32(*(*prg.mem[x].hh()).b0()) <= independentBeingFixed {
				if int32(*(*prg.mem[x].hh()).b0()) < independentBeingFixed {
					p = prg.getAvail()
					*(*prg.mem[p].hh()).rh() = s
					s = p
					*(*prg.mem[s].hh()).lh() = x
					*(*prg.mem[x].hh()).b0() = byte(independentBeingFixed)
				}
				*prg.mem[int32(q)+1].int() = *prg.mem[int32(q)+1].int() / 4
				if *prg.mem[int32(q)+1].int() == 0 {
					*(*prg.mem[r1].hh()).rh() = *(*prg.mem[q].hh()).rh()
					prg.freeNode(q, halfword(depNodeSize))
					q = r1
				}
			}
			r1 = q
		}

	done:
		;
		r1 = *(*prg.mem[q].hh()).rh()
		if int32(q) == int32(*(*prg.mem[int32(t)+1].hh()).rh()) {
			prg.makeKnown(t, q)
		}
	}
	for int32(s) != memMin {
		p = *(*prg.mem[s].hh()).rh()
		x = *(*prg.mem[s].hh()).lh()
		{
			*(*prg.mem[s].hh()).rh() = prg.avail
			prg.avail = s
			prg.dynUsed = prg.dynUsed - 1
		}
		s = p
		*(*prg.mem[x].hh()).b0() = byte(independent)
		*prg.mem[int32(x)+1].int() = *prg.mem[int32(x)+1].int() + 2
	}
	prg.fixNeeded = false
}

// \4
// Declare the recycling subroutines
func (prg *prg) tossKnotList(p halfword) {
	var (
		q  halfword // the node being freed
		r1 halfword // the next node
	)
	q = p
	for {
		r1 = *(*prg.mem[q].hh()).rh()
		prg.freeNode(q, halfword(knotNodeSize))
		q = r1
		if int32(q) == int32(p) {
			break
		}
	}
}

func (prg *prg) tossEdges(h halfword) {
	var (
		p, q halfword // for list manipulation
	)
	q = *(*prg.mem[h].hh()).rh()
	for int32(q) != int32(h) {
		prg.flushList(*(*prg.mem[int32(q)+1].hh()).rh())
		if int32(*(*prg.mem[int32(q)+1].hh()).lh()) > memMin+1 {
			prg.flushList(*(*prg.mem[int32(q)+1].hh()).lh())
		}
		p = q
		q = *(*prg.mem[q].hh()).rh()
		prg.freeNode(p, halfword(rowNodeSize))
	}
	prg.freeNode(h, halfword(edgeHeaderSize))
}

func (prg *prg) tossPen(p halfword) {
	var (
		k/* 1..8 */ byte          // relative header locations
		w, ww            halfword // pointers to offset nodes
	)
	if int32(p) != memMin+3 {
		for ii := int32(1); ii <= 8; ii++ {
			k = byte(ii)
			_ = k
			w = *(*prg.mem[int32(p)+int32(k)].hh()).rh()
			for {
				ww = *(*prg.mem[w].hh()).rh()
				prg.freeNode(w, halfword(coordNodeSize))
				w = ww
				if int32(w) == int32(*(*prg.mem[int32(p)+int32(k)].hh()).rh()) {
					break
				}
			}
		}
		prg.freeNode(p, halfword(penNodeSize))
	}
}

func (prg *prg) ringDelete(p halfword) {
	var (
		q halfword
	)
	q = uint16(*prg.mem[int32(p)+1].int())
	if int32(q) != memMin {
		if int32(q) != int32(p) {
			for *prg.mem[int32(q)+1].int() != int32(p) {
				q = uint16(*prg.mem[int32(q)+1].int())
			}
			*prg.mem[int32(q)+1].int() = *prg.mem[int32(p)+1].int()
		}
	}
}

func (prg *prg) recycleValue(p halfword) {
	var (
		t            smallNumber // a type code
		v            int32       // a value
		vv           int32       // another value
		q, r1, s, pp halfword    // link manipulation registers
	)
	t = *(*prg.mem[p].hh()).b0()
	if int32(t) < dependent {
		v = *prg.mem[int32(p)+1].int()
	}
	switch t {
	case undefined, vacuous, booleanType, known,
		numericType:
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath:
		prg.ringDelete(p)
	case stringType:
		if int32(prg.strRef[v]) < maxStrRef {
			if int32(prg.strRef[v]) > 1 {
				prg.strRef[v] = byte(int32(prg.strRef[v]) - 1)
			} else {
				prg.flushString(strNumber(v))
			}
		}
	case penType:
		if int32(*(*prg.mem[v].hh()).lh()) == memMin {
			prg.tossPen(halfword(v))
		} else {
			*(*prg.mem[v].hh()).lh() = uint16(int32(*(*prg.mem[v].hh()).lh()) - 1)
		}
	case pathType, futurePen:
		prg.tossKnotList(halfword(v))
	case pictureType:
		prg.tossEdges(halfword(v))
	case pairType, transformType:
		// Recycle a big node
		if v != memMin {
			q = uint16(v + int32(prg.bigNodeSize[t-13]))
			for {
				q = uint16(int32(q) - 2)
				prg.recycleValue(q)
				if int32(q) == v {
					break
				}
			}
			prg.freeNode(halfword(v), halfword(prg.bigNodeSize[t-13]))
		}

	case dependent, protoDependent:
		// Recycle a dependency list
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[q].hh()).lh()) != memMin {
			q = *(*prg.mem[q].hh()).rh()
		}
		*(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh() = *(*prg.mem[q].hh()).rh()
		*(*prg.mem[int32(*(*prg.mem[q].hh()).rh())+1].hh()).lh() = *(*prg.mem[int32(p)+1].hh()).lh()
		*(*prg.mem[q].hh()).rh() = uint16(memMin)
		prg.flushNodeList(*(*prg.mem[int32(p)+1].hh()).rh())

	case independent:
		// Recycle an independent variable
		prg.maxC[dependent-17] = 0
		prg.maxC[protoDependent-17] = 0

		prg.maxLink[dependent-17] = uint16(memMin)
		prg.maxLink[protoDependent-17] = uint16(memMin)

		q = *(*prg.mem[memMin+3+10].hh()).rh()
		for int32(q) != memMin+3+10 {
			s = uint16(int32(q) + 1) // now |link(s)=dep_list(q)|
			for true {
				r1 = *(*prg.mem[s].hh()).rh()
				if int32(*(*prg.mem[r1].hh()).lh()) == memMin {
					goto done
				}
				if int32(*(*prg.mem[r1].hh()).lh()) != int32(p) {
					s = r1
				} else {
					t = *(*prg.mem[q].hh()).b0()
					*(*prg.mem[s].hh()).rh() = *(*prg.mem[r1].hh()).rh()
					*(*prg.mem[r1].hh()).lh() = q
					if abs(*prg.mem[int32(r1)+1].int()) > prg.maxC[t-17] {
						if prg.maxC[t-17] > 0 {
							*(*prg.mem[prg.maxPtr[t-17]].hh()).rh() = prg.maxLink[t-17]
							prg.maxLink[t-17] = prg.maxPtr[t-17]
						}
						prg.maxC[t-17] = abs(*prg.mem[int32(r1)+1].int())
						prg.maxPtr[t-17] = r1
					} else {
						*(*prg.mem[r1].hh()).rh() = prg.maxLink[t-17]
						prg.maxLink[t-17] = r1
					}
				}
			}

		done:
			q = *(*prg.mem[r1].hh()).rh()
		}
		if prg.maxC[dependent-17] > 0 || prg.maxC[protoDependent-17] > 0 {
			if prg.maxC[dependent-17]/010000 >= prg.maxC[protoDependent-17] {
				t = byte(dependent)
			} else {
				t = byte(protoDependent)
			}

			// Determine the dependency list |s| to substitute for the independent variable~|p|
			s = prg.maxPtr[t-17]
			pp = *(*prg.mem[s].hh()).lh()
			v = *prg.mem[int32(s)+1].int()
			if int32(t) == dependent {
				*prg.mem[int32(s)+1].int() = -02000000000
			} else {
				*prg.mem[int32(s)+1].int() = -0200000
			}
			r1 = *(*prg.mem[int32(pp)+1].hh()).rh()
			*(*prg.mem[s].hh()).rh() = r1
			for int32(*(*prg.mem[r1].hh()).lh()) != memMin {
				r1 = *(*prg.mem[r1].hh()).rh()
			}
			q = *(*prg.mem[r1].hh()).rh()
			*(*prg.mem[r1].hh()).rh() = uint16(memMin)
			*(*prg.mem[int32(q)+1].hh()).lh() = *(*prg.mem[int32(pp)+1].hh()).lh()
			*(*prg.mem[*(*prg.mem[int32(pp)+1].hh()).lh()].hh()).rh() = q
			{
				if prg.serialNo > 017777777777-sScale {
					prg.overflow(strNumber( /* "independent variables" */ 587), prg.serialNo/sScale)
				} /* \xref[METAFONT capacity exceeded independent variables][\quad independent variables]  */
				*(*prg.mem[pp].hh()).b0() = byte(independent)
				prg.serialNo = prg.serialNo + sScale
				*prg.mem[int32(pp)+1].int() = prg.serialNo
			}
			if prg.curExp == int32(pp) {
				if int32(prg.curType) == int32(t) {
					prg.curType = byte(independent)
				}
			}
			if prg.internal[tracingEquations-1] > 0 {
				if prg.interesting(p) {
					prg.beginDiagnostic()
					prg.printNl(strNumber( /* "### " */ 767))
					// \xref[]]]\#\#\#_][\.[\#\#\#]]
					if v > 0 {
						prg.printChar(asciiCode('-'))
					}
					if int32(t) == dependent {
						vv = prg.roundFraction(prg.maxC[dependent-17])
					} else {
						vv = prg.maxC[protoDependent-17]
					}
					if vv != 0200000 {
						prg.printScaled(vv)
					}
					prg.printVariableName(p)
					for *prg.mem[int32(p)+1].int()%sScale > 0 {
						prg.print( /* "*4" */ 589)
						*prg.mem[int32(p)+1].int() = *prg.mem[int32(p)+1].int() - 2
					}
					if int32(t) == dependent {
						prg.printChar(asciiCode('='))
					} else {
						prg.print( /* " = " */ 768)
					}
					prg.printDependency(s, t)
					prg.endDiagnostic(false)
				}
			}
			t = byte(dependent + protoDependent - int32(t)) // complement |t|
			if prg.maxC[t-17] > 0 {
				*(*prg.mem[prg.maxPtr[t-17]].hh()).rh() = prg.maxLink[t-17]
				prg.maxLink[t-17] = prg.maxPtr[t-17]
			}
			if int32(t) != dependent {
				for ii := int32(dependent); ii <= protoDependent; ii++ {
					t = smallNumber(ii)
					_ = t
					r1 = prg.maxLink[t-17]
					for int32(r1) != memMin {
						q = *(*prg.mem[r1].hh()).lh()
						*(*prg.mem[int32(q)+1].hh()).rh() = prg.pPlusFq(*(*prg.mem[int32(q)+1].hh()).rh(), prg.makeFraction(*prg.mem[int32(r1)+1].int(), -v), s, t, smallNumber(dependent))
						if int32(*(*prg.mem[int32(q)+1].hh()).rh()) == int32(prg.depFinal) {
							prg.makeKnown(q, prg.depFinal)
						}
						q = r1
						r1 = *(*prg.mem[r1].hh()).rh()
						prg.freeNode(q, halfword(depNodeSize))
					}
				}
			} else {
				// Substitute new proto-dependencies in place of |p|
				for ii := int32(dependent); ii <= protoDependent; ii++ {
					t = smallNumber(ii)
					_ = t
					r1 = prg.maxLink[t-17]
					for int32(r1) != memMin {
						q = *(*prg.mem[r1].hh()).lh()
						if int32(t) == dependent {
							if prg.curExp == int32(q) {
								if int32(prg.curType) == dependent {
									prg.curType = byte(protoDependent)
								}
							}
							*(*prg.mem[int32(q)+1].hh()).rh() = prg.pOverV(*(*prg.mem[int32(q)+1].hh()).rh(), scaled(0200000), smallNumber(dependent), smallNumber(protoDependent))
							*(*prg.mem[q].hh()).b0() = byte(protoDependent)
							*prg.mem[int32(r1)+1].int() = prg.roundFraction(*prg.mem[int32(r1)+1].int())
						}
						*(*prg.mem[int32(q)+1].hh()).rh() = prg.pPlusFq(*(*prg.mem[int32(q)+1].hh()).rh(), prg.makeScaled(*prg.mem[int32(r1)+1].int(), -v), s, smallNumber(protoDependent), smallNumber(protoDependent))
						if int32(*(*prg.mem[int32(q)+1].hh()).rh()) == int32(prg.depFinal) {
							prg.makeKnown(q, prg.depFinal)
						}
						q = r1
						r1 = *(*prg.mem[r1].hh()).rh()
						prg.freeNode(q, halfword(depNodeSize))
					}
				}
			}
			prg.flushNodeList(s)
			if prg.fixNeeded {
				prg.fixDependencies()
			}
			{
				if prg.arithError {
					prg.clearArith()
				}
			}
		}

	case tokenList, structured:
		prg.confusion(strNumber( /* "recycle" */ 766))
	// \xref[this can't happen recycle][\quad recycle]
	case unsuffixedMacro, suffixedMacro:
		prg.deleteMacRef(halfword(*prg.mem[int32(p)+1].int()))
	} // there are no other cases
	*(*prg.mem[p].hh()).b0() = byte(undefined)
}

// \4
// Declare the procedure called |flush_cur_exp|
func (prg *prg) flushCurExp(v scaled) {
	switch prg.curType {
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath, transformType, pairType, dependent,
		protoDependent, independent:
		prg.recycleValue(halfword(prg.curExp))
		prg.freeNode(halfword(prg.curExp), halfword(valueNodeSize))

	case penType:
		if int32(*(*prg.mem[prg.curExp].hh()).lh()) == memMin {
			prg.tossPen(halfword(prg.curExp))
		} else {
			*(*prg.mem[prg.curExp].hh()).lh() = uint16(int32(*(*prg.mem[prg.curExp].hh()).lh()) - 1)
		}
	case stringType:
		if int32(prg.strRef[prg.curExp]) < maxStrRef {
			if int32(prg.strRef[prg.curExp]) > 1 {
				prg.strRef[prg.curExp] = byte(int32(prg.strRef[prg.curExp]) - 1)
			} else {
				prg.flushString(strNumber(prg.curExp))
			}
		}
	case futurePen, pathType:
		prg.tossKnotList(halfword(prg.curExp))
	case pictureType:
		prg.tossEdges(halfword(prg.curExp))

	default:
	}

	prg.curType = byte(known)
	prg.curExp = v
}

func (prg *prg) flushError(v scaled) { prg.error1(); prg.flushCurExp(v) } // \2

func (prg *prg) putGetError() { prg.backError(); prg.getXNext() }

func (prg *prg) putGetFlushError(v scaled) {
	prg.putGetError()
	prg.flushCurExp(v)
}

// \4
// Declare the procedure called |flush_below_variable|
func (prg *prg) flushBelowVariable(p halfword) {
	var (
		q, r1 halfword // list manipulation registers
	)
	if int32(*(*prg.mem[p].hh()).b0()) != structured {
		prg.recycleValue(p)
	} else {
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[q].hh()).b1()) == subscr {
			prg.flushBelowVariable(q)
			r1 = q
			q = *(*prg.mem[q].hh()).rh()
			prg.freeNode(r1, halfword(subscrNodeSize))
		}
		r1 = *(*prg.mem[int32(p)+1].hh()).lh()
		q = *(*prg.mem[r1].hh()).rh()
		prg.recycleValue(r1)
		if int32(*(*prg.mem[p].hh()).b1()) <= savedRoot {
			prg.freeNode(r1, halfword(valueNodeSize))
		} else {
			prg.freeNode(r1, halfword(subscrNodeSize))
		}
		// we assume that |subscr_node_size=attr_node_size|
		for {
			prg.flushBelowVariable(q)
			r1 = q
			q = *(*prg.mem[q].hh()).rh()
			prg.freeNode(r1, halfword(attrNodeSize))
			if int32(q) == memMin+3+10+2+2 {
				break
			}
		}
		*(*prg.mem[p].hh()).b0() = byte(undefined)
	}
}

func (prg *prg) flushVariable(p, t halfword, discardSuffixes bool) {
	var (
		q, r1 halfword // list manipulation
		n     halfword // attribute to match
	)
	for int32(t) != memMin {
		if int32(*(*prg.mem[p].hh()).b0()) != structured {
			goto exit
		}
		n = *(*prg.mem[t].hh()).lh()
		t = *(*prg.mem[t].hh()).rh()
		if int32(n) == collectiveSubscript {
			r1 = uint16(int32(p) + 1)
			q = *(*prg.mem[r1].hh()).rh() // |q=subscr_head(p)|
			for int32(*(*prg.mem[q].hh()).b1()) == subscr {
				prg.flushVariable(q, t, discardSuffixes)
				if int32(t) == memMin {
					if int32(*(*prg.mem[q].hh()).b0()) == structured {
						r1 = q
					} else {
						*(*prg.mem[r1].hh()).rh() = *(*prg.mem[q].hh()).rh()
						prg.freeNode(q, halfword(subscrNodeSize))
					}
				} else {
					r1 = q
				}
				q = *(*prg.mem[r1].hh()).rh()
			}
		}
		p = *(*prg.mem[int32(p)+1].hh()).lh()
		for {
			r1 = p
			p = *(*prg.mem[p].hh()).rh()
			if int32(*(*prg.mem[int32(p)+2].hh()).lh()) >= int32(n) {
				break
			}
		}
		if int32(*(*prg.mem[int32(p)+2].hh()).lh()) != int32(n) {
			goto exit
		}
	}
	if discardSuffixes {
		prg.flushBelowVariable(p)
	} else {
		if int32(*(*prg.mem[p].hh()).b0()) == structured {
			p = *(*prg.mem[int32(p)+1].hh()).lh()
		}
		prg.recycleValue(p)
	}

exit:
}

// 248.

// tangle:pos ../../mf.web:5518:3:

// Just before assigning a new value to a variable, we will recycle the
// old value and make the old value undefined. The |und_type| routine
// determines what type of undefined value should be given, based on
// the current type before recycling.
func (prg *prg) undType(p halfword) (r smallNumber) {
	switch *(*prg.mem[p].hh()).b0() {
	case undefined, vacuous:
		r = byte(undefined)
	case booleanType, unknownBoolean:
		r = byte(unknownBoolean)
	case stringType, unknownString:
		r = byte(unknownString)
	case penType, unknownPen, futurePen:
		r = byte(unknownPen)
	case pathType, unknownPath:
		r = byte(unknownPath)
	case pictureType, unknownPicture:
		r = byte(unknownPicture)
	case transformType, pairType, numericType:
		r = *(*prg.mem[p].hh()).b0()
	case known, dependent, protoDependent, independent:
		r = byte(numericType)
	} // there are no other cases
	return r
}

// 249.

// tangle:pos ../../mf.web:5536:3:

// The |clear_symbol| routine is used when we want to redefine the equivalent
// of a symbolic token. It must remove any variable structure or macro
// definition that is currently attached to that symbol. If the |saving|
// parameter is true, a subsidiary structure is saved instead of destroyed.
func (prg *prg) clearSymbol(p halfword, saving bool) {
	var (
		q halfword // |equiv(p)|
	)
	q = *prg.eqtb[p-1].rh()
	switch int32(*prg.eqtb[p-1].lh()) % outerTag {
	case definedMacro, secondaryPrimaryMacro, tertiarySecondaryMacro, expressionTertiaryMacro:
		if !saving {
			prg.deleteMacRef(q)
		}
	case tagToken:
		if int32(q) != memMin {
			if saving {
				*(*prg.mem[q].hh()).b1() = byte(savedRoot)
			} else {
				prg.flushBelowVariable(q)
				prg.freeNode(q, halfword(valueNodeSize))
			}
		}

	default:
	}

	prg.eqtb[p-1] = prg.eqtb[hashBase+hashSize+12-1]
}

// 252.

// tangle:pos ../../mf.web:5596:3:

// The |save_variable| routine is given a hash address |q|; it salts this
// address away in the save stack, together with its current equivalent,
// then makes token~|q| behave as though it were brand new.
//
// Nothing is stacked when |save_ptr=null|, however; there's no way to remove
// things from the stack when the program is not inside a group, so there's
// no point in wasting the space.
func (prg *prg) saveVariable(q halfword) {
	var (
		p halfword // temporary register
	)
	if int32(prg.savePtr) != memMin {
		p = prg.getNode(saveNodeSize)
		*(*prg.mem[p].hh()).lh() = q
		*(*prg.mem[p].hh()).rh() = prg.savePtr
		*prg.mem[int32(p)+1].hh() = prg.eqtb[q-1]
		prg.savePtr = p
	}
	prg.clearSymbol(q, int32(prg.savePtr) != memMin)
}

// 253.

// tangle:pos ../../mf.web:5613:3:

// Similarly, |save_internal| is given the location |q| of an internal
// quantity like |tracing_pens|. It creates a save stack entry of the
// third kind.
func (prg *prg) saveInternal(q halfword) {
	var (
		p halfword // new item for the save stack
	)
	if int32(prg.savePtr) != memMin {
		p = prg.getNode(saveNodeSize)
		*(*prg.mem[p].hh()).lh() = uint16(hashBase + hashSize + 12 + int32(q))
		*(*prg.mem[p].hh()).rh() = prg.savePtr
		*prg.mem[int32(p)+1].int() = prg.internal[q-1]
		prg.savePtr = p
	}
}

// 254.

// tangle:pos ../../mf.web:5625:3:

// At the end of a group, the |unsave| routine restores all of the saved
// equivalents in reverse order. This routine will be called only when there
// is at least one boundary item on the save stack.
func (prg *prg) unsave() {
	var (
		q halfword // index to saved item
		p halfword // temporary register
	)
	for int32(*(*prg.mem[prg.savePtr].hh()).lh()) != 0 {
		q = *(*prg.mem[prg.savePtr].hh()).lh()
		if int32(q) > hashBase+hashSize+12 {
			if prg.internal[tracingRestores-1] > 0 {
				prg.beginDiagnostic()
				prg.printNl(strNumber( /* "[restoring " */ 516))
				prg.slowPrint(int32(prg.intName[int32(q)-(hashBase+hashSize+12)-1]))
				prg.printChar(asciiCode('='))
				prg.printScaled(*prg.mem[int32(prg.savePtr)+1].int())
				prg.printChar(asciiCode('}'))
				prg.endDiagnostic(false)
			}
			prg.internal[int32(q)-(hashBase+hashSize+12)-1] = *prg.mem[int32(prg.savePtr)+1].int()
		} else {
			if prg.internal[tracingRestores-1] > 0 {
				prg.beginDiagnostic()
				prg.printNl(strNumber( /* "[restoring " */ 516))
				prg.slowPrint(int32(*prg.hash[q-1].rh()))
				prg.printChar(asciiCode('}'))
				prg.endDiagnostic(false)
			}
			prg.clearSymbol(q, false)
			prg.eqtb[q-1] = *prg.mem[int32(prg.savePtr)+1].hh()
			if int32(*prg.eqtb[q-1].lh())%outerTag == tagToken {
				p = *prg.eqtb[q-1].rh()
				if int32(p) != memMin {
					*(*prg.mem[p].hh()).b1() = byte(root)
				}
			}
		}
		p = *(*prg.mem[prg.savePtr].hh()).rh()
		prg.freeNode(prg.savePtr, halfword(saveNodeSize))
		prg.savePtr = p
	}
	p = *(*prg.mem[prg.savePtr].hh()).rh()
	{
		*(*prg.mem[prg.savePtr].hh()).rh() = prg.avail
		prg.avail = prg.savePtr
		prg.dynUsed = prg.dynUsed - 1
	}
	prg.savePtr = p
}

// 255. \[17] Data structures for paths

// tangle:pos ../../mf.web:5660:36:

// When a \MF\ user specifies a path, \MF\ will create a list of knots
// and control points for the associated cubic spline curves. If the
// knots are $z_0$, $z_1$, \dots, $z_n$, there are control points
// $z_k^+$ and $z_[k+1]^-$ such that the cubic splines between knots
// $z_k$ and $z_[k+1]$ are defined by B\'ezier's formula
// \xref[Bezier][B\'ezier, Pierre Etienne]
// $$\eqalign[z(t)&=B(z_k,z_k^+,z_[k+1]^-,z_[k+1];t)\cr
// &=(1-t)^3z_k+3(1-t)^2tz_k^++3(1-t)t^2z_[k+1]^-+t^3z_[k+1]\cr]$$
// for |0<=t<=1|.
//
// There is a 7-word node for each knot $z_k$, containing one word of
// control information and six words for the |x| and |y| coordinates
// of $z_k^-$ and $z_k$ and~$z_k^+$. The control information appears
// in the |left_type| and |right_type| fields, which each occupy
// a quarter of the first word in the node; they specify properties
// of the curve as it enters and leaves the knot. There's also a
// halfword |link| field, which points to the following knot.
//
// If the path is a closed contour, knots 0 and |n| are identical;
// i.e., the |link| in knot |n-1| points to knot~0. But if the path
// is not closed, the |left_type| of knot~0 and the |right_type| of knot~|n|
// are equal to |endpoint|. In the latter case the |link| in knot~|n| points
// to knot~0, and the control points $z_0^-$ and $z_n^+$ are not used.

// 256.

// tangle:pos ../../mf.web:5696:3:

// Before the B\'ezier control points have been calculated, the memory
// space they will ultimately occupy is taken up by information that can be
// used to compute them. There are four cases:
//
// \yskip
// \textindent[$\bullet$] If |right_type=open|, the curve should leave
// the knot in the same direction it entered; \MF\ will figure out a
// suitable direction.
//
// \yskip
// \textindent[$\bullet$] If |right_type=curl|, the curve should leave the
// knot in a direction depending on the angle at which it enters the next
// knot and on the curl parameter stored in |right_curl|.
//
// \yskip
// \textindent[$\bullet$] If |right_type=given|, the curve should leave the
// knot in a nonzero direction stored as an |angle| in |right_given|.
//
// \yskip
// \textindent[$\bullet$] If |right_type=explicit|, the B\'ezier control
// point for leaving this knot has already been computed; it is in the
// |right_x| and |right_y| fields.
//
// \yskip\noindent
// The rules for |left_type| are similar, but they refer to the curve entering
// the knot, and to \\[left] fields instead of \\[right] fields.
//
// Non-|explicit| control points will be chosen based on ``tension'' parameters
// in the |left_tension| and |right_tension| fields. The
// `\&[atleast]' option is represented by negative tension values.
// \xref[at_least_][\&[atleast] primitive]
//
// For example, the \MF\ path specification
// $$\.[z0..z1..tension atleast 1..\[curl 2\]z2..z3\[-1,-2\]..tension
//   3 and 4..p],$$
// where \.p is the path `\.[z4..controls z45 and z54..z5]', will be represented
// by the six knots
// \def\lodash[\hbox to 1.1em[\thinspace\hrulefill\thinspace]]
// $$\vbox[\halign[#\hfil&&\qquad#\hfil\cr
// |left_type|&\\[left] info&|x_coord,y_coord|&|right_type|&\\[right] info\cr
// \noalign[\yskip]
// |endpoint|&\lodash$,\,$\lodash&$x_0,y_0$&|curl|&$1.0,1.0$\cr
// |open|&\lodash$,1.0$&$x_1,y_1$&|open|&\lodash$,-1.0$\cr
// |curl|&$2.0,-1.0$&$x_2,y_2$&|curl|&$2.0,1.0$\cr
// |given|&$d,1.0$&$x_3,y_3$&|given|&$d,3.0$\cr
// |open|&\lodash$,4.0$&$x_4,y_4$&|explicit|&$x_[45],y_[45]$\cr
// |explicit|&$x_[54],y_[54]$&$x_5,y_5$&|endpoint|&\lodash$,\,$\lodash\cr]]$$
// Here |d| is the |angle| obtained by calling |n_arg(-unity,-two)|.
// Of course, this example is more complicated than anything a normal user
// would ever write.
//
// These types must satisfy certain restrictions because of the form of \MF's
// path syntax:
// (i)~|open| type never appears in the same node together with |endpoint|,
// |given|, or |curl|.
// (ii)~The |right_type| of a node is |explicit| if and only if the
// |left_type| of the following node is |explicit|.
// (iii)~|endpoint| types occur only at the ends, as mentioned above.

// 264.

// tangle:pos ../../mf.web:5865:3:

// If we want to duplicate a knot node, we can say |copy_knot|:
func (prg *prg) copyKnot(p halfword) (r halfword) {
	var (
		q                             halfword // the copy
		k/* 0..knotNodeSize-1 */ byte          // runs through the words of a knot node
	)
	q = prg.getNode(knotNodeSize)
	for ii := int32(0); ii <= knotNodeSize-1; ii++ {
		k = byte(ii)
		_ = k
		prg.mem[int32(q)+int32(k)] = prg.mem[int32(p)+int32(k)]
	}
	r = q
	return r
}

// 265.

// tangle:pos ../../mf.web:5875:3:

// The |copy_path| routine makes a clone of a given path.
func (prg *prg) copyPath(p halfword) (r halfword) {
	var (
		q, pp, qq halfword // for list manipulation
	)
	q = prg.getNode(knotNodeSize) // this will correspond to |p|
	qq = q
	pp = p
	for true {
		*(*prg.mem[qq].hh()).b0() = *(*prg.mem[pp].hh()).b0()
		*(*prg.mem[qq].hh()).b1() = *(*prg.mem[pp].hh()).b1()

		*prg.mem[int32(qq)+1].int() = *prg.mem[int32(pp)+1].int()
		*prg.mem[int32(qq)+2].int() = *prg.mem[int32(pp)+2].int()

		*prg.mem[int32(qq)+3].int() = *prg.mem[int32(pp)+3].int()
		*prg.mem[int32(qq)+4].int() = *prg.mem[int32(pp)+4].int()

		*prg.mem[int32(qq)+5].int() = *prg.mem[int32(pp)+5].int()
		*prg.mem[int32(qq)+6].int() = *prg.mem[int32(pp)+6].int()

		if int32(*(*prg.mem[pp].hh()).rh()) == int32(p) {
			*(*prg.mem[qq].hh()).rh() = q
			r = q
			goto exit
		}
		*(*prg.mem[qq].hh()).rh() = prg.getNode(knotNodeSize)
		qq = *(*prg.mem[qq].hh()).rh()
		pp = *(*prg.mem[pp].hh()).rh()
	}

exit:
	;
	return r
}

// 266.

// tangle:pos ../../mf.web:5894:3:

// Similarly, there's a way to copy the [\sl reverse\/] of a path. This procedure
// returns a pointer to the first node of the copy, if the path is a cycle,
// but to the final node of a non-cyclic copy. The global
// variable |path_tail| will point to the final node of the original path;
// this trick makes it easier to implement `\&[doublepath]'.
//
// All node types are assumed to be |endpoint| or |explicit| only.
func (prg *prg) htapYpoc(p halfword) (r halfword) {
	var (
		q, pp, qq, rr halfword // for list manipulation
	)
	q = prg.getNode(knotNodeSize) // this will correspond to |p|
	qq = q
	pp = p
	for true {
		*(*prg.mem[qq].hh()).b1() = *(*prg.mem[pp].hh()).b0()
		*(*prg.mem[qq].hh()).b0() = *(*prg.mem[pp].hh()).b1()

		*prg.mem[int32(qq)+1].int() = *prg.mem[int32(pp)+1].int()
		*prg.mem[int32(qq)+2].int() = *prg.mem[int32(pp)+2].int()

		*prg.mem[int32(qq)+5].int() = *prg.mem[int32(pp)+3].int()
		*prg.mem[int32(qq)+6].int() = *prg.mem[int32(pp)+4].int()

		*prg.mem[int32(qq)+3].int() = *prg.mem[int32(pp)+5].int()
		*prg.mem[int32(qq)+4].int() = *prg.mem[int32(pp)+6].int()

		if int32(*(*prg.mem[pp].hh()).rh()) == int32(p) {
			*(*prg.mem[q].hh()).rh() = qq
			prg.pathTail = pp
			r = q
			goto exit
		}
		rr = prg.getNode(knotNodeSize)
		*(*prg.mem[rr].hh()).rh() = qq
		qq = rr
		pp = *(*prg.mem[pp].hh()).rh()
	}

exit:
	;
	return r
}

// 269. \[18] Choosing control points

// tangle:pos ../../mf.web:5933:34:

// Now we must actually delve into one of \MF's more difficult routines,
// the |make_choices| procedure that chooses angles and control points for
// the splines of a curve when the user has not specified them explicitly.
// The parameter to |make_choices| points to a list of knots and
// path information, as described above.
//
// A path decomposes into independent segments at “breakpoint” knots,
// which are knots whose left and right angles are both prespecified in
// some way (i.e., their |left_type| and |right_type| aren't both open).
// \4
// Declare the procedure called |solve_choices|
// \4
// Declare subroutines needed by |solve_choices|
func (prg *prg) curlRatio(gamma, aTension, bTension scaled) (r fraction) {
	var (
		alpha, beta, num, denom, ff fraction // registers
	)
	alpha = prg.makeFraction(0200000, aTension)
	beta = prg.makeFraction(0200000, bTension)

	if alpha <= beta {
		ff = prg.makeFraction(alpha, beta)
		ff = prg.takeFraction(ff, ff)
		gamma = prg.takeFraction(gamma, ff)

		beta = beta / 010000 // convert |fraction| to |scaled|
		denom = prg.takeFraction(gamma, alpha) + 0600000 - beta
		num = prg.takeFraction(gamma, 06000000000-alpha) + beta
	} else {
		ff = prg.makeFraction(beta, alpha)
		ff = prg.takeFraction(ff, ff)
		beta = prg.takeFraction(beta, ff) / 010000 // convert |fraction| to |scaled|
		denom = prg.takeFraction(gamma, alpha) + ff/1365 - beta
		// $1365\approx 2^[12]/3$
		num = prg.takeFraction(gamma, 06000000000-alpha) + beta
	}
	if num >= denom+denom+denom+denom {
		r = 010000000000
	} else {
		r = prg.makeFraction(num, denom)
	}
	return r
}

func (prg *prg) setControls(p, q halfword, k int32) {
	var (
		rr, ss fraction // velocities, divided by thrice the tension
		lt, rt scaled   // tensions
		sine   fraction // $\sin(\theta+\phi)$
	)
	lt = abs(*prg.mem[int32(q)+4].int())
	rt = abs(*prg.mem[int32(p)+6].int())
	rr = prg.velocity(prg.st, prg.ct, prg.sf, prg.cf, rt)
	ss = prg.velocity(prg.sf, prg.cf, prg.st, prg.ct, lt)
	if *prg.mem[int32(p)+6].int() < 0 || *prg.mem[int32(q)+4].int() < 0 {
		if prg.st >= 0 && prg.sf >= 0 || prg.st <= 0 && prg.sf <= 0 {
			sine = prg.takeFraction(abs(prg.st), prg.cf) + prg.takeFraction(abs(prg.sf), prg.ct)
			if sine > 0 {
				sine = prg.takeFraction(sine, 02000000000+0200000) // safety factor
				if *prg.mem[int32(p)+6].int() < 0 {
					if prg.abVsCd(abs(prg.sf), 02000000000, rr, sine) < 0 {
						rr = prg.makeFraction(abs(prg.sf), sine)
					}
				}
				if *prg.mem[int32(q)+4].int() < 0 {
					if prg.abVsCd(abs(prg.st), 02000000000, ss, sine) < 0 {
						ss = prg.makeFraction(abs(prg.st), sine)
					}
				}
			}
		}
	}
	*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int() + prg.takeFraction(prg.takeFraction(prg.deltaX[k], prg.ct)-prg.takeFraction(prg.deltaY[k], prg.st), rr)
	*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int() + prg.takeFraction(prg.takeFraction(prg.deltaY[k], prg.ct)+prg.takeFraction(prg.deltaX[k], prg.st), rr)
	*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+1].int() - prg.takeFraction(prg.takeFraction(prg.deltaX[k], prg.cf)+prg.takeFraction(prg.deltaY[k], prg.sf), ss)
	*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+2].int() - prg.takeFraction(prg.takeFraction(prg.deltaY[k], prg.cf)-prg.takeFraction(prg.deltaX[k], prg.sf), ss)
	*(*prg.mem[p].hh()).b1() = byte(explicit)
	*(*prg.mem[q].hh()).b0() = byte(explicit)
}

func (prg *prg) solveChoices(p, q halfword, n halfword) {
	var (
		k/* 0..pathSize */ uint16          // current knot number
		r1, s, t                  halfword // registers for list traversal

		// Other local variables for |solve_choices|
		aa, bb, cc, ff, acc fraction // temporary registers
		dd, ee              scaled   // likewise, but |scaled|
		lt, rt              scaled   // tension values
	)
	k = 0
	s = p
	for true {
		t = *(*prg.mem[s].hh()).rh()
		if int32(k) == 0 {
			switch *(*prg.mem[s].hh()).b1() {
			case given:
				if int32(*(*prg.mem[t].hh()).b0()) == given {
					aa = prg.nArg(prg.deltaX[0], prg.deltaY[0])

					prg.nSinCos(*prg.mem[int32(p)+5].int() - aa)
					prg.ct = prg.nCos
					prg.st = prg.nSin

					prg.nSinCos(*prg.mem[int32(q)+3].int() - aa)
					prg.cf = prg.nCos
					prg.sf = -prg.nSin

					prg.setControls(p, q, 0)
					goto exit
				} else {
					// Set up the equation for a given value of $\theta_0$
					prg.vv[0] = *prg.mem[int32(s)+5].int() - prg.nArg(prg.deltaX[0], prg.deltaY[0])
					if abs(prg.vv[0]) > 01320000000 {
						if prg.vv[0] > 0 {
							prg.vv[0] = prg.vv[0] - 02640000000
						} else {
							prg.vv[0] = prg.vv[0] + 02640000000
						}
					}
					prg.uu[0] = 0
					prg.ww[0] = 0
				}

			case curl:
				if int32(*(*prg.mem[t].hh()).b0()) == curl {
					*(*prg.mem[p].hh()).b1() = byte(explicit)
					*(*prg.mem[q].hh()).b0() = byte(explicit)
					lt = abs(*prg.mem[int32(q)+4].int())
					rt = abs(*prg.mem[int32(p)+6].int())
					if rt == 0200000 {
						if prg.deltaX[0] >= 0 {
							*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int() + (prg.deltaX[0]+1)/3
						} else {
							*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int() + (prg.deltaX[0]-1)/3
						}
						if prg.deltaY[0] >= 0 {
							*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int() + (prg.deltaY[0]+1)/3
						} else {
							*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int() + (prg.deltaY[0]-1)/3
						}
					} else {
						ff = prg.makeFraction(0200000, 3*rt) // $\alpha/3$
						*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int() + prg.takeFraction(prg.deltaX[0], ff)
						*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int() + prg.takeFraction(prg.deltaY[0], ff)
					}
					if lt == 0200000 {
						if prg.deltaX[0] >= 0 {
							*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+1].int() - (prg.deltaX[0]+1)/3
						} else {
							*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+1].int() - (prg.deltaX[0]-1)/3
						}
						if prg.deltaY[0] >= 0 {
							*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+2].int() - (prg.deltaY[0]+1)/3
						} else {
							*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+2].int() - (prg.deltaY[0]-1)/3
						}
					} else {
						ff = prg.makeFraction(0200000, 3*lt) // $\beta/3$
						*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+1].int() - prg.takeFraction(prg.deltaX[0], ff)
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+2].int() - prg.takeFraction(prg.deltaY[0], ff)
					}

					goto exit
				} else {
					// Set up the equation for a curl at $\theta_0$
					cc = *prg.mem[int32(s)+5].int()
					lt = abs(*prg.mem[int32(t)+4].int())
					rt = abs(*prg.mem[int32(s)+6].int())
					if rt == 0200000 && lt == 0200000 {
						prg.uu[0] = prg.makeFraction(cc+cc+0200000, cc+0400000)
					} else {
						prg.uu[0] = prg.curlRatio(cc, rt, lt)
					}
					prg.vv[0] = -prg.takeFraction(prg.psi[1-1], prg.uu[0])
					prg.ww[0] = 0
				}

			case open:
				prg.uu[0] = 0
				prg.vv[0] = 0
				prg.ww[0] = 02000000000
				// this begins a cycle
			}
		} else {
			switch *(*prg.mem[s].hh()).b0() {
			case endCycle, open:
				// Set up equation to match mock curvatures at $z_k$; then |goto found| with $\theta_n$ adjusted to equal $\theta_0$, if a cycle has ended
				if abs(*prg.mem[int32(r1)+6].int()) == 0200000 {
					aa = 01000000000
					dd = 2 * prg.delta[k]
				} else {
					aa = prg.makeFraction(0200000, 3*abs(*prg.mem[int32(r1)+6].int())-0200000)
					dd = prg.takeFraction(prg.delta[k],
						06000000000-prg.makeFraction(0200000, abs(*prg.mem[int32(r1)+6].int())))
				}
				if abs(*prg.mem[int32(t)+4].int()) == 0200000 {
					bb = 01000000000
					ee = 2 * prg.delta[int32(k)-1]
				} else {
					bb = prg.makeFraction(0200000, 3*abs(*prg.mem[int32(t)+4].int())-0200000)
					ee = prg.takeFraction(prg.delta[int32(k)-1],
						06000000000-prg.makeFraction(0200000, abs(*prg.mem[int32(t)+4].int())))
				}
				cc = 02000000000 - prg.takeFraction(prg.uu[int32(k)-1], aa)

				// Calculate the ratio $\\[ff]=C_k/(C_k+B_k-u_[k-1]A_k)$
				dd = prg.takeFraction(dd, cc)
				lt = abs(*prg.mem[int32(s)+4].int())
				rt = abs(*prg.mem[int32(s)+6].int())
				if lt != rt {
					if lt < rt {
						ff = prg.makeFraction(lt, rt)
						ff = prg.takeFraction(ff, ff) // $\alpha_k^2/\beta_k^2$
						dd = prg.takeFraction(dd, ff)
					} else {
						ff = prg.makeFraction(rt, lt)
						ff = prg.takeFraction(ff, ff) // $\beta_k^2/\alpha_k^2$
						ee = prg.takeFraction(ee, ff)
					}
				}
				ff = prg.makeFraction(ee, ee+dd)
				prg.uu[k] = prg.takeFraction(ff, bb)

				// Calculate the values of $v_k$ and $w_k$
				acc = -prg.takeFraction(prg.psi[int32(k)+1-1], prg.uu[k])
				if int32(*(*prg.mem[r1].hh()).b1()) == curl {
					prg.ww[k] = 0
					prg.vv[k] = acc - prg.takeFraction(prg.psi[1-1], 02000000000-ff)
				} else {
					ff = prg.makeFraction(02000000000-ff, cc) // this is
					//     $B_k/(C_k+B_k-u_[k-1]A_k)<5$

					acc = acc - prg.takeFraction(prg.psi[k-1], ff)
					ff = prg.takeFraction(ff, aa) // this is $A_k/(C_k+B_k-u_[k-1]A_k)$
					prg.vv[k] = acc - prg.takeFraction(prg.vv[int32(k)-1], ff)
					if prg.ww[int32(k)-1] == 0 {
						prg.ww[k] = 0
					} else {
						prg.ww[k] = -prg.takeFraction(prg.ww[int32(k)-1], ff)
					}
				}
				if int32(*(*prg.mem[s].hh()).b0()) == endCycle {
					aa = 0
					bb = 02000000000 // we have |k=n|
					for {
						k = uint16(int32(k) - 1)
						if int32(k) == 0 {
							k = n
						}
						aa = prg.vv[k] - prg.takeFraction(aa, prg.uu[k])
						bb = prg.ww[k] - prg.takeFraction(bb, prg.uu[k])
						if int32(k) == int32(n) {
							break
						}
					} // now $\theta_n=\\[aa]+\\[bb]\cdot\theta_n$
					aa = prg.makeFraction(aa, 02000000000-bb)
					prg.theta[n] = aa
					prg.vv[0] = aa
					for ii := int32(1); ii <= int32(n)-1; ii++ {
						k = uint16(ii)
						_ = k
						prg.vv[k] = prg.vv[k] + prg.takeFraction(aa, prg.ww[k])
					}

					goto found
				}

			case curl:
				// Set up equation for a curl at $\theta_n$ and |goto found|
				cc = *prg.mem[int32(s)+3].int()
				lt = abs(*prg.mem[int32(s)+4].int())
				rt = abs(*prg.mem[int32(r1)+6].int())
				if rt == 0200000 && lt == 0200000 {
					ff = prg.makeFraction(cc+cc+0200000, cc+0400000)
				} else {
					ff = prg.curlRatio(cc, lt, rt)
				}
				prg.theta[n] = -prg.makeFraction(prg.takeFraction(prg.vv[int32(n)-1], ff),
					02000000000-prg.takeFraction(ff, prg.uu[int32(n)-1]))

				goto found

			case given:
				// Calculate the given value of $\theta_n$ and |goto found|
				prg.theta[n] = *prg.mem[int32(s)+3].int() - prg.nArg(prg.deltaX[int32(n)-1], prg.deltaY[int32(n)-1])
				if abs(prg.theta[n]) > 01320000000 {
					if prg.theta[n] > 0 {
						prg.theta[n] = prg.theta[n] - 02640000000
					} else {
						prg.theta[n] = prg.theta[n] + 02640000000
					}
				}

				goto found

			}
		} // there are no other cases
		r1 = s
		s = t
		k = uint16(int32(k) + 1)
	}

found:
	for ii := int32(n) - 1; ii >= 0; ii-- {
		k = uint16(ii)
		_ = k
		prg.theta[k] = prg.vv[k] - prg.takeFraction(prg.theta[int32(k)+1], prg.uu[k])
	}
	s = p
	k = 0
	for {
		t = *(*prg.mem[s].hh()).rh()

		prg.nSinCos(prg.theta[k])
		prg.st = prg.nSin
		prg.ct = prg.nCos

		prg.nSinCos(-prg.psi[int32(k)+1-1] - prg.theta[int32(k)+1])
		prg.sf = prg.nSin
		prg.cf = prg.nCos

		prg.setControls(s, t, int32(k))

		k = uint16(int32(k) + 1)
		s = t
		if int32(k) == int32(n) {
			break
		}
	}

exit:
}

func (prg *prg) makeChoices(knots halfword) {
	var (
		h    halfword // the first breakpoint
		p, q halfword // consecutive breakpoints being processed

		// Other local variables for |make_choices|
		k, n/* 0..pathSize */ uint16          // current and final knot numbers
		s, t                         halfword // registers for list traversal
		delx, dely                   scaled   // directions where |open| meets |explicit|
		sine, cosine                 fraction // trig functions of various angles
	)
	{
		if prg.arithError {
			prg.clearArith()
		}
	} // make sure that |arith_error=false|
	if prg.internal[tracingChoices-1] > 0 {
		prg.printPath(knots, strNumber( /* ", before choices" */ 526), true)
	}

	// If consecutive knots are equal, join them explicitly
	p = knots
	for {
		q = *(*prg.mem[p].hh()).rh()
		if *prg.mem[int32(p)+1].int() == *prg.mem[int32(q)+1].int() {
			if *prg.mem[int32(p)+2].int() == *prg.mem[int32(q)+2].int() {
				if int32(*(*prg.mem[p].hh()).b1()) > explicit {
					*(*prg.mem[p].hh()).b1() = byte(explicit)
					if int32(*(*prg.mem[p].hh()).b0()) == open {
						*(*prg.mem[p].hh()).b0() = byte(curl)
						*prg.mem[int32(p)+3].int() = 0200000
					}
					*(*prg.mem[q].hh()).b0() = byte(explicit)
					if int32(*(*prg.mem[q].hh()).b1()) == open {
						*(*prg.mem[q].hh()).b1() = byte(curl)
						*prg.mem[int32(q)+5].int() = 0200000
					}
					*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int()
					*prg.mem[int32(q)+3].int() = *prg.mem[int32(p)+1].int()

					*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int()
					*prg.mem[int32(q)+4].int() = *prg.mem[int32(p)+2].int()
				}
			}
		}
		p = q
		if int32(p) == int32(knots) {
			break
		}
	}

	// Find the first breakpoint, |h|, on the path; insert an artificial breakpoint if the path is an unbroken cycle
	h = knots
	for true {
		if int32(*(*prg.mem[h].hh()).b0()) != open {
			goto done
		}
		if int32(*(*prg.mem[h].hh()).b1()) != open {
			goto done
		}
		h = *(*prg.mem[h].hh()).rh()
		if int32(h) == int32(knots) {
			*(*prg.mem[h].hh()).b0() = byte(endCycle)
			goto done
		}
	}

done:
	;
	p = h
	for {
		// Fill in the control points between |p| and the next breakpoint, then advance |p| to that breakpoint
		q = *(*prg.mem[p].hh()).rh()
		if int32(*(*prg.mem[p].hh()).b1()) >= given {
			for int32(*(*prg.mem[q].hh()).b0()) == open && int32(*(*prg.mem[q].hh()).b1()) == open {
				q = *(*prg.mem[q].hh()).rh()
			}

			// Fill in the control information between consecutive breakpoints |p| and |q|

			// Calculate the turning angles $\psi_k$ and the distances $d_[k,k+1]$; set $n$ to the length of the path
			k = 0
			s = p
			n = uint16(pathSize)
			for {
				t = *(*prg.mem[s].hh()).rh()
				prg.deltaX[k] = *prg.mem[int32(t)+1].int() - *prg.mem[int32(s)+1].int()
				prg.deltaY[k] = *prg.mem[int32(t)+2].int() - *prg.mem[int32(s)+2].int()
				prg.delta[k] = prg.pythAdd(prg.deltaX[k], prg.deltaY[k])
				if int32(k) > 0 {
					sine = prg.makeFraction(prg.deltaY[int32(k)-1], prg.delta[int32(k)-1])
					cosine = prg.makeFraction(prg.deltaX[int32(k)-1], prg.delta[int32(k)-1])
					prg.psi[k-1] = prg.nArg(prg.takeFraction(prg.deltaX[k], cosine)+prg.takeFraction(prg.deltaY[k], sine), prg.takeFraction(prg.deltaY[k], cosine)-prg.takeFraction(prg.deltaX[k], sine))
				}
				// \xref[METAFONT capacity exceeded path size][\quad path size]
				k = uint16(int32(k) + 1)
				s = t
				if int32(k) == pathSize {
					prg.overflow(strNumber( /* "path size" */ 531), pathSize)
				}
				if int32(s) == int32(q) {
					n = k
				}
				if int32(k) >= int32(n) && int32(*(*prg.mem[s].hh()).b0()) != endCycle {
					break
				}
			}
			if int32(k) == int32(n) {
				prg.psi[n-1] = 0
			} else {
				prg.psi[k-1] = prg.psi[1-1]
			}

			// Remove |open| types at the breakpoints
			if int32(*(*prg.mem[q].hh()).b0()) == open {
				delx = *prg.mem[int32(q)+5].int() - *prg.mem[int32(q)+1].int()
				dely = *prg.mem[int32(q)+6].int() - *prg.mem[int32(q)+2].int()
				if delx == 0 && dely == 0 {
					*(*prg.mem[q].hh()).b0() = byte(curl)
					*prg.mem[int32(q)+3].int() = 0200000
				} else {
					*(*prg.mem[q].hh()).b0() = byte(given)
					*prg.mem[int32(q)+3].int() = prg.nArg(delx, dely)
				}
			}
			if int32(*(*prg.mem[p].hh()).b1()) == open && int32(*(*prg.mem[p].hh()).b0()) == explicit {
				delx = *prg.mem[int32(p)+1].int() - *prg.mem[int32(p)+3].int()
				dely = *prg.mem[int32(p)+2].int() - *prg.mem[int32(p)+4].int()
				if delx == 0 && dely == 0 {
					*(*prg.mem[p].hh()).b1() = byte(curl)
					*prg.mem[int32(p)+5].int() = 0200000
				} else {
					*(*prg.mem[p].hh()).b1() = byte(given)
					*prg.mem[int32(p)+5].int() = prg.nArg(delx, dely)
				}
			}
			prg.solveChoices(p, q, n)
		}
		p = q
		if int32(p) == int32(h) {
			break
		}
	}
	if prg.internal[tracingChoices-1] > 0 {
		prg.printPath(knots, strNumber( /* ", after choices" */ 527), true)
	}
	if prg.arithError {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Some number got too big" */ 528) /* \xref[!\relax]  */
		}
		// \xref[Some number got too big]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "The path that I just computed is out of range." */ 529
			prg.helpLine[0] = /* "So it will probably look funny. Proceed, for a laugh." */ 530
		}
		prg.putGetError()
		prg.arithError = false
	}
}

// 274.

// tangle:pos ../../mf.web:6025:3:

// Before we can go further into the way choices are made, we need to
// consider the underlying theory. The basic ideas implemented in |make_choices|
// are due to John Hobby, who introduced the notion of ``mock curvature''
// \xref[Hobby, John Douglas]
// at a knot. Angles are chosen so that they preserve mock curvature when
// a knot is passed, and this has been found to produce excellent results.
//
// It is convenient to introduce some notations that simplify the necessary
// formulas. Let $d_[k,k+1]=\vert z\k-z_k\vert$ be the (nonzero) distance
// between knots |k| and |k+1|; and let
// $$[z\k-z_k\over z_k-z_[k-1]]=[d_[k,k+1]\over d_[k-1,k]]e^[i\psi_k]$$
// so that a polygonal line from $z_[k-1]$ to $z_k$ to $z\k$ turns left
// through an angle of~$\psi_k$. We assume that $\vert\psi_k\vert\L180^\circ$.
// The control points for the spline from $z_k$ to $z\k$ will be denoted by
// $$\eqalign[z_k^+&=z_k+
//   \textstyle[1\over3]\rho_k e^[i\theta_k](z\k-z_k),\cr
//  z\k^-&=z\k-
//   \textstyle[1\over3]\sigma\k e^[-i\phi\k](z\k-z_k),\cr]$$
// where $\rho_k$ and $\sigma\k$ are nonnegative ``velocity ratios'' at the
// beginning and end of the curve, while $\theta_k$ and $\phi\k$ are the
// corresponding ``offset angles.'' These angles satisfy the condition
// $$\theta_k+\phi_k+\psi_k=0,\eqno(*)$$
// whenever the curve leaves an intermediate knot~|k| in the direction that
// it enters.

// 275.

// tangle:pos ../../mf.web:6050:3:

// Let $\alpha_k$ and $\beta\k$ be the reciprocals of the ``tension'' of
// the curve at its beginning and ending points. This means that
// $\rho_k=\alpha_k f(\theta_k,\phi\k)$ and $\sigma\k=\beta\k f(\phi\k,\theta_k)$,
// where $f(\theta,\phi)$ is \MF's standard velocity function defined in
// the |velocity| subroutine. The cubic spline $B(z_k^[\phantom+],z_k^+,
// z\k^-,z\k^[\phantom+];t)$
// has curvature
// \xref[curvature]
// $$[2\sigma\k\sin(\theta_k+\phi\k)-6\sin\theta_k\over\rho_k^2d_[k,k+1]]
// \qquad[\rm and]\qquad
// [2\rho_k\sin(\theta_k+\phi\k)-6\sin\phi\k\over\sigma\k^2d_[k,k+1]]$$
// at |t=0| and |t=1|, respectively. The mock curvature is the linear
// \xref[mock curvature]
// approximation to this true curvature that arises in the limit for
// small $\theta_k$ and~$\phi\k$, if second-order terms are discarded.
// The standard velocity function satisfies
// $$f(\theta,\phi)=1+O(\theta^2+\theta\phi+\phi^2);$$
// hence the mock curvatures are respectively
// $$[2\beta\k(\theta_k+\phi\k)-6\theta_k\over\alpha_k^2d_[k,k+1]]
// \qquad[\rm and]\qquad
// [2\alpha_k(\theta_k+\phi\k)-6\phi\k\over\beta\k^2d_[k,k+1]].\eqno(**)$$

// 276.

// tangle:pos ../../mf.web:6072:3:

// The turning angles $\psi_k$ are given, and equation $(*)$ above
// determines $\phi_k$ when $\theta_k$ is known, so the task of
// angle selection is essentially to choose appropriate values for each
// $\theta_k$. When equation~$(*)$ is used to eliminate $\phi$~variables
// from $(**)$, we obtain a system of linear equations of the form
// $$A_k\theta_[k-1]+(B_k+C_k)\theta_k+D_k\theta\k=-B_k\psi_k-D_k\psi\k,$$
// where
// $$A_k=[\alpha_[k-1]\over\beta_k^2d_[k-1,k]],
// \qquad B_k=[3-\alpha_[k-1]\over\beta_k^2d_[k-1,k]],
// \qquad C_k=[3-\beta\k\over\alpha_k^2d_[k,k+1]],
// \qquad D_k=[\beta\k\over\alpha_k^2d_[k,k+1]].$$
// The tensions are always $3\over4$ or more, hence each $\alpha$ and~$\beta$
// will be at most $4\over3$. It follows that $B_k\G[5\over4]A_k$ and
// $C_k\G[5\over4]D_k$; hence the equations are diagonally dominant;
// hence they have a unique solution. Moreover, in most cases the tensions
// are equal to~1, so that $B_k=2A_k$ and $C_k=2D_k$. This makes the
// solution numerically stable, and there is an exponential damping
// effect: The data at knot $k\pm j$ affects the angle at knot~$k$ by
// a factor of~$O(2^[-j])$.

// 277.

// tangle:pos ../../mf.web:6092:3:

// However, we still must consider the angles at the starting and ending
// knots of a non-cyclic path. These angles might be given explicitly, or
// they might be specified implicitly in terms of an amount of ``curl.''
//
// Let's assume that angles need to be determined for a non-cyclic path
// starting at $z_0$ and ending at~$z_n$. Then equations of the form
// $$A_k\theta_[k-1]+(B_k+C_k)\theta_k+D_k\theta_[k+1]=R_k$$
// have been given for $0<k<n$, and it will be convenient to introduce
// equations of the same form for $k=0$ and $k=n$, where
// $$A_0=B_0=C_n=D_n=0.$$
// If $\theta_0$ is supposed to have a given value $E_0$, we simply
// define $C_0=1$, $D_0=0$, and $R_0=E_0$. Otherwise a curl
// parameter, $\gamma_0$, has been specified at~$z_0$; this means
// that the mock curvature at $z_0$ should be $\gamma_0$ times the
// mock curvature at $z_1$; i.e.,
// $$[2\beta_1(\theta_0+\phi_1)-6\theta_0\over\alpha_0^2d_[01]]
// =\gamma_0[2\alpha_0(\theta_0+\phi_1)-6\phi_1\over\beta_1^2d_[01]].$$
// This equation simplifies to
// $$(\alpha_0\chi_0+3-\beta_1)\theta_0+
//  \bigl((3-\alpha_0)\chi_0+\beta_1\bigr)\theta_1=
//  -\bigl((3-\alpha_0)\chi_0+\beta_1\bigr)\psi_1,$$
// where $\chi_0=\alpha_0^2\gamma_0/\beta_1^2$; so we can set $C_0=
// \chi_0\alpha_0+3-\beta_1$, $D_0=(3-\alpha_0)\chi_0+\beta_1$, $R_0=-D_0\psi_1$.
// It can be shown that $C_0>0$ and $C_0B_1-A_1D_0>0$ when $\gamma_0\G0$,
// hence the linear equations remain nonsingular.
//
// Similar considerations apply at the right end, when the final angle $\phi_n$
// may or may not need to be determined. It is convenient to let $\psi_n=0$,
// hence $\theta_n=-\phi_n$. We either have an explicit equation $\theta_n=E_n$,
// or we have
// $$\bigl((3-\beta_n)\chi_n+\alpha_[n-1]\bigr)\theta_[n-1]+
// (\beta_n\chi_n+3-\alpha_[n-1])\theta_n=0,\qquad
//   \chi_n=[\beta_n^2\gamma_n\over\alpha_[n-1]^2].$$
//
// When |make_choices| chooses angles, it must compute the coefficients of
// these linear equations, then solve the equations. To compute the coefficients,
// it is necessary to compute arctangents of the given turning angles~$\psi_k$.
// When the equations are solved, the chosen directions $\theta_k$ are put
// back into the form of control points by essentially computing sines and
// cosines.

// 303. \[19] Generating discrete moves

// tangle:pos ../../mf.web:6573:36:

// The purpose of the next part of \MF\ is to compute discrete approximations
// to curves described as parametric polynomial functions $z(t)$.
// We shall start with the low level first, because an efficient ``engine''
// is needed to support the high-level constructions.
//
// Most of the subroutines are based on variations of a single theme,
// namely the idea of [\sl bisection]. Given a Bernshte[\u\i]n polynomial
// \xref[Bernshte[\u\i]n, Serge[\u\i] Natanovich]
// $$B(z_0,z_1,\ldots,z_n;t)=\sum_k[n\choose k]t^k(1-t)^[n-k]z_k,$$
// we can conveniently bisect its range as follows:
//
// \smallskip
// \textindent[1)] Let $z_k^[(0)]=z_k$, for |0<=k<=n|.
//
// \smallskip
// \textindent[2)] Let $z_k^[(j+1)]=[1\over2](z_k^[(j)]+z\k^[(j)])$, for
// |0<=k<n-j|, for |0<=j<n|.
//
// \smallskip\noindent
// Then
// $$B(z_0,z_1,\ldots,z_n;t)=B(z_0^[(0)],z_0^[(1)],\ldots,z_0^[(n)];2t)
//  =B(z_0^[(n)],z_1^[(n-1)],\ldots,z_n^[(0)];2t-1).$$
// This formula gives us the coefficients of polynomials to use over the ranges
// $0\L t\L[1\over2]$ and $[1\over2]\L t\L1$.
//
// In our applications it will usually be possible to work indirectly with
// numbers that allow us to deduce relevant properties of the polynomials
// without actually computing the polynomial values. We will deal with
// coefficients $Z_k=2^l(z_k-z_[k-1])$ for |1<=k<=n|, instead of
// the actual numbers $z_0$, $z_1$, \dots,~$z_n$, and the value of~|l| will
// increase by~1 at each bisection step. This technique reduces the
// amount of calculation needed for bisection and also increases the
// accuracy of evaluation (since one bit of precision is gained at each
// bisection). Indeed, the bisection process now becomes one level shorter:
//
// \smallskip
// \textindent[$1'$)] Let $Z_k^[(1)]=Z_k$, for |1<=k<=n|.
//
// \smallskip
// \textindent[$2'$)] Let $Z_k^[(j+1)]=[1\over2](Z_k^[(j)]+Z\k^[(j)])$, for
// |1<=k<=n-j|, for |1<=j<n|.
//
// \smallskip\noindent
// The relevant coefficients $(Z'_1,\ldots,Z'_n)$ and $(Z''_1,\ldots,Z''_n)$
// for the two subintervals after bisection are respectively
// $(Z_1^[(1)],Z_1^[(2)],\ldots,Z_1^[(n)])$ and
// $(Z_1^[(n)],Z_2^[(n-1)],\ldots,Z_n^[(1)])$.
// And the values of $z_0$ appropriate for the bisected interval are $z'_0=z_0$
// and $z''_0=z_0+(Z'_1+Z'_2+\cdots+Z'_n)/2^[l+1]$.
//
// Step $2'$ involves division by~2, which introduces computational errors
// of at most $1\over2$ at each step; thus after $l$~levels of bisection the
// integers $Z_k$ will differ from their true values by at most $(n-1)l/2$.
// This error rate is quite acceptable, considering that we have $l$~more
// bits of precision in the $Z$'s by comparison with the~$z$'s.  Note also
// that the $Z$'s remain bounded; there's no danger of integer overflow, even
// though we have the identity $Z_k=2^l(z_k-z_[k-1])$ for arbitrarily large~$l$.
//
// In fact, we can show not only that the $Z$'s remain bounded, but also that
// they become nearly equal, since they are control points for a polynomial
// of one less degree. If $\vert Z\k-Z_k\vert\L M$ initially, it is possible
// to prove that $\vert Z\k-Z_k\vert\L\lceil M/2^l\rceil$ after $l$~levels
// of bisection, even in the presence of rounding errors. Here's the
// proof [cf.~Lane and Riesenfeld, [\sl IEEE Trans.\ on Pattern Analysis
// \xref[Lane, Jeffrey Michael]
// \xref[Riesenfeld, Richard Franklin]
// and Machine Intelligence\/ \bf PAMI-2] (1980), 35--46]: Assuming that
// $\vert Z\k-Z_k\vert\L M$ before bisection, we want to prove that
// $\vert Z\k-Z_k\vert\L\lceil M/2\rceil$ afterward. First we show that
// $\vert Z\k^[(j)]-Z_k^[(j)]\vert\L M$ for all $j$ and~$k$, by induction
// on~$j$; this follows from the fact that
// $$\bigl\vert\\[half](a+b)-\\[half](b+c)\bigr\vert\L
//  \max\bigl(\vert a-b\vert,\vert b-c\vert\bigr)$$
// holds for both of the rounding rules $\\[half](x)=\lfloor x/2\rfloor$
// and $\\[half](x)=[\rm sign](x)\lfloor\vert x/2\vert\rfloor$.
// (If $\vert a-b\vert$ and $\vert b-c\vert$ are equal, then
// $a+b$ and $b+c$ are both even or both odd. The rounding errors either
// cancel or round the numbers toward each other; hence
// $$\eqalign[\bigl\vert\\[half](a+b)-\\[half](b+c)\bigr\vert
// &\L\textstyle\bigl\vert[1\over2](a+b)-[1\over2](b+c)\bigr\vert\cr
// &=\textstyle\bigl\vert[1\over2](a-b)+[1\over2](b-c)\bigr\vert
// \L\max\bigl(\vert a-b\vert,\vert b-c\vert\bigr),\cr]$$
// as required. A simpler argument applies if $\vert a-b\vert$ and
// $\vert b-c\vert$ are unequal.)  Now it is easy to see that
// $\vert Z_1^[(j+1)]-Z_1^[(j)]\vert\L\bigl\lfloor[1\over2]
// \vert Z_2^[(j)]-Z_1^[(j)]\vert+[1\over2]\bigr\rfloor
// \L\bigl\lfloor[1\over2](M+1)\bigr\rfloor=\lceil M/2\rceil$.
//
// Another interesting fact about bisection is the identity
// $$Z_1'+\cdots+Z_n'+Z_1''+\cdots+Z_n''=2(Z_1+\cdots+Z_n+E),$$
// where $E$ is the sum of the rounding errors in all of the halving
// operations ($\vert E\vert\L n(n-1)/4$).

// 304.

// tangle:pos ../../mf.web:6667:3:

// We will later reduce the problem of digitizing a complex cubic
// $z(t)=B(z_0,z_1,z_2,z_3;t)$ to the following simpler problem:
// Given two real cubics
// $x(t)=B(x_0,x_1,x_2,x_3;t)$
// and $y(t)=B(y_0,y_1,y_2,y_3;t)$ that are monotone nondecreasing,
// determine the set of integer points
// $$P=\bigl\[\bigl(\lfloor x(t)\rfloor,\lfloor y(t)\rfloor\bigr)
// \bigm\vert 0\L t\L 1\bigr\].$$
// Well, the problem isn't actually quite so clean as this; when the path
// goes very near an integer point $(a,b)$, computational errors may
// make us think that $P$ contains $(a-1,b)$ while in reality it should
// contain $(a,b-1)$. Furthermore, if the path goes [\sl exactly\/]
// through the integer points $(a-1,b-1)$ and
// $(a,b)$, we will want $P$ to contain one
// of the two points $(a-1,b)$ or $(a,b-1)$, so that $P$ can be described
// entirely by ``rook moves'' upwards or to the right; no diagonal
// moves from $(a-1,b-1)$ to~$(a,b)$ will be allowed.
//
// Thus, the set $P$ we wish to compute will merely be an approximation
// to the set described in the formula above. It will consist of
// $\lfloor x(1)\rfloor-\lfloor x(0)\rfloor$ rightward moves and
// $\lfloor y(1)\rfloor-\lfloor y(0)\rfloor$ upward moves, intermixed
// in some order. Our job will be to figure out a suitable order.
//
// The following recursive strategy suggests itself, when we recall that
// $x(0)=x_0$, $x(1)=x_3$, $y(0)=y_0$, and $y(1)=y_3$:
//
// \smallskip
// If $\lfloor x_0\rfloor=\lfloor x_3\rfloor$ then take
// $\lfloor y_3\rfloor-\lfloor y_0\rfloor$ steps up.
//
// Otherwise if $\lfloor y_0\rfloor=\lfloor y_3\rfloor$ then take
// $\lfloor x_3\rfloor-\lfloor x_0\rfloor$ steps to the right.
//
// Otherwise bisect the current cubics and repeat the process on both halves.
//
// \yskip\noindent
// This intuitively appealing formulation does not quite solve the problem,
// because it may never terminate. For example, it's not hard to see that
// no steps will [\sl ever\/] be taken if $(x_0,x_1,x_2,x_3)=(y_0,y_1,y_2,y_3)$!
// However, we can surmount this difficulty with a bit of care; so let's
// proceed to flesh out the algorithm as stated, before worrying about
// such details.
//
// The bisect-and-double strategy discussed above suggests that we represent
// $(x_0,x_1,x_2,x_3)$ by $(X_1,X_2,X_3)$, where $X_k=2^l(x_k-x_[k-1])$
// for some~$l$. Initially $l=16$, since the $x$'s are |scaled|.
// In order to deal with other aspects of the algorithm we will want to
// maintain also the quantities $m=\lfloor x_3\rfloor-\lfloor x_0\rfloor$
// and $R=2^l(x_0\bmod 1)$. Similarly,
// $(y_0,y_1,y_2,y_3)$ will be represented by $(Y_1,Y_2,Y_3)$,
// $n=\lfloor y_3\rfloor-\lfloor y_0\rfloor$,
// and $S=2^l(y_0\bmod 1)$. The algorithm now takes the following form:
//
// \smallskip
// If $m=0$ then take $n$ steps up.
//
// Otherwise if $n=0$ then take $m$ steps to the right.
//
// Otherwise bisect the current cubics and repeat the process on both halves.
//
// \smallskip\noindent
// The bisection process for $(X_1,X_2,X_3,m,R,l)$ reduces, in essence,
// to the following formulas:
// $$\vbox[\halign[$#\hfil$\cr
// X_2'=\\[half](X_1+X_2),\quad
// X_2''=\\[half](X_2+X_3),\quad
// X_3'=\\[half](X_2'+X_2''),\cr
// X_1'=X_1,\quad
// X_1''=X_3',\quad
// X_3''=X_3,\cr
// R'=2R,\quad
// T=X_1'+X_2'+X_3'+R',\quad
// R''=T\bmod 2^[l+1],\cr
// m'=\lfloor T/2^[l+1]\rfloor,\quad
// m''=m-m'.\cr]]$$

// 305.

// tangle:pos ../../mf.web:6744:3:

// When $m=n=1$, the computation can be speeded up because we simply
// need to decide between two alternatives, (up,\thinspace right)
// versus (right,\thinspace up). There appears to be no simple, direct
// way to make the correct decision by looking at the values of
// $(X_1,X_2,X_3,R)$ and
// $(Y_1,Y_2,Y_3,S)$; but we can streamline the bisection process, and
// we can use the fact that only one of the two descendants needs to
// be examined after each bisection. Furthermore, we observed earlier
// that after several levels of bisection the $X$'s and $Y$'s will be nearly
// equal; so we will be justified in assuming that the curve is essentially a
// straight line. (This, incidentally, solves the problem of infinite
// recursion mentioned earlier.)
//
// It is possible to show that
// $$m=\bigl\lfloor(X_1+X_2+X_3+R+E)\,/\,2^l\bigr\rfloor,$$
// where $E$ is an accumulated rounding error that is at most
// $3\cdot(2^[l-16]-1)$ in absolute value. We will make sure that
// the $X$'s are less than $2^[28]$; hence when $l=30$ we must
// have |m<=1|. This proves that the special case $m=n=1$ is
// bound to be reached by the time $l=30$. Furthermore $l=30$ is
// a suitable time to make the straight line approximation,
// if the recursion hasn't already died out, because the maximum
// difference between $X$'s will then be $<2^[14]$; this corresponds
// to an error of $<1$ with respect to the original scaling.
// (Stating this another way, each bisection makes the curve two bits
// closer to a straight line, hence 14 bisections are sufficient for
// 28-bit accuracy.)
//
// In the case of a straight line, the curve goes first right, then up,
// if and only if $(T-2^l)(2^l-S)>(U-2^l)(2^l-R)$, where
// $T=X_1+X_2+X_3+R$ and $U=Y_1+Y_2+Y_3+S$. For the actual curve
// essentially runs from $(R/2^l,S/2^l)$ to $(T/2^l,U/2^l)$, and
// we are testing whether or not $(1,1)$ is above the straight
// line connecting these two points. (This formula assumes that $(1,1)$
// is not exactly on the line.)

// 306.

// tangle:pos ../../mf.web:6780:3:

// We have glossed over the problem of tie-breaking in ambiguous
// cases when the cubic curve passes exactly through integer points.
// \MF\ finesses this problem by assuming that coordinates
// $(x,y)$ actually stand for slightly perturbed values $(x+\xi,y+\eta)$,
// where $\xi$ and~$\eta$ are infinitesimals whose signs will determine
// what to do when $x$ and/or~$y$ are exact integers. The quantities
// $\lfloor x\rfloor$ and~$\lfloor y\rfloor$ in the formulas above
// should actually read $\lfloor x+\xi\rfloor$ and $\lfloor y+\eta\rfloor$.
//
// If $x$ is a |scaled| value, we have $\lfloor x+\xi\rfloor=\lfloor x\rfloor$
// if $\xi>0$, and $\lfloor x+\xi\rfloor=\lfloor x-2^[-16]\rfloor$ if
// $\xi<0$. It is convenient to represent $\xi$ by the integer |xi_corr|,
// defined to be 0~if $\xi>0$ and 1~if $\xi<0$; then, for example, the
// integer $\lfloor x+\xi\rfloor$ can be computed as
// |floor_unscaled(x-xi_corr)|. Similarly, $\eta$ is conveniently
// represented by~|eta_corr|.
//
// In our applications the sign of $\xi-\eta$ will always be the same as
// the sign of $\xi$. Therefore it turns out that the rule for straight
// lines, as stated above, should be modified as follows in the case of
// ties: The line goes first right, then up, if and only if
// $(T-2^l)(2^l-S)+\xi>(U-2^l)(2^l-R)$. And this relation holds iff
// $|ab_vs_cd|(T-2^l,2^l-S,U-2^l,2^l-R)-|xi_corr|\ge0$.
//
// These conventions for rounding are symmetrical, in the sense that the
// digitized moves obtained from $(x_0,x_1,x_2,x_3,y_0,y_1,y_2,y_3,\xi,\eta)$
// will be exactly complementary to the moves that would be obtained from
// $(-x_3,-x_2,-x_1,-x_0,-y_3,-y_2,-y_1,-y_0,-\xi,-\eta)$, if arithmetic
// is exact. However, truncation errors in the bisection process might
// upset the symmetry. We can restore much of the lost symmetry by adding
// |xi_corr| or |eta_corr| when halving the data.

// 307.

// tangle:pos ../../mf.web:6812:3:

// One further possibility needs to be mentioned: The algorithm
// will be applied only to cubic polynomials $B(x_0,x_1,x_2,x_3;t)$ that
// are nondecreasing as $t$~varies from 0 to~1; this condition turns
// out to hold if and only if $x_0\L x_1$ and $x_2\L x_3$, and either
// $x_1\L x_2$ or $(x_1-x_2)^2\L(x_1-x_0)(x_3-x_2)$. If bisection were
// carried out with perfect accuracy, these relations would remain
// invariant. But rounding errors can creep in, hence the bisection
// algorithm can produce non-monotonic subproblems from monotonic
// initial conditions. This leads to the potential danger that $m$ or~$n$
// could become negative in the algorithm described above.
//
// For example, if we start with $(x_1-x_0,x_2-x_1,x_3-x_2)=
// (X_1,X_2,X_3)=(7,-16,39)$, the corresponding polynomial is
// monotonic, because $16^2<7\cdot39$. But the bisection algorithm
// produces the left descendant $(7,-5,3)$, which is nonmonotonic;
// its right descendant is~$(0,-1,3)$.
//
// \def\xt[[\tilde x]]
// Fortunately we can prove that such rounding errors will never cause
// the algorithm to make a tragic mistake. At every stage we are working
// with numbers corresponding to a cubic polynomial $B(\xt_0,
// \xt_1,\xt_2,\xt_3)$ that approximates some
// monotonic polynomial $B(x_0,x_1,x_2,x_3)$. The accumulated errors are
// controlled so that $\vert x_k-\xt_k\vert<\epsilon=3\cdot2^[-16]$.
// If bisection is done at some stage of the recursion, we have
// $m=\lfloor\xt_3\rfloor-\lfloor\xt_0\rfloor>0$, and the algorithm
// computes a bisection value $\bar x$ such that $m'=\lfloor\bar x\rfloor-
// \lfloor\xt_0\rfloor$
// and $m''=\lfloor\xt_3\rfloor-\lfloor\bar x\rfloor$. We want to prove
// that neither $m'$ nor $m''$ can be negative. Since $\bar x$ is an
// approximation to a value in the interval $[x_0,x_3]$, we have
// $\bar x>x_0-\epsilon$ and $\bar x<x_3+\epsilon$, hence $\bar x>
// \xt_0-2\epsilon$ and $\bar x<\xt_3+2\epsilon$.
// If $m'$ is negative we must have $\xt_0\bmod 1<2\epsilon$;
// if $m''$ is negative we must have $\xt_3\bmod 1>1-2\epsilon$.
// In either case the condition $\lfloor\xt_3\rfloor-\lfloor\xt_0\rfloor>0$
// implies that $\xt_3-\xt_0>1-2\epsilon$, hence $x_3-x_0>1-4\epsilon$.
// But it can be shown that if $B(x_0,x_1,x_2,x_3;t)$ is a monotonic
// cubic, then $B(x_0,x_1,x_2,x_3;[1\over2])$ is always between
// $.06[x_0,x_3]$ and $.94[x_0,x_3]$; and it is impossible for $\bar x$
// to be within~$\epsilon$ of such a number. Contradiction!
// (The constant .06 is actually $(2-\sqrt3\,)/4$; the worst case
// occurs for polynomials like $B(0,2-\sqrt3,1-\sqrt3,3;t)$.)

// 311.

// tangle:pos ../../mf.web:6907:3:

// The |make_moves| subroutine is given |scaled| values $(x_0,x_1,x_2,x_3)$
// and $(y_0,y_1,y_2,y_3)$ that represent monotone-nondecreasing polynomials;
// it makes $\lfloor x_3+\xi\rfloor-\lfloor x_0+\xi\rfloor$ rightward moves
// and $\lfloor y_3+\eta\rfloor-\lfloor y_0+\eta\rfloor$ upward moves, as
// explained earlier.  (Here $\lfloor x+\xi\rfloor$ actually stands for
// $\lfloor x/2^[16]-|xi_corr|\rfloor$, if $x$ is regarded as an integer
// without scaling.) The unscaled integers $x_k$ and~$y_k$ should be less
// than $2^[28]$ in magnitude.
//
// It is assumed that $|move_ptr| + \lfloor y_3+\eta\rfloor -
// \lfloor y_0+\eta\rfloor < |move_size|$ when this procedure is called,
// so that the capacity of the |move| array will not be exceeded.
//
// The variables |r| and |s| in this procedure stand respectively for
// $R-|xi_corr|$ and $S-|eta_corr|$ in the theory discussed above.
func (prg *prg) makeMoves(xx0, xx1, xx2, xx3, yy0, yy1, yy2, yy3 scaled, xiCorr, etaCorr smallNumber) {
	var (
		x1, x2, x3, m, r1, y1, y2, y3, n, s, l int32
		// bisection variables explained above
		q, t, u, x2a, x3a, y2a, y3a int32 // additional temporary registers
	)
	if xx3 < xx0 || yy3 < yy0 {
		prg.confusion(strNumber('m'))
	}
	// \xref[this can't happen m][\quad m]
	l = 16
	prg.bisectPtr = 0

	x1 = xx1 - xx0
	x2 = xx2 - xx1
	x3 = xx3 - xx2
	if xx0 >= int32(xiCorr) {
		r1 = (xx0 - int32(xiCorr)) % 0200000
	} else {
		r1 = 0200000 - 1 - (-xx0+int32(xiCorr)-1)%0200000
	}
	m = (xx3 - xx0 + r1) / 0200000

	y1 = yy1 - yy0
	y2 = yy2 - yy1
	y3 = yy3 - yy2
	if yy0 >= int32(etaCorr) {
		s = (yy0 - int32(etaCorr)) % 0200000
	} else {
		s = 0200000 - 1 - (-yy0+int32(etaCorr)-1)%0200000
	}
	n = (yy3 - yy0 + s) / 0200000

	if xx3-xx0 >= 02000000000 || yy3-yy0 >= 02000000000 {
		x1 = (x1 + int32(xiCorr)) / 2
		x2 = (x2 + int32(xiCorr)) / 2
		x3 = (x3 + int32(xiCorr)) / 2
		r1 = (r1 + int32(xiCorr)) / 2

		y1 = (y1 + int32(etaCorr)) / 2
		y2 = (y2 + int32(etaCorr)) / 2
		y3 = (y3 + int32(etaCorr)) / 2
		s = (s + int32(etaCorr)) / 2

		l = 15
	}
	for true {
	continue1:
		if m == 0 {
			for n > 0 {
				prg.movePtr = uint16(int32(prg.movePtr) + 1)
				prg.move[prg.movePtr] = 1
				n = n - 1
			}
		} else if n == 0 {
			prg.move[prg.movePtr] = prg.move[prg.movePtr] + m
		} else if m+n == 2 {
			r1 = prg.twoToThe[l] - r1
			s = prg.twoToThe[l] - s

			for l < 30 {
				x3a = x3
				x2a = (x2 + x3 + int32(xiCorr)) / 2
				x2 = (x1 + x2 + int32(xiCorr)) / 2
				x3 = (x2 + x2a + int32(xiCorr)) / 2
				t = x1 + x2 + x3
				r1 = r1 + r1 - int32(xiCorr)

				y3a = y3
				y2a = (y2 + y3 + int32(etaCorr)) / 2
				y2 = (y1 + y2 + int32(etaCorr)) / 2
				y3 = (y2 + y2a + int32(etaCorr)) / 2
				u = y1 + y2 + y3
				s = s + s - int32(etaCorr)

				if t < r1 {
					if u < s {
						x1 = x3
						x2 = x2a
						x3 = x3a
						r1 = r1 - t
						y1 = y3
						y2 = y2a
						y3 = y3a
						s = s - u
					} else {
						{
							prg.movePtr = uint16(int32(prg.movePtr) + 1)
							prg.move[prg.movePtr] = 2
						}
						goto done
					}
				} else if u < s {
					{
						prg.move[prg.movePtr] = prg.move[prg.movePtr] + 1
						prg.movePtr = uint16(int32(prg.movePtr) + 1)
						prg.move[prg.movePtr] = 1
					}
					goto done
				}
				l = l + 1
			}
			r1 = r1 - int32(xiCorr)
			s = s - int32(etaCorr)
			if prg.abVsCd(x1+x2+x3, s, y1+y2+y3, r1)-int32(xiCorr) >= 0 {
				prg.move[prg.movePtr] = prg.move[prg.movePtr] + 1
				prg.movePtr = uint16(int32(prg.movePtr) + 1)
				prg.move[prg.movePtr] = 1
			} else {
				// Move up then right
				prg.movePtr = uint16(int32(prg.movePtr) + 1)
				prg.move[prg.movePtr] = 2
			}

		done:
		} else {
			l = l + 1
			prg.bisectStack[int32(prg.bisectPtr)+10] = l

			prg.bisectStack[int32(prg.bisectPtr)+2] = x3
			prg.bisectStack[int32(prg.bisectPtr)+1] = (x2 + x3 + int32(xiCorr)) / 2
			x2 = (x1 + x2 + int32(xiCorr)) / 2
			x3 = (x2 + prg.bisectStack[int32(prg.bisectPtr)+1] + int32(xiCorr)) / 2
			prg.bisectStack[prg.bisectPtr] = x3

			r1 = r1 + r1 + int32(xiCorr)
			t = x1 + x2 + x3 + r1

			q = t / prg.twoToThe[l]
			prg.bisectStack[int32(prg.bisectPtr)+3] = t % prg.twoToThe[l]

			prg.bisectStack[int32(prg.bisectPtr)+4] = m - q
			m = q

			prg.bisectStack[int32(prg.bisectPtr)+7] = y3
			prg.bisectStack[int32(prg.bisectPtr)+6] = (y2 + y3 + int32(etaCorr)) / 2
			y2 = (y1 + y2 + int32(etaCorr)) / 2
			y3 = (y2 + prg.bisectStack[int32(prg.bisectPtr)+6] + int32(etaCorr)) / 2
			prg.bisectStack[int32(prg.bisectPtr)+5] = y3

			s = s + s + int32(etaCorr)
			u = y1 + y2 + y3 + s

			q = u / prg.twoToThe[l]
			prg.bisectStack[int32(prg.bisectPtr)+8] = u % prg.twoToThe[l]

			prg.bisectStack[int32(prg.bisectPtr)+9] = n - q
			n = q

			prg.bisectPtr = uint16(int32(prg.bisectPtr) + moveIncrement)
			goto continue1
		}
		if int32(prg.bisectPtr) == 0 {
			goto exit
		}

		// Remove a subproblem for |make_moves| from the stack
		prg.bisectPtr = uint16(int32(prg.bisectPtr) - moveIncrement)

		x1 = prg.bisectStack[prg.bisectPtr]
		x2 = prg.bisectStack[int32(prg.bisectPtr)+1]
		x3 = prg.bisectStack[int32(prg.bisectPtr)+2]
		r1 = prg.bisectStack[int32(prg.bisectPtr)+3]
		m = prg.bisectStack[int32(prg.bisectPtr)+4]

		y1 = prg.bisectStack[int32(prg.bisectPtr)+5]
		y2 = prg.bisectStack[int32(prg.bisectPtr)+6]
		y3 = prg.bisectStack[int32(prg.bisectPtr)+7]
		s = prg.bisectStack[int32(prg.bisectPtr)+8]
		n = prg.bisectStack[int32(prg.bisectPtr)+9]

		l = prg.bisectStack[int32(prg.bisectPtr)+10]
	}

exit:
}

// 321.

// tangle:pos ../../mf.web:7034:3:

// After |make_moves| has acted, possibly for several curves that move toward
// the same octant, a ``smoothing'' operation might be done on the |move| array.
// This removes optical glitches that can arise even when the curve has been
// digitized without rounding errors.
//
// The smoothing process replaces the integers $a_0\ldots a_n$ in
// |move[b..t]| by ``smoothed'' integers $a_0'\ldots a_n'$ defined as
// follows:
// $$a_k'=a_k+\delta\k-\delta_k;\qquad
// \delta_k=\cases[+1,&if $1<k<n$ and $a_[k-2]\G a_[k-1]\ll a_k\G a\k$;\cr
// -1,&if $1<k<n$ and $a_[k-2]\L a_[k-1]\gg a_k\L a\k$;\cr
// 0,&otherwise.\cr]$$
// Here $a\ll b$ means that $a\L b-2$, and $a\gg b$ means that $a\G b+2$.
//
// The smoothing operation is symmetric in the sense that, if $a_0\ldots a_n$
// smooths to $a_0'\ldots a_n'$, then the reverse sequence $a_n\ldots a_0$
// smooths to $a_n'\ldots a_0'$; also the complementary sequence
// $(m-a_0)\ldots(m-a_n)$ smooths to $(m-a_0')\ldots(m-a_n')$.
// We have $a_0'+\cdots+a_n'=a_0+\cdots+a_n$ because $\delta_0=\delta_[n+1]=0$.
func (prg *prg) smoothMoves(b, t int32) {
	var (
		k/* 1..moveSize */ uint16       // index into |move|
		a, aa, aaa                int32 // original values of |move[k],move[k-1],move[k-2]|
	)
	if t-b >= 3 {
		k = uint16(b + 2)
		aa = prg.move[int32(k)-1]
		aaa = prg.move[int32(k)-2]
		for {
			a = prg.move[k]
			if abs(a-aa) > 1 {
				if a > aa {
					if aaa >= aa {
						if a >= prg.move[int32(k)+1] {
							prg.move[int32(k)-1] = prg.move[int32(k)-1] + 1
							prg.move[k] = a - 1
						}
					}
				} else {
					if aaa <= aa {
						if a <= prg.move[int32(k)+1] {
							prg.move[int32(k)-1] = prg.move[int32(k)-1] - 1
							prg.move[k] = a + 1
						}
					}
				}
			}
			k = uint16(int32(k) + 1)
			aaa = aa
			aa = a
			if int32(k) == t {
				break
			}
		}
	}
}

// 323. \[20] Edge structures

// tangle:pos ../../mf.web:7078:26:

// Now we come to \MF's internal scheme for representing what the user can
// actually ``see,'' the edges between pixels. Each pixel has an integer
// weight, obtained by summing the weights on all edges to its left. \MF\
// represents only the nonzero edge weights, since most of the edges are
// weightless; in this way, the data storage requirements grow only linearly
// with respect to the number of pixels per point, even though two-dimensional
// data is being represented. (Well, the actual dependence on the underlying
// resolution is order $n\log n$, but the $\log n$ factor is buried in our
// implicit restriction on the maximum raster size.) The sum of all edge
// weights in each row should be zero.
//
// The data structure for edge weights must be compact and flexible,
// yet it should support efficient updating and display operations. We
// want to be able to have many different edge structures in memory at
// once, and we want the computer to be able to translate them, reflect them,
// and/or merge them together with relative ease.
//
// \MF's solution to this problem requires one single-word node per
// nonzero edge weight, plus one two-word node for each row in a contiguous
// set of rows. There's also a header node that provides global information
// about the entire structure.

// 325.

// tangle:pos ../../mf.web:7144:3:

// The rows themselves are represented by row header nodes that
// contain four link fields. Two of these four, |sorted| and |unsorted|,
// point to the first items of the edge-weight lists just mentioned.
// The other two, |link| and |knil|, point to the headers of the two
// adjacent rows. If |p| points to the header for row number~|n|, then
// |link(p)| points up to the header for row~|n+1|, and |knil(p)| points
// down to the header for row~|n-1|. This double linking makes it
// convenient to move through consecutive rows either upward or downward;
// as usual, we have |link(knil(p))=knil(link(p))=p| for all row headers~|p|.
//
// The row associated with a given value of |n| contains weights for
// edges that run between the lattice points |(m,n)| and |(m,n+1)|.

// 326.

// tangle:pos ../../mf.web:7163:3:

// The main header node |h| for an edge structure has |link| and |knil|
// fields that link it above the topmost row and below the bottommost row.
// It also has fields called |m_min|, |m_max|, |n_min|, and |n_max| that
// bound the current extent of the edge data: All |m| values in edge-weight
// nodes should lie between |m_min(h)-4096| and |m_max(h)-4096|, inclusive.
// Furthermore the topmost row header, pointed to by |knil(h)|,
// is for row number |n_max(h)-4096|; the bottommost row header, pointed to by
// |link(h)|, is for row number |n_min(h)-4096|.
//
// The offset constant |c| that's used in all of the edge-weight data is
// represented implicitly in |m_offset(h)|; its actual value is
// $$\hbox[|c=min_halfword+zero_w+8*m_offset(h)|.]$$
// Notice that it's possible to shift an entire edge structure by an
// amount $(\Delta m,\Delta n)$ by adding $\Delta n$ to |n_min(h)| and |n_max(h)|,
// adding $\Delta m$ to |m_min(h)| and |m_max(h)|, and subtracting
// $\Delta m$ from |m_offset(h)|;
// none of the other edge data needs to be modified. Initially the |m_offset|
// field is~4096, but it will change if the user requests such a shift.
// The contents of these five fields should always be positive and less than
// 8192; |n_max| should, in fact, be less than 8191.  Furthermore
// |m_min+m_offset-4096| and |m_max+m_offset-4096| must also lie strictly
// between 0 and 8192, so that the |info| fields of edge-weight nodes will
// fit in a halfword.
//
// The header node of an edge structure also contains two somewhat unusual
// fields that are called |last_window(h)| and |last_window_time(h)|. When this
// structure is displayed in window~|k| of the user's screen, after that
// window has been updated |t| times, \MF\ sets |last_window(h):=k| and
// |last_window_time(h):=t|; it also sets |unsorted(p):=void| for all row
// headers~|p|, after merging any existing unsorted weights with the sorted
// ones.  A subsequent display in the same window will be able to avoid
// redisplaying rows whose |unsorted| list is still |void|, if the window
// hasn't been used for something else in the meantime.
//
// A pointer to the row header of row |n_pos(h)-4096| is provided in
// |n_rover(h)|. Most of the algorithms that update an edge structure
// are able to get by without random row references; they usually
// access rows that are neighbors of each other or of the current |n_pos| row.
// Exception: If |link(h)=h| (so that the edge structure contains
// no rows), we have |n_rover(h)=h|, and |n_pos(h)| is irrelevant.
func (prg *prg) initEdges(h halfword) {
	*(*prg.mem[h].hh()).lh() = h
	*(*prg.mem[h].hh()).rh() = h

	*(*prg.mem[int32(h)+1].hh()).lh() = uint16(zeroField + 4095)
	*(*prg.mem[int32(h)+1].hh()).rh() = uint16(zeroField - 4095)
	*(*prg.mem[int32(h)+2].hh()).lh() = uint16(zeroField + 4095)
	*(*prg.mem[int32(h)+2].hh()).rh() = uint16(zeroField - 4095)
	*(*prg.mem[int32(h)+3].hh()).lh() = uint16(zeroField)

	*(*prg.mem[int32(h)+3].hh()).rh() = 0
	*prg.mem[int32(h)+4].int() = 0

	*(*prg.mem[int32(h)+5].hh()).rh() = h
	*(*prg.mem[int32(h)+5].hh()).lh() = 0

}

// 328.

// tangle:pos ../../mf.web:7239:3:

// The |fix_offset| routine goes through all the edge-weight nodes of
// |cur_edges| and adds a constant to their |info| fields, so that
// |m_offset(cur_edges)| can be brought back to |zero_field|. (This
// is necessary only in unusual cases when the offset has gotten too
// large or too small.)
func (prg *prg) fixOffset() {
	var (
		p, q  halfword // list traversers
		delta int32    // the amount of change
	)
	delta = 8 * (int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) - zeroField)
	*(*prg.mem[int32(prg.curEdges)+3].hh()).lh() = uint16(zeroField)
	q = *(*prg.mem[prg.curEdges].hh()).rh()
	for int32(q) != int32(prg.curEdges) {
		p = *(*prg.mem[int32(q)+1].hh()).rh()
		for int32(p) != 3000 {
			*(*prg.mem[p].hh()).lh() = uint16(int32(*(*prg.mem[p].hh()).lh()) - delta)
			p = *(*prg.mem[p].hh()).rh()
		}
		p = *(*prg.mem[int32(q)+1].hh()).lh()
		for int32(p) > memMin+1 {
			*(*prg.mem[p].hh()).lh() = uint16(int32(*(*prg.mem[p].hh()).lh()) - delta)
			p = *(*prg.mem[p].hh()).rh()
		}
		q = *(*prg.mem[q].hh()).rh()
	}
}

// 329.

// tangle:pos ../../mf.web:7264:3:

// The |edge_prep| routine makes the |cur_edges| structure ready to
// accept new data whose coordinates satisfy |ml<=m<=mr| and |nl<=n<=nr-1|,
// assuming that |-4096<ml<=mr<4096| and |-4096<nl<=nr<4096|. It makes
// appropriate adjustments to |m_min|, |m_max|, |n_min|, and |n_max|,
// adding new empty rows if necessary.
func (prg *prg) edgePrep(ml, mr, nl, nr int32) {
	var (
		delta halfword // amount of change
		p, q  halfword // for list manipulation
	)
	ml = ml + zeroField
	mr = mr + zeroField
	nl = nl + zeroField
	nr = nr - 1 + zeroField

	if ml < int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) {
		*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = uint16(ml)
	}
	if mr > int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()) {
		*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16(mr)
	}
	if !(abs(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())-zeroField-4096) < 4096) || !(abs(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh())+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())-zeroField-4096) < 4096) {
		prg.fixOffset()
	}
	if int32(*(*prg.mem[prg.curEdges].hh()).rh()) == int32(prg.curEdges) {
		*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(nr + 1)
		*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(nr)
	}
	if nl < int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh()) {
		delta = uint16(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh()) - nl)
		*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(nl)
		p = *(*prg.mem[prg.curEdges].hh()).rh()
		for {
			q = prg.getNode(rowNodeSize)
			*(*prg.mem[int32(q)+1].hh()).rh() = 3000
			*(*prg.mem[int32(q)+1].hh()).lh() = uint16(memMin + 1)
			*(*prg.mem[p].hh()).lh() = q
			*(*prg.mem[q].hh()).rh() = p
			p = q
			delta = uint16(int32(delta) - 1)
			if int32(delta) == 0 {
				break
			}
		}
		*(*prg.mem[p].hh()).lh() = prg.curEdges
		*(*prg.mem[prg.curEdges].hh()).rh() = p
		if int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).rh()) == int32(prg.curEdges) {
			*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(nl - 1)
		}
	}
	if nr > int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) {
		delta = uint16(nr - int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()))
		*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(nr)
		p = *(*prg.mem[prg.curEdges].hh()).lh()
		for {
			q = prg.getNode(rowNodeSize)
			*(*prg.mem[int32(q)+1].hh()).rh() = 3000
			*(*prg.mem[int32(q)+1].hh()).lh() = uint16(memMin + 1)
			*(*prg.mem[p].hh()).rh() = q
			*(*prg.mem[q].hh()).lh() = p
			p = q
			delta = uint16(int32(delta) - 1)
			if int32(delta) == 0 {
				break
			}
		}
		*(*prg.mem[p].hh()).rh() = prg.curEdges
		*(*prg.mem[prg.curEdges].hh()).lh() = p
		if int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).rh()) == int32(prg.curEdges) {
			*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(nr + 1)
		}
	}
}

// 334.

// tangle:pos ../../mf.web:7353:3:

// Here's a trivial subroutine that copies an edge structure. (Let's hope
// that the given structure isn't too gigantic.)
func (prg *prg) copyEdges(h halfword) (r halfword) {
	var (
		p, r1              halfword // variables that traverse the given structure
		hh, pp, qq, rr, ss halfword // variables that traverse the new structure
	)
	hh = prg.getNode(edgeHeaderSize)
	prg.mem[int32(hh)+1] = prg.mem[int32(h)+1]
	prg.mem[int32(hh)+2] = prg.mem[int32(h)+2]
	prg.mem[int32(hh)+3] = prg.mem[int32(h)+3]
	prg.mem[int32(hh)+4] = prg.mem[int32(h)+4] // we've now copied |n_min|, |n_max|,
	//   |m_min|, |m_max|, |m_offset|, |last_window|, and |last_window_time|

	*(*prg.mem[int32(hh)+5].hh()).lh() = uint16(int32(*(*prg.mem[int32(hh)+1].hh()).rh()) + 1)
	*(*prg.mem[int32(hh)+5].hh()).rh() = hh

	p = *(*prg.mem[h].hh()).rh()
	qq = hh
	for int32(p) != int32(h) {
		pp = prg.getNode(rowNodeSize)
		*(*prg.mem[qq].hh()).rh() = pp
		*(*prg.mem[pp].hh()).lh() = qq

		// Copy both |sorted| and |unsorted| lists of |p| to |pp|
		r1 = *(*prg.mem[int32(p)+1].hh()).rh()
		rr = uint16(int32(pp) + 1) // |link(rr)=sorted(pp)|
		for int32(r1) != 3000 {
			ss = prg.getAvail()
			*(*prg.mem[rr].hh()).rh() = ss
			rr = ss
			*(*prg.mem[rr].hh()).lh() = *(*prg.mem[r1].hh()).lh()

			r1 = *(*prg.mem[r1].hh()).rh()
		}
		*(*prg.mem[rr].hh()).rh() = 3000

		r1 = *(*prg.mem[int32(p)+1].hh()).lh()
		rr = uint16(3000 - 1)
		for int32(r1) > memMin+1 {
			ss = prg.getAvail()
			*(*prg.mem[rr].hh()).rh() = ss
			rr = ss
			*(*prg.mem[rr].hh()).lh() = *(*prg.mem[r1].hh()).lh()

			r1 = *(*prg.mem[r1].hh()).rh()
		}
		*(*prg.mem[rr].hh()).rh() = r1
		*(*prg.mem[int32(pp)+1].hh()).lh() = *(*prg.mem[3000-1].hh()).rh()
		p = *(*prg.mem[p].hh()).rh()
		qq = pp
	}
	*(*prg.mem[qq].hh()).rh() = hh
	*(*prg.mem[hh].hh()).lh() = qq
	r = hh
	return r
}

// 336.

// tangle:pos ../../mf.web:7388:3:

// Another trivial routine flips |cur_edges| about the |x|-axis
// (i.e., negates all the |y| coordinates), assuming that at least
// one row is present.
func (prg *prg) yReflectEdges() {
	var (
		p, q, r1 halfword // list manipulation registers
	)
	p = *(*prg.mem[int32(prg.curEdges)+1].hh()).lh()
	*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(zeroField + zeroField - 1 - int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()))
	*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(zeroField + zeroField - 1 - int32(p))
	*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(zeroField + zeroField - 1 - int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()))

	p = *(*prg.mem[prg.curEdges].hh()).rh()
	q = prg.curEdges // we assume that |p<>q|
	for {
		r1 = *(*prg.mem[p].hh()).rh()
		*(*prg.mem[p].hh()).rh() = q
		*(*prg.mem[q].hh()).lh() = p
		q = p
		p = r1
		if int32(q) == int32(prg.curEdges) {
			break
		}
	}
	*prg.mem[int32(prg.curEdges)+4].int() = 0
}

// 337.

// tangle:pos ../../mf.web:7404:3:

// It's somewhat more difficult, yet not too hard, to reflect about the |y|-axis.
func (prg *prg) xReflectEdges() {
	var (
		p, q, r1, s halfword // list manipulation registers
		m           int32    // |info| fields will be reflected with respect to this number
	)
	p = *(*prg.mem[int32(prg.curEdges)+2].hh()).lh()
	*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = uint16(zeroField + zeroField - int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()))
	*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16(zeroField + zeroField - int32(p))
	m = (zeroField+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()))*8 + zeroW + 0 + zeroW + 0
	*(*prg.mem[int32(prg.curEdges)+3].hh()).lh() = uint16(zeroField)
	p = *(*prg.mem[prg.curEdges].hh()).rh()
	for {
		// Reflect the edge-and-weight data in |sorted(p)|
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		r1 = 3000
		for int32(q) != 3000 {
			s = *(*prg.mem[q].hh()).rh()
			*(*prg.mem[q].hh()).rh() = r1
			r1 = q
			*(*prg.mem[r1].hh()).lh() = uint16(m - int32(*(*prg.mem[q].hh()).lh()))
			q = s
		}
		*(*prg.mem[int32(p)+1].hh()).rh() = r1

		// Reflect the edge-and-weight data in |unsorted(p)|
		q = *(*prg.mem[int32(p)+1].hh()).lh()
		for int32(q) > memMin+1 {
			*(*prg.mem[q].hh()).lh() = uint16(m - int32(*(*prg.mem[q].hh()).lh()))
			q = *(*prg.mem[q].hh()).rh()
		}
		p = *(*prg.mem[p].hh()).rh()
		if int32(p) == int32(prg.curEdges) {
			break
		}
	}
	*prg.mem[int32(prg.curEdges)+4].int() = 0
}

// 340.

// tangle:pos ../../mf.web:7443:3:

// Now let's multiply all the $y$~coordinates of a nonempty edge structure
// by a small integer $s>1$:
func (prg *prg) yScaleEdges(s int32) {
	var (
		p, q, pp, r1, rr, ss halfword // list manipulation registers
		t                    int32    // replication counter
	)
	if s*(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh())+1-zeroField) >= 4096 || s*(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh())-zeroField) <= -4096 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Scaled picture would be too big" */ 535) /* \xref[!\relax]  */
		}
		// \xref[Scaled picture...big]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "I can't yscale the picture as requested---it would" */ 536
			prg.helpLine[1] = /* "make some coordinates too large or too small." */ 537
			prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
		}
		prg.putGetError()
	} else {
		*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(s*(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh())+1-zeroField) - 1 + zeroField)
		*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(s*(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh())-zeroField) + zeroField)

		// Replicate every row exactly $s$ times
		p = prg.curEdges
		for {
			q = p
			p = *(*prg.mem[p].hh()).rh()
			for ii := int32(2); ii <= s; ii++ {
				t = ii
				_ = t
				pp = prg.getNode(rowNodeSize)
				*(*prg.mem[q].hh()).rh() = pp
				*(*prg.mem[p].hh()).lh() = pp
				*(*prg.mem[pp].hh()).rh() = p
				*(*prg.mem[pp].hh()).lh() = q
				q = pp

				// Copy both |sorted| and |unsorted|...
				r1 = *(*prg.mem[int32(p)+1].hh()).rh()
				rr = uint16(int32(pp) + 1) // |link(rr)=sorted(pp)|
				for int32(r1) != 3000 {
					ss = prg.getAvail()
					*(*prg.mem[rr].hh()).rh() = ss
					rr = ss
					*(*prg.mem[rr].hh()).lh() = *(*prg.mem[r1].hh()).lh()

					r1 = *(*prg.mem[r1].hh()).rh()
				}
				*(*prg.mem[rr].hh()).rh() = 3000

				r1 = *(*prg.mem[int32(p)+1].hh()).lh()
				rr = uint16(3000 - 1)
				for int32(r1) > memMin+1 {
					ss = prg.getAvail()
					*(*prg.mem[rr].hh()).rh() = ss
					rr = ss
					*(*prg.mem[rr].hh()).lh() = *(*prg.mem[r1].hh()).lh()

					r1 = *(*prg.mem[r1].hh()).rh()
				}
				*(*prg.mem[rr].hh()).rh() = r1
				*(*prg.mem[int32(pp)+1].hh()).lh() = *(*prg.mem[3000-1].hh()).rh()
			}
			if int32(*(*prg.mem[p].hh()).rh()) == int32(prg.curEdges) {
				break
			}
		}
		*prg.mem[int32(prg.curEdges)+4].int() = 0
	}
}

// 342.

// tangle:pos ../../mf.web:7475:3:

// Scaling the $x$~coordinates is, of course, our next task.
func (prg *prg) xScaleEdges(s int32) {
	var (
		p, q                   halfword // list manipulation registers
		t/* 0..65535 */ uint16          // unpacked |info| field
		w/* 0..7 */ byte                // unpacked weight
		delta                  int32    // amount added to scaled |info|
	)
	if s*(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh())-zeroField) >= 4096 || s*(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())-zeroField) <= -4096 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Scaled picture would be too big" */ 535) /* \xref[!\relax]  */
		}
		// \xref[Scaled picture...big]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "I can't xscale the picture as requested---it would" */ 539
			prg.helpLine[1] = /* "make some coordinates too large or too small." */ 537
			prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
		}
		prg.putGetError()
	} else if int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()) != zeroField || int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) != zeroField {
		*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16(s*(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh())-zeroField) + zeroField)
		*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = uint16(s*(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())-zeroField) + zeroField)
		delta = 8*(zeroField-s*int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())) + 0
		*(*prg.mem[int32(prg.curEdges)+3].hh()).lh() = uint16(zeroField)

		// Scale the $x$~coordinates of each row by $s$
		q = *(*prg.mem[prg.curEdges].hh()).rh()
		for {
			p = *(*prg.mem[int32(q)+1].hh()).rh()
			for int32(p) != 3000 {
				t = uint16(int32(*(*prg.mem[p].hh()).lh()) - 0)
				w = byte(int32(t) % 8)
				*(*prg.mem[p].hh()).lh() = uint16((int32(t)-int32(w))*s + int32(w) + delta)
				p = *(*prg.mem[p].hh()).rh()
			}
			p = *(*prg.mem[int32(q)+1].hh()).lh()
			for int32(p) > memMin+1 {
				t = uint16(int32(*(*prg.mem[p].hh()).lh()) - 0)
				w = byte(int32(t) % 8)
				*(*prg.mem[p].hh()).lh() = uint16((int32(t)-int32(w))*s + int32(w) + delta)
				p = *(*prg.mem[p].hh()).rh()
			}
			q = *(*prg.mem[q].hh()).rh()
			if int32(q) == int32(prg.curEdges) {
				break
			}
		}
		*prg.mem[int32(prg.curEdges)+4].int() = 0
	}
}

// 344.

// tangle:pos ../../mf.web:7516:3:

// Here is a routine that changes the signs of all the weights, without
// changing anything else.
func (prg *prg) negateEdges(h halfword) {
	var (
		p, q, r1, s, t, u halfword // structure traversers
	)
	p = *(*prg.mem[h].hh()).rh()
	for int32(p) != int32(h) {
		q = *(*prg.mem[int32(p)+1].hh()).lh()
		for int32(q) > memMin+1 {
			*(*prg.mem[q].hh()).lh() = uint16(8 - 2*((int32(*(*prg.mem[q].hh()).lh())-0)%8) + int32(*(*prg.mem[q].hh()).lh()))
			q = *(*prg.mem[q].hh()).rh()
		}
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		if int32(q) != 3000 {
			for {
				*(*prg.mem[q].hh()).lh() = uint16(8 - 2*((int32(*(*prg.mem[q].hh()).lh())-0)%8) + int32(*(*prg.mem[q].hh()).lh()))
				q = *(*prg.mem[q].hh()).rh()
				if int32(q) == 3000 {
					break
				}
			}

			// Put the list |sorted(p)| back into sort
			u = uint16(int32(p) + 1)
			q = *(*prg.mem[u].hh()).rh()
			r1 = q
			s = *(*prg.mem[r1].hh()).rh() // |q=sorted(p)|
			for true {
				if int32(*(*prg.mem[s].hh()).lh()) > int32(*(*prg.mem[r1].hh()).lh()) {
					*(*prg.mem[u].hh()).rh() = q
					if int32(s) == 3000 {
						goto done
					}
					u = r1
					q = s
					r1 = q
					s = *(*prg.mem[r1].hh()).rh()
				} else {
					t = s
					s = *(*prg.mem[t].hh()).rh()
					*(*prg.mem[t].hh()).rh() = q
					q = t
				}
			}

		done:
			*(*prg.mem[r1].hh()).rh() = 3000
		}
		p = *(*prg.mem[p].hh()).rh()
	}
	*prg.mem[int32(h)+4].int() = 0
}

// 346.

// tangle:pos ../../mf.web:7558:3:

// The |unsorted| edges of a row are merged into the |sorted| ones by
// a subroutine called |sort_edges|. It uses simple insertion sort,
// followed by a merge, because the unsorted list is supposedly quite short.
// However, the unsorted list is assumed to be nonempty.
func (prg *prg) sortEdges(h halfword) {
	var (
		k           halfword // key register that we compare to |info(q)|
		p, q, r1, s halfword
	)
	r1 = *(*prg.mem[int32(h)+1].hh()).lh()
	*(*prg.mem[int32(h)+1].hh()).lh() = uint16(memMin)
	p = *(*prg.mem[r1].hh()).rh()
	*(*prg.mem[r1].hh()).rh() = 3000
	*(*prg.mem[3000-1].hh()).rh() = r1
	for int32(p) > memMin+1 { // sort node |p| into the list that starts at |temp_head|
		k = *(*prg.mem[p].hh()).lh()
		q = uint16(3000 - 1)
		for {
			r1 = q
			q = *(*prg.mem[r1].hh()).rh()
			if int32(k) <= int32(*(*prg.mem[q].hh()).lh()) {
				break
			}
		}
		*(*prg.mem[r1].hh()).rh() = p
		r1 = *(*prg.mem[p].hh()).rh()
		*(*prg.mem[p].hh()).rh() = q
		p = r1
	}

	// Merge the |temp_head| list into |sorted(h)|
	{
		r1 = uint16(int32(h) + 1)
		q = *(*prg.mem[r1].hh()).rh()
		p = *(*prg.mem[3000-1].hh()).rh()
		for true {
			k = *(*prg.mem[p].hh()).lh()
			for int32(k) > int32(*(*prg.mem[q].hh()).lh()) {
				r1 = q
				q = *(*prg.mem[r1].hh()).rh()
			}
			*(*prg.mem[r1].hh()).rh() = p
			s = *(*prg.mem[p].hh()).rh()
			*(*prg.mem[p].hh()).rh() = q
			if int32(s) == 3000 {
				goto done
			}
			r1 = p
			p = s
		}

	done:
	}
}

// 348.

// tangle:pos ../../mf.web:7592:3:

// The |cull_edges| procedure ``optimizes'' an edge structure by making all
// the pixel weights either |w_out| or~|w_in|. The weight will be~|w_in| after the
// operation if and only if it was in the closed interval |[w_lo,w_hi]|
// before, where |w_lo<=w_hi|. Either |w_out| or |w_in| is zero, while the other is
// $\pm1$, $\pm2$, or $\pm3$. The parameters will be such that zero-weight
// pixels will remain of weight zero.  (This is fortunate,
// because there are infinitely many of them.)
//
// The procedure also computes the tightest possible bounds on the resulting
// data, by updating |m_min|, |m_max|, |n_min|, and~|n_max|.
func (prg *prg) cullEdges(wLo, wHi, wOut, wIn int32) {
	var (
		p, q, r1, s   halfword // for list manipulation
		w             int32    // new weight after culling
		d             int32    // data register for unpacking
		m             int32    // the previous column number, including |m_offset|
		mm            int32    // the next column number, including |m_offset|
		ww            int32    // accumulated weight before culling
		prevW         int32    // value of |w| before column |m|
		n, minN, maxN halfword // current and extreme row numbers
		minD, maxD    halfword // extremes of the new edge-and-weight data
	)
	minD = 65535
	maxD = 0
	minN = 65535
	maxN = 0

	p = *(*prg.mem[prg.curEdges].hh()).rh()
	n = *(*prg.mem[int32(prg.curEdges)+1].hh()).lh()
	for int32(p) != int32(prg.curEdges) {
		if int32(*(*prg.mem[int32(p)+1].hh()).lh()) > memMin+1 {
			prg.sortEdges(p)
		}
		if int32(*(*prg.mem[int32(p)+1].hh()).rh()) != 3000 {
			r1 = uint16(3000 - 1)
			q = *(*prg.mem[int32(p)+1].hh()).rh()
			ww = 0
			m = 1000000
			prevW = 0
			for true {
				if int32(q) == 3000 {
					mm = 1000000
				} else {
					d = int32(*(*prg.mem[q].hh()).lh()) - 0
					mm = d / 8
					ww = ww + d%8 - zeroW
				}
				if mm > m {
					if w != prevW {
						s = prg.getAvail()
						*(*prg.mem[r1].hh()).rh() = s
						*(*prg.mem[s].hh()).lh() = uint16(8*m + 0 + zeroW + w - prevW)
						r1 = s
						prevW = w
					}
					if int32(q) == 3000 {
						goto done
					}
				}
				m = mm
				if ww >= wLo {
					if ww <= wHi {
						w = wIn
					} else {
						w = wOut
					}
				} else {
					w = wOut
				}
				s = *(*prg.mem[q].hh()).rh()
				{
					*(*prg.mem[q].hh()).rh() = prg.avail
					prg.avail = q
					prg.dynUsed = prg.dynUsed - 1
				}
				q = s
			}

		done:
			*(*prg.mem[r1].hh()).rh() = 3000
			*(*prg.mem[int32(p)+1].hh()).rh() = *(*prg.mem[3000-1].hh()).rh()
			if int32(r1) != 3000-1 {
				if int32(minN) == 65535 {
					minN = n
				}
				maxN = n
				if int32(minD) > int32(*(*prg.mem[*(*prg.mem[3000-1].hh()).rh()].hh()).lh()) {
					minD = *(*prg.mem[*(*prg.mem[3000-1].hh()).rh()].hh()).lh()
				}
				if int32(maxD) < int32(*(*prg.mem[r1].hh()).lh()) {
					maxD = *(*prg.mem[r1].hh()).lh()
				}
			}
		}
		p = *(*prg.mem[p].hh()).rh()
		n = uint16(int32(n) + 1)
	}

	// Delete empty rows at the top and/or bottom; update the boundary values in the header
	if int32(minN) > int32(maxN) {
		p = *(*prg.mem[prg.curEdges].hh()).rh()
		for int32(p) != int32(prg.curEdges) {
			q = *(*prg.mem[p].hh()).rh()
			prg.freeNode(p, halfword(rowNodeSize))
			p = q
		}
		prg.initEdges(prg.curEdges)
	} else {
		n = *(*prg.mem[int32(prg.curEdges)+1].hh()).lh()
		*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = minN
		for int32(minN) > int32(n) {
			p = *(*prg.mem[prg.curEdges].hh()).rh()
			*(*prg.mem[prg.curEdges].hh()).rh() = *(*prg.mem[p].hh()).rh()
			*(*prg.mem[*(*prg.mem[p].hh()).rh()].hh()).lh() = prg.curEdges
			prg.freeNode(p, halfword(rowNodeSize))
			n = uint16(int32(n) + 1)
		}
		n = *(*prg.mem[int32(prg.curEdges)+1].hh()).rh()
		*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = maxN
		*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(int32(maxN) + 1)
		*(*prg.mem[int32(prg.curEdges)+5].hh()).rh() = prg.curEdges
		for int32(maxN) < int32(n) {
			p = *(*prg.mem[prg.curEdges].hh()).lh()
			*(*prg.mem[prg.curEdges].hh()).lh() = *(*prg.mem[p].hh()).lh()
			*(*prg.mem[*(*prg.mem[p].hh()).lh()].hh()).rh() = prg.curEdges
			prg.freeNode(p, halfword(rowNodeSize))
			n = uint16(int32(n) - 1)
		}
		*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = uint16((int32(minD)-0)/8 - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) + zeroField)
		*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16((int32(maxD)-0)/8 - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) + zeroField)
	}
	*prg.mem[int32(prg.curEdges)+4].int() = 0
}

// 354.

// tangle:pos ../../mf.web:7698:3:

// The last and most difficult routine for transforming an edge structure---and
// the most interesting one!---is |xy_swap_edges|, which interchanges the
// r\^^Doles of rows and columns. Its task can be viewed as the job of
// creating an edge structure that contains only horizontal edges, linked
// together in columns, given an edge structure that contains only
// vertical edges linked together in rows; we must do this without changing
// the implied pixel weights.
//
// Given any two adjacent rows of an edge structure, it is not difficult to
// determine the horizontal edges that lie ``between'' them: We simply look
// for vertically adjacent pixels that have different weight, and insert
// a horizontal edge containing the difference in weights. Every horizontal
// edge determined in this way should be put into an appropriate linked
// list. Since random access to these linked lists is desirable, we use
// the |move| array to hold the list heads. If we work through the given
// edge structure from top to bottom, the constructed lists will not need
// to be sorted, since they will already be in order.
//
// The following algorithm makes use of some ideas suggested by John Hobby.
// \xref[Hobby, John Douglas]
// It assumes that the edge structure is non-null, i.e., that |link(cur_edges)
// <>cur_edges|, hence |m_max(cur_edges)>=m_min(cur_edges)|.
func (prg *prg) xySwapEdges() {
	var (
		mMagic, nMagic int32    // special values that account for offsets
		p, q, r1, s    halfword // pointers that traverse the given structure

		// Other local variables for |xy_swap_edges|
		mSpread                       int32 // the difference between |m_max| and |m_min|
		j, jj/* 0..moveSize */ uint16       // indices into |move|
		m, mm                         int32 // |m| values at vertical edges
		pd, rd                        int32 // data fields from edge-and-weight nodes
		pm, rm                        int32 // |m| values from edge-and-weight nodes
		w                             int32 // the difference in accumulated weight
		ww                            int32 // as much of |w| that can be stored in a single node
		dw                            int32 // an increment to be added to |w|

		extras              int32 // the number of additional nodes to make weights |>3|
		xw/*  -3..3 */ int8       // the additional weight in extra nodes
		k                   int32 // loop counter for inserting extra nodes
	)
	mSpread = int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()) - int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) // this is |>=0| by assumption
	if mSpread > moveSize {
		prg.overflow(strNumber( /* "move table size" */ 540), moveSize)
	}
	// \xref[METAFONT capacity exceeded move table size][\quad move table size]
	for ii := int32(0); ii <= mSpread; ii++ {
		j = uint16(ii)
		_ = j
		prg.move[j] = 3000
	}

	// Insert blank rows at the top and bottom, and set |p| to the new top row
	p = prg.getNode(rowNodeSize)
	*(*prg.mem[int32(p)+1].hh()).rh() = 3000
	*(*prg.mem[int32(p)+1].hh()).lh() = uint16(memMin)

	*(*prg.mem[p].hh()).lh() = prg.curEdges
	*(*prg.mem[*(*prg.mem[prg.curEdges].hh()).rh()].hh()).lh() = p // the new bottom row
	p = prg.getNode(rowNodeSize)
	*(*prg.mem[int32(p)+1].hh()).rh() = 3000
	*(*prg.mem[p].hh()).lh() = *(*prg.mem[prg.curEdges].hh()).lh() // the new top row

	// Compute the magic offset values
	mMagic = int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) + int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) - zeroField
	nMagic = 8*int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) + 8 + zeroW + 0
	for {
		q = *(*prg.mem[p].hh()).lh()
		if int32(*(*prg.mem[int32(q)+1].hh()).lh()) > memMin+1 {
			prg.sortEdges(q)
		}

		// Insert the horizontal edges defined by adjacent rows |p,q|, and destroy row~|p|
		r1 = *(*prg.mem[int32(p)+1].hh()).rh()
		prg.freeNode(p, halfword(rowNodeSize))
		p = r1

		pd = int32(*(*prg.mem[p].hh()).lh()) - 0
		pm = pd / 8

		r1 = *(*prg.mem[int32(q)+1].hh()).rh()
		rd = int32(*(*prg.mem[r1].hh()).lh()) - 0
		rm = rd / 8
		w = 0
		for true {
			if pm < rm {
				mm = pm
			} else {
				mm = rm
			}
			if w != 0 {
				if m != mm {
					if mm-mMagic >= moveSize {
						prg.confusion(strNumber( /* "xy" */ 510))
					}
					// \xref[this can't happen xy][\quad xy]
					extras = (abs(w) - 1) / 3
					if extras > 0 {
						if w > 0 {
							xw = int8(+3)
						} else {
							xw = int8(-3)
						}
						ww = w - extras*int32(xw)
					} else {
						ww = w
					}
					for {
						j = uint16(m - mMagic)
						for ii := int32(1); ii <= extras; ii++ {
							k = ii
							_ = k
							s = prg.getAvail()
							*(*prg.mem[s].hh()).lh() = uint16(nMagic + int32(xw))
							*(*prg.mem[s].hh()).rh() = uint16(prg.move[j])
							prg.move[j] = int32(s)
						}
						s = prg.getAvail()
						*(*prg.mem[s].hh()).lh() = uint16(nMagic + ww)
						*(*prg.mem[s].hh()).rh() = uint16(prg.move[j])
						prg.move[j] = int32(s)

						m = m + 1
						if m == mm {
							break
						}
					}
				}
			}
			if pd < rd {
				dw = pd%8 - zeroW

				// Advance pointer |p| to the next vertical edge, after destroying the previous one
				s = *(*prg.mem[p].hh()).rh()
				{
					*(*prg.mem[p].hh()).rh() = prg.avail
					prg.avail = p
					prg.dynUsed = prg.dynUsed - 1
				}
				p = s
				pd = int32(*(*prg.mem[p].hh()).lh()) - 0
				pm = pd / 8
			} else {
				if int32(r1) == 3000 {
					goto done
				} // |rd=pd=ho(max_halfword)|
				dw = -(rd%8 - zeroW)

				// Advance pointer |r| to the next vertical edge
				r1 = *(*prg.mem[r1].hh()).rh()
				rd = int32(*(*prg.mem[r1].hh()).lh()) - 0
				rm = rd / 8
			}
			m = mm
			w = w + dw
		}

	done:
		;
		p = q
		nMagic = nMagic - 8
		if int32(*(*prg.mem[p].hh()).lh()) == int32(prg.curEdges) {
			break
		}
	}
	prg.freeNode(p, halfword(rowNodeSize)) // now all original rows have been recycled

	// Adjust the header to reflect the new edges
	prg.move[mSpread] = 0
	j = 0
	for prg.move[j] == 3000 {
		j = uint16(int32(j) + 1)
	}
	if int32(j) == mSpread {
		prg.initEdges(prg.curEdges)
	} else {
		mm = int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())
		*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = *(*prg.mem[int32(prg.curEdges)+1].hh()).lh()
		*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) + 1)
		*(*prg.mem[int32(prg.curEdges)+3].hh()).lh() = uint16(zeroField)
		jj = uint16(mSpread - 1)
		for prg.move[jj] == 3000 {
			jj = uint16(int32(jj) - 1)
		}
		*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(int32(j) + mm)
		*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(int32(jj) + mm)
		q = prg.curEdges
		for {
			p = prg.getNode(rowNodeSize)
			*(*prg.mem[q].hh()).rh() = p
			*(*prg.mem[p].hh()).lh() = q
			*(*prg.mem[int32(p)+1].hh()).rh() = uint16(prg.move[j])
			*(*prg.mem[int32(p)+1].hh()).lh() = uint16(memMin)
			j = uint16(int32(j) + 1)
			q = p
			if int32(j) > int32(jj) {
				break
			}
		}
		*(*prg.mem[q].hh()).rh() = prg.curEdges
		*(*prg.mem[prg.curEdges].hh()).lh() = q
		*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) + 1)
		*(*prg.mem[int32(prg.curEdges)+5].hh()).rh() = prg.curEdges
		*prg.mem[int32(prg.curEdges)+4].int() = 0
	}

}

// 361.

// tangle:pos ../../mf.web:7797:3:

// Certain ``magic'' values are needed to make the following code work,
// because of the various offsets in our data structure. For now, let's not
// worry about their precise values; we shall compute |m_magic| and |n_magic|
// later, after we see what the code looks like.

// 366.

// tangle:pos ../../mf.web:7858:3:

// Now let's look at the subroutine that merges the edges from a given
// edge structure into |cur_edges|. The given edge structure loses all its
// edges.
func (prg *prg) mergeEdges(h halfword) {
	var (
		p, q, r1, pp, qq, rr halfword // list manipulation registers
		n                    int32    // row number
		k                    halfword // key register that we compare to |info(q)|
		delta                int32    // change to the edge/weight data
	)
	if int32(*(*prg.mem[h].hh()).rh()) != int32(h) {
		if int32(*(*prg.mem[int32(h)+2].hh()).lh()) < int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) || int32(*(*prg.mem[int32(h)+2].hh()).rh()) > int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()) || int32(*(*prg.mem[int32(h)+1].hh()).lh()) < int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh()) || int32(*(*prg.mem[int32(h)+1].hh()).rh()) > int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) {
			prg.edgePrep(int32(*(*prg.mem[int32(h)+2].hh()).lh())-zeroField, int32(*(*prg.mem[int32(h)+2].hh()).rh())-zeroField, int32(*(*prg.mem[int32(h)+1].hh()).lh())-zeroField, int32(*(*prg.mem[int32(h)+1].hh()).rh())-zeroField+1)
		}
		if int32(*(*prg.mem[int32(h)+3].hh()).lh()) != int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) {
			pp = *(*prg.mem[h].hh()).rh()
			delta = 8 * (int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) - int32(*(*prg.mem[int32(h)+3].hh()).lh()))
			for {
				qq = *(*prg.mem[int32(pp)+1].hh()).rh()
				for int32(qq) != 3000 {
					*(*prg.mem[qq].hh()).lh() = uint16(int32(*(*prg.mem[qq].hh()).lh()) + delta)
					qq = *(*prg.mem[qq].hh()).rh()
				}
				qq = *(*prg.mem[int32(pp)+1].hh()).lh()
				for int32(qq) > memMin+1 {
					*(*prg.mem[qq].hh()).lh() = uint16(int32(*(*prg.mem[qq].hh()).lh()) + delta)
					qq = *(*prg.mem[qq].hh()).rh()
				}
				pp = *(*prg.mem[pp].hh()).rh()
				if int32(pp) == int32(h) {
					break
				}
			}
		}
		n = int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh())
		p = *(*prg.mem[prg.curEdges].hh()).rh()
		pp = *(*prg.mem[h].hh()).rh()
		for n < int32(*(*prg.mem[int32(h)+1].hh()).lh()) {
			n = n + 1
			p = *(*prg.mem[p].hh()).rh()
		}
		for {
			// Merge row |pp| into row |p|
			qq = *(*prg.mem[int32(pp)+1].hh()).lh()
			if int32(qq) > memMin+1 {
				if int32(*(*prg.mem[int32(p)+1].hh()).lh()) <= memMin+1 {
					*(*prg.mem[int32(p)+1].hh()).lh() = qq
				} else {
					for int32(*(*prg.mem[qq].hh()).rh()) > memMin+1 {
						qq = *(*prg.mem[qq].hh()).rh()
					}
					*(*prg.mem[qq].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
					*(*prg.mem[int32(p)+1].hh()).lh() = *(*prg.mem[int32(pp)+1].hh()).lh()
				}
			}
			*(*prg.mem[int32(pp)+1].hh()).lh() = uint16(memMin)
			qq = *(*prg.mem[int32(pp)+1].hh()).rh()
			if int32(qq) != 3000 {
				if int32(*(*prg.mem[int32(p)+1].hh()).lh()) == memMin+1 {
					*(*prg.mem[int32(p)+1].hh()).lh() = uint16(memMin)
				}
				*(*prg.mem[int32(pp)+1].hh()).rh() = 3000
				r1 = uint16(int32(p) + 1)
				q = *(*prg.mem[r1].hh()).rh() // |q=sorted(p)|
				if int32(q) == 3000 {
					*(*prg.mem[int32(p)+1].hh()).rh() = qq
				} else {
					for true {
						k = *(*prg.mem[qq].hh()).lh()
						for int32(k) > int32(*(*prg.mem[q].hh()).lh()) {
							r1 = q
							q = *(*prg.mem[r1].hh()).rh()
						}
						*(*prg.mem[r1].hh()).rh() = qq
						rr = *(*prg.mem[qq].hh()).rh()
						*(*prg.mem[qq].hh()).rh() = q
						if int32(rr) == 3000 {
							goto done
						}
						r1 = qq
						qq = rr
					}
				}
			}

		done:
			;
			pp = *(*prg.mem[pp].hh()).rh()
			p = *(*prg.mem[p].hh()).rh()
			if int32(pp) == int32(h) {
				break
			}
		}
	}
}

// 369.

// tangle:pos ../../mf.web:7926:3:

// The |total_weight| routine computes the total of all pixel weights
// in a given edge structure. It's not difficult to prove that this is
// the sum of $(-w)$ times $x$ taken over all edges,
// where $w$ and~$x$ are the weight and $x$~coordinates stored in an edge.
// It's not necessary to worry that this quantity will overflow the
// size of an |integer| register, because it will be less than~$2^[31]$
// unless the edge structure has more than 174,762 edges. However, we had
// better not try to compute it as a |scaled| integer, because a total
// weight of almost $12\times 2^[12]$ can be produced by only four edges.
func (prg *prg) totalWeight(h halfword) (r int32) { // |h| is an edge header
	var (
		p, q                   halfword // variables that traverse the given structure
		n                      int32    // accumulated total so far
		m/* 0..65535 */ uint16          // packed $x$ and $w$ values, including offsets
	)
	n = 0
	p = *(*prg.mem[h].hh()).rh()
	for int32(p) != int32(h) {
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(q) != 3000 {

			// Add the contribution of node |q| to the total weight, and set |q:=link(q)|
			m = uint16(int32(*(*prg.mem[q].hh()).lh()) - 0)
			n = n - (int32(m)%8-zeroW)*(int32(m)/8)
			q = *(*prg.mem[q].hh()).rh()
		}
		q = *(*prg.mem[int32(p)+1].hh()).lh()
		for int32(q) > memMin+1 {

			// Add the contribution of node |q| to the total weight, and set |q:=link(q)|
			m = uint16(int32(*(*prg.mem[q].hh()).lh()) - 0)
			n = n - (int32(m)%8-zeroW)*(int32(m)/8)
			q = *(*prg.mem[q].hh()).rh()
		}
		p = *(*prg.mem[p].hh()).rh()
	}
	r = n
	return r
}

// 372.

// tangle:pos ../../mf.web:7983:3:

// Edge tracing is initiated by the |begin_edge_tracing| routine,
// continued by the |trace_a_corner| routine, and terminated by the
// |end_edge_tracing| routine.
func (prg *prg) beginEdgeTracing() {
	prg.printDiagnostic(strNumber( /* "Tracing edges" */ 541), strNumber( /* "" */ 285), true)
	prg.print( /* " (weight " */ 542)
	prg.printInt(prg.curWt)
	prg.printChar(asciiCode(')'))
	prg.traceX = -4096
}

func (prg *prg) traceACorner() {
	if int32(prg.fileOffset) > maxPrintLine-13 {
		prg.printNl(strNumber( /* "" */ 285))
	}
	prg.printChar(asciiCode('('))
	prg.printInt(prg.traceX)
	prg.printChar(asciiCode(','))
	prg.printInt(prg.traceYy)
	prg.printChar(asciiCode(')'))
	prg.traceY = prg.traceYy
}

func (prg *prg) endEdgeTracing() {
	if prg.traceX == -4096 {
		prg.printNl(strNumber( /* "(No new edges added.)" */ 543))
	} else {
		prg.traceACorner()
		prg.printChar(asciiCode('.'))
	}
	prg.endDiagnostic(true)
}

// 373.

// tangle:pos ../../mf.web:8006:3:

// Just after a new edge weight has been put into the |info| field of
// node~|r|, in row~|n|, the following routine continues an ongoing trace.
func (prg *prg) traceNewEdge(r1 halfword, n int32) {
	var (
		d                  int32 // temporary data register
		w/*  -3..3 */ int8       // weight associated with an edge transition
		m, n0, n1          int32 // column and row numbers
	)
	d = int32(*(*prg.mem[r1].hh()).lh()) - 0
	w = int8(d%8 - zeroW)
	m = d/8 - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())
	if int32(w) == prg.curWt {
		n0 = n + 1
		n1 = n
	} else {
		n0 = n
		n1 = n + 1
	} // the edges run from |(m,n0)| to |(m,n1)|
	if m != prg.traceX {
		if prg.traceX == -4096 {
			prg.printNl(strNumber( /* "" */ 285))
			prg.traceYy = n0
		} else if prg.traceYy != n0 {
			prg.printChar(asciiCode('?'))
		} else {
			prg.traceACorner()
		}
		prg.traceX = m
		prg.traceACorner()
	} else {
		if n0 != prg.traceYy {
			prg.printChar(asciiCode('!'))
		} // shouldn't happen
		if n0 < n1 && prg.traceY > prg.traceYy || n0 > n1 && prg.traceY < prg.traceYy {
			prg.traceACorner()
		}
	}
	prg.traceYy = n1
}

// 374.

// tangle:pos ../../mf.web:8034:3:

// One way to put new edge weights into an edge structure is to use the
// following routine, which simply draws a straight line from |(x0,y0)| to
// |(x1,y1)|. More precisely, it introduces weights for the edges of the
// discrete path $\bigl(\lfloor t[x_0,x_1]+[1\over2]+\epsilon\rfloor,
// \lfloor t[y_0,y_1]+[1\over2]+\epsilon\delta\rfloor\bigr)$,
// as $t$ varies from 0 to~1, where $\epsilon$ and $\delta$ are extremely small
// positive numbers.
//
// The structure header is assumed to be |cur_edges|; downward edge weights
// will be |cur_wt|, while upward ones will be |-cur_wt|.
//
// Of course, this subroutine will be called only in connection with others
// that eventually draw a complete cycle, so that the sum of the edge weights
// in each row will be zero whenever the row is displayed.
func (prg *prg) lineEdges(x0, y0, x1, y1 scaled) {
	var (
		m0, n0, m1, n1 int32    // rounded and unscaled coordinates
		delx, dely     scaled   // the coordinate differences of the line
		yt             scaled   // smallest |y| coordinate that rounds the same as |y0|
		tx             scaled   // tentative change in |x|
		p, r1          halfword // list manipulation registers
		base           int32    // amount added to edge-and-weight data
		n              int32    // current row number
	)
	n0 = prg.roundUnscaled(y0)
	n1 = prg.roundUnscaled(y1)
	if n0 != n1 {
		m0 = prg.roundUnscaled(x0)
		m1 = prg.roundUnscaled(x1)
		delx = x1 - x0
		dely = y1 - y0
		yt = n0*0200000 - 0100000
		y0 = y0 - yt
		y1 = y1 - yt
		if n0 < n1 {
			base = 8*int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) + 0 + zeroW - prg.curWt
			if m0 <= m1 {
				prg.edgePrep(m0, m1, n0, n1)
			} else {
				prg.edgePrep(m1, m0, n0, n1)
			}

			// Move to row |n0|, pointed to by |p|
			n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
			p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
			if n != n0 {
				if n < n0 {
					for {
						n = n + 1
						p = *(*prg.mem[p].hh()).rh()
						if n == n0 {
							break
						}
					}
				} else {
					for {
						n = n - 1
						p = *(*prg.mem[p].hh()).lh()
						if n == n0 {
							break
						}
					}
				}
			}
			y0 = 0200000 - y0
			for true {
				r1 = prg.getAvail()
				*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
				*(*prg.mem[int32(p)+1].hh()).lh() = r1

				tx = prg.takeFraction(delx, prg.makeFraction(y0, dely))
				if prg.abVsCd(delx, y0, dely, tx) < 0 {
					tx = tx - 1
				}
				// now $|tx|=\lfloor|y0|\cdot|delx|/|dely|\rfloor$
				*(*prg.mem[r1].hh()).lh() = uint16(8*prg.roundUnscaled(x0+tx) + base)

				y1 = y1 - 0200000
				if prg.internal[tracingEdges-1] > 0 {
					prg.traceNewEdge(r1, n)
				}
				if y1 < 0200000 {
					goto done
				}
				p = *(*prg.mem[p].hh()).rh()
				y0 = y0 + 0200000
				n = n + 1
			}

		done:
		} else {
			// Insert downward edges for a line
			base = 8*int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) + 0 + zeroW + prg.curWt
			if m0 <= m1 {
				prg.edgePrep(m0, m1, n1, n0)
			} else {
				prg.edgePrep(m1, m0, n1, n0)
			}
			n0 = n0 - 1
			// Move to row |n0|, pointed to by |p|
			n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
			p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
			if n != n0 {
				if n < n0 {
					for {
						n = n + 1
						p = *(*prg.mem[p].hh()).rh()
						if n == n0 {
							break
						}
					}
				} else {
					for {
						n = n - 1
						p = *(*prg.mem[p].hh()).lh()
						if n == n0 {
							break
						}
					}
				}
			}
			for true {
				r1 = prg.getAvail()
				*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
				*(*prg.mem[int32(p)+1].hh()).lh() = r1

				tx = prg.takeFraction(delx, prg.makeFraction(y0, dely))
				if prg.abVsCd(delx, y0, dely, tx) < 0 {
					tx = tx + 1
				}
				// now $|tx|=\lceil|y0|\cdot|delx|/|dely|\rceil$, since |dely<0|
				*(*prg.mem[r1].hh()).lh() = uint16(8*prg.roundUnscaled(x0-tx) + base)

				y1 = y1 + 0200000
				if prg.internal[tracingEdges-1] > 0 {
					prg.traceNewEdge(r1, n)
				}
				if y1 >= 0 {
					goto done1
				}
				p = *(*prg.mem[p].hh()).lh()
				y0 = y0 + 0200000
				n = n - 1
			}

		done1:
		}
		*(*prg.mem[int32(prg.curEdges)+5].hh()).rh() = p
		*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(n + zeroField)
	}
}

// 378.

// tangle:pos ../../mf.web:8114:3:

// \MF\ inserts most of its edges into edge structures via the
// |move_to_edges| subroutine, which uses the data stored in the |move| array
// to specify a sequence of ``rook moves.'' The starting point |(m0,n0)|
// and finishing point |(m1,n1)| of these moves, as seen from the standpoint
// of the first octant, are supplied as parameters; the moves should, however,
// be rotated into a given octant.  (We're going to study octant
// transformations in great detail later; the reader may wish to come back to
// this part of the program after mastering the mysteries of octants.)
//
// The rook moves themselves are defined as follows, from a |first_octant|
// point of view: ``Go right |move[k]| steps, then go up one, for |0<=k<n1-n0|;
// then go right |move[n1-n0]| steps and stop.'' The sum of |move[k]|
// for |0<=k<=n1-n0| will be equal to |m1-m0|.
//
// As in the |line_edges| routine, we use |+cur_wt| as the weight of
// all downward edges and |-cur_wt| as the weight of all upward edges,
// after the moves have been rotated to the proper octant direction.
//
// There are two main cases to consider: \\[fast\_case] is for moves that
// travel in the direction of octants 1, 4, 5, and~8, while \\[slow\_case]
// is for moves that travel toward octants 2, 3, 6, and~7. The latter directions
// are comparatively cumbersome because they generate more upward or downward
// edges; a curve that travels horizontally doesn't produce any edges at all,
// but a curve that travels vertically touches lots of rows.
func (prg *prg) moveToEdges(m0, n0, m1, n1 int32) {
	var (
		delta/* 0..moveSize */ uint16          // extent of |move| data
		k/* 0..moveSize */ uint16              // index into |move|
		p, r1                         halfword // list manipulation registers
		dx                            int32    // change in edge-weight |info| when |x| changes by 1
		edgeAndWeight                 int32    // |info| to insert
		j                             int32    // number of consecutive vertical moves
		n                             int32    // the current row pointed to by |p|
	// sum:integer; [  ]
	)
	delta = uint16(n1 - n0)
	//  sum:=move[0]; for k:=1 to delta do sum:=sum+abs(move[k]);
	// if sum<>m1-m0 then confusion(["0"=]48); [  ]

	// \xref[this can't happen 0][\quad 0]

	// Prepare for and switch to the appropriate case, based on |octant|
	switch prg.octant {
	case firstOctant:
		dx = 8
		prg.edgePrep(m0, m1, n0, n1)
		goto fastCaseUp

	case secondOctant:
		dx = 8
		prg.edgePrep(n0, n1, m0, m1)
		goto slowCaseUp

	case thirdOctant:
		dx = -8
		prg.edgePrep(-n1, -n0, m0, m1)
		n0 = -n0

		goto slowCaseUp

	case fourthOctant:
		dx = -8
		prg.edgePrep(-m1, -m0, n0, n1)
		m0 = -m0

		goto fastCaseUp

	case fifthOctant:
		dx = -8
		prg.edgePrep(-m1, -m0, -n1, -n0)
		m0 = -m0

		goto fastCaseDown

	case sixthOctant:
		dx = -8
		prg.edgePrep(-n1, -n0, -m1, -m0)
		n0 = -n0

		goto slowCaseDown

	case seventhOctant:
		dx = 8
		prg.edgePrep(n0, n1, -m1, -m0)
		goto slowCaseDown

	case eighthOctant:
		dx = 8
		prg.edgePrep(m0, m1, -n1, -n0)
		goto fastCaseDown

	} // there are only eight octants

fastCaseUp:
	n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
	p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
	if n != n0 {
		if n < n0 {
			for {
				n = n + 1
				p = *(*prg.mem[p].hh()).rh()
				if n == n0 {
					break
				}
			}
		} else {
			for {
				n = n - 1
				p = *(*prg.mem[p].hh()).lh()
				if n == n0 {
					break
				}
			}
		}
	}
	if int32(delta) > 0 {
		k = 0
		edgeAndWeight = 8*(m0+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())) + 0 + zeroW - prg.curWt
		for {
			edgeAndWeight = edgeAndWeight + dx*prg.move[k]
			/*   */ {
				r1 = prg.avail
				if int32(r1) == memMin {
					r1 = prg.getAvail()
				} else {
					prg.avail = *(*prg.mem[r1].hh()).rh()
					*(*prg.mem[r1].hh()).rh() = uint16(memMin)
					prg.dynUsed = prg.dynUsed + 1
				}
			}
			*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
			*(*prg.mem[r1].hh()).lh() = uint16(edgeAndWeight)
			if prg.internal[tracingEdges-1] > 0 {
				prg.traceNewEdge(r1, n)
			}
			*(*prg.mem[int32(p)+1].hh()).lh() = r1
			p = *(*prg.mem[p].hh()).rh()
			k = uint16(int32(k) + 1)
			n = n + 1
			if int32(k) == int32(delta) {
				break
			}
		}
	}

	goto done

fastCaseDown:
	n0 = -n0 - 1
	// Move to row |n0|, pointed to by |p|
	n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
	p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
	if n != n0 {
		if n < n0 {
			for {
				n = n + 1
				p = *(*prg.mem[p].hh()).rh()
				if n == n0 {
					break
				}
			}
		} else {
			for {
				n = n - 1
				p = *(*prg.mem[p].hh()).lh()
				if n == n0 {
					break
				}
			}
		}
	}
	if int32(delta) > 0 {
		k = 0
		edgeAndWeight = 8*(m0+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())) + 0 + zeroW + prg.curWt
		for {
			edgeAndWeight = edgeAndWeight + dx*prg.move[k]
			/*   */ {
				r1 = prg.avail
				if int32(r1) == memMin {
					r1 = prg.getAvail()
				} else {
					prg.avail = *(*prg.mem[r1].hh()).rh()
					*(*prg.mem[r1].hh()).rh() = uint16(memMin)
					prg.dynUsed = prg.dynUsed + 1
				}
			}
			*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
			*(*prg.mem[r1].hh()).lh() = uint16(edgeAndWeight)
			if prg.internal[tracingEdges-1] > 0 {
				prg.traceNewEdge(r1, n)
			}
			*(*prg.mem[int32(p)+1].hh()).lh() = r1
			p = *(*prg.mem[p].hh()).lh()
			k = uint16(int32(k) + 1)
			n = n - 1
			if int32(k) == int32(delta) {
				break
			}
		}
	}

	goto done

slowCaseUp:
	edgeAndWeight = 8*(n0+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())) + 0 + zeroW - prg.curWt
	n0 = m0
	k = 0
	// Move to row |n0|, pointed to by |p|
	n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
	p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
	if n != n0 {
		if n < n0 {
			for {
				n = n + 1
				p = *(*prg.mem[p].hh()).rh()
				if n == n0 {
					break
				}
			}
		} else {
			for {
				n = n - 1
				p = *(*prg.mem[p].hh()).lh()
				if n == n0 {
					break
				}
			}
		}
	}
	for {
		j = prg.move[k]
		for j > 0 {
			{
				r1 = prg.avail
				if int32(r1) == memMin {
					r1 = prg.getAvail()
				} else {
					prg.avail = *(*prg.mem[r1].hh()).rh()
					*(*prg.mem[r1].hh()).rh() = uint16(memMin)
					prg.dynUsed = prg.dynUsed + 1
				}
			}
			*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
			*(*prg.mem[r1].hh()).lh() = uint16(edgeAndWeight)
			if prg.internal[tracingEdges-1] > 0 {
				prg.traceNewEdge(r1, n)
			}
			*(*prg.mem[int32(p)+1].hh()).lh() = r1
			p = *(*prg.mem[p].hh()).rh()
			j = j - 1
			n = n + 1
		}
		edgeAndWeight = edgeAndWeight + dx
		k = uint16(int32(k) + 1)
		if int32(k) > int32(delta) {
			break
		}
	}

	goto done

slowCaseDown:
	edgeAndWeight = 8*(n0+int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())) + 0 + zeroW + prg.curWt
	n0 = -m0 - 1
	k = 0
	// Move to row |n0|, pointed to by |p|
	n = int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) - zeroField
	p = *(*prg.mem[int32(prg.curEdges)+5].hh()).rh()
	if n != n0 {
		if n < n0 {
			for {
				n = n + 1
				p = *(*prg.mem[p].hh()).rh()
				if n == n0 {
					break
				}
			}
		} else {
			for {
				n = n - 1
				p = *(*prg.mem[p].hh()).lh()
				if n == n0 {
					break
				}
			}
		}
	}
	for {
		j = prg.move[k]
		for j > 0 {
			{
				r1 = prg.avail
				if int32(r1) == memMin {
					r1 = prg.getAvail()
				} else {
					prg.avail = *(*prg.mem[r1].hh()).rh()
					*(*prg.mem[r1].hh()).rh() = uint16(memMin)
					prg.dynUsed = prg.dynUsed + 1
				}
			}
			*(*prg.mem[r1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).lh()
			*(*prg.mem[r1].hh()).lh() = uint16(edgeAndWeight)
			if prg.internal[tracingEdges-1] > 0 {
				prg.traceNewEdge(r1, n)
			}
			*(*prg.mem[int32(p)+1].hh()).lh() = r1
			p = *(*prg.mem[p].hh()).lh()
			j = j - 1
			n = n - 1
		}
		edgeAndWeight = edgeAndWeight + dx
		k = uint16(int32(k) + 1)
		if int32(k) > int32(delta) {
			break
		}
	}

	goto done

done:
	*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(n + zeroField)
	*(*prg.mem[int32(prg.curEdges)+5].hh()).rh() = p
}

// 386. \[21] Subdivision into octants

// tangle:pos ../../mf.web:8266:35:

// When \MF\ digitizes a path, it reduces the problem to the special
// case of paths that travel in ``first octant'' directions; i.e.,
// each cubic $z(t)=\bigl(x(t),y(t)\bigr)$ being digitized will have the property
// that $0\L y'(t)\L x'(t)$. This assumption makes digitizing simpler
// and faster than if the direction of motion has to be tested repeatedly.
//
// When $z(t)$ is cubic, $x'(t)$ and $y'(t)$ are quadratic, hence the four
// polynomials $x'(t)$, $y'(t)$, $x'(t)-y'(t)$, and $x'(t)+y'(t)$ cross
// through~0 at most twice each. If we subdivide the given cubic at these
// places, we get at most nine subintervals in each of which
// $x'(t)$, $y'(t)$, $x'(t)-y'(t)$, and $x'(t)+y'(t)$ all have a constant
// sign. The curve can be transformed in each of these subintervals so that
// it travels entirely in first octant directions, if we reflect $x\swap-x$,
// $y\swap-y$, and/or $x\swap y$ as necessary. (Incidentally, it can be
// shown that a cubic such that $x'(t)=16(2t-1)^2+2(2t-1)-1$ and
// $y'(t)=8(2t-1)^2+4(2t-1)$ does indeed split into nine subintervals.)

// 387.

// tangle:pos ../../mf.web:8284:3:

// The transformation that rotates coordinates, so that first octant motion
// can be assumed, is defined by the |skew| subroutine, which sets global
// variables |cur_x| and |cur_y| to the values that are appropriate in a
// given octant.  (Octants are encoded as they were in the |n_arg| subroutine.)
//
// This transformation is ``skewed'' by replacing |(x,y)| by |(x-y,y)|,
// once first octant motion has been established. It turns out that
// skewed coordinates are somewhat better to work with when curves are
// actually digitized.
func (prg *prg) skew(x, y scaled, octant smallNumber) {
	switch octant {
	case firstOctant:
		prg.curX = x - y
		prg.curY = y
	case secondOctant:
		prg.curX = y - x
		prg.curY = x
	case thirdOctant:
		prg.curX = y + x
		prg.curY = -x
	case fourthOctant:
		prg.curX = -x - y
		prg.curY = y
	case fifthOctant:
		prg.curX = -x + y
		prg.curY = -y
	case sixthOctant:
		prg.curX = -y + x
		prg.curY = -x
	case seventhOctant:
		prg.curX = -y - x
		prg.curY = x
	case eighthOctant:
		prg.curX = x + y
		prg.curY = -y
	} // there are no other cases
}

// 390.

// tangle:pos ../../mf.web:8333:3:

// The conversion to skewed and rotated coordinates takes place in
// stages, and at one point in the transformation we will have negated the
// $x$ and/or $y$ coordinates so as to make curves travel in the first
// [\sl quadrant]. At this point the relevant ``octant'' code will be
// either |first_octant| (when no transformation has been done),
// or |fourth_octant=first_octant+negate_x| (when $x$ has been negated),
// or |fifth_octant=first_octant+negate_x+negate_y| (when both have been
// negated), or |eighth_octant=first_octant+negate_y| (when $y$ has been
// negated). The |abnegate| routine is sometimes needed to convert
// from one of these transformations to another.
func (prg *prg) abnegate(x, y scaled,
	octantBefore, octantAfter smallNumber) {
	if octantBefore&1 != 0 == (octantAfter&1 != 0) {
		prg.curX = x
	} else {
		prg.curX = -x
	}
	if int32(octantBefore) > negateY == (int32(octantAfter) > negateY) {
		prg.curY = y
	} else {
		prg.curY = -y
	}
}

// 391.

// tangle:pos ../../mf.web:8352:3:

// Now here's a subroutine that's handy for subdivision: Given a
// quadratic polynomial $B(a,b,c;t)$, the |crossing_point| function
// returns the unique |fraction| value |t| between 0 and~1 at which
// $B(a,b,c;t)$ changes from positive to negative, or returns
// |t=fraction_one+1| if no such value exists. If |a<0| (so that $B(a,b,c;t)$
// is already negative at |t=0|), |crossing_point| returns the value zero.
func (prg *prg) crossingPoint(a, b, c int32) (r fraction) {
	var (
		d                 int32 // recursive counter
		x, xx, x0, x1, x2 int32 // temporary registers for bisection
	)
	if a < 0 {
		r = 0
		goto exit
	}
	if c >= 0 {
		if b >= 0 {
			if c > 0 {
				r = 02000000000 + 1
				goto exit
			} else if a == 0 && b == 0 {
				r = 02000000000 + 1
				goto exit
			} else {
				r = 02000000000
				goto exit
			}
		}
		if a == 0 {
			r = 0
			goto exit
		}
	} else if a == 0 {
		if b <= 0 {
			r = 0
			goto exit
		}
	}

	// Use bisection to find the crossing point, if one exists
	d = 1
	x0 = a
	x1 = a - b
	x2 = b - c
	for {
		x = (x1 + x2) / 2
		if x1-x0 > x0 {
			x2 = x
			x0 = x0 + x0
			d = d + d
		} else {
			xx = x1 + x - x0
			if xx > x0 {
				x2 = x
				x0 = x0 + x0
				d = d + d
			} else {
				x0 = x0 - xx
				if x <= x0 {
					if x+x2 <= x0 {
						r = 02000000000 + 1
						goto exit
					}
				}
				x1 = x
				d = d + d + 1
			}
		}
		if d >= 02000000000 {
			break
		}
	}
	r = d - 02000000000

exit:
	;
	return r
}

// 393.

// tangle:pos ../../mf.web:8422:3:

// Octant subdivision is applied only to cycles, i.e., to closed paths.
// A ``cycle spec'' is a data structure that contains specifications of
//  \xref[cycle spec]
// cubic curves and octant mappings for the cycle that has been subdivided
// into segments belonging to single octants. It is composed entirely of
// knot nodes, similar to those in the representation of paths; but the
// |explicit| type indications have been replaced by positive numbers
// that give further information. Additional |endpoint| data is also
// inserted at the octant boundaries.
//
// Recall that a cubic polynomial is represented by four control points
// that appear in adjacent nodes |p| and~|q| of a knot list. The |x|~coordinates
// are |x_coord(p)|, |right_x(p)|, |left_x(q)|, and |x_coord(q)|; the
// |y|~coordinates are similar. We shall call this ``the cubic following~|p|''
// or ``the cubic between |p| and~|q|'' or ``the cubic preceding~|q|.''
//
// Cycle specs are circular lists of cubic curves mixed with octant
// boundaries. Like cubics, the octant boundaries are represented in
// consecutive knot nodes |p| and~|q|. In such cases |right_type(p)=
// left_type(q)=endpoint|, and the fields |right_x(p)|, |right_y(p)|,
// |left_x(q)|, and |left_y(q)| are replaced by other fields called
// |right_octant(p)|, |right_transition(p)|, |left_octant(q)|, and
// |left_transition(q)|, respectively. For example, when the curve direction
// moves from the third octant to the fourth octant, the boundary nodes say
// |right_octant(p)=third_octant|, |left_octant(q)=fourth_octant|,
// and |right_transition(p)=left_transition(q)=diagonal|. A |diagonal|
// transition occurs when moving between octants 1~\AM~2, 3~\AM~4, 5~\AM~6, or
// 7~\AM~8; an |axis| transition occurs when moving between octants 8~\AM~1,
// 2~\AM~3, 4~\AM~5, 6~\AM~7. (Such transition information is redundant
// but convenient.) Fields |x_coord(p)| and |y_coord(p)| will contain
// coordinates of the transition point after rotation from third octant
// to first octant; i.e., if the true coordinates are $(x,y)$, the
// coordinates $(y,-x)$ will appear in node~|p|. Similarly, a fourth-octant
// transformation will have been applied after the transition, so
// we will have |x_coord(q)=$-x$| and |y_coord(q)=y|.
//
// The cubic between |p| and |q| will contain positive numbers in the
// fields |right_type(p)| and |left_type(q)|; this makes cubics
// distinguishable from octant boundaries, because |endpoint=0|.
// The value of |right_type(p)| will be the current octant code,
// during the time that cycle specs are being constructed; it will
// refer later to a pen offset position, if the envelope of a cycle is
// being computed. A cubic that comes from some subinterval of the $k$th
// step in the original cyclic path will have |left_type(q)=k|.

// 394.

// tangle:pos ../../mf.web:8474:3:

// Here's a routine that prints a cycle spec in symbolic form, so that it
// is possible to see what subdivision has been made.  The point coordinates
// are converted back from \MF's internal ``rotated'' form to the external
// ``true'' form. The global variable~|cur_spec| should point to a knot just
// after the beginning of an octant boundary, i.e., such that
// |left_type(cur_spec)=endpoint|.
func (prg *prg) printSpec(s strNumber) {
	var (
		p, q   halfword    // for list traversal
		octant smallNumber // the current octant code
	)
	prg.printDiagnostic(strNumber( /* "Cycle spec" */ 544), s, true)
	// \xref[Cycle spec at line...]
	p = prg.curSpec
	octant = byte(*prg.mem[int32(p)+3].int())
	prg.printLn()
	prg.unskew(*prg.mem[int32(prg.curSpec)+1].int(), *prg.mem[int32(prg.curSpec)+2].int(), octant)
	prg.printTwo(prg.curX, prg.curY)
	prg.print( /* " % beginning in octant `" */ 545)
	for true {
		prg.print(int32(prg.octantDir[octant-1]))
		prg.printChar(asciiCode('\''))
		for true {
			q = *(*prg.mem[p].hh()).rh()
			if int32(*(*prg.mem[p].hh()).b1()) == endpoint {
				goto notFound
			}

			// Print the cubic between |p| and |q|
			{
				prg.printNl(strNumber( /* "   ..controls " */ 556))
				prg.unskew(*prg.mem[int32(p)+5].int(), *prg.mem[int32(p)+6].int(), octant)
				prg.printTwo(prg.curX, prg.curY)
				prg.print( /* " and " */ 523)
				prg.unskew(*prg.mem[int32(q)+3].int(), *prg.mem[int32(q)+4].int(), octant)
				prg.printTwo(prg.curX, prg.curY)
				prg.printNl(strNumber( /* " .." */ 520))
				prg.unskew(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), octant)
				prg.printTwo(prg.curX, prg.curY)
				prg.print( /* " % segment " */ 557)
				prg.printInt(int32(*(*prg.mem[q].hh()).b0()) - 1)
			}
			p = q
		}

	notFound:
		if int32(q) == int32(prg.curSpec) {
			goto done
		}
		p = q
		octant = byte(*prg.mem[int32(p)+3].int())
		prg.printNl(strNumber( /* "% entering octant `" */ 546))
	}
	// \xref[entering the nth octant]

	// \xref[entering the nth octant]
done:
	prg.printNl(strNumber( /* " & cycle" */ 547))
	prg.endDiagnostic(true)
}

// 398.

// tangle:pos ../../mf.web:8530:3:

// A much more compact version of a spec is printed to help users identify
// ``strange paths.''
func (prg *prg) printStrange(s strNumber) {
	var (
		p halfword // for list traversal
		f halfword // starting point in the cycle
		q halfword // octant boundary to be printed
		t int32    // segment number, plus 1
	)
	if int32(prg.interaction) == errorStopMode {
	}
	prg.printNl(strNumber('>'))
	// \xref[>\relax]

	// Find the starting point, |f|
	p = prg.curSpec
	t = maxQuarterword + 1
	for {
		p = *(*prg.mem[p].hh()).rh()
		if int32(*(*prg.mem[p].hh()).b0()) != endpoint {
			if int32(*(*prg.mem[p].hh()).b0()) < t {
				f = p
			}
			t = int32(*(*prg.mem[p].hh()).b0())
		}
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}

	// Determine the octant boundary |q| that precedes |f|
	p = prg.curSpec
	q = p
	for {
		p = *(*prg.mem[p].hh()).rh()
		if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
			q = p
		}
		if int32(p) == int32(f) {
			break
		}
	}
	t = 0
	for {
		if int32(*(*prg.mem[p].hh()).b0()) != endpoint {
			if int32(*(*prg.mem[p].hh()).b0()) != t {
				t = int32(*(*prg.mem[p].hh()).b0())
				prg.printChar(asciiCode(' '))
				prg.printInt(t - 1)
			}
			if int32(q) != memMin {
				if int32(*(*prg.mem[*(*prg.mem[q].hh()).rh()].hh()).b0()) == endpoint {
					prg.print( /* " (" */ 558)
					prg.print(int32(prg.octantDir[*prg.mem[int32(q)+3].int()-1]))
					q = *(*prg.mem[q].hh()).rh()
					for int32(*(*prg.mem[*(*prg.mem[q].hh()).rh()].hh()).b0()) == endpoint {
						prg.printChar(asciiCode(' '))
						prg.print(int32(prg.octantDir[*prg.mem[int32(q)+3].int()-1]))
						q = *(*prg.mem[q].hh()).rh()
					}
					prg.printChar(asciiCode(')'))
				}
				prg.printChar(asciiCode(' '))
				prg.print(int32(prg.octantDir[*prg.mem[int32(q)+3].int()-1]))
				q = uint16(memMin)
			}
		} else if int32(q) == memMin {
			q = p
		}
		p = *(*prg.mem[p].hh()).rh()
		if int32(p) == int32(f) {
			break
		}
	}
	prg.printChar(asciiCode(' '))
	prg.printInt(int32(*(*prg.mem[p].hh()).b0()) - 1)
	if int32(q) != memMin {
		if int32(*(*prg.mem[*(*prg.mem[q].hh()).rh()].hh()).b0()) == endpoint {
			prg.print( /* " (" */ 558)
			prg.print(int32(prg.octantDir[*prg.mem[int32(q)+3].int()-1]))
			q = *(*prg.mem[q].hh()).rh()
			for int32(*(*prg.mem[*(*prg.mem[q].hh()).rh()].hh()).b0()) == endpoint {
				prg.printChar(asciiCode(' '))
				prg.print(int32(prg.octantDir[*prg.mem[int32(q)+3].int()-1]))
				q = *(*prg.mem[q].hh()).rh()
			}
			prg.printChar(asciiCode(')'))
		}
	}
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print(int32(s)) /* \xref[!\relax]  */
	}
}

// 402.

// tangle:pos ../../mf.web:8597:3:

// The |make_spec| routine is what subdivides paths into octants:
// Given a pointer |cur_spec| to a cyclic path, |make_spec| mungs the path data
// and returns a pointer to the corresponding cyclic spec.
// All “dead” cubics (i.e., cubics that don't move at all from
// their starting points) will have been removed from the result.
//
//	\xref[dead cubics]
//
// The idea of |make_spec| is fairly simple: Each cubic is first
// subdivided, if necessary, into pieces belonging to single octants;
// then the octant boundaries are inserted. But some of the details of
// this transformation are not quite obvious.
//
// If |autorounding>0|, the path will be adjusted so that critical tangent
// directions occur at “good” points with respect to the pen called |cur_pen|.
//
// The resulting spec will have all |x| and |y| coordinates at most
// $2^[28]-|half_unit|-1-|safety_margin|$ in absolute value.  The pointer
// that is returned will start some octant, as required by |print_spec|.
// \4
// Declare subroutines needed by |make_spec|
func (prg *prg) removeCubic(p halfword) { // removes the cubic following~|p|
	var (
		q halfword // the node that disappears
	)
	q = *(*prg.mem[p].hh()).rh()
	*(*prg.mem[p].hh()).b1() = *(*prg.mem[q].hh()).b1()
	*(*prg.mem[p].hh()).rh() = *(*prg.mem[q].hh()).rh()

	*prg.mem[int32(p)+1].int() = *prg.mem[int32(q)+1].int()
	*prg.mem[int32(p)+2].int() = *prg.mem[int32(q)+2].int()

	*prg.mem[int32(p)+5].int() = *prg.mem[int32(q)+5].int()
	*prg.mem[int32(p)+6].int() = *prg.mem[int32(q)+6].int()

	prg.freeNode(q, halfword(knotNodeSize))
}

// \4
// Declare the procedure called |split_cubic|
func (prg *prg) splitCubic(p halfword, t fraction,
	xq, yq scaled) { // splits the cubic after |p|
	var (
		v     scaled   // an intermediate value
		q, r1 halfword // for list manipulation
	)
	q = *(*prg.mem[p].hh()).rh()
	r1 = prg.getNode(knotNodeSize)
	*(*prg.mem[p].hh()).rh() = r1
	*(*prg.mem[r1].hh()).rh() = q

	*(*prg.mem[r1].hh()).b0() = *(*prg.mem[q].hh()).b0()
	*(*prg.mem[r1].hh()).b1() = *(*prg.mem[p].hh()).b1()

	v = *prg.mem[int32(p)+5].int() - prg.takeFraction(*prg.mem[int32(p)+5].int()-*prg.mem[int32(q)+3].int(), t)
	*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+1].int() - prg.takeFraction(*prg.mem[int32(p)+1].int()-*prg.mem[int32(p)+5].int(), t)
	*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+3].int() - prg.takeFraction(*prg.mem[int32(q)+3].int()-xq, t)
	*prg.mem[int32(r1)+3].int() = *prg.mem[int32(p)+5].int() - prg.takeFraction(*prg.mem[int32(p)+5].int()-v, t)
	*prg.mem[int32(r1)+5].int() = v - prg.takeFraction(v-*prg.mem[int32(q)+3].int(), t)
	*prg.mem[int32(r1)+1].int() = *prg.mem[int32(r1)+3].int() - prg.takeFraction(*prg.mem[int32(r1)+3].int()-*prg.mem[int32(r1)+5].int(), t)

	v = *prg.mem[int32(p)+6].int() - prg.takeFraction(*prg.mem[int32(p)+6].int()-*prg.mem[int32(q)+4].int(), t)
	*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+2].int() - prg.takeFraction(*prg.mem[int32(p)+2].int()-*prg.mem[int32(p)+6].int(), t)
	*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+4].int() - prg.takeFraction(*prg.mem[int32(q)+4].int()-yq, t)
	*prg.mem[int32(r1)+4].int() = *prg.mem[int32(p)+6].int() - prg.takeFraction(*prg.mem[int32(p)+6].int()-v, t)
	*prg.mem[int32(r1)+6].int() = v - prg.takeFraction(v-*prg.mem[int32(q)+4].int(), t)
	*prg.mem[int32(r1)+2].int() = *prg.mem[int32(r1)+4].int() - prg.takeFraction(*prg.mem[int32(r1)+4].int()-*prg.mem[int32(r1)+6].int(), t)
}

func (prg *prg) quadrantSubdivide() {
	var (
		p, q, r1, s, pp, qq         halfword // for traversing the lists
		firstX, firstY              scaled   // unnegated coordinates of node |cur_spec|
		del1, del2, del3, del, dmax scaled   // proportional to the control
		//   points of a quadratic derived from a cubic

		t            fraction // where a quadratic crosses zero
		destX, destY scaled   // final values of |x| and |y| in the current cubic
		constantX    bool     // is |x| constant between |p| and |q|?
	)
	p = prg.curSpec
	firstX = *prg.mem[int32(prg.curSpec)+1].int()
	firstY = *prg.mem[int32(prg.curSpec)+2].int()
	for {
	continue1:
		q = *(*prg.mem[p].hh()).rh()

		// Subdivide the cubic between |p| and |q| so that the results travel toward the right halfplane
		if int32(q) == int32(prg.curSpec) {
			destX = firstX
			destY = firstY
		} else {
			destX = *prg.mem[int32(q)+1].int()
			destY = *prg.mem[int32(q)+2].int()
		}
		del1 = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+1].int()
		del2 = *prg.mem[int32(q)+3].int() - *prg.mem[int32(p)+5].int()
		del3 = destX - *prg.mem[int32(q)+3].int()

		// Scale up |del1|, |del2|, and |del3| for greater accuracy; also set |del| to the first nonzero element of |(del1,del2,del3)|
		if del1 != 0 {
			del = del1
		} else if del2 != 0 {
			del = del2
		} else {
			del = del3
		}
		if del != 0 {
			dmax = abs(del1)
			if abs(del2) > dmax {
				dmax = abs(del2)
			}
			if abs(del3) > dmax {
				dmax = abs(del3)
			}
			for dmax < 01000000000 {
				dmax = dmax + dmax
				del1 = del1 + del1
				del2 = del2 + del2
				del3 = del3 + del3
			}
		}
		if del == 0 {
			constantX = true
		} else {
			constantX = false
			if del < 0 {
				*prg.mem[int32(p)+1].int() = -*prg.mem[int32(p)+1].int()
				*prg.mem[int32(p)+5].int() = -*prg.mem[int32(p)+5].int()
				*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()

				del1 = -del1
				del2 = -del2
				del3 = -del3

				destX = -destX
				*(*prg.mem[p].hh()).b1() = byte(firstOctant + negateX)
			}
			t = prg.crossingPoint(del1, del2, del3)
			if t < 02000000000 {
				prg.splitCubic(p, t, destX, destY)
				r1 = *(*prg.mem[p].hh()).rh()
				if int32(*(*prg.mem[r1].hh()).b1()) > negateX {
					*(*prg.mem[r1].hh()).b1() = byte(firstOctant)
				} else {
					*(*prg.mem[r1].hh()).b1() = byte(firstOctant + negateX)
				}
				if *prg.mem[int32(r1)+1].int() < *prg.mem[int32(p)+1].int() {
					*prg.mem[int32(r1)+1].int() = *prg.mem[int32(p)+1].int()
				}
				*prg.mem[int32(r1)+3].int() = *prg.mem[int32(r1)+1].int()
				if *prg.mem[int32(p)+5].int() > *prg.mem[int32(r1)+1].int() {
					*prg.mem[int32(p)+5].int() = *prg.mem[int32(r1)+1].int()
				}
				// we always have |x_coord(p)<=right_x(p)|
				*prg.mem[int32(r1)+1].int() = -*prg.mem[int32(r1)+1].int()
				*prg.mem[int32(r1)+5].int() = *prg.mem[int32(r1)+1].int()
				*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()
				destX = -destX

				del2 = del2 - prg.takeFraction(del2-del3, t)
				// now |0,del2,del3| represent $x'$ on the remaining interval
				if del2 > 0 {
					del2 = 0
				}
				t = prg.crossingPoint(0, -del2, -del3)
				if t < 02000000000 {
					prg.splitCubic(r1, t, destX, destY)
					s = *(*prg.mem[r1].hh()).rh()
					if *prg.mem[int32(s)+1].int() < destX {
						*prg.mem[int32(s)+1].int() = destX
					}
					if *prg.mem[int32(s)+1].int() < *prg.mem[int32(r1)+1].int() {
						*prg.mem[int32(s)+1].int() = *prg.mem[int32(r1)+1].int()
					}
					*(*prg.mem[s].hh()).b1() = *(*prg.mem[p].hh()).b1()
					*prg.mem[int32(s)+3].int() = *prg.mem[int32(s)+1].int() // now |x_coord(r)=right_x(r)<=left_x(s)|
					if *prg.mem[int32(q)+3].int() < destX {
						*prg.mem[int32(q)+3].int() = -destX
					} else if *prg.mem[int32(q)+3].int() > *prg.mem[int32(s)+1].int() {
						*prg.mem[int32(q)+3].int() = -*prg.mem[int32(s)+1].int()
					} else {
						*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()
					}
					*prg.mem[int32(s)+1].int() = -*prg.mem[int32(s)+1].int()
					*prg.mem[int32(s)+5].int() = *prg.mem[int32(s)+1].int()
				} else {
					if *prg.mem[int32(r1)+1].int() > destX {
						*prg.mem[int32(r1)+1].int() = destX
						*prg.mem[int32(r1)+3].int() = -*prg.mem[int32(r1)+1].int()
						*prg.mem[int32(r1)+5].int() = *prg.mem[int32(r1)+1].int()
					}
					if *prg.mem[int32(q)+3].int() > destX {
						*prg.mem[int32(q)+3].int() = destX
					} else if *prg.mem[int32(q)+3].int() < *prg.mem[int32(r1)+1].int() {
						*prg.mem[int32(q)+3].int() = *prg.mem[int32(r1)+1].int()
					}
				}
			}
		}

		// Subdivide all cubics between |p| and |q| so that the results travel toward the first quadrant; but |return| or |goto continue| if the cubic from |p| to |q| was dead
		pp = p
		for {
			qq = *(*prg.mem[pp].hh()).rh()
			prg.abnegate(*prg.mem[int32(qq)+1].int(), *prg.mem[int32(qq)+2].int(), *(*prg.mem[qq].hh()).b1(), *(*prg.mem[pp].hh()).b1())
			destX = prg.curX
			destY = prg.curY

			del1 = *prg.mem[int32(pp)+6].int() - *prg.mem[int32(pp)+2].int()
			del2 = *prg.mem[int32(qq)+4].int() - *prg.mem[int32(pp)+6].int()
			del3 = destY - *prg.mem[int32(qq)+4].int()

			// Scale up |del1|, |del2|, and |del3| for greater accuracy; also set |del| to the first nonzero element of |(del1,del2,del3)|
			if del1 != 0 {
				del = del1
			} else if del2 != 0 {
				del = del2
			} else {
				del = del3
			}
			if del != 0 {
				dmax = abs(del1)
				if abs(del2) > dmax {
					dmax = abs(del2)
				}
				if abs(del3) > dmax {
					dmax = abs(del3)
				}
				for dmax < 01000000000 {
					dmax = dmax + dmax
					del1 = del1 + del1
					del2 = del2 + del2
					del3 = del3 + del3
				}
			}
			if del != 0 {
				if del < 0 {
					*prg.mem[int32(pp)+2].int() = -*prg.mem[int32(pp)+2].int()
					*prg.mem[int32(pp)+6].int() = -*prg.mem[int32(pp)+6].int()
					*prg.mem[int32(qq)+4].int() = -*prg.mem[int32(qq)+4].int()

					del1 = -del1
					del2 = -del2
					del3 = -del3

					destY = -destY
					*(*prg.mem[pp].hh()).b1() = byte(int32(*(*prg.mem[pp].hh()).b1()) + negateY)
				}
				t = prg.crossingPoint(del1, del2, del3)
				if t < 02000000000 {
					prg.splitCubic(pp, t, destX, destY)
					r1 = *(*prg.mem[pp].hh()).rh()
					if int32(*(*prg.mem[r1].hh()).b1()) > negateY {
						*(*prg.mem[r1].hh()).b1() = byte(int32(*(*prg.mem[r1].hh()).b1()) - negateY)
					} else {
						*(*prg.mem[r1].hh()).b1() = byte(int32(*(*prg.mem[r1].hh()).b1()) + negateY)
					}
					if *prg.mem[int32(r1)+2].int() < *prg.mem[int32(pp)+2].int() {
						*prg.mem[int32(r1)+2].int() = *prg.mem[int32(pp)+2].int()
					}
					*prg.mem[int32(r1)+4].int() = *prg.mem[int32(r1)+2].int()
					if *prg.mem[int32(pp)+6].int() > *prg.mem[int32(r1)+2].int() {
						*prg.mem[int32(pp)+6].int() = *prg.mem[int32(r1)+2].int()
					}
					// we always have |y_coord(pp)<=right_y(pp)|
					*prg.mem[int32(r1)+2].int() = -*prg.mem[int32(r1)+2].int()
					*prg.mem[int32(r1)+6].int() = *prg.mem[int32(r1)+2].int()
					*prg.mem[int32(qq)+4].int() = -*prg.mem[int32(qq)+4].int()
					destY = -destY

					if *prg.mem[int32(r1)+1].int() < *prg.mem[int32(pp)+1].int() {
						*prg.mem[int32(r1)+1].int() = *prg.mem[int32(pp)+1].int()
					} else if *prg.mem[int32(r1)+1].int() > destX {
						*prg.mem[int32(r1)+1].int() = destX
					}
					if *prg.mem[int32(r1)+3].int() > *prg.mem[int32(r1)+1].int() {
						*prg.mem[int32(r1)+3].int() = *prg.mem[int32(r1)+1].int()
						if *prg.mem[int32(pp)+5].int() > *prg.mem[int32(r1)+1].int() {
							*prg.mem[int32(pp)+5].int() = *prg.mem[int32(r1)+1].int()
						}
					}
					if *prg.mem[int32(r1)+5].int() < *prg.mem[int32(r1)+1].int() {
						*prg.mem[int32(r1)+5].int() = *prg.mem[int32(r1)+1].int()
						if *prg.mem[int32(qq)+3].int() < *prg.mem[int32(r1)+1].int() {
							*prg.mem[int32(qq)+3].int() = *prg.mem[int32(r1)+1].int()
						}
					}
					del2 = del2 - prg.takeFraction(del2-del3, t)
					// now |0,del2,del3| represent $y'$ on the remaining interval
					if del2 > 0 {
						del2 = 0
					}
					t = prg.crossingPoint(0, -del2, -del3)
					if t < 02000000000 {
						prg.splitCubic(r1, t, destX, destY)
						s = *(*prg.mem[r1].hh()).rh()

						if *prg.mem[int32(s)+2].int() < destY {
							*prg.mem[int32(s)+2].int() = destY
						}
						if *prg.mem[int32(s)+2].int() < *prg.mem[int32(r1)+2].int() {
							*prg.mem[int32(s)+2].int() = *prg.mem[int32(r1)+2].int()
						}
						*(*prg.mem[s].hh()).b1() = *(*prg.mem[pp].hh()).b1()
						*prg.mem[int32(s)+4].int() = *prg.mem[int32(s)+2].int() // now |y_coord(r)=right_y(r)<=left_y(s)|
						if *prg.mem[int32(qq)+4].int() < destY {
							*prg.mem[int32(qq)+4].int() = -destY
						} else if *prg.mem[int32(qq)+4].int() > *prg.mem[int32(s)+2].int() {
							*prg.mem[int32(qq)+4].int() = -*prg.mem[int32(s)+2].int()
						} else {
							*prg.mem[int32(qq)+4].int() = -*prg.mem[int32(qq)+4].int()
						}
						*prg.mem[int32(s)+2].int() = -*prg.mem[int32(s)+2].int()
						*prg.mem[int32(s)+6].int() = *prg.mem[int32(s)+2].int()
						if *prg.mem[int32(s)+1].int() < *prg.mem[int32(r1)+1].int() {
							*prg.mem[int32(s)+1].int() = *prg.mem[int32(r1)+1].int()
						} else if *prg.mem[int32(s)+1].int() > destX {
							*prg.mem[int32(s)+1].int() = destX
						}
						if *prg.mem[int32(s)+3].int() > *prg.mem[int32(s)+1].int() {
							*prg.mem[int32(s)+3].int() = *prg.mem[int32(s)+1].int()
							if *prg.mem[int32(r1)+5].int() > *prg.mem[int32(s)+1].int() {
								*prg.mem[int32(r1)+5].int() = *prg.mem[int32(s)+1].int()
							}
						}
						if *prg.mem[int32(s)+5].int() < *prg.mem[int32(s)+1].int() {
							*prg.mem[int32(s)+5].int() = *prg.mem[int32(s)+1].int()
							if *prg.mem[int32(qq)+3].int() < *prg.mem[int32(s)+1].int() {
								*prg.mem[int32(qq)+3].int() = *prg.mem[int32(s)+1].int()
							}
						}
					} else {
						if *prg.mem[int32(r1)+2].int() > destY {
							*prg.mem[int32(r1)+2].int() = destY
							*prg.mem[int32(r1)+4].int() = -*prg.mem[int32(r1)+2].int()
							*prg.mem[int32(r1)+6].int() = *prg.mem[int32(r1)+2].int()
						}
						if *prg.mem[int32(qq)+4].int() > destY {
							*prg.mem[int32(qq)+4].int() = destY
						} else if *prg.mem[int32(qq)+4].int() < *prg.mem[int32(r1)+2].int() {
							*prg.mem[int32(qq)+4].int() = *prg.mem[int32(r1)+2].int()
						}
					}
				}
			} else if constantX {
				if int32(q) != int32(p) {
					prg.removeCubic(p) // remove the dead cycle and recycle node |q|
					if int32(prg.curSpec) != int32(q) {
						goto continue1
					} else {
						prg.curSpec = p
						goto exit
					} // the final cubic was dead and is gone
				}
			} else if !(*(*prg.mem[pp].hh()).b1()&1 != 0) {
				*prg.mem[int32(pp)+2].int() = -*prg.mem[int32(pp)+2].int()
				*prg.mem[int32(pp)+6].int() = -*prg.mem[int32(pp)+6].int()
				*prg.mem[int32(qq)+4].int() = -*prg.mem[int32(qq)+4].int()

				del1 = -del1
				del2 = -del2
				del3 = -del3

				destY = -destY
				*(*prg.mem[pp].hh()).b1() = byte(int32(*(*prg.mem[pp].hh()).b1()) + negateY)
			}
			pp = qq
			if int32(pp) == int32(q) {
				break
			}
		}
		if constantX {
			pp = p
			for {
				qq = *(*prg.mem[pp].hh()).rh()
				if int32(*(*prg.mem[pp].hh()).b1()) > negateY {
					*(*prg.mem[pp].hh()).b1() = byte(int32(*(*prg.mem[pp].hh()).b1()) + negateX)
					*prg.mem[int32(pp)+1].int() = -*prg.mem[int32(pp)+1].int()
					*prg.mem[int32(pp)+5].int() = -*prg.mem[int32(pp)+5].int()
					*prg.mem[int32(qq)+3].int() = -*prg.mem[int32(qq)+3].int()
				}
				pp = qq
				if int32(pp) == int32(q) {
					break
				}
			}
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}

exit:
}

func (prg *prg) octantSubdivide() {
	var (
		p, q, r1, s                 halfword // for traversing the lists
		del1, del2, del3, del, dmax scaled   // proportional to the control
		//   points of a quadratic derived from a cubic

		t            fraction // where a quadratic crosses zero
		destX, destY scaled   // final values of |x| and |y| in the current cubic
	)
	p = prg.curSpec
	for {
		q = *(*prg.mem[p].hh()).rh()

		*prg.mem[int32(p)+1].int() = *prg.mem[int32(p)+1].int() - *prg.mem[int32(p)+2].int()
		*prg.mem[int32(p)+5].int() = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+6].int()
		*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+3].int() - *prg.mem[int32(q)+4].int()

		// Subdivide the cubic between |p| and |q| so that the results travel toward the first octant

		// Set up the variables |(del1,del2,del3)| to represent $x'-y'$
		if int32(q) == int32(prg.curSpec) {
			prg.unskew(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), *(*prg.mem[q].hh()).b1())
			prg.skew(prg.curX, prg.curY, *(*prg.mem[p].hh()).b1())
			destX = prg.curX
			destY = prg.curY
		} else {
			prg.abnegate(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), *(*prg.mem[q].hh()).b1(), *(*prg.mem[p].hh()).b1())
			destX = prg.curX - prg.curY
			destY = prg.curY
		}
		del1 = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+1].int()
		del2 = *prg.mem[int32(q)+3].int() - *prg.mem[int32(p)+5].int()
		del3 = destX - *prg.mem[int32(q)+3].int()

		// Scale up |del1|, |del2|, and |del3| for greater accuracy; also set |del| to the first nonzero element of |(del1,del2,del3)|
		if del1 != 0 {
			del = del1
		} else if del2 != 0 {
			del = del2
		} else {
			del = del3
		}
		if del != 0 {
			dmax = abs(del1)
			if abs(del2) > dmax {
				dmax = abs(del2)
			}
			if abs(del3) > dmax {
				dmax = abs(del3)
			}
			for dmax < 01000000000 {
				dmax = dmax + dmax
				del1 = del1 + del1
				del2 = del2 + del2
				del3 = del3 + del3
			}
		}
		if del != 0 {
			if del < 0 {
				*prg.mem[int32(p)+2].int() = *prg.mem[int32(p)+1].int() + *prg.mem[int32(p)+2].int()
				*prg.mem[int32(p)+1].int() = -*prg.mem[int32(p)+1].int()

				*prg.mem[int32(p)+6].int() = *prg.mem[int32(p)+5].int() + *prg.mem[int32(p)+6].int()
				*prg.mem[int32(p)+5].int() = -*prg.mem[int32(p)+5].int()

				*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+3].int() + *prg.mem[int32(q)+4].int()
				*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()

				del1 = -del1
				del2 = -del2
				del3 = -del3

				destY = destX + destY
				destX = -destX

				*(*prg.mem[p].hh()).b1() = byte(int32(*(*prg.mem[p].hh()).b1()) + switchXAndY)
			}
			t = prg.crossingPoint(del1, del2, del3)
			if t < 02000000000 {
				prg.splitCubic(p, t, destX, destY)
				r1 = *(*prg.mem[p].hh()).rh()
				if int32(*(*prg.mem[r1].hh()).b1()) > switchXAndY {
					*(*prg.mem[r1].hh()).b1() = byte(int32(*(*prg.mem[r1].hh()).b1()) - switchXAndY)
				} else {
					*(*prg.mem[r1].hh()).b1() = byte(int32(*(*prg.mem[r1].hh()).b1()) + switchXAndY)
				}
				if *prg.mem[int32(r1)+2].int() < *prg.mem[int32(p)+2].int() {
					*prg.mem[int32(r1)+2].int() = *prg.mem[int32(p)+2].int()
				} else if *prg.mem[int32(r1)+2].int() > destY {
					*prg.mem[int32(r1)+2].int() = destY
				}
				if *prg.mem[int32(p)+1].int()+*prg.mem[int32(r1)+2].int() > destX+destY {
					*prg.mem[int32(r1)+2].int() = destX + destY - *prg.mem[int32(p)+1].int()
				}
				if *prg.mem[int32(r1)+4].int() > *prg.mem[int32(r1)+2].int() {
					*prg.mem[int32(r1)+4].int() = *prg.mem[int32(r1)+2].int()
					if *prg.mem[int32(p)+6].int() > *prg.mem[int32(r1)+2].int() {
						*prg.mem[int32(p)+6].int() = *prg.mem[int32(r1)+2].int()
					}
				}
				if *prg.mem[int32(r1)+6].int() < *prg.mem[int32(r1)+2].int() {
					*prg.mem[int32(r1)+6].int() = *prg.mem[int32(r1)+2].int()
					if *prg.mem[int32(q)+4].int() < *prg.mem[int32(r1)+2].int() {
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(r1)+2].int()
					}
				}
				if *prg.mem[int32(r1)+1].int() < *prg.mem[int32(p)+1].int() {
					*prg.mem[int32(r1)+1].int() = *prg.mem[int32(p)+1].int()
				} else if *prg.mem[int32(r1)+1].int()+*prg.mem[int32(r1)+2].int() > destX+destY {
					*prg.mem[int32(r1)+1].int() = destX + destY - *prg.mem[int32(r1)+2].int()
				}
				*prg.mem[int32(r1)+3].int() = *prg.mem[int32(r1)+1].int()
				if *prg.mem[int32(p)+5].int() > *prg.mem[int32(r1)+1].int() {
					*prg.mem[int32(p)+5].int() = *prg.mem[int32(r1)+1].int()
				}
				// we always have |x_coord(p)<=right_x(p)|
				*prg.mem[int32(r1)+2].int() = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(r1)+1].int()
				*prg.mem[int32(r1)+6].int() = *prg.mem[int32(r1)+6].int() + *prg.mem[int32(r1)+1].int()

				*prg.mem[int32(r1)+1].int() = -*prg.mem[int32(r1)+1].int()
				*prg.mem[int32(r1)+5].int() = *prg.mem[int32(r1)+1].int()

				*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+4].int() + *prg.mem[int32(q)+3].int()
				*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()

				destY = destY + destX
				destX = -destX
				if *prg.mem[int32(r1)+6].int() < *prg.mem[int32(r1)+2].int() {
					*prg.mem[int32(r1)+6].int() = *prg.mem[int32(r1)+2].int()
					if *prg.mem[int32(q)+4].int() < *prg.mem[int32(r1)+2].int() {
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(r1)+2].int()
					}
				}
				del2 = del2 - prg.takeFraction(del2-del3, t)
				// now |0,del2,del3| represent $x'-y'$ on the remaining interval
				if del2 > 0 {
					del2 = 0
				}
				t = prg.crossingPoint(0, -del2, -del3)
				if t < 02000000000 {
					prg.splitCubic(r1, t, destX, destY)
					s = *(*prg.mem[r1].hh()).rh()

					if *prg.mem[int32(s)+2].int() < *prg.mem[int32(r1)+2].int() {
						*prg.mem[int32(s)+2].int() = *prg.mem[int32(r1)+2].int()
					} else if *prg.mem[int32(s)+2].int() > destY {
						*prg.mem[int32(s)+2].int() = destY
					}
					if *prg.mem[int32(r1)+1].int()+*prg.mem[int32(s)+2].int() > destX+destY {
						*prg.mem[int32(s)+2].int() = destX + destY - *prg.mem[int32(r1)+1].int()
					}
					if *prg.mem[int32(s)+4].int() > *prg.mem[int32(s)+2].int() {
						*prg.mem[int32(s)+4].int() = *prg.mem[int32(s)+2].int()
						if *prg.mem[int32(r1)+6].int() > *prg.mem[int32(s)+2].int() {
							*prg.mem[int32(r1)+6].int() = *prg.mem[int32(s)+2].int()
						}
					}
					if *prg.mem[int32(s)+6].int() < *prg.mem[int32(s)+2].int() {
						*prg.mem[int32(s)+6].int() = *prg.mem[int32(s)+2].int()
						if *prg.mem[int32(q)+4].int() < *prg.mem[int32(s)+2].int() {
							*prg.mem[int32(q)+4].int() = *prg.mem[int32(s)+2].int()
						}
					}
					if *prg.mem[int32(s)+1].int()+*prg.mem[int32(s)+2].int() > destX+destY {
						*prg.mem[int32(s)+1].int() = destX + destY - *prg.mem[int32(s)+2].int()
					} else {
						if *prg.mem[int32(s)+1].int() < destX {
							*prg.mem[int32(s)+1].int() = destX
						}
						if *prg.mem[int32(s)+1].int() < *prg.mem[int32(r1)+1].int() {
							*prg.mem[int32(s)+1].int() = *prg.mem[int32(r1)+1].int()
						}
					}
					*(*prg.mem[s].hh()).b1() = *(*prg.mem[p].hh()).b1()
					*prg.mem[int32(s)+3].int() = *prg.mem[int32(s)+1].int() // now |x_coord(r)=right_x(r)<=left_x(s)|
					if *prg.mem[int32(q)+3].int() < destX {
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+4].int() + destX
						*prg.mem[int32(q)+3].int() = -destX
					} else if *prg.mem[int32(q)+3].int() > *prg.mem[int32(s)+1].int() {
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+4].int() + *prg.mem[int32(s)+1].int()
						*prg.mem[int32(q)+3].int() = -*prg.mem[int32(s)+1].int()
					} else {
						*prg.mem[int32(q)+4].int() = *prg.mem[int32(q)+4].int() + *prg.mem[int32(q)+3].int()
						*prg.mem[int32(q)+3].int() = -*prg.mem[int32(q)+3].int()
					}
					*prg.mem[int32(s)+2].int() = *prg.mem[int32(s)+2].int() + *prg.mem[int32(s)+1].int()
					*prg.mem[int32(s)+6].int() = *prg.mem[int32(s)+6].int() + *prg.mem[int32(s)+1].int()

					*prg.mem[int32(s)+1].int() = -*prg.mem[int32(s)+1].int()
					*prg.mem[int32(s)+5].int() = *prg.mem[int32(s)+1].int()

					if *prg.mem[int32(s)+6].int() < *prg.mem[int32(s)+2].int() {
						*prg.mem[int32(s)+6].int() = *prg.mem[int32(s)+2].int()
						if *prg.mem[int32(q)+4].int() < *prg.mem[int32(s)+2].int() {
							*prg.mem[int32(q)+4].int() = *prg.mem[int32(s)+2].int()
						}
					}
				} else {
					if *prg.mem[int32(r1)+1].int() > destX {
						*prg.mem[int32(r1)+1].int() = destX
						*prg.mem[int32(r1)+3].int() = -*prg.mem[int32(r1)+1].int()
						*prg.mem[int32(r1)+5].int() = *prg.mem[int32(r1)+1].int()
					}
					if *prg.mem[int32(q)+3].int() > destX {
						*prg.mem[int32(q)+3].int() = destX
					} else if *prg.mem[int32(q)+3].int() < *prg.mem[int32(r1)+1].int() {
						*prg.mem[int32(q)+3].int() = *prg.mem[int32(r1)+1].int()
					}
				}
			}
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}
}

func (prg *prg) makeSafe() {
	var (
		k/* 0..maxWiggle */ uint16        // runs through the list of inputs
		allSafe                    bool   // does everything look OK so far?
		nextA                      scaled // |after[k]| before it might have changed
		deltaA, deltaB             scaled // |after[k+1]-after[k]| and |before[k+1]-before[k]|
	)
	prg.before[prg.curRoundingPtr] = prg.before[0] // wrap around
	prg.nodeToRound[prg.curRoundingPtr] = prg.nodeToRound[0]
	for {
		prg.after[prg.curRoundingPtr] = prg.after[0]
		allSafe = true
		nextA = prg.after[0]
		for ii := int32(0); ii <= int32(prg.curRoundingPtr)-1; ii++ {
			k = uint16(ii)
			_ = k
			deltaB = prg.before[int32(k)+1] - prg.before[k]
			if deltaB >= 0 {
				deltaA = prg.after[int32(k)+1] - nextA
			} else {
				deltaA = nextA - prg.after[int32(k)+1]
			}
			nextA = prg.after[int32(k)+1]
			if deltaA < 0 || deltaA > abs(deltaB+deltaB) {
				allSafe = false
				prg.after[k] = prg.before[k]
				if int32(k) == int32(prg.curRoundingPtr)-1 {
					prg.after[0] = prg.before[0]
				} else {
					prg.after[int32(k)+1] = prg.before[int32(k)+1]
				}
			}
		}
		if allSafe {
			break
		}
	}
}

func (prg *prg) beforeAndAfter(b, a scaled, p halfword) {
	if int32(prg.curRoundingPtr) == int32(prg.maxRoundingPtr) {
		if int32(prg.maxRoundingPtr) < maxWiggle {
			prg.maxRoundingPtr = uint16(int32(prg.maxRoundingPtr) + 1)
		} else {
			prg.overflow(strNumber( /* "rounding table size" */ 568), maxWiggle)
		}
	}
	// \xref[METAFONT capacity exceeded rounding table size][\quad rounding table size]
	prg.after[prg.curRoundingPtr] = a
	prg.before[prg.curRoundingPtr] = b
	prg.nodeToRound[prg.curRoundingPtr] = p
	prg.curRoundingPtr = uint16(int32(prg.curRoundingPtr) + 1)
}

func (prg *prg) goodVal(b, o scaled) (r scaled) {
	var (
		a scaled // accumulator
	)
	a = b + o
	if a >= 0 {
		a = a - a%prg.curGran - o
	} else {
		a = a + -(a+1)%prg.curGran - prg.curGran + 1 - o
	}
	if b-a < a+prg.curGran-b {
		r = a
	} else {
		r = a + prg.curGran
	}
	return r
}

func (prg *prg) compromise(u, v scaled) (r scaled) {
	r = prg.goodVal(u+u, -u-v) / 2
	return r
}

func (prg *prg) xyRound() {
	var (
		p, q    halfword // list manipulation registers
		b, a    scaled   // before and after values
		penEdge scaled   // offset that governs rounding
		alpha   fraction // coefficient of linear transformation
	)
	prg.curGran = abs(prg.internal[granularity-1])
	if prg.curGran == 0 {
		prg.curGran = 0200000
	}
	p = prg.curSpec
	prg.curRoundingPtr = 0
	for {
		q = *(*prg.mem[p].hh()).rh()

		// If node |q| is a transition point for |x| coordinates, compute and save its before-and-after coordinates
		if *(*prg.mem[p].hh()).b1()&1 != 0 != (*(*prg.mem[q].hh()).b1()&1 != 0) {
			if *(*prg.mem[q].hh()).b1()&1 != 0 {
				b = *prg.mem[int32(q)+1].int()
			} else {
				b = -*prg.mem[int32(q)+1].int()
			}
			if abs(*prg.mem[int32(q)+1].int()-*prg.mem[int32(q)+5].int()) < 655 || abs(*prg.mem[int32(q)+1].int()+*prg.mem[int32(q)+3].int()) < 655 {
				if int32(prg.curPen) == memMin+3 {
					penEdge = 0
				} else if int32(prg.curPathType) == doublePathCode {
					penEdge = prg.compromise(*prg.mem[int32(*(*prg.mem[int32(prg.curPen)+secondOctant].hh()).rh())+2].int(), *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+seventhOctant].hh()).rh())+2].int())
				} else if *(*prg.mem[q].hh()).b1()&1 != 0 {
					penEdge = *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+seventhOctant].hh()).rh())+2].int()
				} else {
					penEdge = *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+secondOctant].hh()).rh())+2].int()
				}
				a = prg.goodVal(b, penEdge)
			} else {
				a = b
			}
			if abs(a) > prg.maxAllowed {
				if a > 0 {
					a = prg.maxAllowed
				} else {
					a = -prg.maxAllowed
				}
			}
			prg.beforeAndAfter(b, a, q)
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}
	if int32(prg.curRoundingPtr) > 0 {
		prg.makeSafe()
		for {
			prg.curRoundingPtr = uint16(int32(prg.curRoundingPtr) - 1)
			if prg.after[prg.curRoundingPtr] != prg.before[prg.curRoundingPtr] || prg.after[int32(prg.curRoundingPtr)+1] != prg.before[int32(prg.curRoundingPtr)+1] {
				p = prg.nodeToRound[prg.curRoundingPtr]
				if *(*prg.mem[p].hh()).b1()&1 != 0 {
					b = prg.before[prg.curRoundingPtr]
					a = prg.after[prg.curRoundingPtr]
				} else {
					b = -prg.before[prg.curRoundingPtr]
					a = -prg.after[prg.curRoundingPtr]
				}
				if prg.before[prg.curRoundingPtr] == prg.before[int32(prg.curRoundingPtr)+1] {
					alpha = 02000000000
				} else {
					alpha = prg.makeFraction(prg.after[int32(prg.curRoundingPtr)+1]-prg.after[prg.curRoundingPtr], prg.before[int32(prg.curRoundingPtr)+1]-prg.before[prg.curRoundingPtr])
				}
				for {
					*prg.mem[int32(p)+1].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+1].int()-b) + a
					*prg.mem[int32(p)+5].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+5].int()-b) + a
					p = *(*prg.mem[p].hh()).rh()
					*prg.mem[int32(p)+3].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+3].int()-b) + a
					if int32(p) == int32(prg.nodeToRound[int32(prg.curRoundingPtr)+1]) {
						break
					}
				}
			}
			if int32(prg.curRoundingPtr) == 0 {
				break
			}
		}
	}
	p = prg.curSpec
	prg.curRoundingPtr = 0
	for {
		q = *(*prg.mem[p].hh()).rh()

		// If node |q| is a transition point for |y| coordinates, compute and save its before-and-after coordinates
		if int32(*(*prg.mem[p].hh()).b1()) > negateY != (int32(*(*prg.mem[q].hh()).b1()) > negateY) {
			if int32(*(*prg.mem[q].hh()).b1()) <= negateY {
				b = *prg.mem[int32(q)+2].int()
			} else {
				b = -*prg.mem[int32(q)+2].int()
			}
			if abs(*prg.mem[int32(q)+2].int()-*prg.mem[int32(q)+6].int()) < 655 || abs(*prg.mem[int32(q)+2].int()+*prg.mem[int32(q)+4].int()) < 655 {
				if int32(prg.curPen) == memMin+3 {
					penEdge = 0
				} else if int32(prg.curPathType) == doublePathCode {
					penEdge = prg.compromise(*prg.mem[int32(*(*prg.mem[int32(prg.curPen)+fourthOctant].hh()).rh())+2].int(), *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+firstOctant].hh()).rh())+2].int())
				} else if int32(*(*prg.mem[q].hh()).b1()) <= negateY {
					penEdge = *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+firstOctant].hh()).rh())+2].int()
				} else {
					penEdge = *prg.mem[int32(*(*prg.mem[int32(prg.curPen)+fourthOctant].hh()).rh())+2].int()
				}
				a = prg.goodVal(b, penEdge)
			} else {
				a = b
			}
			if abs(a) > prg.maxAllowed {
				if a > 0 {
					a = prg.maxAllowed
				} else {
					a = -prg.maxAllowed
				}
			}
			prg.beforeAndAfter(b, a, q)
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}
	if int32(prg.curRoundingPtr) > 0 {
		prg.makeSafe()
		for {
			prg.curRoundingPtr = uint16(int32(prg.curRoundingPtr) - 1)
			if prg.after[prg.curRoundingPtr] != prg.before[prg.curRoundingPtr] || prg.after[int32(prg.curRoundingPtr)+1] != prg.before[int32(prg.curRoundingPtr)+1] {
				p = prg.nodeToRound[prg.curRoundingPtr]
				if int32(*(*prg.mem[p].hh()).b1()) <= negateY {
					b = prg.before[prg.curRoundingPtr]
					a = prg.after[prg.curRoundingPtr]
				} else {
					b = -prg.before[prg.curRoundingPtr]
					a = -prg.after[prg.curRoundingPtr]
				}
				if prg.before[prg.curRoundingPtr] == prg.before[int32(prg.curRoundingPtr)+1] {
					alpha = 02000000000
				} else {
					alpha = prg.makeFraction(prg.after[int32(prg.curRoundingPtr)+1]-prg.after[prg.curRoundingPtr], prg.before[int32(prg.curRoundingPtr)+1]-prg.before[prg.curRoundingPtr])
				}
				for {
					*prg.mem[int32(p)+2].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+2].int()-b) + a
					*prg.mem[int32(p)+6].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+6].int()-b) + a
					p = *(*prg.mem[p].hh()).rh()
					*prg.mem[int32(p)+4].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+4].int()-b) + a
					if int32(p) == int32(prg.nodeToRound[int32(prg.curRoundingPtr)+1]) {
						break
					}
				}
			}
			if int32(prg.curRoundingPtr) == 0 {
				break
			}
		}
	}
}

func (prg *prg) diagRound() {
	var (
		p, q, pp                   halfword // list manipulation registers
		b, a, bb, aa, d, c, dd, cc scaled   // before and after values
		penEdge                    scaled   // offset that governs rounding
		alpha, beta                fraction // coefficients of linear transformation
		nextA                      scaled   // |after[k]| before it might have changed
		allSafe                    bool     // does everything look OK so far?
		k/* 0..maxWiggle */ uint16          // runs through before-and-after values
		firstX, firstY             scaled   // coordinates before rounding
	)
	p = prg.curSpec
	prg.curRoundingPtr = 0
	for {
		q = *(*prg.mem[p].hh()).rh()

		// If node |q| is a transition point between octants, compute and save its before-and-after coordinates
		if int32(*(*prg.mem[p].hh()).b1()) != int32(*(*prg.mem[q].hh()).b1()) {
			if int32(*(*prg.mem[q].hh()).b1()) > switchXAndY {
				b = -*prg.mem[int32(q)+1].int()
			} else {
				b = *prg.mem[int32(q)+1].int()
			}
			if abs(int32(*(*prg.mem[q].hh()).b1())-int32(*(*prg.mem[p].hh()).b1())) == switchXAndY {
				if abs(*prg.mem[int32(q)+1].int()-*prg.mem[int32(q)+5].int()) < 655 || abs(*prg.mem[int32(q)+1].int()+*prg.mem[int32(q)+3].int()) < 655 {
					if int32(prg.curPen) == memMin+3 {
						penEdge = 0
					} else if int32(prg.curPathType) == doublePathCode {
						switch *(*prg.mem[q].hh()).b1() {
						case firstOctant, secondOctant:
							penEdge = prg.compromise(*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+firstOctant].hh()).rh()].hh()).lh())+1].int(), -*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+fifthOctant].hh()).rh()].hh()).lh())+1].int())
						case fifthOctant, sixthOctant:
							penEdge = -prg.compromise(*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+firstOctant].hh()).rh()].hh()).lh())+1].int(), -*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+fifthOctant].hh()).rh()].hh()).lh())+1].int())
						case thirdOctant, fourthOctant:
							penEdge = prg.compromise(*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+fourthOctant].hh()).rh()].hh()).lh())+1].int(), -*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+eighthOctant].hh()).rh()].hh()).lh())+1].int())
						case seventhOctant, eighthOctant:
							penEdge = -prg.compromise(*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+fourthOctant].hh()).rh()].hh()).lh())+1].int(), -*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+eighthOctant].hh()).rh()].hh()).lh())+1].int())
						}
					} else if int32(*(*prg.mem[q].hh()).b1()) <= switchXAndY {
						penEdge = *prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+int32(*(*prg.mem[q].hh()).b1())].hh()).rh()].hh()).lh())+1].int()
					} else {
						penEdge = -*prg.mem[int32(*(*prg.mem[*(*prg.mem[int32(prg.curPen)+int32(*(*prg.mem[q].hh()).b1())].hh()).rh()].hh()).lh())+1].int()
					}
					if *(*prg.mem[q].hh()).b1()&1 != 0 {
						a = prg.goodVal(b, penEdge+prg.curGran/2)
					} else {
						a = prg.goodVal(b-1, penEdge+prg.curGran/2)
					}
				} else {
					a = b
				}
			} else {
				a = b
			}
			prg.beforeAndAfter(b, a, q)
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}
	if int32(prg.curRoundingPtr) > 0 {
		p = prg.nodeToRound[0]
		firstX = *prg.mem[int32(p)+1].int()
		firstY = *prg.mem[int32(p)+2].int()

		// Make sure that all the diagonal roundings are safe
		prg.before[prg.curRoundingPtr] = prg.before[0] // cf.~|make_safe|
		prg.nodeToRound[prg.curRoundingPtr] = prg.nodeToRound[0]
		for {
			prg.after[prg.curRoundingPtr] = prg.after[0]
			allSafe = true
			nextA = prg.after[0]
			for ii := int32(0); ii <= int32(prg.curRoundingPtr)-1; ii++ {
				k = uint16(ii)
				_ = k
				a = nextA
				b = prg.before[k]
				nextA = prg.after[int32(k)+1]
				aa = nextA
				bb = prg.before[int32(k)+1]
				if a != b || aa != bb {
					p = prg.nodeToRound[k]
					pp = prg.nodeToRound[int32(k)+1]

					// Determine the before-and-after values of both coordinates
					if aa == bb {
						if int32(pp) == int32(prg.nodeToRound[0]) {
							prg.unskew(firstX, firstY, *(*prg.mem[pp].hh()).b1())
						} else {
							prg.unskew(*prg.mem[int32(pp)+1].int(), *prg.mem[int32(pp)+2].int(), *(*prg.mem[pp].hh()).b1())
						}
						prg.skew(prg.curX, prg.curY, *(*prg.mem[p].hh()).b1())
						bb = prg.curX
						aa = bb
						dd = prg.curY
						cc = dd
						if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
							b = -b
							a = -a
						}
					} else {
						if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
							bb = -bb
							aa = -aa
							b = -b
							a = -a
						}
						if int32(pp) == int32(prg.nodeToRound[0]) {
							dd = firstY - bb
						} else {
							dd = *prg.mem[int32(pp)+2].int() - bb
						}
						if (aa-bb)&1 != 0 {
							if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
								cc = dd - (aa-bb+1)/2
							} else {
								cc = dd - (aa-bb-1)/2
							}
						} else {
							cc = dd - (aa-bb)/2
						}
					}
					d = *prg.mem[int32(p)+2].int()
					if (a-b)&1 != 0 {
						if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
							c = d - (a-b-1)/2
						} else {
							c = d - (a-b+1)/2
						}
					} else {
						c = d - (a-b)/2
					}
					if aa < a || cc < c || aa-a > 2*(bb-b) || cc-c > 2*(dd-d) {
						allSafe = false
						prg.after[k] = prg.before[k]
						if int32(k) == int32(prg.curRoundingPtr)-1 {
							prg.after[0] = prg.before[0]
						} else {
							prg.after[int32(k)+1] = prg.before[int32(k)+1]
						}
					}
				}
			}
			if allSafe {
				break
			}
		}
		for ii := int32(0); ii <= int32(prg.curRoundingPtr)-1; ii++ {
			k = uint16(ii)
			_ = k
			a = prg.after[k]
			b = prg.before[k]
			aa = prg.after[int32(k)+1]
			bb = prg.before[int32(k)+1]
			if a != b || aa != bb {
				p = prg.nodeToRound[k]
				pp = prg.nodeToRound[int32(k)+1]

				// Determine the before-and-after values of both coordinates
				if aa == bb {
					if int32(pp) == int32(prg.nodeToRound[0]) {
						prg.unskew(firstX, firstY, *(*prg.mem[pp].hh()).b1())
					} else {
						prg.unskew(*prg.mem[int32(pp)+1].int(), *prg.mem[int32(pp)+2].int(), *(*prg.mem[pp].hh()).b1())
					}
					prg.skew(prg.curX, prg.curY, *(*prg.mem[p].hh()).b1())
					bb = prg.curX
					aa = bb
					dd = prg.curY
					cc = dd
					if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
						b = -b
						a = -a
					}
				} else {
					if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
						bb = -bb
						aa = -aa
						b = -b
						a = -a
					}
					if int32(pp) == int32(prg.nodeToRound[0]) {
						dd = firstY - bb
					} else {
						dd = *prg.mem[int32(pp)+2].int() - bb
					}
					if (aa-bb)&1 != 0 {
						if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
							cc = dd - (aa-bb+1)/2
						} else {
							cc = dd - (aa-bb-1)/2
						}
					} else {
						cc = dd - (aa-bb)/2
					}
				}
				d = *prg.mem[int32(p)+2].int()
				if (a-b)&1 != 0 {
					if int32(*(*prg.mem[p].hh()).b1()) > switchXAndY {
						c = d - (a-b-1)/2
					} else {
						c = d - (a-b+1)/2
					}
				} else {
					c = d - (a-b)/2
				}
				if b == bb {
					alpha = 02000000000
				} else {
					alpha = prg.makeFraction(aa-a, bb-b)
				}
				if d == dd {
					beta = 02000000000
				} else {
					beta = prg.makeFraction(cc-c, dd-d)
				}
				for {
					*prg.mem[int32(p)+1].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+1].int()-b) + a
					*prg.mem[int32(p)+2].int() = prg.takeFraction(beta, *prg.mem[int32(p)+2].int()-d) + c
					*prg.mem[int32(p)+5].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+5].int()-b) + a
					*prg.mem[int32(p)+6].int() = prg.takeFraction(beta, *prg.mem[int32(p)+6].int()-d) + c
					p = *(*prg.mem[p].hh()).rh()
					*prg.mem[int32(p)+3].int() = prg.takeFraction(alpha, *prg.mem[int32(p)+3].int()-b) + a
					*prg.mem[int32(p)+4].int() = prg.takeFraction(beta, *prg.mem[int32(p)+4].int()-d) + c
					if int32(p) == int32(pp) {
						break
					}
				}
			}
		}
	}
}

func (prg *prg) newBoundary(p halfword, octant smallNumber) {
	var (
		q, r1 halfword // for list manipulation
	)
	q = *(*prg.mem[p].hh()).rh() // we assume that |right_type(q)<>endpoint|
	r1 = prg.getNode(knotNodeSize)
	*(*prg.mem[r1].hh()).rh() = q
	*(*prg.mem[p].hh()).rh() = r1
	*(*prg.mem[r1].hh()).b0() = *(*prg.mem[q].hh()).b0() // but possibly |left_type(q)=endpoint|
	*prg.mem[int32(r1)+3].int() = *prg.mem[int32(q)+3].int()
	*prg.mem[int32(r1)+4].int() = *prg.mem[int32(q)+4].int()
	*(*prg.mem[r1].hh()).b1() = byte(endpoint)
	*(*prg.mem[q].hh()).b0() = byte(endpoint)
	*prg.mem[int32(r1)+5].int() = int32(octant)
	*prg.mem[int32(q)+3].int() = int32(*(*prg.mem[q].hh()).b1())
	prg.unskew(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), *(*prg.mem[q].hh()).b1())
	prg.skew(prg.curX, prg.curY, octant)
	*prg.mem[int32(r1)+1].int() = prg.curX
	*prg.mem[int32(r1)+2].int() = prg.curY
}

func (prg *prg) makeSpec(h halfword,
	safetyMargin scaled, tracing int32) (r halfword) {
	var (
		p, q, r1, s halfword // for traversing the lists
		k           int32    // serial number of path segment, or octant code
		chopped     int32    // positive if data truncated,
		//           negative if data dangerously large

		// Other local variables for |make_spec|
		o1, o2             smallNumber // octant numbers
		clockwise          bool        // should we turn clockwise?
		dx1, dy1, dx2, dy2 int32       // directions of travel at a cusp
		dmax, del          int32       // temporary registers
	)
	prg.curSpec = h
	if tracing > 0 {
		prg.printPath(prg.curSpec, strNumber( /* ", before subdivision into octants" */ 559), true)
	}
	prg.maxAllowed = 02000000000 - 0100000 - 1 - safetyMargin

	// Truncate the values of all coordinates that exceed |max_allowed|, and stamp segment numbers in each |left_type| field
	p = prg.curSpec
	k = 1
	chopped = 0
	dmax = prg.maxAllowed / 2
	for {
		if abs(*prg.mem[int32(p)+3].int()) >= dmax {
			if abs(*prg.mem[int32(p)+3].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+3].int() > 0 {
					*prg.mem[int32(p)+3].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+3].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}
		if abs(*prg.mem[int32(p)+4].int()) >= dmax {
			if abs(*prg.mem[int32(p)+4].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+4].int() > 0 {
					*prg.mem[int32(p)+4].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+4].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}
		if abs(*prg.mem[int32(p)+1].int()) >= dmax {
			if abs(*prg.mem[int32(p)+1].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+1].int() > 0 {
					*prg.mem[int32(p)+1].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+1].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}
		if abs(*prg.mem[int32(p)+2].int()) >= dmax {
			if abs(*prg.mem[int32(p)+2].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+2].int() > 0 {
					*prg.mem[int32(p)+2].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+2].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}
		if abs(*prg.mem[int32(p)+5].int()) >= dmax {
			if abs(*prg.mem[int32(p)+5].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+5].int() > 0 {
					*prg.mem[int32(p)+5].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+5].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}
		if abs(*prg.mem[int32(p)+6].int()) >= dmax {
			if abs(*prg.mem[int32(p)+6].int()) > prg.maxAllowed {
				chopped = 1
				if *prg.mem[int32(p)+6].int() > 0 {
					*prg.mem[int32(p)+6].int() = prg.maxAllowed
				} else {
					*prg.mem[int32(p)+6].int() = -prg.maxAllowed
				}
			} else if chopped == 0 {
				chopped = -1
			}
		}

		p = *(*prg.mem[p].hh()).rh()
		*(*prg.mem[p].hh()).b0() = byte(k)
		if k < maxQuarterword {
			k = k + 1
		} else {
			k = 1
		}
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}
	if chopped > 0 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Curve out of range" */ 563) /* \xref[!\relax]  */
		}
		// \xref[Curve out of range]
		{
			prg.helpPtr = 4
			prg.helpLine[3] = /* "At least one of the coordinates in the path I'm about to" */ 564
			prg.helpLine[2] = /* "digitize was really huge (potentially bigger than 4095)." */ 565
			prg.helpLine[1] = /* "So I've cut it back to the maximum size." */ 566
			prg.helpLine[0] = /* "The results will probably be pretty wild." */ 567
		}
		prg.putGetError()
	}
	prg.quadrantSubdivide() // subdivide each cubic into pieces belonging to quadrants
	if prg.internal[autorounding-1] > 0 && chopped == 0 {
		prg.xyRound()
	}
	prg.octantSubdivide() // complete the subdivision
	if prg.internal[autorounding-1] > 0200000 && chopped == 0 {
		prg.diagRound()
	}

	// Remove dead cubics
	p = prg.curSpec
	for {
	continue1:
		q = *(*prg.mem[p].hh()).rh()
		if int32(p) != int32(q) {
			if *prg.mem[int32(p)+1].int() == *prg.mem[int32(p)+5].int() {
				if *prg.mem[int32(p)+2].int() == *prg.mem[int32(p)+6].int() {
					if *prg.mem[int32(p)+1].int() == *prg.mem[int32(q)+3].int() {
						if *prg.mem[int32(p)+2].int() == *prg.mem[int32(q)+4].int() {
							prg.unskew(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), *(*prg.mem[q].hh()).b1())
							prg.skew(prg.curX, prg.curY, *(*prg.mem[p].hh()).b1())
							if *prg.mem[int32(p)+1].int() == prg.curX {
								if *prg.mem[int32(p)+2].int() == prg.curY {
									prg.removeCubic(p) // remove the cubic following |p|
									if int32(q) != int32(prg.curSpec) {
										goto continue1
									}
									prg.curSpec = p
									q = p
								}
							}
						}
					}
				}
			}
		}
		p = q
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}

	// Insert octant boundaries and compute the turning number
	prg.turningNumber = 0
	p = prg.curSpec
	q = *(*prg.mem[p].hh()).rh()
	for {
		r1 = *(*prg.mem[q].hh()).rh()
		if int32(*(*prg.mem[p].hh()).b1()) != int32(*(*prg.mem[q].hh()).b1()) || int32(q) == int32(r1) {
			prg.newBoundary(p, *(*prg.mem[p].hh()).b1())
			s = *(*prg.mem[p].hh()).rh()
			o1 = prg.octantNumber[*(*prg.mem[p].hh()).b1()-1]
			o2 = prg.octantNumber[*(*prg.mem[q].hh()).b1()-1]
			switch int32(o2) - int32(o1) {
			case 1, -7, 7, -1:
				goto done
			case 2, -6:
				clockwise = false
			case 3, -5, 4, -4,
				5, -3:
				// Decide whether or not to go clockwise
				dx1 = *prg.mem[int32(s)+1].int() - *prg.mem[int32(s)+3].int()
				dy1 = *prg.mem[int32(s)+2].int() - *prg.mem[int32(s)+4].int()
				if dx1 == 0 {
					if dy1 == 0 {
						dx1 = *prg.mem[int32(s)+1].int() - *prg.mem[int32(p)+5].int()
						dy1 = *prg.mem[int32(s)+2].int() - *prg.mem[int32(p)+6].int()
						if dx1 == 0 {
							if dy1 == 0 {
								dx1 = *prg.mem[int32(s)+1].int() - *prg.mem[int32(p)+1].int()
								dy1 = *prg.mem[int32(s)+2].int() - *prg.mem[int32(p)+2].int()
							}
						} // and they [\sl can't] both be zero
					}
				}
				dmax = abs(dx1)
				if abs(dy1) > dmax {
					dmax = abs(dy1)
				}
				for dmax < 02000000000 {
					dmax = dmax + dmax
					dx1 = dx1 + dx1
					dy1 = dy1 + dy1
				}
				dx2 = *prg.mem[int32(q)+5].int() - *prg.mem[int32(q)+1].int()
				dy2 = *prg.mem[int32(q)+6].int() - *prg.mem[int32(q)+2].int()
				if dx2 == 0 {
					if dy2 == 0 {
						dx2 = *prg.mem[int32(r1)+3].int() - *prg.mem[int32(q)+1].int()
						dy2 = *prg.mem[int32(r1)+4].int() - *prg.mem[int32(q)+2].int()
						if dx2 == 0 {
							if dy2 == 0 {
								if int32(*(*prg.mem[r1].hh()).b1()) == endpoint {
									prg.curX = *prg.mem[int32(r1)+1].int()
									prg.curY = *prg.mem[int32(r1)+2].int()
								} else {
									prg.unskew(*prg.mem[int32(r1)+1].int(), *prg.mem[int32(r1)+2].int(), *(*prg.mem[r1].hh()).b1())
									prg.skew(prg.curX, prg.curY, *(*prg.mem[q].hh()).b1())
								}
								dx2 = prg.curX - *prg.mem[int32(q)+1].int()
								dy2 = prg.curY - *prg.mem[int32(q)+2].int()
							}
						} // and they [\sl can't] both be zero
					}
				}
				dmax = abs(dx2)
				if abs(dy2) > dmax {
					dmax = abs(dy2)
				}
				for dmax < 02000000000 {
					dmax = dmax + dmax
					dx2 = dx2 + dx2
					dy2 = dy2 + dy2
				}
				prg.unskew(dx1, dy1, *(*prg.mem[p].hh()).b1())
				del = prg.pythAdd(prg.curX, prg.curY)

				dx1 = prg.makeFraction(prg.curX, del)
				dy1 = prg.makeFraction(prg.curY, del)
				// $\cos\theta_1$ and $\sin\theta_1$
				prg.unskew(dx2, dy2, *(*prg.mem[q].hh()).b1())
				del = prg.pythAdd(prg.curX, prg.curY)

				dx2 = prg.makeFraction(prg.curX, del)
				dy2 = prg.makeFraction(prg.curY, del)
				// $\cos\theta_2$ and $\sin\theta_2$
				del = prg.takeFraction(dx1, dy2) - prg.takeFraction(dx2, dy1) // $\sin(\theta_2-\theta_1)$
				if del > 4684844 {
					clockwise = false
				} else if del < -4684844 {
					clockwise = true
				} else {
					clockwise = prg.revTurns
				}

			case 6, -2:
				clockwise = true
			case 0:
				clockwise = prg.revTurns
			} // there are no other cases

			// Insert additional boundary nodes, then |goto done|
			for true {
				if clockwise {
					if int32(o1) == 1 {
						o1 = 8
					} else {
						o1 = byte(int32(o1) - 1)
					}
				} else if int32(o1) == 8 {
					o1 = 1
				} else {
					o1 = byte(int32(o1) + 1)
				}
				if int32(o1) == int32(o2) {
					goto done
				}
				prg.newBoundary(s, prg.octantCode[o1-1])
				s = *(*prg.mem[s].hh()).rh()
				*prg.mem[int32(s)+3].int() = *prg.mem[int32(s)+5].int()
			}

		done:
			if int32(q) == int32(r1) {
				q = *(*prg.mem[q].hh()).rh()
				r1 = q
				p = s
				*(*prg.mem[s].hh()).rh() = q
				*prg.mem[int32(q)+3].int() = *prg.mem[int32(q)+5].int()
				*(*prg.mem[q].hh()).b0() = byte(endpoint)
				prg.freeNode(prg.curSpec, halfword(knotNodeSize))
				prg.curSpec = q
			}

			// Fix up the transition fields and adjust the turning number
			p = *(*prg.mem[p].hh()).rh()
			for {
				s = *(*prg.mem[p].hh()).rh()
				o1 = prg.octantNumber[*prg.mem[int32(p)+5].int()-1]
				o2 = prg.octantNumber[*prg.mem[int32(s)+3].int()-1]
				if abs(int32(o1)-int32(o2)) == 1 {
					if int32(o2) < int32(o1) {
						o2 = o1
					}
					if o2&1 != 0 {
						*prg.mem[int32(p)+6].int() = axis
					} else {
						*prg.mem[int32(p)+6].int() = diagonal
					}
				} else {
					if int32(o1) == 8 {
						prg.turningNumber = prg.turningNumber + 1
					} else {
						prg.turningNumber = prg.turningNumber - 1
					}
					*prg.mem[int32(p)+6].int() = axis
				}
				*prg.mem[int32(s)+4].int() = *prg.mem[int32(p)+6].int()
				p = s
				if int32(p) == int32(q) {
					break
				}
			}
		}
		p = q
		q = r1
		if int32(p) == int32(prg.curSpec) {
			break
		}
	}

	for int32(*(*prg.mem[prg.curSpec].hh()).b0()) != endpoint {
		prg.curSpec = *(*prg.mem[prg.curSpec].hh()).rh()
	}
	if tracing > 0 {
		if prg.internal[autorounding-1] <= 0 || chopped != 0 {
			prg.printSpec(strNumber( /* ", after subdivision" */ 560))
		} else if prg.internal[autorounding-1] > 0200000 {
			prg.printSpec(strNumber( /* ", after subdivision and double autorounding" */ 561))
		} else {
			prg.printSpec(strNumber( /* ", after subdivision and autorounding" */ 562))
		}
	}
	r = prg.curSpec
	return r
}

// 422.

// tangle:pos ../../mf.web:9070:3:

// The swapping here doesn't simply interchange |x| and |y| values,
// because the coordinates are skewed. It turns out that this is easier
// than ordinary swapping, because it can be done in two assignment statements
// rather than three.

// 460. \[22] Filling a contour

// tangle:pos ../../mf.web:9791:28:

// Given the low-level machinery for making moves and for transforming a
// cyclic path into a cycle spec, we're almost able to fill a digitized path.
// All we need is a high-level routine that walks through the cycle spec and
// controls the overall process.
//
// Our overall goal is to plot the integer points $\bigl(\round(x(t)),
// \round(y(t))\bigr)$ and to connect them by rook moves, assuming that
// $\round(x(t))$ and $\round(y(t))$ don't both jump simultaneously from
// one integer to another as $t$~varies; these rook moves will be the edge
// of the contour that will be filled. We have reduced this problem to the
// case of curves that travel in first octant directions, i.e., curves
// such that $0\L y'(t)\L x'(t)$, by transforming the original coordinates.
//
// \def\xtilde[[\tilde x]] \def\ytilde[[\tilde y]]
// Another transformation makes the problem still simpler. We shall say that
// we are working with [\sl biased coordinates\/] when $(x,y)$ has been
// replaced by $(\xtilde,\ytilde)=(x-y,y+[1\over2])$. When a curve travels
// in first octant directions, the corresponding curve with biased
// coordinates travels in first [\sl quadrant\/] directions; the latter
// condition is symmetric in $x$ and~$y$, so it has advantages for the
// design of algorithms. The |make_spec| routine gives us skewed coordinates
// $(x-y,y)$, hence we obtain biased coordinates by simply adding $1\over2$
// to the second component.
//
// The most important fact about biased coordinates is that we can determine the
// rounded unbiased path $\bigl(\round(x(t)),\round(y(t))\bigr)$ from the
// truncated biased path $\bigl(\lfloor\xtilde(t)\rfloor,\lfloor\ytilde(t)\rfloor
// \bigr)$ and information about the initial and final endpoints. If the
// unrounded and unbiased
// path begins at $(x_0,y_0)$ and ends at $(x_1,y_1)$, it's possible to
// prove (by induction on the length of the truncated biased path) that the
// rounded unbiased path is obtained by the following construction:
//
// \yskip\textindent[1)] Start at $\bigl(\round(x_0),\round(y_0)\bigr)$.
//
// \yskip\textindent[2)] If $(x_0+[1\over2])\bmod1\G(y_0+[1\over2])\bmod1$,
// move one step right.
//
// \yskip\textindent[3)] Whenever the path
// $\bigl(\lfloor\xtilde(t)\rfloor,\lfloor\ytilde(t)\rfloor\bigr)$
// takes an upward step (i.e., when
// $\lfloor\xtilde(t+\epsilon)\rfloor=\lfloor\xtilde(t)\rfloor$ and
// $\lfloor\ytilde(t+\epsilon)\rfloor=\lfloor\ytilde(t)\rfloor+1$),
// move one step up and then one step right.
//
// \yskip\textindent[4)] Whenever the path
// $\bigl(\lfloor\xtilde(t)\rfloor,\lfloor\ytilde(t)\rfloor\bigr)$
// takes a rightward step (i.e., when
// $\lfloor\xtilde(t+\epsilon)\rfloor=\lfloor\xtilde(t)\rfloor+1$ and
// $\lfloor\ytilde(t+\epsilon)\rfloor=\lfloor\ytilde(t)\rfloor$),
// move one step right.
//
// \yskip\textindent[5)] Finally, if
// $(x_1+[1\over2])\bmod1\G(y_1+[1\over2])\bmod1$, move one step left (thereby
// cancelling the previous move, which was one step right). You will now be
// at the point $\bigl(\round(x_1),\round(y_1)\bigr)$.

// 463.

// tangle:pos ../../mf.web:9913:3:

// Here's a procedure that handles the details of rounding at the
// endpoints: Given skewed coordinates |(x,y)|, it sets |(m1,n1)|
// to the corresponding rounded lattice points, taking the current
// |octant| into account. Global variable |d1| is also set to 1 if
// $(x+y+[1\over2])\bmod1\G(y+[1\over2])\bmod1$.
func (prg *prg) endRound(x, y scaled) {
	y = y + 0100000 - int32(prg.yCorr[prg.octant-1])
	x = x + y - int32(prg.xCorr[prg.octant-1])
	prg.m1 = prg.floorUnscaled(x)
	prg.n1 = prg.floorUnscaled(y)
	if x-0200000*prg.m1 >= y-0200000*prg.n1+int32(prg.zCorr[prg.octant-1]) {
		prg.d1 = 1
	} else {
		prg.d1 = 0
	}
}

// 465.

// tangle:pos ../../mf.web:9933:3:

// We're ready now to fill the pixels enclosed by a given cycle spec~|h|;
// the knot list that represents the cycle is destroyed in the process.
// The edge structure that gets all the resulting data is |cur_edges|,
// and the edges are weighted by |cur_wt|.
func (prg *prg) fillSpec(h halfword) {
	var (
		p, q, r1, s halfword // for list traversal
	)
	if prg.internal[tracingEdges-1] > 0 {
		prg.beginEdgeTracing()
	}
	p = h // we assume that |left_type(h)=endpoint|
	for {
		prg.octant = byte(*prg.mem[int32(p)+3].int())

		// Set variable |q| to the node at the end of the current octant
		q = p
		for int32(*(*prg.mem[q].hh()).b1()) != endpoint {
			q = *(*prg.mem[q].hh()).rh()
		}
		if int32(q) != int32(p) {
			prg.endRound(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2].int())
			prg.m0 = prg.m1
			prg.n0 = prg.n1
			prg.d0 = prg.d1

			prg.endRound(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int())

			// Make the moves for the current octant
			if prg.n1-prg.n0 >= moveSize {
				prg.overflow(strNumber( /* "move table size" */ 540), moveSize)
			}
			// \xref[METAFONT capacity exceeded move table size][\quad move table size]
			prg.move[0] = int32(prg.d0)
			prg.movePtr = 0
			r1 = p
			for {
				s = *(*prg.mem[r1].hh()).rh()

				prg.makeMoves(*prg.mem[int32(r1)+1].int(), *prg.mem[int32(r1)+5].int(), *prg.mem[int32(s)+3].int(), *prg.mem[int32(s)+1].int(), *prg.mem[int32(r1)+2].int()+0100000, *prg.mem[int32(r1)+6].int()+0100000, *prg.mem[int32(s)+4].int()+0100000, *prg.mem[int32(s)+2].int()+0100000, prg.xyCorr[prg.octant-1], prg.yCorr[prg.octant-1])
				r1 = s
				if int32(r1) == int32(q) {
					break
				}
			}
			prg.move[prg.movePtr] = prg.move[prg.movePtr] - int32(prg.d1)
			if prg.internal[smoothing-1] > 0 {
				prg.smoothMoves(0, int32(prg.movePtr))
			}
			prg.moveToEdges(prg.m0, prg.n0, prg.m1, prg.n1)
		}
		p = *(*prg.mem[q].hh()).rh()
		if int32(p) == int32(h) {
			break
		}
	}
	prg.tossKnotList(h)
	if prg.internal[tracingEdges-1] > 0 {
		prg.endEdgeTracing()
	}
}

// 469. \[23] Polygonal pens

// tangle:pos ../../mf.web:9980:25:

// The next few parts of the program deal with the additional complications
// associated with ``envelopes,'' leading up to an algorithm that fills a
// contour with respect to a pen whose boundary is a convex polygon. The
// mathematics underlying this algorithm is based on simple aspects of the
// theory of tracings developed by Leo Guibas, Lyle Ramshaw, and Jorge
// Stolfi [``A kinetic framework for computational geometry,''
// [\sl Proc.\ IEEE Symp.\ Foundations of Computer Science\/ \bf24] (1983),
// 100--111].
// \xref[Guibas, Leonidas Ioannis]
// \xref[Ramshaw, Lyle Harold]
// \xref[Stolfi, Jorge]
//
// If the vertices of the polygon are $w_0$, $w_1$, \dots, $w_[n-1]$, $w_n=w_0$,
// in counterclockwise order, the convexity condition requires that ``left
// turns'' are made at each vertex when a person proceeds from $w_0$ to
// $w_1$ to $\cdots$ to~$w_n$. The envelope is obtained if we offset a given
// curve $z(t)$ by $w_k$ when that curve is traveling in a direction
// $z'(t)$ lying between the directions $w_k-w_[k-1]$ and $w\k-w_k$.
// At times~$t$ when the curve direction $z'(t)$ increases past
// $w\k-w_k$, we temporarily stop plotting the offset curve and we insert
// a straight line from $z(t)+w_k$ to $z(t)+w\k$; notice that this straight
// line is tangent to the offset curve. Similarly, when the curve direction
// decreases past $w_k-w_[k-1]$, we stop plotting and insert a straight
// line from $z(t)+w_k$ to $z(t)+w_[k-1]$; the latter line is actually a
// ``retrograde'' step, which won't be part of the final envelope under
// \MF's assumptions. The result of this construction is a continuous path
// that consists of alternating curves and straight line segments. The
// segments are usually so short, in practice, that they blend with the
// curves; after all, it's possible to represent any digitized path as
// a sequence of digitized straight lines.
//
// The nicest feature of this approach to envelopes is that it blends
// perfectly with the octant subdivision process we have already developed.
// The envelope travels in the same direction as the curve itself, as we
// plot it, and we need merely be careful what offset is being added.
// Retrograde motion presents a problem, but we will see that there is
// a decent way to handle it.

// 470.

// tangle:pos ../../mf.web:10019:3:

// We shall represent pens by maintaining eight lists of offsets,
// one for each octant direction. The offsets at the boundary points
// where a curve turns into a new octant will appear in the lists for
// both octants. This means that we can restrict consideration to
// segments of the original polygon whose directions aim in the first
// octant, as we have done in the simpler case when envelopes were not
// required.
//
// An example should help to clarify this situation: Consider the
// quadrilateral whose vertices are $w_0=(0,-1)$, $w_1=(3,-1)$,
// $w_2=(6,1)$, and $w_3=(1,2)$. A curve that travels in the first octant
// will be offset by $w_1$ or $w_2$, unless its slope drops to zero
// en route to the eighth octant; in the latter case we should switch to $w_0$ as
// we cross the octant boundary. Our list for the first octant will
// contain the three offsets $w_0$, $w_1$,~$w_2$. By convention we will
// duplicate a boundary offset if the angle between octants doesn't
// explicitly appear; in this case there is no explicit line of slope~1
// at the end of the list, so the full list is
// $$w_0\;w_1\;w_2\;w_2\;=\;(0,-1)\;(3,-1)\;(6,1)\;(6,1).$$
// With skewed coordinates $(u-v,v)$ instead of $(u,v)$ we obtain the list
// $$w_0\;w_1\;w_2\;w_2\;\mapsto\;(1,-1)\;(4,-1)\;(5,1)\;(5,1),$$
// which is what actually appears in the data structure. In the second
// octant there's only one offset; we list it twice (with coordinates
// interchanged, so as to make the second octant look like the first),
// and skew those coordinates, obtaining
// $$\tabskip\centering
// \halign to\hsize[$\hfil#\;\mapsto\;[]$\tabskip=0pt&
//   $#\hfil$&\quad in the #\hfil\tabskip\centering\cr
// w_2\;w_2&(-5,6)\;(-5,6)\cr
// \noalign[\vskip\belowdisplayskip
// \vbox[\noindent\strut as the list of transformed and skewed offsets to use
// when curves travel in the second octant. Similarly, we will have\strut]
// \vskip\abovedisplayskip]
// w_2\;w_2&(7,-6)\;(7,-6)&third;\cr
// w_2\;w_2\;w_3\;w_3&(-7,1)\;(-7,1)\;(-3,2)\;(-3,2)&fourth;\cr
// w_3\;w_3&(1,-2)\;(1,-2)&fifth;\cr
// w_3\;w_3\;w_0\;w_0&(-1,1)\;(-1,1)\;(1,0)\;(1,0)&sixth;\cr
// w_0\;w_0&(1,0)\;(1,0)&seventh;\cr
// w_0\;w_0&(-1,1)\;(-1,1)&eighth.\cr]$$
// Notice that $w_1$ is considered here to be internal to the first octant;
// it's not part of the eighth. We could equally well have taken $w_0$ out
// of the first octant list and put it into the eighth; then the first octant
// list would have been
// $$w_1\;w_1\;w_2\;w_2\;\mapsto\;(4,-1)\;(4,-1)\;(5,1)\;(5,1)$$
// and the eighth octant list would have been
// $$w_0\;w_0\;w_1\;\mapsto\;(-1,1)\;(-1,1)\;(2,1).$$
//
// Actually, there's one more complication: The order of offsets is reversed
// in even-numbered octants, because the transformation of coordinates has
// reversed counterclockwise and clockwise orientations in those octants.
// The offsets in the fourth octant, for example, are really $w_3$, $w_3$,
// $w_2$,~$w_2$, not $w_2$, $w_2$, $w_3$,~$w_3$.

// 471.

// tangle:pos ../../mf.web:10072:3:

// In general, the list of offsets for an octant will have the form
// $$w_0\;\;w_1\;\;\ldots\;\;w_n\;\;w_[n+1]$$
// (if we renumber the subscripts in each list), where $w_0$ and $w_[n+1]$
// are offsets common to the neighboring lists. We'll often have $w_0=w_1$
// and/or $w_n=w_[n+1]$, but the other $w$'s will be distinct. Curves
// that travel between slope~0 and direction $w_2-w_1$ will use offset~$w_1$;
// curves that travel between directions $w_k-w_[k-1]$ and $w\k-w_k$ will
// use offset~$w_k$, for $1<k<n$; curves between direction $w_n-w_[n-1]$
// and slope~1 (actually slope~$\infty$ after skewing) will use offset~$w_n$.
// In even-numbered octants, the directions are actually $w_k-w\k$ instead
// of $w\k-w_k$, because the offsets have been listed in reverse order.
//
// Each offset $w_k$ is represented by skewed coordinates $(u_k-v_k,v_k)$,
// where $(u_k,v_k)$ is the representation of $w_k$ after it has been rotated
// into a first-octant disguise.

// 472.

// tangle:pos ../../mf.web:10088:3:

// The top-level data structure of a pen polygon is a 10-word node containing
// a reference count followed by pointers to the eight offset lists, followed
// by an indication of the pen's range of values.
// \xref[reference counts]
//
// If |p|~points to such a node, and if the
// offset list for, say, the fourth octant has entries $w_0$, $w_1$, \dots,
// $w_n$,~$w_[n+1]$, then |info(p+fourth_octant)| will equal~$n$, and
// |link(p+fourth_octant)| will point to the offset node containing~$w_0$.
// Memory location |p+fourth_octant| is said to be the [\sl header\/] of
// the pen-offset list for the fourth octant. Since this is an even-numbered
// octant, $w_0$ is the offset that goes with the fifth octant, and
// $w_[n+1]$ goes with the third.
//
// The elements of the offset list themselves are doubly linked 3-word nodes,
// containing coordinates in their |x_coord| and |y_coord| fields.
// The two link fields are called |link| and |knil|; if |w|~points to
// the node for~$w_k$, then |link(w)| and |knil(w)| point respectively
// to the nodes for $w\k$ and~$w_[k-1]$. If |h| is the list header,
// |link(h)| points to the node for~$w_0$ and |knil(link(h))| to the
// node for~$w_[n+1]$.
//
// The tenth word of a pen header node contains the maximum absolute value of
// an $x$ or $y$ coordinate among all of the unskewed pen offsets.
//
// The |link| field of a pen header node should be |null| if and only if
// the pen is a single point.

// 476.

// tangle:pos ../../mf.web:10171:3:

// Here's a trivial subroutine that inserts a copy of an offset
// on the |link| side of its clone in the doubly linked list.
func (prg *prg) dupOffset(w halfword) {
	var (
		r1 halfword // the new node
	)
	r1 = prg.getNode(coordNodeSize)
	*prg.mem[int32(r1)+1].int() = *prg.mem[int32(w)+1].int()
	*prg.mem[int32(r1)+2].int() = *prg.mem[int32(w)+2].int()
	*(*prg.mem[r1].hh()).rh() = *(*prg.mem[w].hh()).rh()
	*(*prg.mem[*(*prg.mem[w].hh()).rh()].hh()).lh() = r1
	*(*prg.mem[r1].hh()).lh() = w
	*(*prg.mem[w].hh()).rh() = r1
}

// 477.

// tangle:pos ../../mf.web:10183:3:

// The following algorithm is somewhat more interesting: It converts a
// knot list for a cyclic path into a pen polygon, ignoring everything
// but the |x_coord|, |y_coord|, and |link| fields. If the given path
// vertices do not define a convex polygon, an error message is issued
// and the null pen is returned.
func (prg *prg) makePen(h halfword) (r halfword) {
	var (
		o, oo, k        smallNumber // octant numbers---old, new, and current
		p               halfword    // top-level node for the new pen
		q, r1, s, w, hh halfword    // for list manipulation
		n               int32       // offset counter
		dx, dy          scaled      // polygon direction
		mc              scaled      // the largest coordinate
	)
	q = h
	r1 = *(*prg.mem[q].hh()).rh()
	mc = abs(*prg.mem[int32(h)+1].int())
	if int32(q) == int32(r1) {
		hh = h
		*(*prg.mem[h].hh()).b1() = 0 // this trick is explained below
		if mc < abs(*prg.mem[int32(h)+2].int()) {
			mc = abs(*prg.mem[int32(h)+2].int())
		}
	} else {
		o = 0
		hh = uint16(memMin)
		for true {
			s = *(*prg.mem[r1].hh()).rh()
			if mc < abs(*prg.mem[int32(r1)+1].int()) {
				mc = abs(*prg.mem[int32(r1)+1].int())
			}
			if mc < abs(*prg.mem[int32(r1)+2].int()) {
				mc = abs(*prg.mem[int32(r1)+2].int())
			}
			dx = *prg.mem[int32(r1)+1].int() - *prg.mem[int32(q)+1].int()
			dy = *prg.mem[int32(r1)+2].int() - *prg.mem[int32(q)+2].int()
			if dx == 0 {
				if dy == 0 {
					goto notFound
				}
			} // double point
			if prg.abVsCd(dx, *prg.mem[int32(s)+2].int()-*prg.mem[int32(r1)+2].int(), dy, *prg.mem[int32(s)+1].int()-*prg.mem[int32(r1)+1].int()) < 0 {
				goto notFound
			} // right turn

			// Determine the octant code for direction |(dx,dy)|
			if dx > 0 {
				prg.octant = byte(firstOctant)
			} else if dx == 0 {
				if dy > 0 {
					prg.octant = byte(firstOctant)
				} else {
					prg.octant = byte(firstOctant + negateX)
				}
			} else {
				dx = -dx
				prg.octant = byte(firstOctant + negateX)
			}
			if dy < 0 {
				dy = -dy
				prg.octant = byte(int32(prg.octant) + negateY)
			} else if dy == 0 {
				if int32(prg.octant) > firstOctant {
					prg.octant = byte(firstOctant + negateX + negateY)
				}
			}
			if dx < dy {
				prg.octant = byte(int32(prg.octant) + switchXAndY)
			}
			*(*prg.mem[q].hh()).b1() = prg.octant
			oo = prg.octantNumber[prg.octant-1]
			if int32(o) > int32(oo) {
				if int32(hh) != memMin {
					goto notFound
				} // $>360^\circ$
				hh = q
			}
			o = oo
			if int32(q) == int32(h) && int32(hh) != memMin {
				goto done
			}
			q = r1
			r1 = s
		}

	done:
	}
	if mc >= 02000000000-0100000 {
		goto notFound
	}
	p = prg.getNode(penNodeSize)
	q = hh
	*prg.mem[int32(p)+9].int() = mc
	*(*prg.mem[p].hh()).lh() = uint16(memMin)
	if int32(*(*prg.mem[q].hh()).rh()) != int32(q) {
		*(*prg.mem[p].hh()).rh() = uint16(memMin + 1)
	}
	for ii := int32(1); ii <= 8; ii++ {
		k = smallNumber(ii)
		_ = k
		// Construct the offset list for the |k|th octant
		prg.octant = prg.octantCode[k-1]
		n = 0
		h = uint16(int32(p) + int32(prg.octant))
		for true {
			r1 = prg.getNode(coordNodeSize)
			prg.skew(*prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int(), prg.octant)
			*prg.mem[int32(r1)+1].int() = prg.curX
			*prg.mem[int32(r1)+2].int() = prg.curY
			if n == 0 {
				*(*prg.mem[h].hh()).rh() = r1
			} else if k&1 != 0 {
				*(*prg.mem[w].hh()).rh() = r1
				*(*prg.mem[r1].hh()).lh() = w
			} else {
				*(*prg.mem[w].hh()).lh() = r1
				*(*prg.mem[r1].hh()).rh() = w
			}
			w = r1
			if int32(*(*prg.mem[q].hh()).b1()) != int32(prg.octant) {
				goto done1
			}
			q = *(*prg.mem[q].hh()).rh()
			n = n + 1
		}

	done1:
		r1 = *(*prg.mem[h].hh()).rh()
		if k&1 != 0 {
			*(*prg.mem[w].hh()).rh() = r1
			*(*prg.mem[r1].hh()).lh() = w
		} else {
			*(*prg.mem[w].hh()).lh() = r1
			*(*prg.mem[r1].hh()).rh() = w
			*(*prg.mem[h].hh()).rh() = w
			r1 = w
		}
		if *prg.mem[int32(r1)+2].int() != *prg.mem[int32(*(*prg.mem[r1].hh()).rh())+2].int() || n == 0 {
			prg.dupOffset(r1)
			n = n + 1
		}
		r1 = *(*prg.mem[r1].hh()).lh()
		if *prg.mem[int32(r1)+1].int() != *prg.mem[int32(*(*prg.mem[r1].hh()).lh())+1].int() {
			prg.dupOffset(r1)
		} else {
			n = n - 1
		}
		if n >= maxQuarterword {
			prg.overflow(strNumber( /* "pen polygon size" */ 579), maxQuarterword)
		}
		// \xref[METAFONT capacity exceeded pen polygon size][\quad pen polygon size]
		*(*prg.mem[h].hh()).lh() = uint16(n)
	}

	goto found

notFound:
	p = uint16(memMin + 3)
	// Complain about a bad pen path
	if mc >= 02000000000-0100000 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Pen too large" */ 573) /* \xref[!\relax]  */
		}
		// \xref[Pen too large]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "The cycle you specified has a coordinate of 4095.5 or more." */ 574
			prg.helpLine[0] = /* "So I've replaced it by the trivial path `(0,0)..cycle'." */ 575
		}

	} else {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Pen cycle must be convex" */ 576) /* \xref[!\relax]  */
		}
		// \xref[Pen cycle must be convex]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "The cycle you specified either has consecutive equal points" */ 577
			prg.helpLine[1] = /* "or turns right or turns through more than 360 degrees." */ 578
			prg.helpLine[0] = /* "So I've replaced it by the trivial path `(0,0)..cycle'." */ 575
		}

	}
	prg.putGetError()

found:
	if prg.internal[tracingPens-1] > 0 {
		prg.printPen(p, strNumber( /* " (newly created)" */ 572), true)
	}
	r = p
	return r
}

// 484.

// tangle:pos ../../mf.web:10332:3:

// Conversely, |make_path| goes back from a pen to a cyclic path that
// might have generated it. The structure of this subroutine is essentially
// the same as |print_pen|.
// \4
// Declare the function called |trivial_knot|
func (prg *prg) trivialKnot(x, y scaled) (r halfword) {
	var (
		p halfword // a new knot for explicit coordinates |x| and |y|
	)
	p = prg.getNode(knotNodeSize)
	*(*prg.mem[p].hh()).b0() = byte(explicit)
	*(*prg.mem[p].hh()).b1() = byte(explicit)

	*prg.mem[int32(p)+1].int() = x
	*prg.mem[int32(p)+3].int() = x
	*prg.mem[int32(p)+5].int() = x

	*prg.mem[int32(p)+2].int() = y
	*prg.mem[int32(p)+4].int() = y
	*prg.mem[int32(p)+6].int() = y

	r = p
	return r
}

func (prg *prg) makePath(penHead halfword) (r halfword) {
	var (
		p                halfword // the most recently copied knot
		k/* 1..8 */ byte          // octant number
		h                halfword // offset list head
		m, n             int32    // offset indices
		w, ww            halfword // pointers that traverse the offset list
	)
	p = uint16(3000 - 1)
	for ii := int32(1); ii <= 8; ii++ {
		k = byte(ii)
		_ = k
		prg.octant = prg.octantCode[k-1]
		h = uint16(int32(penHead) + int32(prg.octant))
		n = int32(*(*prg.mem[h].hh()).lh())
		w = *(*prg.mem[h].hh()).rh()
		if !(k&1 != 0) {
			w = *(*prg.mem[w].hh()).lh()
		} // in even octants, start at $w_[n+1]$
		for ii := int32(1); ii <= n+1; ii++ {
			m = ii
			_ = m
			if k&1 != 0 {
				ww = *(*prg.mem[w].hh()).rh()
			} else {
				ww = *(*prg.mem[w].hh()).lh()
			}
			if *prg.mem[int32(ww)+1].int() != *prg.mem[int32(w)+1].int() || *prg.mem[int32(ww)+2].int() != *prg.mem[int32(w)+2].int() {
				prg.unskew(*prg.mem[int32(ww)+1].int(), *prg.mem[int32(ww)+2].int(), prg.octant)
				*(*prg.mem[p].hh()).rh() = prg.trivialKnot(prg.curX, prg.curY)
				p = *(*prg.mem[p].hh()).rh()
			}
			w = ww
		}
	}
	if int32(p) == 3000-1 {
		w = *(*prg.mem[int32(penHead)+firstOctant].hh()).rh()
		p = prg.trivialKnot(*prg.mem[int32(w)+1].int()+*prg.mem[int32(w)+2].int(), *prg.mem[int32(w)+2].int())
		*(*prg.mem[3000-1].hh()).rh() = p
	}
	*(*prg.mem[p].hh()).rh() = *(*prg.mem[3000-1].hh()).rh()
	r = *(*prg.mem[3000-1].hh()).rh()
	return r
}

// 488.

// tangle:pos ../../mf.web:10396:3:

// The |find_offset| procedure sets |(cur_x,cur_y)| to the offset associated
// with a given direction~|(x,y)| and a given pen~|p|. If |x=y=0|, the
// result is |(0,0)|. If two different offsets apply, one of them is
// chosen arbitrarily.
func (prg *prg) findOffset(x, y scaled, p halfword) {
	var (
		octant/* firstOctant..sixthOctant */ byte          // octant code for |(x,y)|
		s/*  -1.. +1 */ int8                               // sign of the octant
		n                                         int32    // number of offsets remaining
		h, w, ww                                  halfword // list traversal registers
	)
	if x > 0 {
		octant = byte(firstOctant)
	} else if x == 0 {
		if y <= 0 {
			if y == 0 {
				prg.curX = 0
				prg.curY = 0
				goto exit
			} else {
				octant = byte(firstOctant + negateX)
			}
		} else {
			octant = byte(firstOctant)
		}
	} else {
		x = -x
		if y == 0 {
			octant = byte(firstOctant + negateX + negateY)
		} else {
			octant = byte(firstOctant + negateX)
		}
	}
	if y < 0 {
		octant = byte(int32(octant) + negateY)
		y = -y
	}
	if x >= y {
		x = x - y
	} else {
		octant = byte(int32(octant) + switchXAndY)
		x = y - x
		y = y - x
	}
	if prg.octantNumber[octant-1]&1 != 0 {
		s = int8(-1)
	} else {
		s = int8(+1)
	}
	h = uint16(int32(p) + int32(octant))
	w = *(*prg.mem[*(*prg.mem[h].hh()).rh()].hh()).rh()
	ww = *(*prg.mem[w].hh()).rh()
	n = int32(*(*prg.mem[h].hh()).lh())
	for n > 1 {
		if prg.abVsCd(x, *prg.mem[int32(ww)+2].int()-*prg.mem[int32(w)+2].int(), y, *prg.mem[int32(ww)+1].int()-*prg.mem[int32(w)+1].int()) != int32(s) {
			goto done
		}
		w = ww
		ww = *(*prg.mem[w].hh()).rh()
		n = n - 1
	}

done:
	prg.unskew(*prg.mem[int32(w)+1].int(), *prg.mem[int32(w)+2].int(), octant)

exit:
}

// 490. \[24] Filling an envelope

// tangle:pos ../../mf.web:10438:30:

// We are about to reach the culmination of \MF's digital plotting routines:
// Almost all of the previous algorithms will be brought to bear on \MF's
// most difficult task, which is to fill the envelope of a given cyclic path
// with respect to a given pen polygon.
//
// But we still must complete some of the preparatory work before taking such
// a big plunge.

// 491.

// tangle:pos ../../mf.web:10447:3:

// Given a pointer |c| to a nonempty list of cubics,
// and a pointer~|h| to the header information of a pen polygon segment,
// the |offset_prep| routine changes the list into cubics that are
// associated with particular pen offsets. Namely, the cubic between |p|
// and~|q| should be associated with the |k|th offset when |right_type(p)=k|.
//
// List |c| is actually part of a cycle spec, so it terminates at the
// first node whose |right_type| is |endpoint|. The cubics all have
// monotone-nondecreasing $x(t)$ and $y(t)$.
// \4
// Declare subroutines needed by |offset_prep|
func (prg *prg) splitForOffset(p halfword, t fraction) {
	var (
		q  halfword // the successor of |p|
		r1 halfword // the new node
	)
	q = *(*prg.mem[p].hh()).rh()
	prg.splitCubic(p, t, *prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int())
	r1 = *(*prg.mem[p].hh()).rh()
	if *prg.mem[int32(r1)+2].int() < *prg.mem[int32(p)+2].int() {
		*prg.mem[int32(r1)+2].int() = *prg.mem[int32(p)+2].int()
	} else if *prg.mem[int32(r1)+2].int() > *prg.mem[int32(q)+2].int() {
		*prg.mem[int32(r1)+2].int() = *prg.mem[int32(q)+2].int()
	}
	if *prg.mem[int32(r1)+1].int() < *prg.mem[int32(p)+1].int() {
		*prg.mem[int32(r1)+1].int() = *prg.mem[int32(p)+1].int()
	} else if *prg.mem[int32(r1)+1].int() > *prg.mem[int32(q)+1].int() {
		*prg.mem[int32(r1)+1].int() = *prg.mem[int32(q)+1].int()
	}
}

func (prg *prg) finOffsetPrep(p halfword, k halfword, w halfword,
	x0, x1, x2, y0, y1, y2 int32, rising bool, n int32) {
	var (
		ww         halfword // for list manipulation
		du, dv     scaled   // for slope calculation
		t0, t1, t2 int32    // test coefficients
		t          fraction // place where the derivative passes a critical slope
		s          fraction // slope or reciprocal slope
		v          int32    // intermediate value for updating |x0..y2|
	)
	for true {
		*(*prg.mem[p].hh()).b1() = byte(k)
		if rising {
			if int32(k) == n {
				goto exit
			} else {
				ww = *(*prg.mem[w].hh()).rh()
			}
		} else if int32(k) == 1 {
			goto exit
		} else {
			ww = *(*prg.mem[w].hh()).lh()
		} // a pointer to $w_[k-1]$

		// Compute test coefficients |(t0,t1,t2)| for $s(t)$ versus $s_k$ or $s_[k-1]$
		du = *prg.mem[int32(ww)+1].int() - *prg.mem[int32(w)+1].int()
		dv = *prg.mem[int32(ww)+2].int() - *prg.mem[int32(w)+2].int()
		if abs(du) >= abs(dv) {
			s = prg.makeFraction(dv, du)
			t0 = prg.takeFraction(x0, s) - y0
			t1 = prg.takeFraction(x1, s) - y1
			t2 = prg.takeFraction(x2, s) - y2
		} else {
			s = prg.makeFraction(du, dv)
			t0 = x0 - prg.takeFraction(y0, s)
			t1 = x1 - prg.takeFraction(y1, s)
			t2 = x2 - prg.takeFraction(y2, s)
		}
		t = prg.crossingPoint(t0, t1, t2)
		if t >= 02000000000 {
			goto exit
		}

		// Split the cubic at $t$, and split off another cubic if the derivative crosses back
		{
			prg.splitForOffset(p, t)
			*(*prg.mem[p].hh()).b1() = byte(k)
			p = *(*prg.mem[p].hh()).rh()

			v = x0 - prg.takeFraction(x0-x1, t)
			x1 = x1 - prg.takeFraction(x1-x2, t)
			x0 = v - prg.takeFraction(v-x1, t)

			v = y0 - prg.takeFraction(y0-y1, t)
			y1 = y1 - prg.takeFraction(y1-y2, t)
			y0 = v - prg.takeFraction(v-y1, t)

			t1 = t1 - prg.takeFraction(t1-t2, t)
			if t1 > 0 {
				t1 = 0
			} // without rounding error, |t1| would be |<=0|
			t = prg.crossingPoint(0, -t1, -t2)
			if t < 02000000000 {
				prg.splitForOffset(p, t)
				*(*prg.mem[*(*prg.mem[p].hh()).rh()].hh()).b1() = byte(k)

				v = x1 - prg.takeFraction(x1-x2, t)
				x1 = x0 - prg.takeFraction(x0-x1, t)
				x2 = x1 - prg.takeFraction(x1-v, t)

				v = y1 - prg.takeFraction(y1-y2, t)
				y1 = y0 - prg.takeFraction(y0-y1, t)
				y2 = y1 - prg.takeFraction(y1-v, t)
			}
		}
		if rising {
			k = uint16(int32(k) + 1)
		} else {
			k = uint16(int32(k) - 1)
		}
		w = ww
	}

exit:
}

func (prg *prg) offsetPrep(c, h halfword) {
	var (
		n                halfword // the number of pen offsets
		p, q, r1, lh, ww halfword // for list manipulation
		k                halfword // the current offset index
		w                halfword // a pointer to offset $w_k$

		// Other local variables for |offset_prep|
		x0, x1, x2, y0, y1, y2       int32    // representatives of derivatives
		t0, t1, t2                   int32    // coefficients of polynomial for slope testing
		du, dv, dx, dy               int32    // for slopes of the pen and the curve
		maxCoef                      int32    // used while scaling
		x0a, x1a, x2a, y0a, y1a, y2a int32    // intermediate values
		t                            fraction // where the derivative passes through zero
		s                            fraction // slope or reciprocal slope
	)
	p = c
	n = *(*prg.mem[h].hh()).lh()
	lh = *(*prg.mem[h].hh()).rh() // now |lh| points to $w_0$
	for int32(*(*prg.mem[p].hh()).b1()) != endpoint {
		q = *(*prg.mem[p].hh()).rh()

		// Split the cubic between |p| and |q|, if necessary, into cubics associated with single offsets, after which |q| should point to the end of the final such cubic
		if int32(n) <= 1 {
			*(*prg.mem[p].hh()).b1() = 1
		} else {
			x0 = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+1].int() // should be |>=0|
			x2 = *prg.mem[int32(q)+1].int() - *prg.mem[int32(q)+3].int() // likewise
			x1 = *prg.mem[int32(q)+3].int() - *prg.mem[int32(p)+5].int() // but this might be negative
			y0 = *prg.mem[int32(p)+6].int() - *prg.mem[int32(p)+2].int()
			y2 = *prg.mem[int32(q)+2].int() - *prg.mem[int32(q)+4].int()
			y1 = *prg.mem[int32(q)+4].int() - *prg.mem[int32(p)+6].int()
			maxCoef = abs(x0) // we take |abs| just to make sure
			if abs(x1) > maxCoef {
				maxCoef = abs(x1)
			}
			if abs(x2) > maxCoef {
				maxCoef = abs(x2)
			}
			if abs(y0) > maxCoef {
				maxCoef = abs(y0)
			}
			if abs(y1) > maxCoef {
				maxCoef = abs(y1)
			}
			if abs(y2) > maxCoef {
				maxCoef = abs(y2)
			}
			if maxCoef == 0 {
				goto notFound
			}
			for maxCoef < 01000000000 {
				maxCoef = maxCoef + maxCoef
				x0 = x0 + x0
				x1 = x1 + x1
				x2 = x2 + x2
				y0 = y0 + y0
				y1 = y1 + y1
				y2 = y2 + y2
			}

			// Find the initial slope, |dy/dx|
			dx = x0
			dy = y0
			if dx == 0 {
				if dy == 0 {
					dx = x1
					dy = y1
					if dx == 0 {
						if dy == 0 {
							dx = x2
							dy = y2
						}
					}
				}
			}
			if dx == 0 {
				prg.finOffsetPrep(p, n, *(*prg.mem[*(*prg.mem[lh].hh()).lh()].hh()).lh(), -x0, -x1, -x2, -y0, -y1, -y2, false, int32(n))
			} else {
				k = 1
				w = *(*prg.mem[lh].hh()).rh()
				for true {
					if int32(k) == int32(n) {
						goto done
					}
					ww = *(*prg.mem[w].hh()).rh()
					if prg.abVsCd(dy, abs(*prg.mem[int32(ww)+1].int()-*prg.mem[int32(w)+1].int()), dx, abs(*prg.mem[int32(ww)+2].int()-*prg.mem[int32(w)+2].int())) >= 0 {
						k = uint16(int32(k) + 1)
						w = ww
					} else {
						goto done
					}
				}

			done:
				;

				// Complete the offset splitting process
				if int32(k) == 1 {
					t = 02000000000 + 1
				} else {
					ww = *(*prg.mem[w].hh()).lh()
					// Compute test coeff...
					du = *prg.mem[int32(ww)+1].int() - *prg.mem[int32(w)+1].int()
					dv = *prg.mem[int32(ww)+2].int() - *prg.mem[int32(w)+2].int()
					if abs(du) >= abs(dv) {
						s = prg.makeFraction(dv, du)
						t0 = prg.takeFraction(x0, s) - y0
						t1 = prg.takeFraction(x1, s) - y1
						t2 = prg.takeFraction(x2, s) - y2
					} else {
						s = prg.makeFraction(du, dv)
						t0 = x0 - prg.takeFraction(y0, s)
						t1 = x1 - prg.takeFraction(y1, s)
						t2 = x2 - prg.takeFraction(y2, s)
					}
					t = prg.crossingPoint(-t0, -t1, -t2)
				}
				if t >= 02000000000 {
					prg.finOffsetPrep(p, k, w, x0, x1, x2, y0, y1, y2, true, int32(n))
				} else {
					prg.splitForOffset(p, t)
					r1 = *(*prg.mem[p].hh()).rh()

					x1a = x0 - prg.takeFraction(x0-x1, t)
					x1 = x1 - prg.takeFraction(x1-x2, t)
					x2a = x1a - prg.takeFraction(x1a-x1, t)

					y1a = y0 - prg.takeFraction(y0-y1, t)
					y1 = y1 - prg.takeFraction(y1-y2, t)
					y2a = y1a - prg.takeFraction(y1a-y1, t)

					prg.finOffsetPrep(p, k, w, x0, x1a, x2a, y0, y1a, y2a, true, int32(n))
					x0 = x2a
					y0 = y2a
					t1 = t1 - prg.takeFraction(t1-t2, t)
					if t1 < 0 {
						t1 = 0
					}
					t = prg.crossingPoint(0, t1, t2)
					if t < 02000000000 {
						prg.splitForOffset(r1, t)

						x1a = x1 - prg.takeFraction(x1-x2, t)
						x1 = x0 - prg.takeFraction(x0-x1, t)
						x0a = x1 - prg.takeFraction(x1-x1a, t)

						y1a = y1 - prg.takeFraction(y1-y2, t)
						y1 = y0 - prg.takeFraction(y0-y1, t)
						y0a = y1 - prg.takeFraction(y1-y1a, t)

						prg.finOffsetPrep(*(*prg.mem[r1].hh()).rh(), k, w, x0a, x1a, x2, y0a, y1a, y2, true, int32(n))
						x2 = x0a
						y2 = y0a
					}
					prg.finOffsetPrep(r1, halfword(int32(k)-1), ww, -x0, -x1, -x2, -y0, -y1, -y2, false, int32(n))
				}
			}

		notFound:
		}

		// Advance |p| to node |q|, removing any “dead” cubics that might have been introduced by the splitting process
		for {
			r1 = *(*prg.mem[p].hh()).rh()
			if *prg.mem[int32(p)+1].int() == *prg.mem[int32(p)+5].int() {
				if *prg.mem[int32(p)+2].int() == *prg.mem[int32(p)+6].int() {
					if *prg.mem[int32(p)+1].int() == *prg.mem[int32(r1)+3].int() {
						if *prg.mem[int32(p)+2].int() == *prg.mem[int32(r1)+4].int() {
							if *prg.mem[int32(p)+1].int() == *prg.mem[int32(r1)+1].int() {
								if *prg.mem[int32(p)+2].int() == *prg.mem[int32(r1)+2].int() {
									prg.removeCubic(p)
									if int32(r1) == int32(q) {
										q = p
									}
									r1 = p
								}
							}
						}
					}
				}
			}
			p = r1
			if int32(p) == int32(q) {
				break
			}
		}
	}
}

// 500.

// tangle:pos ../../mf.web:10652:3:

// Now we must consider the general problem of |offset_prep|, when
// nothing is known about a given cubic. We start by finding its
// slope $s(0)$ in the vicinity of |t=0|.
//
// If $z'(t)=0$, the given cubic is numerically unstable, since the
// slope direction is probably being influenced primarily by rounding
// errors. A user who specifies such cuspy curves should expect to generate
// rather wild results. The present code tries its best to believe the
// existing data, as if no rounding errors were present.

// 506.

// tangle:pos ../../mf.web:10725:3:

// OK, it's time now for the biggie. The |fill_envelope| routine generalizes
// |fill_spec| to polygonal envelopes. Its outer structure is essentially the
// same as before, except that octants with no cubics do contribute to
// the envelope.
// \4
// Declare the procedure called |skew_line_edges|
func (prg *prg) skewLineEdges(p, w, ww halfword) {
	var (
		x0, y0, x1, y1 scaled // from and to
	)
	if *prg.mem[int32(w)+1].int() != *prg.mem[int32(ww)+1].int() || *prg.mem[int32(w)+2].int() != *prg.mem[int32(ww)+2].int() {
		x0 = *prg.mem[int32(p)+1].int() + *prg.mem[int32(w)+1].int()
		y0 = *prg.mem[int32(p)+2].int() + *prg.mem[int32(w)+2].int()

		x1 = *prg.mem[int32(p)+1].int() + *prg.mem[int32(ww)+1].int()
		y1 = *prg.mem[int32(p)+2].int() + *prg.mem[int32(ww)+2].int()

		prg.unskew(x0, y0, prg.octant) // unskew and unrotate the coordinates
		x0 = prg.curX
		y0 = prg.curY

		prg.unskew(x1, y1, prg.octant)

		if prg.internal[tracingEdges-1] > 0200000 {
			prg.printNl(strNumber( /* "@ retrograde line from " */ 584))
			// \xref[]]]\AT!_retro_][\.[\AT! retrograde line...]]
			// \xref[retrograde line...]
			prg.printTwo(x0, y0)
			prg.print( /* " to " */ 583)
			prg.printTwo(prg.curX, prg.curY)
			prg.printNl(strNumber( /* "" */ 285))
		}

		prg.lineEdges(x0, y0, prg.curX, prg.curY) // then draw a straight line
	}
}

// \4
// Declare the procedure called |dual_moves|
func (prg *prg) dualMoves(h, p, q halfword) {
	var (
		r1, s halfword // for list traversal

		// Other local variables for |fill_envelope|
		m, n                                         int32    // current lattice position
		mm0, mm1                                     int32    // skewed equivalents of |m0| and |m1|
		k                                            int32    // current offset number
		w, ww                                        halfword // pointers to the current offset and its neighbor
		smoothBot, smoothTop/* 0..moveSize */ uint16          // boundaries of smoothing
		xx, yy, xp, yp, delx, dely, tx, ty           scaled
	// registers for coordinate calculations
	)
	k = int32(*(*prg.mem[h].hh()).lh()) + 1
	ww = *(*prg.mem[h].hh()).rh()
	w = *(*prg.mem[ww].hh()).lh()

	mm0 = prg.floorUnscaled(*prg.mem[int32(p)+1].int() + *prg.mem[int32(w)+1].int() - int32(prg.xyCorr[prg.octant-1]))
	mm1 = prg.floorUnscaled(*prg.mem[int32(q)+1].int() + *prg.mem[int32(ww)+1].int() - int32(prg.xyCorr[prg.octant-1]))
	for ii := int32(1); ii <= prg.n1-prg.n0+1; ii++ {
		n = ii
		_ = n
		prg.envMove[n] = mm1
	}
	prg.envMove[0] = mm0
	prg.movePtr = 0
	m = mm0
	r1 = p // recall that |right_type(q)=endpoint=0| now
	for true {
		if int32(r1) == int32(q) {
			smoothTop = prg.movePtr
		}
		for int32(*(*prg.mem[r1].hh()).b1()) != k {

			// Insert a line segment dually to approach the correct offset
			xx = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
			yy = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
			if prg.internal[tracingEdges-1] > 0200000 {
				prg.printNl(strNumber( /* "@ transition line " */ 585))
				prg.printInt(k)
				prg.print( /* ", from " */ 586)
				// \xref[]]]\AT!_trans_][\.[\AT! transition line...]]
				// \xref[transition line...]
				prg.unskew(xx, yy-0100000, prg.octant)
				prg.printTwo(prg.curX, prg.curY)
			}

			if int32(*(*prg.mem[r1].hh()).b1()) < k {
				k = k - 1
				w = *(*prg.mem[w].hh()).lh()
				xp = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
				yp = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
				if yp != yy {
					ty = prg.floorScaled(yy - int32(prg.yCorr[prg.octant-1]))
					dely = yp - yy
					yy = yy - ty
					ty = yp - int32(prg.yCorr[prg.octant-1]) - ty
					if ty >= 0200000 {
						delx = xp - xx
						yy = 0200000 - yy
						for true {
							if m < prg.envMove[prg.movePtr] {
								prg.envMove[prg.movePtr] = m
							}
							tx = prg.takeFraction(delx, prg.makeFraction(yy, dely))
							if prg.abVsCd(tx, dely, delx, yy)+int32(prg.xyCorr[prg.octant-1]) > 0 {
								tx = tx - 1
							}
							m = prg.floorUnscaled(xx + tx)
							ty = ty - 0200000
							prg.movePtr = uint16(int32(prg.movePtr) + 1)
							if ty < 0200000 {
								goto done1
							}
							yy = yy + 0200000
						}

					done1:
						if m < prg.envMove[prg.movePtr] {
							prg.envMove[prg.movePtr] = m
						}
					}
				}
			} else {
				k = k + 1
				w = *(*prg.mem[w].hh()).rh()
				xp = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
				yp = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
			}
			if prg.internal[tracingEdges-1] > 0200000 {
				prg.print( /* " to " */ 583)
				prg.unskew(xp, yp-0100000, prg.octant)
				prg.printTwo(prg.curX, prg.curY)
				prg.printNl(strNumber( /* "" */ 285))
			}

			m = prg.floorUnscaled(xp - int32(prg.xyCorr[prg.octant-1]))
			prg.movePtr = uint16(prg.floorUnscaled(yp-int32(prg.yCorr[prg.octant-1])) - prg.n0)
			if m < prg.envMove[prg.movePtr] {
				prg.envMove[prg.movePtr] = m
			}
		}
		if int32(r1) == int32(p) {
			smoothBot = prg.movePtr
		}
		if int32(r1) == int32(q) {
			goto done
		}
		prg.move[prg.movePtr] = 1
		n = int32(prg.movePtr)
		s = *(*prg.mem[r1].hh()).rh()

		prg.makeMoves(*prg.mem[int32(r1)+1].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(r1)+5].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(s)+3].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(s)+1].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(r1)+2].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(r1)+6].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(s)+4].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(s)+2].int()+*prg.mem[int32(w)+2].int()+0100000, prg.xyCorr[prg.octant-1], prg.yCorr[prg.octant-1])

		// Transfer moves dually from the |move| array to |env_move|
		for {
			if m < prg.envMove[n] {
				prg.envMove[n] = m
			}
			m = m + prg.move[n] - 1
			n = n + 1
			if n > int32(prg.movePtr) {
				break
			}
		}
		r1 = s
	}

done:
	prg.move[0] = int32(prg.d0) + prg.envMove[1] - mm0
	for ii := int32(1); ii <= int32(prg.movePtr); ii++ {
		n = ii
		_ = n
		prg.move[n] = prg.envMove[n+1] - prg.envMove[n] + 1
	}
	prg.move[prg.movePtr] = prg.move[prg.movePtr] - int32(prg.d1)
	if prg.internal[smoothing-1] > 0 {
		prg.smoothMoves(int32(smoothBot), int32(smoothTop))
	}
	prg.moveToEdges(prg.m0, prg.n0, prg.m1, prg.n1)
	if *prg.mem[int32(q)+6].int() == diagonal {
		w = *(*prg.mem[h].hh()).rh()
		prg.skewLineEdges(q, w, *(*prg.mem[w].hh()).lh())
	}
}

func (prg *prg) fillEnvelope(specHead halfword) {
	var (
		p, q, r1, s halfword // for list traversal
		h           halfword // head of pen offset list for current octant
		www         halfword // a pen offset of temporary interest

		// Other local variables for |fill_envelope|
		m, n                                         int32    // current lattice position
		mm0, mm1                                     int32    // skewed equivalents of |m0| and |m1|
		k                                            int32    // current offset number
		w, ww                                        halfword // pointers to the current offset and its neighbor
		smoothBot, smoothTop/* 0..moveSize */ uint16          // boundaries of smoothing
		xx, yy, xp, yp, delx, dely, tx, ty           scaled
	// registers for coordinate calculations
	)
	if prg.internal[tracingEdges-1] > 0 {
		prg.beginEdgeTracing()
	}
	p = specHead // we assume that |left_type(spec_head)=endpoint|
	for {
		prg.octant = byte(*prg.mem[int32(p)+3].int())
		h = uint16(int32(prg.curPen) + int32(prg.octant))

		// Set variable |q| to the node at the end of the current octant
		q = p
		for int32(*(*prg.mem[q].hh()).b1()) != endpoint {
			q = *(*prg.mem[q].hh()).rh()
		}

		// Determine the envelope's starting and ending lattice points |(m0,n0)| and |(m1,n1)|
		w = *(*prg.mem[h].hh()).rh()
		if *prg.mem[int32(p)+4].int() == diagonal {
			w = *(*prg.mem[w].hh()).lh()
		}
		if prg.internal[tracingEdges-1] > 0200000 {
			prg.printNl(strNumber( /* "@ Octant " */ 580))
			prg.print(int32(prg.octantDir[prg.octant-1]))
			// \xref[]]]\AT!_Octant][\.[\AT! Octant...]]
			prg.print( /* " (" */ 558)
			prg.printInt(int32(*(*prg.mem[h].hh()).lh()))
			prg.print( /* " offset" */ 581)
			if int32(*(*prg.mem[h].hh()).lh()) != 1 {
				prg.printChar(asciiCode('s'))
			}
			prg.print( /* "), from " */ 582)
			prg.unskew(*prg.mem[int32(p)+1].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(p)+2].int()+*prg.mem[int32(w)+2].int(), prg.octant)
			prg.printTwo(prg.curX, prg.curY)

			ww = *(*prg.mem[h].hh()).rh()
			if *prg.mem[int32(q)+6].int() == diagonal {
				ww = *(*prg.mem[ww].hh()).lh()
			}
			prg.print( /* " to " */ 583)
			prg.unskew(*prg.mem[int32(q)+1].int()+*prg.mem[int32(ww)+1].int(), *prg.mem[int32(q)+2].int()+*prg.mem[int32(ww)+2].int(), prg.octant)
			prg.printTwo(prg.curX, prg.curY)
		}

		ww = *(*prg.mem[h].hh()).rh()
		www = ww // starting and ending offsets
		if prg.octantNumber[prg.octant-1]&1 != 0 {
			www = *(*prg.mem[www].hh()).lh()
		} else {
			ww = *(*prg.mem[ww].hh()).lh()
		}
		if int32(w) != int32(ww) {
			prg.skewLineEdges(p, w, ww)
		}
		prg.endRound(*prg.mem[int32(p)+1].int()+*prg.mem[int32(ww)+1].int(), *prg.mem[int32(p)+2].int()+*prg.mem[int32(ww)+2].int())
		prg.m0 = prg.m1
		prg.n0 = prg.n1
		prg.d0 = prg.d1

		prg.endRound(*prg.mem[int32(q)+1].int()+*prg.mem[int32(www)+1].int(), *prg.mem[int32(q)+2].int()+*prg.mem[int32(www)+2].int())
		if prg.n1-prg.n0 >= moveSize {
			prg.overflow(strNumber( /* "move table size" */ 540), moveSize)
		}
		prg.offsetPrep(p, h) // this may clobber node~|q|, if it becomes ``dead''

		// Set variable |q| to the node at the end of the current octant
		q = p
		for int32(*(*prg.mem[q].hh()).b1()) != endpoint {
			q = *(*prg.mem[q].hh()).rh()
		}

		// Make the envelope moves for the current octant and insert them in the pixel data
		if prg.octantNumber[prg.octant-1]&1 != 0 {
			k = 0
			w = *(*prg.mem[h].hh()).rh()
			ww = *(*prg.mem[w].hh()).lh()
			mm0 = prg.floorUnscaled(*prg.mem[int32(p)+1].int() + *prg.mem[int32(w)+1].int() - int32(prg.xyCorr[prg.octant-1]))
			mm1 = prg.floorUnscaled(*prg.mem[int32(q)+1].int() + *prg.mem[int32(ww)+1].int() - int32(prg.xyCorr[prg.octant-1]))
			for ii := int32(0); ii <= prg.n1-prg.n0-1; ii++ {
				n = ii
				_ = n
				prg.envMove[n] = mm0
			}
			prg.envMove[prg.n1-prg.n0] = mm1
			prg.movePtr = 0
			m = mm0
			r1 = p
			*(*prg.mem[q].hh()).b1() = byte(int32(*(*prg.mem[h].hh()).lh()) + 1)
			for true {
				if int32(r1) == int32(q) {
					smoothTop = prg.movePtr
				}
				for int32(*(*prg.mem[r1].hh()).b1()) != k {

					// Insert a line segment to approach the correct offset
					xx = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
					yy = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
					if prg.internal[tracingEdges-1] > 0200000 {
						prg.printNl(strNumber( /* "@ transition line " */ 585))
						prg.printInt(k)
						prg.print( /* ", from " */ 586)
						// \xref[]]]\AT!_trans_][\.[\AT! transition line...]]
						// \xref[transition line...]
						prg.unskew(xx, yy-0100000, prg.octant)
						prg.printTwo(prg.curX, prg.curY)
					}

					if int32(*(*prg.mem[r1].hh()).b1()) > k {
						k = k + 1
						w = *(*prg.mem[w].hh()).rh()
						xp = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
						yp = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
						if yp != yy {
							ty = prg.floorScaled(yy - int32(prg.yCorr[prg.octant-1]))
							dely = yp - yy
							yy = yy - ty
							ty = yp - int32(prg.yCorr[prg.octant-1]) - ty
							if ty >= 0200000 {
								delx = xp - xx
								yy = 0200000 - yy
								for true {
									tx = prg.takeFraction(delx, prg.makeFraction(yy, dely))
									if prg.abVsCd(tx, dely, delx, yy)+int32(prg.xyCorr[prg.octant-1]) > 0 {
										tx = tx - 1
									}
									m = prg.floorUnscaled(xx + tx)
									if m > prg.envMove[prg.movePtr] {
										prg.envMove[prg.movePtr] = m
									}
									ty = ty - 0200000
									if ty < 0200000 {
										goto done1
									}
									yy = yy + 0200000
									prg.movePtr = uint16(int32(prg.movePtr) + 1)
								}

							done1:
							}
						}
					} else {
						k = k - 1
						w = *(*prg.mem[w].hh()).lh()
						xp = *prg.mem[int32(r1)+1].int() + *prg.mem[int32(w)+1].int()
						yp = *prg.mem[int32(r1)+2].int() + *prg.mem[int32(w)+2].int() + 0100000
					}
					if prg.internal[tracingEdges-1] > 0200000 {
						prg.print( /* " to " */ 583)
						prg.unskew(xp, yp-0100000, prg.octant)
						prg.printTwo(prg.curX, prg.curY)
						prg.printNl(strNumber( /* "" */ 285))
					}

					m = prg.floorUnscaled(xp - int32(prg.xyCorr[prg.octant-1]))
					prg.movePtr = uint16(prg.floorUnscaled(yp-int32(prg.yCorr[prg.octant-1])) - prg.n0)
					if m > prg.envMove[prg.movePtr] {
						prg.envMove[prg.movePtr] = m
					}
				}
				if int32(r1) == int32(p) {
					smoothBot = prg.movePtr
				}
				if int32(r1) == int32(q) {
					goto done
				}
				prg.move[prg.movePtr] = 1
				n = int32(prg.movePtr)
				s = *(*prg.mem[r1].hh()).rh()

				prg.makeMoves(*prg.mem[int32(r1)+1].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(r1)+5].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(s)+3].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(s)+1].int()+*prg.mem[int32(w)+1].int(), *prg.mem[int32(r1)+2].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(r1)+6].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(s)+4].int()+*prg.mem[int32(w)+2].int()+0100000, *prg.mem[int32(s)+2].int()+*prg.mem[int32(w)+2].int()+0100000, prg.xyCorr[prg.octant-1], prg.yCorr[prg.octant-1])

				// Transfer moves from the |move| array to |env_move|
				for {
					m = m + prg.move[n] - 1
					if m > prg.envMove[n] {
						prg.envMove[n] = m
					}
					n = n + 1
					if n > int32(prg.movePtr) {
						break
					}
				}
				r1 = s
			}

		done:
			prg.move[0] = int32(prg.d0) + prg.envMove[0] - mm0
			for ii := int32(1); ii <= int32(prg.movePtr); ii++ {
				n = ii
				_ = n
				prg.move[n] = prg.envMove[n] - prg.envMove[n-1] + 1
			}
			prg.move[prg.movePtr] = prg.move[prg.movePtr] - int32(prg.d1)
			if prg.internal[smoothing-1] > 0 {
				prg.smoothMoves(int32(smoothBot), int32(smoothTop))
			}
			prg.moveToEdges(prg.m0, prg.n0, prg.m1, prg.n1)
			if *prg.mem[int32(q)+6].int() == axis {
				w = *(*prg.mem[h].hh()).rh()
				prg.skewLineEdges(q, *(*prg.mem[w].hh()).lh(), w)
			}
		} else {
			prg.dualMoves(h, p, q)
		}
		*(*prg.mem[q].hh()).b1() = byte(endpoint)
		p = *(*prg.mem[q].hh()).rh()
		if int32(p) == int32(specHead) {
			break
		}
	}
	if prg.internal[tracingEdges-1] > 0 {
		prg.endEdgeTracing()
	}
	prg.tossKnotList(specHead)
}

// 524. \[25] Elliptical pens

// tangle:pos ../../mf.web:11071:26:

// To get the envelope of a cyclic path with respect to an ellipse, \MF\
// calculates the envelope with respect to a polygonal approximation to
// the ellipse, using an approach due to John Hobby (Ph.D. thesis,
// Stanford University, 1985).
// \xref[Hobby, John Douglas]
// This has two important advantages over trying to obtain the ``exact''
// envelope:
//
// \yskip\textindent[1)]It gives better results, because the polygon has been
// designed to counteract problems that arise from digitization; the
// polygon includes sub-pixel corrections to an exact ellipse that make
// the results essentially independent of where the path falls on the raster.
// For example, the exact envelope with respect to a pen of diameter~1
// blackens a pixel if and only if the path intersects a circle of diameter~1
// inscribed in that pixel; the resulting pattern has ``blots'' when the path
// is traveling diagonally in unfortunate raster positions. A much better
// result is obtained when pixels are blackened only when the path intersects
// an inscribed [\sl diamond\/] of diameter~1. Such a diamond is precisely
// the polygon that \MF\ uses in the special case of a circle whose diameter is~1.
//
// \yskip\textindent[2)]Polygonal envelopes of cubic splines are cubic
// splines, hence it isn't necessary to introduce completely different
// routines. By contrast, exact envelopes of cubic splines with respect
// to circles are complicated curves, more difficult to plot than cubics.

// 525.

// tangle:pos ../../mf.web:11097:3:

// Hobby's construction involves some interesting number theory.
// If $u$ and~$v$ are relatively prime integers, we divide the
// set of integer points $(m,n)$ into equivalence classes by saying
// that $(m,n)$ belongs to class $um+vn$. Then any two integer points
// that lie on a line of slope $-u/v$ belong to the same class, because
// such points have the form $(m+tv,n-tu)$. Neighboring lines of slope $-u/v$
// that go through integer points are separated by distance $1/\psqrt[u^2+v^2]$
// from each other, and these lines are perpendicular to lines of slope~$v/u$.
// If we start at the origin and travel a distance $k/\psqrt[u^2+v^2]$ in
// direction $(u,v)$, we reach the line of slope~$-u/v$ whose points
// belong to class~$k$.
//
// For example, let $u=2$ and $v=3$. Then the points $(0,0)$, $(3,-2)$,
// $\ldots$ belong to class~0; the points $(-1,1)$, $(2,-1)$, $\ldots$ belong
// to class~1; and the distance between these two lines is $1/\sqrt[13]$.
// The point $(2,3)$ itself belongs to class~13, hence its distance from
// the origin is $13/\sqrt[13]=\sqrt[13]$ (which we already knew).
//
// Suppose we wish to plot envelopes with respect to polygons with
// integer vertices. Then the best polygon for curves that travel in
// direction $(v,-u)$ will contain the points of class~$k$ such that
// $k/\psqrt[u^2+v^2]$ is as close as possible to~$d$, where $d$ is the
// maximum distance of the given ellipse from the line $ux+vy=0$.
//
// The |fillin| correction assumes that a diagonal line has an
// apparent thickness $$2f\cdot\min(\vert u\vert,\vert v\vert)/\psqrt[u^2+v^2]$$
// greater than would be obtained with truly square pixels. (If a
// white pixel at an exterior corner is assumed to have apparent
// darkness $f_1$ and a black pixel at an interior corner is assumed
// to have apparent darkness $1-f_2$, then $f=f_1-f_2$ is the |fillin|
// parameter.) Under this assumption we want to choose $k$ so that
// $\bigl(k+2f\cdot\min(\vert u\vert,\vert v\vert)\bigr)\big/\psqrt[u^2+v^2]$
// is as close as possible to $d$.
//
// Integer coordinates for the vertices work nicely because the thickness of
// the envelope at any given slope is independent of the position of the
// path with respect to the raster. It turns out, in fact, that the same
// property holds for polygons whose vertices have coordinates that are
// integer multiples of~$1\over2$, because ellipses are symmetric about
// the origin. It's convenient to double all dimensions and require the
// resulting polygon to have vertices with integer coordinates. For example,
// to get a circle of [\sl diameter]~$r$, we shall compute integer
// coordinates for a circle of [\sl radius]~$r$. The circle of radius~$r$
// will want to be represented by a polygon that contains the boundary
// points $(0,\pm r)$ and~$(\pm r,0)$; later we will divide everything
// by~2 and get a polygon with $(0,\pm[1\over2]r)$ and $(\pm[1\over2]r,0)$
// on its boundary.

// 526.

// tangle:pos ../../mf.web:11145:3:

// In practice the important slopes are those having small values of
// $u$ and~$v$; these make regular patterns in which our eyes quickly
// spot irregularities. For example, horizontal and vertical lines
// (when $u=0$ and $\vert v\vert=1$, or $\vert u\vert=1$ and $v=0$)
// are the most important; diagonal lines (when $\vert u\vert=\vert v\vert=1$)
// are next; and then come lines with slope $\pm2$ or $\pm1/2$.
//
// The nicest way to generate all rational directions having small
// numerators and denominators is to generalize the Stern--Brocot tree
// [cf.~[\sl Concrete Mathematics], section 4.5]
// \xref[Brocot, Achille]
// \xref[Stern, Moritz Abraham]
// to a ``Stern--Brocot wreath'' as follows: Begin with four nodes
// arranged in a circle, containing the respective directions
// $(u,v)=(1,0)$, $(0,1)$, $(-1,0)$, and~$(0,-1)$. Then between pairs of
// consecutive terms $(u,v)$ and $(u',v')$ of the wreath, insert the
// direction $(u+u',v+v')$; continue doing this until some stopping
// criterion is fulfilled.
//
// It is not difficult to verify that, regardless of the stopping
// criterion, consecutive directions $(u,v)$ and $(u',v')$ of this
// wreath will always satisfy the relation $uv'-u'v=1$. Such pairs
// of directions have a nice property with respect to the equivalence
// classes described above. Let $l$ be a line of equivalent integer points
// $(m+tv,n-tu)$ with respect to~$(u,v)$, and let $l'$ be a line of
// equivalent integer points $(m'+tv',n'-tu')$ with respect to~$(u',v')$.
// Then $l$ and~$l'$ intersect in an integer point $(m'',n'')$, because
// the determinant of the linear equations for intersection is $uv'-u'v=1$.
// Notice that the class number of $(m'',n'')$ with respect to $(u+u',v+v')$
// is the sum of its class numbers with respect to $(u,v)$ and~$(u',v')$.
// Moreover, consecutive points on~$l$ and~$l'$ belong to classes that
// differ by exactly~1 with respect to $(u+u',v+v')$.
//
// This leads to a nice algorithm in which we construct a polygon having
// ``correct'' class numbers for as many small-integer directions $(u,v)$
// as possible: Assuming that lines $l$ and~$l'$ contain points of the
// correct class for $(u,v)$ and~$(u',v')$, respectively, we determine
// the intersection $(m'',n'')$ and compute its class with respect to
// $(u+u',v+v')$. If the class is too large to be the best approximation,
// we move back the proper number of steps from $(m'',n'')$ toward smaller
// class numbers on both $l$ and~$l'$, unless this requires moving to points
// that are no longer in the polygon; in this way we arrive at two points that
// determine a line~$l''$ having the appropriate class. The process continues
// recursively, until it cannot proceed without removing the last remaining
// point from the class for $(u,v)$ or the class for $(u',v')$.

// 527.

// tangle:pos ../../mf.web:11191:3:

// The |make_ellipse| subroutine produces a pointer to a cyclic path
// whose vertices define a polygon suitable for envelopes. The control
// points on this path will be ignored; in fact, the fields in knot nodes
// that are usually reserved for control points are occupied by other
// data that helps |make_ellipse| compute the desired polygon.
//
// Parameters |major_axis| and |minor_axis| define the axes of the ellipse;
// and parameter |theta| is an angle by which the ellipse is rotated
// counterclockwise. If |theta=0|, the ellipse has the equation
// $(x/a)^2+(y/b)^2=1$, where |a=major_axis/2| and |b=minor_axis/2|.
// In general, the points of the ellipse are generated in the complex plane
// by the formula $e^[i\theta](a\cos t+ib\sin t)$, as $t$~ranges over all
// angles. Notice that if |major_axis=minor_axis=d|, we obtain a circle
// of diameter~|d|, regardless of the value of |theta|.
//
// The method sketched above is used to produce the elliptical polygon,
// except that the main work is done only in the halfplane obtained from
// the three starting directions $(0,-1)$, $(1,0)$,~$(0,1)$. Since the ellipse
// has circular symmetry, we use the fact that the last half of the polygon
// is simply the negative of the first half. Furthermore, we need to compute only
// one quarter of the polygon if the ellipse has axis symmetry.
func (prg *prg) makeEllipse(majorAxis, minorAxis scaled,
	theta angle) (r halfword) {
	var (
		p, q, r1, s               halfword // for list manipulation
		h                         halfword // head of the constructed knot list
		alpha, beta, gamma, delta int32    // special points
		c, d                      int32    // class numbers
		u, v                      int32    // directions
		symmetric                 bool     // should the result be symmetric about the axes?
	)
	if majorAxis == minorAxis || theta%0550000000 == 0 {
		symmetric = true
		alpha = 0
		if theta/0550000000&1 != 0 {
			beta = majorAxis
			gamma = minorAxis
			prg.nSin = 02000000000
			prg.nCos = 0 // |n_sin| and |n_cos| are used later
		} else {
			beta = minorAxis
			gamma = majorAxis
			theta = 0
		} // |n_sin| and |n_cos| aren't needed in this case
	} else {
		symmetric = false
		prg.nSinCos(theta) // set up $|n_sin|=\sin\theta$ and $|n_cos|=\cos\theta$
		gamma = prg.takeFraction(majorAxis, prg.nSin)
		delta = prg.takeFraction(minorAxis, prg.nCos)
		beta = prg.pythAdd(gamma, delta)
		alpha = prg.takeFraction(prg.takeFraction(majorAxis, prg.makeFraction(gamma, beta)), prg.nCos) - prg.takeFraction(prg.takeFraction(minorAxis, prg.makeFraction(delta, beta)), prg.nSin)
		alpha = (alpha + 0100000) / 0200000
		gamma = prg.pythAdd(prg.takeFraction(majorAxis, prg.nCos), prg.takeFraction(minorAxis, prg.nSin))
	}
	beta = (beta + 0100000) / 0200000
	gamma = (gamma + 0100000) / 0200000
	p = prg.getNode(knotNodeSize)
	q = prg.getNode(knotNodeSize)
	r1 = prg.getNode(knotNodeSize)
	if symmetric {
		s = uint16(memMin)
	} else {
		s = prg.getNode(knotNodeSize)
	}
	h = p
	*(*prg.mem[p].hh()).rh() = q
	*(*prg.mem[q].hh()).rh() = r1
	*(*prg.mem[r1].hh()).rh() = s // |s=null| or |link(s)=null|

	// Revise the values of $\alpha$, $\beta$, $\gamma$, if necessary, so that degenerate lines of length zero will not be obtained
	if beta == 0 {
		beta = 1
	}
	if gamma == 0 {
		gamma = 1
	}
	if gamma <= abs(alpha) {
		if alpha > 0 {
			alpha = gamma - 1
		} else {
			alpha = 1 - gamma
		}
	}
	*prg.mem[int32(p)+1].int() = -(alpha * 0100000)
	*prg.mem[int32(p)+2].int() = -(beta * 0100000)
	*prg.mem[int32(q)+1].int() = gamma * 0100000

	*prg.mem[int32(q)+2].int() = *prg.mem[int32(p)+2].int()
	*prg.mem[int32(r1)+1].int() = *prg.mem[int32(q)+1].int()

	*prg.mem[int32(p)+5].int() = 0
	*prg.mem[int32(q)+3].int() = -0100000

	*prg.mem[int32(q)+5].int() = 0100000
	*prg.mem[int32(r1)+3].int() = 0

	*prg.mem[int32(r1)+5].int() = 0
	*prg.mem[int32(p)+6].int() = beta
	*prg.mem[int32(q)+6].int() = gamma
	*prg.mem[int32(r1)+6].int() = beta

	*prg.mem[int32(q)+4].int() = gamma + alpha
	if symmetric {
		*prg.mem[int32(r1)+2].int() = 0
		*prg.mem[int32(r1)+4].int() = beta
	} else {
		*prg.mem[int32(r1)+2].int() = -*prg.mem[int32(p)+2].int()
		*prg.mem[int32(r1)+4].int() = beta + beta

		*prg.mem[int32(s)+1].int() = -*prg.mem[int32(p)+1].int()
		*prg.mem[int32(s)+2].int() = *prg.mem[int32(r1)+2].int()

		*prg.mem[int32(s)+3].int() = 0100000
		*prg.mem[int32(s)+4].int() = gamma - alpha
	}

	// Interpolate new vertices in the ellipse data structure until improvement is impossible
	for true {
		u = *prg.mem[int32(p)+5].int() + *prg.mem[int32(q)+5].int()
		v = *prg.mem[int32(q)+3].int() + *prg.mem[int32(r1)+3].int()
		c = *prg.mem[int32(p)+6].int() + *prg.mem[int32(q)+6].int()

		// Compute the distance |d| from class~0 to the edge of the ellipse in direction |(u,v)|, times $\psqrt[u^2+v^2]$, rounded to the nearest integer
		delta = prg.pythAdd(u, v)
		if majorAxis == minorAxis {
			d = majorAxis
		} else {
			if theta == 0 {
				alpha = u
				beta = v
			} else {
				alpha = prg.takeFraction(u, prg.nCos) + prg.takeFraction(v, prg.nSin)
				beta = prg.takeFraction(v, prg.nCos) - prg.takeFraction(u, prg.nSin)
			}
			alpha = prg.makeFraction(alpha, delta)
			beta = prg.makeFraction(beta, delta)
			d = prg.pythAdd(prg.takeFraction(majorAxis, alpha), prg.takeFraction(minorAxis, beta))
		}
		alpha = abs(u)
		beta = abs(v)
		if alpha < beta {
			alpha = abs(v)
			beta = abs(u)
		} // now $\alpha=\max(\vert u\vert,\vert v\vert)$,
		//       $\beta=\min(\vert u\vert,\vert v\vert)$

		if prg.internal[fillin-1] != 0 {
			d = d - prg.takeFraction(prg.internal[fillin-1], prg.makeFraction(beta+beta, delta))
		}
		d = prg.takeFraction((d+4)/8, delta)
		alpha = alpha / 0100000
		if d < alpha {
			d = alpha
		}
		delta = c - d // we want to move |delta| steps back
		//       from the intersection vertex~|q|

		if delta > 0 {
			if delta > *prg.mem[int32(r1)+4].int() {
				delta = *prg.mem[int32(r1)+4].int()
			}
			if delta >= *prg.mem[int32(q)+4].int() {
				delta = *prg.mem[int32(q)+4].int()

				*prg.mem[int32(p)+6].int() = c - delta
				*prg.mem[int32(p)+5].int() = u
				*prg.mem[int32(q)+3].int() = v

				*prg.mem[int32(q)+1].int() = *prg.mem[int32(q)+1].int() - delta**prg.mem[int32(r1)+3].int()
				*prg.mem[int32(q)+2].int() = *prg.mem[int32(q)+2].int() + delta**prg.mem[int32(q)+5].int()

				*prg.mem[int32(r1)+4].int() = *prg.mem[int32(r1)+4].int() - delta
			} else {
				// Insert a new line for direction |(u,v)| between |p| and~|q|
				s = prg.getNode(knotNodeSize)
				*(*prg.mem[p].hh()).rh() = s
				*(*prg.mem[s].hh()).rh() = q

				*prg.mem[int32(s)+1].int() = *prg.mem[int32(q)+1].int() + delta**prg.mem[int32(q)+3].int()
				*prg.mem[int32(s)+2].int() = *prg.mem[int32(q)+2].int() - delta**prg.mem[int32(p)+5].int()

				*prg.mem[int32(q)+1].int() = *prg.mem[int32(q)+1].int() - delta**prg.mem[int32(r1)+3].int()
				*prg.mem[int32(q)+2].int() = *prg.mem[int32(q)+2].int() + delta**prg.mem[int32(q)+5].int()

				*prg.mem[int32(s)+3].int() = *prg.mem[int32(q)+3].int()
				*prg.mem[int32(s)+5].int() = u
				*prg.mem[int32(q)+3].int() = v

				*prg.mem[int32(s)+6].int() = c - delta

				*prg.mem[int32(s)+4].int() = *prg.mem[int32(q)+4].int() - delta
				*prg.mem[int32(q)+4].int() = delta
				*prg.mem[int32(r1)+4].int() = *prg.mem[int32(r1)+4].int() - delta
			}
		} else {
			p = q
		}

		// Move to the next remaining triple |(p,q,r)|, removing and skipping past zero-length lines that might be present; |goto done| if all triples have been processed
		for true {
			q = *(*prg.mem[p].hh()).rh()
			if int32(q) == memMin {
				goto done
			}
			if *prg.mem[int32(q)+4].int() == 0 {
				*(*prg.mem[p].hh()).rh() = *(*prg.mem[q].hh()).rh()
				*prg.mem[int32(p)+6].int() = *prg.mem[int32(q)+6].int()
				*prg.mem[int32(p)+5].int() = *prg.mem[int32(q)+5].int()
				prg.freeNode(q, halfword(knotNodeSize))
			} else {
				r1 = *(*prg.mem[q].hh()).rh()
				if int32(r1) == memMin {
					goto done
				}
				if *prg.mem[int32(r1)+4].int() == 0 {
					*(*prg.mem[p].hh()).rh() = r1
					prg.freeNode(q, halfword(knotNodeSize))
					p = r1
				} else {
					goto found
				}
			}
		}

	found:
	}

done:
	;
	if symmetric {
		s = uint16(memMin)
		q = h
		for true {
			r1 = prg.getNode(knotNodeSize)
			*(*prg.mem[r1].hh()).rh() = s
			s = r1

			*prg.mem[int32(s)+1].int() = *prg.mem[int32(q)+1].int()
			*prg.mem[int32(s)+2].int() = -*prg.mem[int32(q)+2].int()
			if int32(q) == int32(p) {
				goto done1
			}
			q = *(*prg.mem[q].hh()).rh()
			if *prg.mem[int32(q)+2].int() == 0 {
				goto done1
			}
		}

	done1:
		if int32(*(*prg.mem[p].hh()).rh()) != memMin {
			prg.freeNode(*(*prg.mem[p].hh()).rh(), halfword(knotNodeSize))
		}
		*(*prg.mem[p].hh()).rh() = s
		beta = -*prg.mem[int32(h)+2].int()
		for *prg.mem[int32(p)+2].int() != beta {
			p = *(*prg.mem[p].hh()).rh()
		}
		q = *(*prg.mem[p].hh()).rh()
	}

	// Complete the ellipse by copying the negative of the half already computed
	if int32(q) != memMin {
		if *prg.mem[int32(h)+5].int() == 0 {
			p = h
			h = *(*prg.mem[h].hh()).rh()
			prg.freeNode(p, halfword(knotNodeSize))

			*prg.mem[int32(q)+1].int() = -*prg.mem[int32(h)+1].int()
		}
		p = q
	} else {
		q = p
	}
	r1 = *(*prg.mem[h].hh()).rh() // now |p=q|, |x_coord(p)=-x_coord(h)|, |y_coord(p)=-y_coord(h)|
	for {
		s = prg.getNode(knotNodeSize)
		*(*prg.mem[p].hh()).rh() = s
		p = s

		*prg.mem[int32(p)+1].int() = -*prg.mem[int32(r1)+1].int()
		*prg.mem[int32(p)+2].int() = -*prg.mem[int32(r1)+2].int()
		r1 = *(*prg.mem[r1].hh()).rh()
		if int32(r1) == int32(q) {
			break
		}
	}
	*(*prg.mem[p].hh()).rh() = h
	r = h
	return r
}

// 538. \[26] Direction and intersection times

// tangle:pos ../../mf.web:11496:43:

// A path of length $n$ is defined parametrically by functions $x(t)$ and
// $y(t)$, for |0<=t<=n|; we can regard $t$ as the ``time'' at which the path
// reaches the point $\bigl(x(t),y(t)\bigr)$.  In this section of the program
// we shall consider operations that determine special times associated with
// given paths: the first time that a path travels in a given direction, and
// a pair of times at which two paths cross each other.

// 539.

// tangle:pos ../../mf.web:11504:3:

// Let's start with the easier task. The function |find_direction_time| is
// given a direction |(x,y)| and a path starting at~|h|. If the path never
// travels in direction |(x,y)|, the direction time will be~|-1|; otherwise
// it will be nonnegative.
//
// Certain anomalous cases can arise: If |(x,y)=(0,0)|, so that the given
// direction is undefined, the direction time will be~0. If $\bigl(x'(t),
// y'(t)\bigr)=(0,0)$, so that the path direction is undefined, it will be
// assumed to match any given direction at time~|t|.
//
// The routine solves this problem in nondegenerate cases by rotating the path
// and the given direction so that |(x,y)=(1,0)|; i.e., the main task will be
// to find when a given path first travels ``due east.''
func (prg *prg) findDirectionTime(x, y scaled, h halfword) (r scaled) {
	var (
		max  scaled   // $\max\bigl(\vert x\vert,\vert y\vert\bigr)$
		p, q halfword // for list traversal
		n    scaled   // the direction time at knot |p|
		tt   scaled   // the direction time within a cubic

		// Other local variables for |find_direction_time|
		x1, x2, x3, y1, y2, y3 scaled   // multiples of rotated derivatives
		theta, phi             angle    // angles of exit and entry at a knot
		t                      fraction // temp storage
	)
	if abs(x) < abs(y) {
		x = prg.makeFraction(x, abs(y))
		if y > 0 {
			y = 02000000000
		} else {
			y = -02000000000
		}
	} else if x == 0 {
		r = 0
		goto exit
	} else {
		y = prg.makeFraction(y, abs(x))
		if x > 0 {
			x = 02000000000
		} else {
			x = -02000000000
		}
	}
	n = 0
	p = h
	for true {
		if int32(*(*prg.mem[p].hh()).b1()) == endpoint {
			goto notFound
		}
		q = *(*prg.mem[p].hh()).rh()

		// Rotate the cubic between |p| and |q|; then |goto found| if the rotated cubic travels due east at some time |tt|; but |goto not_found| if an entire cyclic path has been traversed
		tt = 0

		// Set local variables |x1,x2,x3| and |y1,y2,y3| to multiples of the control points of the rotated derivatives
		x1 = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+1].int()
		x2 = *prg.mem[int32(q)+3].int() - *prg.mem[int32(p)+5].int()
		x3 = *prg.mem[int32(q)+1].int() - *prg.mem[int32(q)+3].int()

		y1 = *prg.mem[int32(p)+6].int() - *prg.mem[int32(p)+2].int()
		y2 = *prg.mem[int32(q)+4].int() - *prg.mem[int32(p)+6].int()
		y3 = *prg.mem[int32(q)+2].int() - *prg.mem[int32(q)+4].int()

		max = abs(x1)
		if abs(x2) > max {
			max = abs(x2)
		}
		if abs(x3) > max {
			max = abs(x3)
		}
		if abs(y1) > max {
			max = abs(y1)
		}
		if abs(y2) > max {
			max = abs(y2)
		}
		if abs(y3) > max {
			max = abs(y3)
		}
		if max == 0 {
			goto found
		}
		for max < 01000000000 {
			max = max + max
			x1 = x1 + x1
			x2 = x2 + x2
			x3 = x3 + x3
			y1 = y1 + y1
			y2 = y2 + y2
			y3 = y3 + y3
		}
		t = x1
		x1 = prg.takeFraction(x1, x) + prg.takeFraction(y1, y)
		y1 = prg.takeFraction(y1, x) - prg.takeFraction(t, y)

		t = x2
		x2 = prg.takeFraction(x2, x) + prg.takeFraction(y2, y)
		y2 = prg.takeFraction(y2, x) - prg.takeFraction(t, y)

		t = x3
		x3 = prg.takeFraction(x3, x) + prg.takeFraction(y3, y)
		y3 = prg.takeFraction(y3, x) - prg.takeFraction(t, y)
		if y1 == 0 {
			if x1 >= 0 {
				goto found
			}
		}
		if n > 0 {
			theta = prg.nArg(x1, y1)
			if theta >= 0 {
				if phi <= 0 {
					if phi >= theta-01320000000 {
						goto found
					}
				}
			}
			if theta <= 0 {
				if phi >= 0 {
					if phi <= theta+01320000000 {
						goto found
					}
				}
			}
			if int32(p) == int32(h) {
				goto notFound
			}
		}
		if x3 != 0 || y3 != 0 {
			phi = prg.nArg(x3, y3)
		}

		// Exit to |found| if the curve whose derivatives are specified by |x1,x2,x3,y1,y2,y3| travels eastward at some time~|tt|
		if x1 < 0 {
			if x2 < 0 {
				if x3 < 0 {
					goto done
				}
			}
		}
		if prg.abVsCd(y1, y3, y2, y2) == 0 {
			if prg.abVsCd(y1, y2, 0, 0) < 0 {
				t = prg.makeFraction(y1, y1-y2)
				x1 = x1 - prg.takeFraction(x1-x2, t)
				x2 = x2 - prg.takeFraction(x2-x3, t)
				if x1-prg.takeFraction(x1-x2, t) >= 0 {
					tt = (t + 04000) / 010000
					goto found
				}
			} else if y3 == 0 {
				if y1 == 0 {
					t = prg.crossingPoint(-x1, -x2, -x3)
					if t <= 02000000000 {
						tt = (t + 04000) / 010000
						goto found
					}
					if prg.abVsCd(x1, x3, x2, x2) <= 0 {
						t = prg.makeFraction(x1, x1-x2)
						{
							tt = (t + 04000) / 010000
							goto found
						}
					}
				} else if x3 >= 0 {
					tt = 0200000
					goto found
				}
			}

			goto done
		}
		if y1 <= 0 {
			if y1 < 0 {
				y1 = -y1
				y2 = -y2
				y3 = -y3
			} else if y2 > 0 {
				y2 = -y2
				y3 = -y3
			}
		}

		// Check the places where $B(y_1,y_2,y_3;t)=0$ to see if $B(x_1,x_2,x_3;t)\ge0$
		t = prg.crossingPoint(y1, y2, y3)
		if t > 02000000000 {
			goto done
		}
		y2 = y2 - prg.takeFraction(y2-y3, t)
		x1 = x1 - prg.takeFraction(x1-x2, t)
		x2 = x2 - prg.takeFraction(x2-x3, t)
		x1 = x1 - prg.takeFraction(x1-x2, t)
		if x1 >= 0 {
			tt = (t + 04000) / 010000
			goto found
		}
		if y2 > 0 {
			y2 = 0
		}
		tt = t
		t = prg.crossingPoint(0, -y2, -y3)
		if t > 02000000000 {
			goto done
		}
		x1 = x1 - prg.takeFraction(x1-x2, t)
		x2 = x2 - prg.takeFraction(x2-x3, t)
		if x1-prg.takeFraction(x1-x2, t) >= 0 {
			t = tt - prg.takeFraction(tt-02000000000, t)
			{
				tt = (t + 04000) / 010000
				goto found
			}
		}

	done:
		;
		p = q
		n = n + 0200000
	}

notFound:
	r = -0200000
	goto exit

found:
	r = n + tt

exit:
	;
	return r
}

// 545.

// tangle:pos ../../mf.web:11608:3:

// In this step we want to use the |crossing_point| routine to find the
// roots of the quadratic equation $B(y_1,y_2,y_3;t)=0$.
// Several complications arise: If the quadratic equation has a double root,
// the curve never crosses zero, and |crossing_point| will find nothing;
// this case occurs iff $y_1y_3=y_2^2$ and $y_1y_2<0$. If the quadratic
// equation has simple roots, or only one root, we may have to negate it
// so that $B(y_1,y_2,y_3;t)$ crosses from positive to negative at its first root.
// And finally, we need to do special things if $B(y_1,y_2,y_3;t)$ is
// identically zero.

// 550.

// tangle:pos ../../mf.web:11692:3:

// The intersection of two cubics can be found by an interesting variant
// of the general bisection scheme described in the introduction to |make_moves|.\
// Given $w(t)=B(w_0,w_1,w_2,w_3;t)$ and $z(t)=B(z_0,z_1,z_2,z_3;t)$,
// we wish to find a pair of times $(t_1,t_2)$ such that $w(t_1)=z(t_2)$,
// if an intersection exists. First we find the smallest rectangle that
// encloses the points $\[w_0,w_1,w_2,w_3\]$ and check that it overlaps
// the smallest rectangle that encloses
// $\[z_0,z_1,z_2,z_3\]$; if not, the cubics certainly don't intersect.
// But if the rectangles do overlap, we bisect the intervals, getting
// new cubics $w'$ and~$w''$, $z'$~and~$z''$; the intersection routine first
// tries for an intersection between $w'$ and~$z'$, then (if unsuccessful)
// between $w'$ and~$z''$, then (if still unsuccessful) between $w''$ and~$z'$,
// finally (if thrice unsuccessful) between $w''$ and~$z''$. After $l$~successful
// levels of bisection we will have determined the intersection times $t_1$
// and~$t_2$ to $l$~bits of accuracy.
//
// \def\submin[_[\rm min]] \def\submax[_[\rm max]]
// As before, it is better to work with the numbers $W_k=2^l(w_k-w_[k-1])$
// and $Z_k=2^l(z_k-z_[k-1])$ rather than the coefficients $w_k$ and $z_k$
// themselves. We also need one other quantity, $\Delta=2^l(w_0-z_0)$,
// to determine when the enclosing rectangles overlap. Here's why:
// The $x$~coordinates of~$w(t)$ are between $u\submin$ and $u\submax$,
// and the $x$~coordinates of~$z(t)$ are between $x\submin$ and $x\submax$,
// if we write $w_k=(u_k,v_k)$ and $z_k=(x_k,y_k)$ and $u\submin=
// \min(u_0,u_1,u_2,u_3)$, etc. These intervals of $x$~coordinates
// overlap if and only if $u\submin\L x\submax$ and
// $x\submin\L u\submax$. Letting
// $$U\submin=\min(0,U_1,U_1+U_2,U_1+U_2+U_3),\;
//   U\submax=\max(0,U_1,U_1+U_2,U_1+U_2+U_3),$$
// we have $2^lu\submin=2^lu_0+U\submin$, etc.; the condition for overlap
// reduces to
// $$X\submin-U\submax\L 2^l(u_0-x_0)\L X\submax-U\submin.$$
// Thus we want to maintain the quantity $2^l(u_0-x_0)$; similarly,
// the quantity $2^l(v_0-y_0)$ accounts for the $y$~coordinates. The
// coordinates of $\Delta=2^l(w_0-z_0)$ must stay bounded as $l$ increases,
// because of the overlap condition; i.e., we know that $X\submin$,
// $X\submax$, and their relatives are bounded, hence $X\submax-
// U\submin$ and $X\submin-U\submax$ are bounded.

// 551.

// tangle:pos ../../mf.web:11731:3:

// Incidentally, if the given cubics intersect more than once, the process
// just sketched will not necessarily find the lexicographically smallest pair
// $(t_1,t_2)$. The solution actually obtained will be smallest in ``shuffled
// order''; i.e., if $t_1=(.a_1a_2\ldots a_[16])_2$ and
// $t_2=(.b_1b_2\ldots b_[16])_2$, then we will minimize
// $a_1b_1a_2b_2\ldots a_[16]b_[16]$, not
// $a_1a_2\ldots a_[16]b_1b_2\ldots b_[16]$.
// Shuffled order agrees with lexicographic order if all pairs of solutions
// $(t_1,t_2)$ and $(t_1',t_2')$ have the property that $t_1<t_1'$ iff
// $t_2<t_2'$; but in general, lexicographic order can be quite different,
// and the bisection algorithm would be substantially less efficient if it were
// constrained by lexicographic order.
//
// For example, suppose that an overlap has been found for $l=3$ and
// $(t_1,t_2)= (.101,.011)$ in binary, but that no overlap is produced by
// either of the alternatives $(.1010,.0110)$, $(.1010,.0111)$ at level~4.
// Then there is probably an intersection in one of the subintervals
// $(.1011,.011x)$; but lexicographic order would require us to explore
// $(.1010,.1xxx)$ and $(.1011,.00xx)$ and $(.1011,.010x)$ first. We wouldn't
// want to store all of the subdivision data for the second path, so the
// subdivisions would have to be regenerated many times. Such inefficiencies
// would be associated with every `1' in the binary representation of~$t_1$.

// 554.

// tangle:pos ../../mf.web:11839:3:

// Computation of the min and max is a tedious but fairly fast sequence of
// instructions; exactly four comparisons are made in each branch.

// 556.

// tangle:pos ../../mf.web:11886:3:

// The given cubics $B(w_0,w_1,w_2,w_3;t)$ and
// $B(z_0,z_1,z_2,z_3;t)$ are specified in adjacent knot nodes |(p,link(p))|
// and |(pp,link(pp))|, respectively.
func (prg *prg) cubicIntersection(p, pp halfword) {
	var (
		q, qq halfword // |link(p)|, |link(pp)|
	)
	prg.timeToGo = maxPatience
	prg.maxT = 2

	// Initialize for intersections at level zero
	q = *(*prg.mem[p].hh()).rh()
	qq = *(*prg.mem[pp].hh()).rh()
	prg.bisectPtr = uint16(intPackets)

	prg.bisectStack[int32(prg.bisectPtr)-5] = *prg.mem[int32(p)+5].int() - *prg.mem[int32(p)+1].int()
	prg.bisectStack[int32(prg.bisectPtr)-5+1] = *prg.mem[int32(q)+3].int() - *prg.mem[int32(p)+5].int()
	prg.bisectStack[int32(prg.bisectPtr)-5+2] = *prg.mem[int32(q)+1].int() - *prg.mem[int32(q)+3].int()
	if prg.bisectStack[int32(prg.bisectPtr)-5] < 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-5+2] >= 0 {
			if prg.bisectStack[int32(prg.bisectPtr)-5+1] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
			} else {
				prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5]
			}
			prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
			if prg.bisectStack[int32(prg.bisectPtr)-5+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-5+4] = 0
			}
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
			if prg.bisectStack[int32(prg.bisectPtr)-5+3] > prg.bisectStack[int32(prg.bisectPtr)-5] {
				prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5]
			}
			prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
			if prg.bisectStack[int32(prg.bisectPtr)-5+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-5+4] = 0
			}
		}
	} else if prg.bisectStack[int32(prg.bisectPtr)-5+2] <= 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-5+1] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5]
		}
		prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
		if prg.bisectStack[int32(prg.bisectPtr)-5+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-5+3] = 0
		}
	} else {
		prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
		if prg.bisectStack[int32(prg.bisectPtr)-5+4] < prg.bisectStack[int32(prg.bisectPtr)-5] {
			prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5]
		}
		prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
		if prg.bisectStack[int32(prg.bisectPtr)-5+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-5+3] = 0
		}
	}

	prg.bisectStack[int32(prg.bisectPtr)-10] = *prg.mem[int32(p)+6].int() - *prg.mem[int32(p)+2].int()
	prg.bisectStack[int32(prg.bisectPtr)-10+1] = *prg.mem[int32(q)+4].int() - *prg.mem[int32(p)+6].int()
	prg.bisectStack[int32(prg.bisectPtr)-10+2] = *prg.mem[int32(q)+2].int() - *prg.mem[int32(q)+4].int()
	if prg.bisectStack[int32(prg.bisectPtr)-10] < 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-10+2] >= 0 {
			if prg.bisectStack[int32(prg.bisectPtr)-10+1] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
			} else {
				prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10]
			}
			prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
			if prg.bisectStack[int32(prg.bisectPtr)-10+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-10+4] = 0
			}
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
			if prg.bisectStack[int32(prg.bisectPtr)-10+3] > prg.bisectStack[int32(prg.bisectPtr)-10] {
				prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10]
			}
			prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
			if prg.bisectStack[int32(prg.bisectPtr)-10+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-10+4] = 0
			}
		}
	} else if prg.bisectStack[int32(prg.bisectPtr)-10+2] <= 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-10+1] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10]
		}
		prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
		if prg.bisectStack[int32(prg.bisectPtr)-10+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-10+3] = 0
		}
	} else {
		prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
		if prg.bisectStack[int32(prg.bisectPtr)-10+4] < prg.bisectStack[int32(prg.bisectPtr)-10] {
			prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10]
		}
		prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
		if prg.bisectStack[int32(prg.bisectPtr)-10+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-10+3] = 0
		}
	}

	prg.bisectStack[int32(prg.bisectPtr)-15] = *prg.mem[int32(pp)+5].int() - *prg.mem[int32(pp)+1].int()
	prg.bisectStack[int32(prg.bisectPtr)-15+1] = *prg.mem[int32(qq)+3].int() - *prg.mem[int32(pp)+5].int()
	prg.bisectStack[int32(prg.bisectPtr)-15+2] = *prg.mem[int32(qq)+1].int() - *prg.mem[int32(qq)+3].int()
	if prg.bisectStack[int32(prg.bisectPtr)-15] < 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-15+2] >= 0 {
			if prg.bisectStack[int32(prg.bisectPtr)-15+1] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
			} else {
				prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15]
			}
			prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
			if prg.bisectStack[int32(prg.bisectPtr)-15+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-15+4] = 0
			}
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
			if prg.bisectStack[int32(prg.bisectPtr)-15+3] > prg.bisectStack[int32(prg.bisectPtr)-15] {
				prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15]
			}
			prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
			if prg.bisectStack[int32(prg.bisectPtr)-15+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-15+4] = 0
			}
		}
	} else if prg.bisectStack[int32(prg.bisectPtr)-15+2] <= 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-15+1] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15]
		}
		prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
		if prg.bisectStack[int32(prg.bisectPtr)-15+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-15+3] = 0
		}
	} else {
		prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
		if prg.bisectStack[int32(prg.bisectPtr)-15+4] < prg.bisectStack[int32(prg.bisectPtr)-15] {
			prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15]
		}
		prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
		if prg.bisectStack[int32(prg.bisectPtr)-15+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-15+3] = 0
		}
	}

	prg.bisectStack[int32(prg.bisectPtr)-20] = *prg.mem[int32(pp)+6].int() - *prg.mem[int32(pp)+2].int()
	prg.bisectStack[int32(prg.bisectPtr)-20+1] = *prg.mem[int32(qq)+4].int() - *prg.mem[int32(pp)+6].int()
	prg.bisectStack[int32(prg.bisectPtr)-20+2] = *prg.mem[int32(qq)+2].int() - *prg.mem[int32(qq)+4].int()
	if prg.bisectStack[int32(prg.bisectPtr)-20] < 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-20+2] >= 0 {
			if prg.bisectStack[int32(prg.bisectPtr)-20+1] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
			} else {
				prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20]
			}
			prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
			if prg.bisectStack[int32(prg.bisectPtr)-20+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-20+4] = 0
			}
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
			if prg.bisectStack[int32(prg.bisectPtr)-20+3] > prg.bisectStack[int32(prg.bisectPtr)-20] {
				prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20]
			}
			prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
			if prg.bisectStack[int32(prg.bisectPtr)-20+4] < 0 {
				prg.bisectStack[int32(prg.bisectPtr)-20+4] = 0
			}
		}
	} else if prg.bisectStack[int32(prg.bisectPtr)-20+2] <= 0 {
		if prg.bisectStack[int32(prg.bisectPtr)-20+1] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
		} else {
			prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20]
		}
		prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
		if prg.bisectStack[int32(prg.bisectPtr)-20+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-20+3] = 0
		}
	} else {
		prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
		if prg.bisectStack[int32(prg.bisectPtr)-20+4] < prg.bisectStack[int32(prg.bisectPtr)-20] {
			prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20]
		}
		prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
		if prg.bisectStack[int32(prg.bisectPtr)-20+3] > 0 {
			prg.bisectStack[int32(prg.bisectPtr)-20+3] = 0
		}
	}

	prg.delx = *prg.mem[int32(p)+1].int() - *prg.mem[int32(pp)+1].int()
	prg.dely = *prg.mem[int32(p)+2].int() - *prg.mem[int32(pp)+2].int()

	prg.tol = 0
	prg.uv = prg.bisectPtr
	prg.xy = prg.bisectPtr
	prg.threeL = 0
	prg.curT = 1
	prg.curTt = 1
	for true {
	continue1:
		if prg.delx-prg.tol <= prg.bisectStack[int32(prg.xy)-15+4]-prg.bisectStack[int32(prg.uv)-5+3] {
			if prg.delx+prg.tol >= prg.bisectStack[int32(prg.xy)-15+3]-prg.bisectStack[int32(prg.uv)-5+4] {
				if prg.dely-prg.tol <= prg.bisectStack[int32(prg.xy)-20+4]-prg.bisectStack[int32(prg.uv)-10+3] {
					if prg.dely+prg.tol >= prg.bisectStack[int32(prg.xy)-20+3]-prg.bisectStack[int32(prg.uv)-10+4] {
						if prg.curT >= prg.maxT {
							if prg.maxT == 0400000 {
								prg.curT = (prg.curT + 1) / 2
								prg.curTt = (prg.curTt + 1) / 2
								goto exit
							}
							prg.maxT = prg.maxT + prg.maxT
							prg.apprT = prg.curT
							prg.apprTt = prg.curTt
						}

						// Subdivide for a new level of intersection
						prg.bisectStack[prg.bisectPtr] = prg.delx
						prg.bisectStack[int32(prg.bisectPtr)+1] = prg.dely
						prg.bisectStack[int32(prg.bisectPtr)+2] = prg.tol
						prg.bisectStack[int32(prg.bisectPtr)+3] = int32(prg.uv)
						prg.bisectStack[int32(prg.bisectPtr)+4] = int32(prg.xy)
						prg.bisectPtr = uint16(int32(prg.bisectPtr) + intIncrement)

						prg.curT = prg.curT + prg.curT
						prg.curTt = prg.curTt + prg.curTt

						prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] = prg.bisectStack[int32(prg.uv)-5]
						prg.bisectStack[int32(prg.bisectPtr)-5+2] = prg.bisectStack[int32(prg.uv)-5+2]
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.uv)-5+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-5+1] = (prg.bisectStack[int32(prg.bisectPtr)-5+2] + prg.bisectStack[int32(prg.uv)-5+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-5] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2]
						if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] > prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] < prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-5] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+1]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-5+3] = 0
							}
						}
						if prg.bisectStack[int32(prg.bisectPtr)-5] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-5+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-5+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5]
								}
								prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
								if prg.bisectStack[int32(prg.bisectPtr)-5+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-5+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
								if prg.bisectStack[int32(prg.bisectPtr)-5+3] > prg.bisectStack[int32(prg.bisectPtr)-5] {
									prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5]
								}
								prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
								if prg.bisectStack[int32(prg.bisectPtr)-5+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-5+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-5+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-5+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5]
							}
							prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
							if prg.bisectStack[int32(prg.bisectPtr)-5+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-5+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1] + prg.bisectStack[int32(prg.bisectPtr)-5+2]
							if prg.bisectStack[int32(prg.bisectPtr)-5+4] < prg.bisectStack[int32(prg.bisectPtr)-5] {
								prg.bisectStack[int32(prg.bisectPtr)-5+4] = prg.bisectStack[int32(prg.bisectPtr)-5]
							}
							prg.bisectStack[int32(prg.bisectPtr)-5+3] = prg.bisectStack[int32(prg.bisectPtr)-5] + prg.bisectStack[int32(prg.bisectPtr)-5+1]
							if prg.bisectStack[int32(prg.bisectPtr)-5+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-5+3] = 0
							}
						}

						prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] = prg.bisectStack[int32(prg.uv)-10]
						prg.bisectStack[int32(prg.bisectPtr)-10+2] = prg.bisectStack[int32(prg.uv)-10+2]
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.uv)-10+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-10+1] = (prg.bisectStack[int32(prg.bisectPtr)-10+2] + prg.bisectStack[int32(prg.uv)-10+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-10] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2]
						if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] > prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] < prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-10] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+1]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-10+3] = 0
							}
						}
						if prg.bisectStack[int32(prg.bisectPtr)-10] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-10+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-10+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10]
								}
								prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
								if prg.bisectStack[int32(prg.bisectPtr)-10+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-10+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
								if prg.bisectStack[int32(prg.bisectPtr)-10+3] > prg.bisectStack[int32(prg.bisectPtr)-10] {
									prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10]
								}
								prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
								if prg.bisectStack[int32(prg.bisectPtr)-10+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-10+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-10+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-10+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10]
							}
							prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
							if prg.bisectStack[int32(prg.bisectPtr)-10+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-10+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1] + prg.bisectStack[int32(prg.bisectPtr)-10+2]
							if prg.bisectStack[int32(prg.bisectPtr)-10+4] < prg.bisectStack[int32(prg.bisectPtr)-10] {
								prg.bisectStack[int32(prg.bisectPtr)-10+4] = prg.bisectStack[int32(prg.bisectPtr)-10]
							}
							prg.bisectStack[int32(prg.bisectPtr)-10+3] = prg.bisectStack[int32(prg.bisectPtr)-10] + prg.bisectStack[int32(prg.bisectPtr)-10+1]
							if prg.bisectStack[int32(prg.bisectPtr)-10+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-10+3] = 0
							}
						}

						prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] = prg.bisectStack[int32(prg.xy)-15]
						prg.bisectStack[int32(prg.bisectPtr)-15+2] = prg.bisectStack[int32(prg.xy)-15+2]
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.xy)-15+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-15+1] = (prg.bisectStack[int32(prg.bisectPtr)-15+2] + prg.bisectStack[int32(prg.xy)-15+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-15] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2]
						if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] > prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] < prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-15] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+1]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-15+3] = 0
							}
						}
						if prg.bisectStack[int32(prg.bisectPtr)-15] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-15+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-15+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15]
								}
								prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
								if prg.bisectStack[int32(prg.bisectPtr)-15+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-15+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
								if prg.bisectStack[int32(prg.bisectPtr)-15+3] > prg.bisectStack[int32(prg.bisectPtr)-15] {
									prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15]
								}
								prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
								if prg.bisectStack[int32(prg.bisectPtr)-15+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-15+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-15+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-15+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15]
							}
							prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
							if prg.bisectStack[int32(prg.bisectPtr)-15+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-15+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1] + prg.bisectStack[int32(prg.bisectPtr)-15+2]
							if prg.bisectStack[int32(prg.bisectPtr)-15+4] < prg.bisectStack[int32(prg.bisectPtr)-15] {
								prg.bisectStack[int32(prg.bisectPtr)-15+4] = prg.bisectStack[int32(prg.bisectPtr)-15]
							}
							prg.bisectStack[int32(prg.bisectPtr)-15+3] = prg.bisectStack[int32(prg.bisectPtr)-15] + prg.bisectStack[int32(prg.bisectPtr)-15+1]
							if prg.bisectStack[int32(prg.bisectPtr)-15+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-15+3] = 0
							}
						}

						prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] = prg.bisectStack[int32(prg.xy)-20]
						prg.bisectStack[int32(prg.bisectPtr)-20+2] = prg.bisectStack[int32(prg.xy)-20+2]
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.xy)-20+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-20+1] = (prg.bisectStack[int32(prg.bisectPtr)-20+2] + prg.bisectStack[int32(prg.xy)-20+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2] = (prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+1]) / 2
						prg.bisectStack[int32(prg.bisectPtr)-20] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2]
						if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] > prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20]
								}
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1]
								if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+2]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] < prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+4] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20]
							}
							prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = prg.bisectStack[int32(prg.bisectPtr)-intPackets-20] + prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+1]
							if prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-intPackets-20+3] = 0
							}
						}
						if prg.bisectStack[int32(prg.bisectPtr)-20] < 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-20+2] >= 0 {
								if prg.bisectStack[int32(prg.bisectPtr)-20+1] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
								} else {
									prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20]
								}
								prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
								if prg.bisectStack[int32(prg.bisectPtr)-20+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-20+4] = 0
								}
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
								if prg.bisectStack[int32(prg.bisectPtr)-20+3] > prg.bisectStack[int32(prg.bisectPtr)-20] {
									prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20]
								}
								prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
								if prg.bisectStack[int32(prg.bisectPtr)-20+4] < 0 {
									prg.bisectStack[int32(prg.bisectPtr)-20+4] = 0
								}
							}
						} else if prg.bisectStack[int32(prg.bisectPtr)-20+2] <= 0 {
							if prg.bisectStack[int32(prg.bisectPtr)-20+1] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
							} else {
								prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20]
							}
							prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
							if prg.bisectStack[int32(prg.bisectPtr)-20+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-20+3] = 0
							}
						} else {
							prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1] + prg.bisectStack[int32(prg.bisectPtr)-20+2]
							if prg.bisectStack[int32(prg.bisectPtr)-20+4] < prg.bisectStack[int32(prg.bisectPtr)-20] {
								prg.bisectStack[int32(prg.bisectPtr)-20+4] = prg.bisectStack[int32(prg.bisectPtr)-20]
							}
							prg.bisectStack[int32(prg.bisectPtr)-20+3] = prg.bisectStack[int32(prg.bisectPtr)-20] + prg.bisectStack[int32(prg.bisectPtr)-20+1]
							if prg.bisectStack[int32(prg.bisectPtr)-20+3] > 0 {
								prg.bisectStack[int32(prg.bisectPtr)-20+3] = 0
							}
						}

						prg.uv = uint16(int32(prg.bisectPtr) - intPackets)
						prg.xy = uint16(int32(prg.bisectPtr) - intPackets)
						prg.delx = prg.delx + prg.delx
						prg.dely = prg.dely + prg.dely

						prg.tol = prg.tol - prg.threeL + int32(prg.tolStep)
						prg.tol = prg.tol + prg.tol
						prg.threeL = prg.threeL + int32(prg.tolStep)

						goto continue1
					}
				}
			}
		}
		if prg.timeToGo > 0 {
			prg.timeToGo = prg.timeToGo - 1
		} else {
			for prg.apprT < 0200000 {
				prg.apprT = prg.apprT + prg.apprT
				prg.apprTt = prg.apprTt + prg.apprTt
			}
			prg.curT = prg.apprT
			prg.curTt = prg.apprTt
			goto exit
		}

		// Advance to the next pair |(cur_t,cur_tt)|

		// Advance to the next pair |(cur_t,cur_tt)|
	notFound:
		if prg.curTt&1 != 0 {
			if prg.curT&1 != 0 {
				prg.curT = prg.curT / 2
				prg.curTt = prg.curTt / 2
				if prg.curT == 0 {
					goto exit
				}
				prg.bisectPtr = uint16(int32(prg.bisectPtr) - intIncrement)
				prg.threeL = prg.threeL - int32(prg.tolStep)
				prg.delx = prg.bisectStack[prg.bisectPtr]
				prg.dely = prg.bisectStack[int32(prg.bisectPtr)+1]
				prg.tol = prg.bisectStack[int32(prg.bisectPtr)+2]
				prg.uv = uint16(prg.bisectStack[int32(prg.bisectPtr)+3])
				prg.xy = uint16(prg.bisectStack[int32(prg.bisectPtr)+4])

				goto notFound
			} else {
				prg.curT = prg.curT + 1
				prg.delx = prg.delx + prg.bisectStack[int32(prg.uv)-5] + prg.bisectStack[int32(prg.uv)-5+1] + prg.bisectStack[int32(prg.uv)-5+2]
				prg.dely = prg.dely + prg.bisectStack[int32(prg.uv)-10] + prg.bisectStack[int32(prg.uv)-10+1] + prg.bisectStack[int32(prg.uv)-10+2]
				prg.uv = uint16(int32(prg.uv) + intPackets) // switch from |l_packets| to |r_packets|
				prg.curTt = prg.curTt - 1
				prg.xy = uint16(int32(prg.xy) - intPackets) // switch from |r_packets| to |l_packets|
				prg.delx = prg.delx + prg.bisectStack[int32(prg.xy)-15] + prg.bisectStack[int32(prg.xy)-15+1] + prg.bisectStack[int32(prg.xy)-15+2]
				prg.dely = prg.dely + prg.bisectStack[int32(prg.xy)-20] + prg.bisectStack[int32(prg.xy)-20+1] + prg.bisectStack[int32(prg.xy)-20+2]
			}
		} else {
			prg.curTt = prg.curTt + 1
			prg.tol = prg.tol + prg.threeL
			prg.delx = prg.delx - prg.bisectStack[int32(prg.xy)-15] - prg.bisectStack[int32(prg.xy)-15+1] - prg.bisectStack[int32(prg.xy)-15+2]
			prg.dely = prg.dely - prg.bisectStack[int32(prg.xy)-20] - prg.bisectStack[int32(prg.xy)-20+1] - prg.bisectStack[int32(prg.xy)-20+2]
			prg.xy = uint16(int32(prg.xy) + intPackets) // switch from |l_packets| to |r_packets|
		}
	}

exit:
}

// 562.

// tangle:pos ../../mf.web:12006:3:

// The |path_intersection| procedure is much simpler.
// It invokes |cubic_intersection| in lexicographic order until finding a
// pair of cubics that intersect. The final intersection times are placed in
// |cur_t| and~|cur_tt|.
func (prg *prg) pathIntersection(h, hh halfword) {
	var (
		p, pp halfword // link registers that traverse the given paths
		n, nn int32    // integer parts of intersection times, minus |unity|
	)
	if int32(*(*prg.mem[h].hh()).b1()) == endpoint {
		*prg.mem[int32(h)+5].int() = *prg.mem[int32(h)+1].int()
		*prg.mem[int32(h)+3].int() = *prg.mem[int32(h)+1].int()
		*prg.mem[int32(h)+6].int() = *prg.mem[int32(h)+2].int()
		*prg.mem[int32(h)+4].int() = *prg.mem[int32(h)+2].int()
		*(*prg.mem[h].hh()).b1() = byte(explicit)
	}
	if int32(*(*prg.mem[hh].hh()).b1()) == endpoint {
		*prg.mem[int32(hh)+5].int() = *prg.mem[int32(hh)+1].int()
		*prg.mem[int32(hh)+3].int() = *prg.mem[int32(hh)+1].int()
		*prg.mem[int32(hh)+6].int() = *prg.mem[int32(hh)+2].int()
		*prg.mem[int32(hh)+4].int() = *prg.mem[int32(hh)+2].int()
		*(*prg.mem[hh].hh()).b1() = byte(explicit)
	}

	prg.tolStep = 0
	for {
		n = -0200000
		p = h
		for {
			if int32(*(*prg.mem[p].hh()).b1()) != endpoint {
				nn = -0200000
				pp = hh
				for {
					if int32(*(*prg.mem[pp].hh()).b1()) != endpoint {
						prg.cubicIntersection(p, pp)
						if prg.curT > 0 {
							prg.curT = prg.curT + n
							prg.curTt = prg.curTt + nn
							goto exit
						}
					}
					nn = nn + 0200000
					pp = *(*prg.mem[pp].hh()).rh()
					if int32(pp) == int32(hh) {
						break
					}
				}
			}
			n = n + 0200000
			p = *(*prg.mem[p].hh()).rh()
			if int32(p) == int32(h) {
				break
			}
		}
		prg.tolStep = byte(int32(prg.tolStep) + 3)
		if int32(prg.tolStep) > 3 {
			break
		}
	}
	prg.curT = -0200000
	prg.curTt = -0200000

exit:
}

// 564. \[27] Online graphic output

// tangle:pos ../../mf.web:12046:32:

// \MF\ displays images on the user's screen by means of a few primitive
// operations that are defined below. These operations have deliberately been
// kept simple so that they can be implemented without great difficulty on a
// wide variety of machines. Since \PASCAL\ has no traditional standards for
// graphic output, some system-dependent code needs to be written in order to
// support this aspect of \MF; but the necessary routines are usually quite
// easy to write.
// \xref[system dependencies]
//
// In fact, there are exactly four such routines:
//
// \yskip\hang
// |init_screen| does whatever initialization is necessary to
// support the other operations; it is a boolean function that returns
// |false| if graphic output cannot be supported (e.g., if the other three
// routines have not been written, or if the user doesn't have the
// right kind of terminal).
//
// \yskip\hang
// |blank_rectangle| updates a buffer area in memory so that
// all pixels in a specified rectangle will be set to the background color.
//
// \yskip\hang
// |paint_row| assigns values to specified pixels in a row of
// the buffer just mentioned, based on ``transition'' indices explained below.
//
// \yskip\hang
// |update_screen| displays the current screen buffer; the
// effects of |blank_rectangle| and |paint_row| commands may or may not
// become visible until the next |update_screen| operation is performed.
// (Thus, |update_screen| is analogous to |update_terminal|.)
//
// \yskip\noindent
// The \PASCAL\ code here is a minimum version of |init_screen| and
// |update_screen|, usable on \MF\ installations that don't
// support screen output. If |init_screen| is changed to return |true|
// instead of |false|, the other routines will simply log the fact
// that they have been called; they won't really display anything.
// The standard test routines for \MF\ use this log information to check
// that \MF\ is working properly, but the |wlog| instructions should be
// removed from production versions of \MF.
func (prg *prg) initScreen() (r bool) {
	r = true // screen instructions will be logged
	return r
}

func (prg *prg) updateScreen() {
	prg.logFile.Writeln("Calling UPDATESCREEN") // for testing only
}

// 567.

// tangle:pos ../../mf.web:12126:3:

// The |blank_rectangle| routine simply whitens all pixels that lie in
// columns |left_col| through |right_col-1|, inclusive, of rows
// |top_row| through |bot_row-1|, inclusive, given four parameters that satisfy
// the relations
// $$\hbox[|0<=left_col<=right_col<=screen_width|,\quad
//   |0<=top_row<=bot_row<=screen_depth|.]$$
// If |left_col=right_col| or |top_row=bot_row|, nothing happens.
//
// The commented-out code in the following procedure is for illustrative
// purposes only.
// \xref[system dependencies]
func (prg *prg) blankRectangle(leftCol, rightCol screenCol,
	topRow, botRow screenRow) {
	prg.logFile.Writeln() // this will be done only after |init_screen=true|
	prg.logFile.Writeln("Calling BLANKRECTANGLE(", leftCol, knuth.WriteWidth(1), ",", rightCol, knuth.WriteWidth(1), ",", topRow, knuth.WriteWidth(1), ",", botRow, knuth.WriteWidth(1), ")")
}

// 568.

// tangle:pos ../../mf.web:12150:3:

// The real work of screen display is done by |paint_row|. But it's not
// hard work, because the operation affects only
// one of the screen rows, and it affects only a contiguous set of columns
// in that row. There are four parameters: |r|~(the row),
// |b|~(the initial color),
// |a|~(the array of transition specifications),
// and |n|~(the number of transitions). The elements of~|a| will satisfy
// $$0\L a[0]<a[1]<\cdots<a[n]\L |screen_width|;$$
// the value of |r| will satisfy |0<=r<screen_depth|; and |n| will be positive.
//
// The general idea is to paint blocks of pixels in alternate colors;
// the precise details are best conveyed by means of a \PASCAL\
// program (see the commented-out code below).
// \xref[system dependencies]
func (prg *prg) paintRow(r1 screenRow, b pixelColor, a transSpec,
	n screenCol) {
	var (
		k screenCol // an index into |a|
	)
	prg.logFile.Write("Calling PAINTROW(", r1, knuth.WriteWidth(1), ",", b, knuth.WriteWidth(1), ";")
	// this is done only after |init_screen=true|
	for ii := int32(0); ii <= int32(n); ii++ {
		k = screenCol(ii)
		_ = k
		prg.logFile.Write(a[k], knuth.WriteWidth(1))
		if int32(k) != int32(n) {
			prg.logFile.Write(",")
		}
	}
	prg.logFile.Writeln(")")
}

// 574.

// tangle:pos ../../mf.web:12259:3:

// Opening a window isn't like opening a file, because you can open it
// as often as you like, and you never have to close it again. The idea is
// simply to define special points on the current screen display.
//
// Overlapping window specifications may cause complex effects that can
// be understood only by scrutinizing \MF's display algorithms; thus it
// has been left undefined in the \MF\ user manual, although the behavior
// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]
// is in fact predictable.
//
// Here is a subroutine that implements the command `\&[openwindow]~|k|
// \&[from]~$(\\[r0],\\[c0])$ \&[to]~$(\\[r1],\\[c1])$ \&[at]~$(x,y)$'.
func (prg *prg) openAWindow(k windowNumber, r0, c0, r11, c1 scaled,
	x, y scaled) {
	var (
		m, n int32 // pixel coordinates
	)
	if r0 < 0 {
		r0 = 0
	} else {
		r0 = prg.roundUnscaled(r0)
	}
	r11 = prg.roundUnscaled(r11)
	if r11 > screenDepth {
		r11 = screenDepth
	}
	if r11 < r0 {
		if r0 > screenDepth {
			r0 = r11
		} else {
			r11 = r0
		}
	}
	if c0 < 0 {
		c0 = 0
	} else {
		c0 = prg.roundUnscaled(c0)
	}
	c1 = prg.roundUnscaled(c1)
	if c1 > screenWidth {
		c1 = screenWidth
	}
	if c1 < c0 {
		if c0 > screenWidth {
			c0 = c1
		} else {
			c1 = c0
		}
	}
	prg.windowOpen[k] = true
	prg.windowTime[k] = prg.windowTime[k] + 1

	prg.leftCol[k] = byte(c0)
	prg.rightCol[k] = byte(c1)
	prg.topRow[k] = byte(r0)
	prg.botRow[k] = byte(r11)

	// Compute the offsets between screen coordinates and actual coordinates
	m = prg.roundUnscaled(x)
	n = prg.roundUnscaled(y) - 1

	prg.mWindow[k] = c0 - m
	prg.nWindow[k] = r0 + n
	{
		if !prg.screenStarted {
			prg.screenOk = prg.initScreen()
			prg.screenStarted = true
		}
	}
	if prg.screenOk {
		prg.blankRectangle(screenCol(c0), screenCol(c1), screenRow(r0), screenRow(r11))
		prg.updateScreen()
	}
}

// 577.

// tangle:pos ../../mf.web:12319:3:

// Now here comes \MF's most complicated operation related to window
// display: Given the number~|k| of an open window, the pixels of positive
// weight in |cur_edges| will be shown as |black| in the window; all other
// pixels will be shown as |white|.
func (prg *prg) dispEdges(k windowNumber) {
	var (
		p, q         halfword // for list manipulation
		alreadyThere bool     // is a previous incarnation in the window?
		r1           int32    // row number

		// Other local variables for |disp_edges|
		n           screenCol  // the highest active index in |row_transition|
		w, ww       int32      // old and new accumulated weights
		b           pixelColor // status of first pixel in the row transitions
		m, mm       int32      // old and new screen column positions
		d           int32      // edge-and-weight without |min_halfword| compensation
		mAdjustment int32      // conversion between edge and screen coordinates
		rightEdge   int32      // largest edge-and-weight that could affect the window
		minCol      screenCol  // the smallest screen column number in the window
	)
	if prg.screenOk {
		if int32(prg.leftCol[k]) < int32(prg.rightCol[k]) {
			if int32(prg.topRow[k]) < int32(prg.botRow[k]) {
				alreadyThere = false
				if int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).rh()) == int32(k) {
					if *prg.mem[int32(prg.curEdges)+4].int() == prg.windowTime[k] {
						alreadyThere = true
					}
				}
				if !alreadyThere {
					prg.blankRectangle(prg.leftCol[k], prg.rightCol[k], prg.topRow[k], prg.botRow[k])
				}

				// Initialize for the display computations
				mAdjustment = prg.mWindow[k] - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())

				rightEdge = 8 * (int32(prg.rightCol[k]) - mAdjustment)

				minCol = prg.leftCol[k]
				p = *(*prg.mem[prg.curEdges].hh()).rh()
				r1 = prg.nWindow[k] - (int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh()) - zeroField)
				for int32(p) != int32(prg.curEdges) && r1 >= int32(prg.topRow[k]) {
					if r1 < int32(prg.botRow[k]) {
						if int32(*(*prg.mem[int32(p)+1].hh()).lh()) > memMin+1 {
							prg.sortEdges(p)
						} else if int32(*(*prg.mem[int32(p)+1].hh()).lh()) == memMin+1 {
							if alreadyThere {
								goto done
							}
						}
						*(*prg.mem[int32(p)+1].hh()).lh() = uint16(memMin + 1) // this time we'll paint, but maybe not next time

						// Set up the parameters needed for |paint_row|; but |goto done| if no painting is needed after all
						n = 0
						ww = 0
						m = -1
						w = 0
						q = *(*prg.mem[int32(p)+1].hh()).rh()
						prg.rowTransition[0] = minCol
						for true {
							if int32(q) == 3000 {
								d = rightEdge
							} else {
								d = int32(*(*prg.mem[q].hh()).lh()) - 0
							}
							mm = d/8 + mAdjustment
							if mm != m {
								if w <= 0 {
									if ww > 0 {
										if m > int32(minCol) {
											if int32(n) == 0 {
												if alreadyThere {
													b = byte(white)
													n = byte(int32(n) + 1)
												} else {
													b = byte(black)
												}
											} else {
												n = byte(int32(n) + 1)
											}
											prg.rowTransition[n] = byte(m)
										}
									}
								} else if ww <= 0 {
									if m > int32(minCol) {
										if int32(n) == 0 {
											b = byte(black)
										}
										n = byte(int32(n) + 1)
										prg.rowTransition[n] = byte(m)
									}
								}
								m = mm
								w = ww
							}
							if d >= rightEdge {
								goto found
							}
							ww = ww + d%8 - zeroW
							q = *(*prg.mem[q].hh()).rh()
						}

					found:
						if alreadyThere || ww > 0 {
							if int32(n) == 0 {
								if ww > 0 {
									b = byte(black)
								} else {
									b = byte(white)
								}
							}
							n = byte(int32(n) + 1)
							prg.rowTransition[n] = prg.rightCol[k]
						} else if int32(n) == 0 {
							goto done
						}

						prg.paintRow(screenRow(r1), b, prg.rowTransition, n)

					done:
					}
					p = *(*prg.mem[p].hh()).rh()
					r1 = r1 - 1
				}
				prg.updateScreen()
				prg.windowTime[k] = prg.windowTime[k] + 1
				*(*prg.mem[int32(prg.curEdges)+3].hh()).rh() = uint16(k)
				*prg.mem[int32(prg.curEdges)+4].int() = prg.windowTime[k]
			}
		}
	}
}

// 588.

// tangle:pos ../../mf.web:12536:3:

// Actually the description above contains a little white lie. There's
// another kind of variable called |proto_dependent|, which is
// just like a |dependent| one except that the $\alpha$ coefficients
// in its dependency list are |scaled| instead of being fractions.
// Proto-dependency lists are mixed with dependency lists in the
// nodes reachable from |dep_head|.

// 591.

// tangle:pos ../../mf.web:12578:3:

// The maximum absolute value of a coefficient in a given dependency list
// is returned by the following simple function.
func (prg *prg) maxCoef(p halfword) (r fraction) {
	var (
		x fraction // the maximum so far
	)
	x = 0
	for int32(*(*prg.mem[p].hh()).lh()) != memMin {
		if abs(*prg.mem[int32(p)+1].int()) > x {
			x = abs(*prg.mem[int32(p)+1].int())
		}
		p = *(*prg.mem[p].hh()).rh()
	}
	r = x
	return r
}

// 597.

// tangle:pos ../../mf.web:12697:3:

// It is convenient to have another subroutine for the special case
// of |p_plus_fq| when |f=1.0|. In this routine lists |p| and |q| are
// both of the same type~|t| (either |dependent| or |proto_dependent|).
func (prg *prg) pPlusQ(p halfword, q halfword, t smallNumber) (r halfword) {
	var (
		pp, qq    halfword // |info(p)| and |info(q)|, respectively
		r1, s     halfword // for list manipulation
		threshold int32    // defines a neighborhood of zero
		v         int32    // temporary register
	)
	if int32(t) == dependent {
		threshold = fractionThreshold
	} else {
		threshold = scaledThreshold
	}
	r1 = uint16(3000 - 1)
	pp = *(*prg.mem[p].hh()).lh()
	qq = *(*prg.mem[q].hh()).lh()
	for true {
		if int32(pp) == int32(qq) {
			if int32(pp) == memMin {
				goto done
			} else {
				// Contribute a term from |p|, plus the corresponding term from |q|
				v = *prg.mem[int32(p)+1].int() + *prg.mem[int32(q)+1].int()
				*prg.mem[int32(p)+1].int() = v
				s = p
				p = *(*prg.mem[p].hh()).rh()
				pp = *(*prg.mem[p].hh()).lh()
				if abs(v) < threshold {
					prg.freeNode(s, halfword(depNodeSize))
				} else {
					if abs(v) >= 04525252525 {
						if prg.watchCoefs {
							*(*prg.mem[qq].hh()).b0() = byte(independentNeedingFix)
							prg.fixNeeded = true
						}
					}
					*(*prg.mem[r1].hh()).rh() = s
					r1 = s
				}
				q = *(*prg.mem[q].hh()).rh()
				qq = *(*prg.mem[q].hh()).lh()
			}
		} else if *prg.mem[int32(pp)+1].int() < *prg.mem[int32(qq)+1].int() {
			s = prg.getNode(depNodeSize)
			*(*prg.mem[s].hh()).lh() = qq
			*prg.mem[int32(s)+1].int() = *prg.mem[int32(q)+1].int()
			q = *(*prg.mem[q].hh()).rh()
			qq = *(*prg.mem[q].hh()).lh()
			*(*prg.mem[r1].hh()).rh() = s
			r1 = s
		} else {
			*(*prg.mem[r1].hh()).rh() = p
			r1 = p
			p = *(*prg.mem[p].hh()).rh()
			pp = *(*prg.mem[p].hh()).lh()
		}
	}

done:
	*prg.mem[int32(p)+1].int() = prg.slowAdd(*prg.mem[int32(p)+1].int(), *prg.mem[int32(q)+1].int())
	*(*prg.mem[r1].hh()).rh() = p
	prg.depFinal = p
	r = *(*prg.mem[3000-1].hh()).rh()
	return r
}

// 599.

// tangle:pos ../../mf.web:12736:3:

// A somewhat simpler routine will multiply a dependency list
// by a given constant~|v|. The constant is either a |fraction| less than
// |fraction_one|, or it is |scaled|. In the latter case we might be forced to
// convert a dependency list to a proto-dependency list.
// Parameters |t0| and |t1| are the list types before and after;
// they should agree unless |t0=dependent| and |t1=proto_dependent|
// and |v_is_scaled=true|.
func (prg *prg) pTimesV(p halfword, v int32,
	t0, t1 smallNumber, vIsScaled bool) (r halfword) {
	var (
		r1, s       halfword // for list manipulation
		w           int32    // tentative coefficient
		threshold   int32
		scalingDown bool
	)
	if int32(t0) != int32(t1) {
		scalingDown = true
	} else {
		scalingDown = !vIsScaled
	}
	if int32(t1) == dependent {
		threshold = halfFractionThreshold
	} else {
		threshold = halfScaledThreshold
	}
	r1 = uint16(3000 - 1)
	for int32(*(*prg.mem[p].hh()).lh()) != memMin {
		if scalingDown {
			w = prg.takeFraction(v, *prg.mem[int32(p)+1].int())
		} else {
			w = prg.takeScaled(v, *prg.mem[int32(p)+1].int())
		}
		if abs(w) <= threshold {
			s = *(*prg.mem[p].hh()).rh()
			prg.freeNode(p, halfword(depNodeSize))
			p = s
		} else {
			if abs(w) >= 04525252525 {
				prg.fixNeeded = true
				*(*prg.mem[*(*prg.mem[p].hh()).lh()].hh()).b0() = byte(independentNeedingFix)
			}
			*(*prg.mem[r1].hh()).rh() = p
			r1 = p
			*prg.mem[int32(p)+1].int() = w
			p = *(*prg.mem[p].hh()).rh()
		}
	}
	*(*prg.mem[r1].hh()).rh() = p
	if vIsScaled {
		*prg.mem[int32(p)+1].int() = prg.takeScaled(*prg.mem[int32(p)+1].int(), v)
	} else {
		*prg.mem[int32(p)+1].int() = prg.takeFraction(*prg.mem[int32(p)+1].int(), v)
	}
	r = *(*prg.mem[3000-1].hh()).rh()
	return r
}

// 601.

// tangle:pos ../../mf.web:12804:3:

// Here's another utility routine for dependency lists. When an independent
// variable becomes dependent, we want to remove it from all existing
// dependencies. The |p_with_x_becoming_q| function computes the
// dependency list of~|p| after variable~|x| has been replaced by~|q|.
//
// This procedure has basically the same calling conventions as |p_plus_fq|:
// List~|q| is unchanged; list~|p| is destroyed; the constant node and the
// final link are inherited from~|p|; and the fourth parameter tells whether
// or not |p| is |proto_dependent|. However, the global variable |dep_final|
// is not altered if |x| does not occur in list~|p|.
func (prg *prg) pWithXBecomingQ(p, x, q halfword, t smallNumber) (r halfword) {
	var (
		r1, s halfword // for list manipulation
		v     int32    // coefficient of |x|
		sx    int32    // serial number of |x|
	)
	s = p
	r1 = uint16(3000 - 1)
	sx = *prg.mem[int32(x)+1].int()
	for *prg.mem[int32(*(*prg.mem[s].hh()).lh())+1].int() > sx {
		r1 = s
		s = *(*prg.mem[s].hh()).rh()
	}
	if int32(*(*prg.mem[s].hh()).lh()) != int32(x) {
		r = p
	} else {
		*(*prg.mem[3000-1].hh()).rh() = p
		*(*prg.mem[r1].hh()).rh() = *(*prg.mem[s].hh()).rh()
		v = *prg.mem[int32(s)+1].int()
		prg.freeNode(s, halfword(depNodeSize))
		r = prg.pPlusFq(*(*prg.mem[3000-1].hh()).rh(), v, q, t, smallNumber(dependent))
	}
	return r
}

// 606.

// tangle:pos ../../mf.web:12916:3:

// The |new_dep| routine installs a dependency list~|p| into the value node~|q|,
// linking it into the list of all known dependencies. We assume that
// |dep_final| points to the final node of list~|p|.
func (prg *prg) newDep(q, p halfword) {
	var (
		r1 halfword // what used to be the first dependency
	)
	*(*prg.mem[int32(q)+1].hh()).rh() = p
	*(*prg.mem[int32(q)+1].hh()).lh() = uint16(memMin + 3 + 10)
	r1 = *(*prg.mem[memMin+3+10].hh()).rh()
	*(*prg.mem[prg.depFinal].hh()).rh() = r1
	*(*prg.mem[int32(r1)+1].hh()).lh() = prg.depFinal
	*(*prg.mem[memMin+3+10].hh()).rh() = q
}

// 607.

// tangle:pos ../../mf.web:12927:3:

// Here is one of the ways a dependency list gets started.
// The |const_dependency| routine produces a list that has nothing but
// a constant term.
func (prg *prg) constDependency(v scaled) (r halfword) {
	prg.depFinal = prg.getNode(depNodeSize)
	*prg.mem[int32(prg.depFinal)+1].int() = v
	*(*prg.mem[prg.depFinal].hh()).lh() = uint16(memMin)
	r = prg.depFinal
	return r
}

// 608.

// tangle:pos ../../mf.web:12937:3:

// And here's a more interesting way to start a dependency list from scratch:
// The parameter to |single_dependency| is the location of an
// independent variable~|x|, and the result is the simple dependency list
// `|x+0|'.
//
// In the unlikely event that the given independent variable has been doubled so
// often that we can't refer to it with a nonzero coefficient,
// |single_dependency| returns the simple list `0'.  This case can be
// recognized by testing that the returned list pointer is equal to
// |dep_final|.
func (prg *prg) singleDependency(p halfword) (r halfword) {
	var (
		q halfword // the new dependency list
		m int32    // the number of doublings
	)
	m = *prg.mem[int32(p)+1].int() % sScale
	if m > 28 {
		r = prg.constDependency(scaled(0))
	} else {
		q = prg.getNode(depNodeSize)
		*prg.mem[int32(q)+1].int() = prg.twoToThe[28-m]
		*(*prg.mem[q].hh()).lh() = p

		*(*prg.mem[q].hh()).rh() = prg.constDependency(scaled(0))
		r = q
	}
	return r
}

// 609.

// tangle:pos ../../mf.web:12959:3:

// We sometimes need to make an exact copy of a dependency list.
func (prg *prg) copyDepList(p halfword) (r halfword) {
	var (
		q halfword // the new dependency list
	)
	q = prg.getNode(depNodeSize)
	prg.depFinal = q
	for true {
		*(*prg.mem[prg.depFinal].hh()).lh() = *(*prg.mem[p].hh()).lh()
		*prg.mem[int32(prg.depFinal)+1].int() = *prg.mem[int32(p)+1].int()
		if int32(*(*prg.mem[prg.depFinal].hh()).lh()) == memMin {
			goto done
		}
		*(*prg.mem[prg.depFinal].hh()).rh() = prg.getNode(depNodeSize)
		prg.depFinal = *(*prg.mem[prg.depFinal].hh()).rh()
		p = *(*prg.mem[p].hh()).rh()
	}

done:
	r = q
	return r
}

// 610.

// tangle:pos ../../mf.web:12973:3:

// But how do variables normally become known? Ah, now we get to the heart of the
// equation-solving mechanism. The |linear_eq| procedure is given a |dependent|
// or |proto_dependent| list,~|p|, in which at least one independent variable
// appears. It equates this list to zero, by choosing an independent variable
// with the largest coefficient and making it dependent on the others. The
// newly dependent variable is eliminated from all current dependencies,
// thereby possibly making other dependent variables known.
//
// The given list |p| is, of course, totally destroyed by all this processing.
func (prg *prg) linearEq(p halfword, t smallNumber) {
	var (
		q, r1, s  halfword // for link manipulation
		x         halfword // the variable that loses its independence
		n         int32    // the number of times |x| had been halved
		v         int32    // the coefficient of |x| in list |p|
		prevR     halfword // lags one step behind |r|
		finalNode halfword // the constant term of the new dependency list
		w         int32    // a tentative coefficient
	)
	q = p
	r1 = *(*prg.mem[p].hh()).rh()
	v = *prg.mem[int32(q)+1].int()
	for int32(*(*prg.mem[r1].hh()).lh()) != memMin {
		if abs(*prg.mem[int32(r1)+1].int()) > abs(v) {
			q = r1
			v = *prg.mem[int32(r1)+1].int()
		}
		r1 = *(*prg.mem[r1].hh()).rh()
	}
	x = *(*prg.mem[q].hh()).lh()
	n = *prg.mem[int32(x)+1].int() % sScale

	// Divide list |p| by |-v|, removing node |q|
	s = uint16(3000 - 1)
	*(*prg.mem[s].hh()).rh() = p
	r1 = p
	for {
		if int32(r1) == int32(q) {
			*(*prg.mem[s].hh()).rh() = *(*prg.mem[r1].hh()).rh()
			prg.freeNode(r1, halfword(depNodeSize))
		} else {
			w = prg.makeFraction(*prg.mem[int32(r1)+1].int(), v)
			if abs(w) <= halfFractionThreshold {
				*(*prg.mem[s].hh()).rh() = *(*prg.mem[r1].hh()).rh()
				prg.freeNode(r1, halfword(depNodeSize))
			} else {
				*prg.mem[int32(r1)+1].int() = -w
				s = r1
			}
		}
		r1 = *(*prg.mem[s].hh()).rh()
		if int32(*(*prg.mem[r1].hh()).lh()) == memMin {
			break
		}
	}
	if int32(t) == protoDependent {
		*prg.mem[int32(r1)+1].int() = -prg.makeScaled(*prg.mem[int32(r1)+1].int(), v)
	} else if v != -02000000000 {
		*prg.mem[int32(r1)+1].int() = -prg.makeFraction(*prg.mem[int32(r1)+1].int(), v)
	}
	finalNode = r1
	p = *(*prg.mem[3000-1].hh()).rh()
	if prg.internal[tracingEquations-1] > 0 {
		if prg.interesting(x) {
			prg.beginDiagnostic()
			prg.printNl(strNumber( /* "## " */ 596))
			prg.printVariableName(x)
			// \xref[]]]\#\#_][\.[\#\#]]
			w = n
			for w > 0 {
				prg.print( /* "*4" */ 589)
				w = w - 2
			}
			prg.printChar(asciiCode('='))
			prg.printDependency(p, smallNumber(dependent))
			prg.endDiagnostic(false)
		}
	}

	// Simplify all existing dependencies by substituting for |x|
	prevR = uint16(memMin + 3 + 10)
	r1 = *(*prg.mem[memMin+3+10].hh()).rh()
	for int32(r1) != memMin+3+10 {
		s = *(*prg.mem[int32(r1)+1].hh()).rh()
		q = prg.pWithXBecomingQ(s, x, p, *(*prg.mem[r1].hh()).b0())
		if int32(*(*prg.mem[q].hh()).lh()) == memMin {
			prg.makeKnown(r1, q)
		} else {
			*(*prg.mem[int32(r1)+1].hh()).rh() = q
			for {
				q = *(*prg.mem[q].hh()).rh()
				if int32(*(*prg.mem[q].hh()).lh()) == memMin {
					break
				}
			}
			prevR = q
		}
		r1 = *(*prg.mem[prevR].hh()).rh()
	}

	// Change variable |x| from |independent| to |dependent| or |known|
	if n > 0 {
		s = uint16(3000 - 1)
		*(*prg.mem[3000-1].hh()).rh() = p
		r1 = p
		for {
			if n > 30 {
				w = 0
			} else {
				w = *prg.mem[int32(r1)+1].int() / prg.twoToThe[n]
			}
			if abs(w) <= halfFractionThreshold && int32(*(*prg.mem[r1].hh()).lh()) != memMin {
				*(*prg.mem[s].hh()).rh() = *(*prg.mem[r1].hh()).rh()
				prg.freeNode(r1, halfword(depNodeSize))
			} else {
				*prg.mem[int32(r1)+1].int() = w
				s = r1
			}
			r1 = *(*prg.mem[s].hh()).rh()
			if int32(*(*prg.mem[s].hh()).lh()) == memMin {
				break
			}
		}
		p = *(*prg.mem[3000-1].hh()).rh()
	}
	if int32(*(*prg.mem[p].hh()).lh()) == memMin {
		*(*prg.mem[x].hh()).b0() = byte(known)
		*prg.mem[int32(x)+1].int() = *prg.mem[int32(p)+1].int()
		if abs(*prg.mem[int32(x)+1].int()) >= 02000000000 {
			prg.valTooBig(*prg.mem[int32(x)+1].int())
		}
		prg.freeNode(p, halfword(depNodeSize))
		if prg.curExp == int32(x) {
			if int32(prg.curType) == independent {
				prg.curExp = *prg.mem[int32(x)+1].int()
				prg.curType = byte(known)
				prg.freeNode(x, halfword(valueNodeSize))
			}
		}
	} else {
		*(*prg.mem[x].hh()).b0() = byte(dependent)
		prg.depFinal = finalNode
		prg.newDep(x, p)
		if prg.curExp == int32(x) {
			if int32(prg.curType) == independent {
				prg.curType = byte(dependent)
			}
		}
	}
	if prg.fixNeeded {
		prg.fixDependencies()
	}
}

// 618. \[29] Dynamic nonlinear equations

// tangle:pos ../../mf.web:13105:38:

// Variables of numeric type are maintained by the general scheme of
// independent, dependent, and known values that we have just studied;
// and the components of pair and transform variables are handled in the
// same way. But \MF\ also has five other types of values: \&[boolean],
// \&[string], \&[pen], \&[path], and \&[picture]; what about them?
//
// Equations are allowed between nonlinear quantities, but only in a
// simple form. Two variables that haven't yet been assigned values are
// either equal to each other, or they're not.
//
// Before a boolean variable has received a value, its type is |unknown_boolean|;
// similarly, there are variables whose type is |unknown_string|, |unknown_pen|,
// |unknown_path|, and |unknown_picture|. In such cases the value is either
// |null| (which means that no other variables are equivalent to this one), or
// it points to another variable of the same undefined type. The pointers in the
// latter case form a cycle of nodes, which we shall call a ``ring.''
// Rings of undefined variables may include capsules, which arise as
// intermediate results within expressions or as \&[expr] parameters to macros.
//
// When one member of a ring receives a value, the same value is given to
// all the other members. In the case of paths and pictures, this implies
// making separate copies of a potentially large data structure; users should
// restrain their enthusiasm for such generality, unless they have lots and
// lots of memory space.

// 619.

// tangle:pos ../../mf.web:13131:3:

// The following procedure is called when a capsule node is being
// added to a ring (e.g., when an unknown variable is mentioned in an expression).
func (prg *prg) newRingEntry(p halfword) (r halfword) {
	var (
		q halfword // the new capsule node
	)
	q = prg.getNode(valueNodeSize)
	*(*prg.mem[q].hh()).b1() = byte(capsule)
	*(*prg.mem[q].hh()).b0() = *(*prg.mem[p].hh()).b0()
	if *prg.mem[int32(p)+1].int() == memMin {
		*prg.mem[int32(q)+1].int() = int32(p)
	} else {
		*prg.mem[int32(q)+1].int() = *prg.mem[int32(p)+1].int()
	}
	*prg.mem[int32(p)+1].int() = int32(q)
	r = q
	return r
}

// 621.

// tangle:pos ../../mf.web:13157:3:

// Eventually there might be an equation that assigns values to all of the
// variables in a ring. The |nonlinear_eq| subroutine does the necessary
// propagation of values.
//
// If the parameter |flush_p| is |true|, node |p| itself needn't receive a
// value; it will soon be recycled.
func (prg *prg) nonlinearEq(v int32, p halfword, flushP bool) {
	var (
		t     smallNumber // the type of ring |p|
		q, r1 halfword    // link manipulation registers
	)
	t = byte(int32(*(*prg.mem[p].hh()).b0()) - unknownTag)
	q = uint16(*prg.mem[int32(p)+1].int())
	if flushP {
		*(*prg.mem[p].hh()).b0() = byte(vacuous)
	} else {
		p = q
	}
	for {
		r1 = uint16(*prg.mem[int32(q)+1].int())
		*(*prg.mem[q].hh()).b0() = t
		switch t {
		case booleanType:
			*prg.mem[int32(q)+1].int() = v
		case stringType:
			*prg.mem[int32(q)+1].int() = v
			{
				if int32(prg.strRef[v]) < maxStrRef {
					prg.strRef[v] = byte(int32(prg.strRef[v]) + 1)
				}
			}

		case penType:
			*prg.mem[int32(q)+1].int() = v
			*(*prg.mem[v].hh()).lh() = uint16(int32(*(*prg.mem[v].hh()).lh()) + 1)

		case pathType:
			*prg.mem[int32(q)+1].int() = int32(prg.copyPath(halfword(v)))
		case pictureType:
			*prg.mem[int32(q)+1].int() = int32(prg.copyEdges(halfword(v)))
		} // there ain't no more cases
		q = r1
		if int32(q) == int32(p) {
			break
		}
	}
}

// 622.

// tangle:pos ../../mf.web:13183:3:

// If two members of rings are equated, and if they have the same type,
// the |ring_merge| procedure is called on to make them equivalent.
func (prg *prg) ringMerge(p, q halfword) {
	var (
		r1 halfword // traverses one list
	)
	r1 = uint16(*prg.mem[int32(p)+1].int())
	for int32(r1) != int32(p) {
		if int32(r1) == int32(q) {
			{
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Redundant equation" */ 599) /* \xref[!\relax]  */
				}

				// \xref[Redundant equation]
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "I already knew that this equation was true." */ 600
					prg.helpLine[0] = /* "But perhaps no harm has been done; let's continue." */ 601
				}

				prg.putGetError()
			}

			goto exit
		}
		r1 = uint16(*prg.mem[int32(r1)+1].int())
	}
	r1 = uint16(*prg.mem[int32(p)+1].int())
	*prg.mem[int32(p)+1].int() = *prg.mem[int32(q)+1].int()
	*prg.mem[int32(q)+1].int() = int32(r1)

exit:
}

// 626.

// tangle:pos ../../mf.web:13271:3:

// Here is a procedure that displays a given command in braces, in the
// user's transcript file.
func (prg *prg) showCmdMod(c, m int32) {
	prg.beginDiagnostic()
	prg.printNl(strNumber('{'))
	prg.printCmdMod(c, m)
	prg.printChar(asciiCode('}'))
	prg.endDiagnostic(false)
} // \2

func (prg *prg) showContext() {
	var (
		oldSetting/* 0..maxSelector */ byte // saved |selector| setting

		// Local variables for formatting calculations
		i/* 0..bufSize */ uint16       // index into |buffer|
		l                        int32 // length of descriptive information on line 1
		m                        int32 // context information gathered for line 2
		n/* 0..errorLine */ byte       // length of line 1
		p                        int32 // starting or ending place in |trick_buf|
		q                        int32 // temporary index
	)
	prg.filePtr = prg.inputPtr
	prg.inputStack[prg.filePtr] = prg.curInput
	// store current state
	for true {
		prg.curInput = prg.inputStack[prg.filePtr] // enter into the context

		// Display the current context
		if int32(prg.filePtr) == int32(prg.inputPtr) || int32(prg.curInput.indexField) <= maxInOpen || int32(prg.curInput.indexField) != backedUp || int32(prg.curInput.locField) != memMin {
			prg.tally = 0 // get ready to count characters
			oldSetting = prg.selector
			if int32(prg.curInput.indexField) <= maxInOpen {
				if int32(prg.curInput.nameField) <= 1 {
					if int32(prg.curInput.nameField) == 0 && int32(prg.filePtr) == 0 {
						prg.printNl(strNumber( /* "<*>" */ 603))
					} else {
						prg.printNl(strNumber( /* "<insert>" */ 604))
					}
				} else if int32(prg.curInput.nameField) == 2 {
					prg.printNl(strNumber( /* "<scantokens>" */ 605))
				} else {
					prg.printNl(strNumber( /* "l." */ 606))
					prg.printInt(prg.line)
				}
				prg.printChar(asciiCode(' '))

				// Pseudoprint the line
				{
					l = prg.tally
					prg.tally = 0
					prg.selector = byte(pseudo)
					prg.trickCount = 1000000
				}
				if int32(prg.curInput.limitField) > 0 {
					for ii := int32(prg.curInput.startField); ii <= int32(prg.curInput.limitField)-1; ii++ {
						i = uint16(ii)
						_ = i
						if int32(i) == int32(prg.curInput.locField) {
							prg.firstCount = prg.tally
							prg.trickCount = prg.tally + 1 + errorLine - halfErrorLine
							if prg.trickCount < errorLine {
								prg.trickCount = errorLine
							}
						}
						prg.print(int32(prg.buffer[i]))
					}
				}
			} else {
				switch prg.curInput.indexField {
				case foreverText:
					prg.printNl(strNumber( /* "<forever> " */ 607))
				case loopText:
					// Print the current loop value
					prg.printNl(strNumber( /* "<for(" */ 612))
					p = int32(prg.paramStack[prg.curInput.limitField])
					if p != memMin {
						if int32(*(*prg.mem[p].hh()).rh()) == memMin+1 {
							prg.printExp(halfword(p), smallNumber(0))
						} else {
							prg.showTokenList(p, memMin, 20, prg.tally)
						}
					}
					prg.print( /* ")> " */ 613)

				case parameter:
					prg.printNl(strNumber( /* "<argument> " */ 608))
				case backedUp:
					if int32(prg.curInput.locField) == memMin {
						prg.printNl(strNumber( /* "<recently read> " */ 609))
					} else {
						prg.printNl(strNumber( /* "<to be read again> " */ 610))
					}
				case inserted:
					prg.printNl(strNumber( /* "<inserted text> " */ 611))
				case macro:
					prg.printLn()
					if int32(prg.curInput.nameField) != memMin {
						prg.slowPrint(int32(*prg.hash[prg.curInput.nameField-1].rh()))
					} else {
						// Print the name of a \&[vardef]'d macro
						p = int32(prg.paramStack[prg.curInput.limitField])
						if p == memMin {
							prg.showTokenList(int32(prg.paramStack[int32(prg.curInput.limitField)+1]), memMin, 20, prg.tally)
						} else {
							q = p
							for int32(*(*prg.mem[q].hh()).rh()) != memMin {
								q = int32(*(*prg.mem[q].hh()).rh())
							}
							*(*prg.mem[q].hh()).rh() = prg.paramStack[int32(prg.curInput.limitField)+1]
							prg.showTokenList(p, memMin, 20, prg.tally)
							*(*prg.mem[q].hh()).rh() = uint16(memMin)
						}
					}
					prg.print( /* "->" */ 501)

				default:
					prg.printNl(strNumber('?')) // this should never happen
					// \xref[?\relax]
				}

				// Pseudoprint the token list
				{
					l = prg.tally
					prg.tally = 0
					prg.selector = byte(pseudo)
					prg.trickCount = 1000000
				}
				if int32(prg.curInput.indexField) != macro {
					prg.showTokenList(int32(prg.curInput.startField), int32(prg.curInput.locField), 100000, 0)
				} else {
					prg.showMacro(prg.curInput.startField, int32(prg.curInput.locField), 100000)
				}
			}
			prg.selector = oldSetting // stop pseudoprinting

			// Print two lines using the tricky pseudoprinted information
			if prg.trickCount == 1000000 {
				prg.firstCount = prg.tally
				prg.trickCount = prg.tally + 1 + errorLine - halfErrorLine
				if prg.trickCount < errorLine {
					prg.trickCount = errorLine
				}
			}
			// |set_trick_count| must be performed
			if prg.tally < prg.trickCount {
				m = prg.tally - prg.firstCount
			} else {
				m = prg.trickCount - prg.firstCount
			} // context on line 2
			if l+prg.firstCount <= halfErrorLine {
				p = 0
				n = byte(l + prg.firstCount)
			} else {
				prg.print( /* "..." */ 276)
				p = l + prg.firstCount - halfErrorLine + 3
				n = byte(halfErrorLine)
			}
			for ii := p; ii <= prg.firstCount-1; ii++ {
				q = ii
				_ = q
				prg.printChar(prg.trickBuf[q%errorLine])
			}
			prg.printLn()
			for ii := int32(1); ii <= int32(n); ii++ {
				q = ii
				_ = q
				prg.printChar(asciiCode(' '))
			} // print |n| spaces to begin line~2
			if m+int32(n) <= errorLine {
				p = prg.firstCount + m
			} else {
				p = prg.firstCount + (errorLine - int32(n) - 3)
			}
			for ii := prg.firstCount; ii <= p-1; ii++ {
				q = ii
				_ = q
				prg.printChar(prg.trickBuf[q%errorLine])
			}
			if m+int32(n) > errorLine {
				prg.print( /* "..." */ 276)
			}
		}
		if int32(prg.curInput.indexField) <= maxInOpen {
			if int32(prg.curInput.nameField) > 2 || int32(prg.filePtr) == 0 {
				goto done
			}
		}
		prg.filePtr = byte(int32(prg.filePtr) - 1)
	}

done:
	prg.curInput = prg.inputStack[prg.inputPtr] // restore original state
}

// 642.

// tangle:pos ../../mf.web:13601:3:

// The following code tells the print routines to gather
// the desired information.

// 647. \[32] Maintaining the input stacks

// tangle:pos ../../mf.web:13655:39:

// The following subroutines change the input status in commonly needed ways.
//
// First comes |push_input|, which stores the current state and creates a
// new level (having, initially, the same properties as the old).

// 648.

// tangle:pos ../../mf.web:13671:3:

// And of course what goes up must come down.

// 649.

// tangle:pos ../../mf.web:13677:3:

// Here is a procedure that starts a new level of token-list input, given
// a token list |p| and its type |t|. If |t=macro|, the calling routine should
// set |name|, reset~|loc|, and increase the macro's reference count.
func (prg *prg) beginTokenList(p halfword, t quarterword) {
	{
		if int32(prg.inputPtr) > int32(prg.maxInStack) {
			prg.maxInStack = prg.inputPtr
			if int32(prg.inputPtr) == stackSize {
				prg.overflow(strNumber( /* "input stack size" */ 614), stackSize)
			} /* \xref[METAFONT capacity exceeded input stack size][\quad input stack size]  */
		}
		prg.inputStack[prg.inputPtr] = prg.curInput
		prg.inputPtr = byte(int32(prg.inputPtr) + 1)
	}
	prg.curInput.startField = p
	prg.curInput.indexField = t
	prg.curInput.limitField = uint16(prg.paramPtr)
	prg.curInput.locField = p
}

// 650.

// tangle:pos ../../mf.web:13688:3:

// When a token list has been fully scanned, the following computations
// should be done as we leave that level of input.
// \xref[inner loop]
func (prg *prg) endTokenList() {
	var (
		p halfword // temporary register
	)
	if int32(prg.curInput.indexField) >= backedUp {
		if int32(prg.curInput.indexField) <= inserted {
			prg.flushTokenList(prg.curInput.startField)
			goto done
		} else {
			prg.deleteMacRef(prg.curInput.startField)
		}
	} // update reference count
	for int32(prg.paramPtr) > int32(prg.curInput.limitField) { // parameters must be flushed
		prg.paramPtr = byte(int32(prg.paramPtr) - 1)
		p = prg.paramStack[prg.paramPtr]
		if int32(p) != memMin {
			if int32(*(*prg.mem[p].hh()).rh()) == memMin+1 {
				prg.recycleValue(p)
				prg.freeNode(p, halfword(valueNodeSize))
			} else {
				prg.flushTokenList(p)
			}
		} // it's a \&[suffix] or \&[text] parameter
	}

done:
	{
		prg.inputPtr = byte(int32(prg.inputPtr) - 1)
		prg.curInput = prg.inputStack[prg.inputPtr]
	}
	{
		if prg.interrupt != 0 {
			prg.pauseForInstructions()
		}
	}
}

// 651.

// tangle:pos ../../mf.web:13712:3:

// The contents of |cur_cmd,cur_mod,cur_sym| are placed into an equivalent
// token by the |cur_tok| routine.
// \xref[inner loop]
// \4
// Declare the procedure called |make_exp_copy|
// \4
// Declare subroutines needed by |make_exp_copy|
func (prg *prg) encapsulate(p halfword) {
	prg.curExp = int32(prg.getNode(valueNodeSize))
	*(*prg.mem[prg.curExp].hh()).b0() = prg.curType
	*(*prg.mem[prg.curExp].hh()).b1() = byte(capsule)
	prg.newDep(halfword(prg.curExp), p)
}

func (prg *prg) install(r1, q halfword) {
	var (
		p halfword // temporary register
	)
	if int32(*(*prg.mem[q].hh()).b0()) == known {
		*prg.mem[int32(r1)+1].int() = *prg.mem[int32(q)+1].int()
		*(*prg.mem[r1].hh()).b0() = byte(known)
	} else if int32(*(*prg.mem[q].hh()).b0()) == independent {
		p = prg.singleDependency(q)
		if int32(p) == int32(prg.depFinal) {
			*(*prg.mem[r1].hh()).b0() = byte(known)
			*prg.mem[int32(r1)+1].int() = 0
			prg.freeNode(p, halfword(depNodeSize))
		} else {
			*(*prg.mem[r1].hh()).b0() = byte(dependent)
			prg.newDep(r1, p)
		}
	} else {
		*(*prg.mem[r1].hh()).b0() = *(*prg.mem[q].hh()).b0()
		prg.newDep(r1, prg.copyDepList(*(*prg.mem[int32(q)+1].hh()).rh()))
	}
}

func (prg *prg) makeExpCopy(p halfword) {
	var (
		q, r1, t halfword // registers for list manipulation
	)
restart:
	prg.curType = *(*prg.mem[p].hh()).b0()
	switch prg.curType {
	case vacuous, booleanType, known:
		prg.curExp = *prg.mem[int32(p)+1].int()
	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath:
		prg.curExp = int32(prg.newRingEntry(p))
	case stringType:
		prg.curExp = *prg.mem[int32(p)+1].int()
		{
			if int32(prg.strRef[prg.curExp]) < maxStrRef {
				prg.strRef[prg.curExp] = byte(int32(prg.strRef[prg.curExp]) + 1)
			}
		}

	case penType:
		prg.curExp = *prg.mem[int32(p)+1].int()
		*(*prg.mem[prg.curExp].hh()).lh() = uint16(int32(*(*prg.mem[prg.curExp].hh()).lh()) + 1)

	case pictureType:
		prg.curExp = int32(prg.copyEdges(halfword(*prg.mem[int32(p)+1].int())))
	case pathType, futurePen:
		prg.curExp = int32(prg.copyPath(halfword(*prg.mem[int32(p)+1].int())))
	case transformType, pairType:
		// Copy the big node |p|
		if *prg.mem[int32(p)+1].int() == memMin {
			prg.initBigNode(p)
		}
		t = prg.getNode(valueNodeSize)
		*(*prg.mem[t].hh()).b1() = byte(capsule)
		*(*prg.mem[t].hh()).b0() = prg.curType
		prg.initBigNode(t)

		q = uint16(*prg.mem[int32(p)+1].int() + int32(prg.bigNodeSize[prg.curType-13]))
		r1 = uint16(*prg.mem[int32(t)+1].int() + int32(prg.bigNodeSize[prg.curType-13]))
		for {
			q = uint16(int32(q) - 2)
			r1 = uint16(int32(r1) - 2)
			prg.install(r1, q)
			if int32(q) == *prg.mem[int32(p)+1].int() {
				break
			}
		}
		prg.curExp = int32(t)

	case dependent, protoDependent:
		prg.encapsulate(prg.copyDepList(*(*prg.mem[int32(p)+1].hh()).rh()))
	case numericType:
		{
			if prg.serialNo > 017777777777-sScale {
				prg.overflow(strNumber( /* "independent variables" */ 587), prg.serialNo/sScale)
			} /* \xref[METAFONT capacity exceeded independent variables][\quad independent variables]  */
			*(*prg.mem[p].hh()).b0() = byte(independent)
			prg.serialNo = prg.serialNo + sScale
			*prg.mem[int32(p)+1].int() = prg.serialNo
		}
		goto restart

	case independent:
		q = prg.singleDependency(p)
		if int32(q) == int32(prg.depFinal) {
			prg.curType = byte(known)
			prg.curExp = 0
			prg.freeNode(q, halfword(depNodeSize))
		} else {
			prg.curType = byte(dependent)
			prg.encapsulate(q)
		}

	default:
		prg.confusion(strNumber( /* "copy" */ 800))
		// \xref[this can't happen copy][\quad copy]
	}
}

func (prg *prg) curTok() (r halfword) {
	var (
		p        halfword    // a new token node
		saveType smallNumber // |cur_type| to be restored
		saveExp  int32       // |cur_exp| to be restored
	)
	if int32(prg.curSym) == 0 {
		if int32(prg.curCmd) == capsuleToken {
			saveType = prg.curType
			saveExp = prg.curExp
			prg.makeExpCopy(halfword(prg.curMod))
			p = prg.stashCurExp()
			*(*prg.mem[p].hh()).rh() = uint16(memMin)
			prg.curType = saveType
			prg.curExp = saveExp
		} else {
			p = prg.getNode(tokenNodeSize)
			*prg.mem[int32(p)+1].int() = prg.curMod
			*(*prg.mem[p].hh()).b1() = byte(token)
			if int32(prg.curCmd) == numericToken {
				*(*prg.mem[p].hh()).b0() = byte(known)
			} else {
				*(*prg.mem[p].hh()).b0() = byte(stringType)
			}
		}
	} else {
		{
			p = prg.avail
			if int32(p) == memMin {
				p = prg.getAvail()
			} else {
				prg.avail = *(*prg.mem[p].hh()).rh()
				*(*prg.mem[p].hh()).rh() = uint16(memMin)
				prg.dynUsed = prg.dynUsed + 1
			}
		}
		*(*prg.mem[p].hh()).lh() = prg.curSym
	}
	r = p
	return r
}

// 652.

// tangle:pos ../../mf.web:13737:3:

// Sometimes \MF\ has read too far and wants to ``unscan'' what it has
// seen. The |back_input| procedure takes care of this by putting the token
// just scanned back into the input stream, ready to be read again.
// If |cur_sym<>0|, the values of |cur_cmd| and |cur_mod| are irrelevant.
func (prg *prg) backInput() { // undoes one token of input
	var (
		p halfword // a token list of length one
	)
	p = prg.curTok()
	for int32(prg.curInput.indexField) > maxInOpen && int32(prg.curInput.locField) == memMin {
		prg.endTokenList()
	} // conserve stack space
	prg.beginTokenList(p, quarterword(backedUp))
}

func (prg *prg) backError() {
	prg.okToInterrupt = false
	prg.backInput()
	prg.okToInterrupt = true
	prg.error1()
}

func (prg *prg) insError() {
	prg.okToInterrupt = false
	prg.backInput()
	prg.curInput.indexField = byte(inserted)
	prg.okToInterrupt = true
	prg.error1()
} // \2

func (prg *prg) beginFileReading() {
	if int32(prg.inOpen) == maxInOpen {
		prg.overflow(strNumber( /* "text input levels" */ 615), maxInOpen)
	}
	// \xref[METAFONT capacity exceeded text input levels][\quad text input levels]
	if int32(prg.first) == bufSize {
		prg.overflow(strNumber( /* "buffer size" */ 256), bufSize)
	}
	// \xref[METAFONT capacity exceeded buffer size][\quad buffer size]
	prg.inOpen = byte(int32(prg.inOpen) + 1) /*   */
	{
		if int32(prg.inputPtr) > int32(prg.maxInStack) {
			prg.maxInStack = prg.inputPtr
			if int32(prg.inputPtr) == stackSize {
				prg.overflow(strNumber( /* "input stack size" */ 614), stackSize)
			} /* \xref[METAFONT capacity exceeded input stack size][\quad input stack size]  */
		}
		prg.inputStack[prg.inputPtr] = prg.curInput
		prg.inputPtr = byte(int32(prg.inputPtr) + 1)
	}
	prg.curInput.indexField = prg.inOpen
	prg.lineStack[prg.curInput.indexField-1] = prg.line
	prg.curInput.startField = prg.first
	prg.curInput.nameField = 0 // |terminal_input| is now |true|
}

// 655.

// tangle:pos ../../mf.web:13778:3:

// Conversely, the variables must be downdated when such a level of input
// is finished:
func (prg *prg) endFileReading() {
	prg.first = prg.curInput.startField
	prg.line = prg.lineStack[prg.curInput.indexField-1]
	if int32(prg.curInput.indexField) != int32(prg.inOpen) {
		prg.confusion(strNumber( /* "endinput" */ 616))
	}
	// \xref[this can't happen endinput][\quad endinput]
	if int32(prg.curInput.nameField) > 2 {
		prg.aClose(prg.inputFile[prg.curInput.indexField-1])
	} // forget it
	//
	{
		prg.inputPtr = byte(int32(prg.inputPtr) - 1)
		prg.curInput = prg.inputStack[prg.inputPtr]
	}
	prg.inOpen = byte(int32(prg.inOpen) - 1)
} // \2

func (prg *prg) clearForErrorPrompt() {
	for int32(prg.curInput.indexField) <= maxInOpen && int32(prg.curInput.nameField) == 0 && int32(prg.inputPtr) > 0 && int32(prg.curInput.locField) == int32(prg.curInput.limitField) {
		prg.endFileReading()
	}
	prg.printLn()
}

// 658. \[33] Getting the next token

// tangle:pos ../../mf.web:13813:33:

// The heart of \MF's input mechanism is the |get_next| procedure, which
// we shall develop in the next few sections of the program. Perhaps we
// shouldn't actually call it the ``heart,'' however; it really acts as \MF's
// eyes and mouth, reading the source files and gobbling them up. And it also
// helps \MF\ to regurgitate stored token lists that are to be processed again.
//
// The main duty of |get_next| is to input one token and to set |cur_cmd|
// and |cur_mod| to that token's command code and modifier. Furthermore, if
// the input token is a symbolic token, that token's |hash| address
// is stored in |cur_sym|; otherwise |cur_sym| is set to zero.
//
// Underlying this simple description is a certain amount of complexity
// because of all the cases that need to be handled.
// However, the inner loop of |get_next| is reasonably short and fast.

// 661.

// tangle:pos ../../mf.web:13856:3:

// The following subroutine
// is called when an `\&[outer]' symbolic token has been scanned or
// when the end of a file has been reached. These two cases are distinguished
// by |cur_sym|, which is zero at the end of a file.
func (prg *prg) checkOuterValidity() (r bool) {
	var (
		p halfword // points to inserted token list
	)
	if int32(prg.scannerStatus) == normal {
		r = true
	} else {
		prg.deletionsAllowed = false

		// Back up an outer symbolic token so that it can be reread
		if int32(prg.curSym) != 0 {
			p = prg.getAvail()
			*(*prg.mem[p].hh()).lh() = prg.curSym
			prg.beginTokenList(p, quarterword(backedUp)) // prepare to read the symbolic token again
		}
		if int32(prg.scannerStatus) > skipping {
			prg.runaway() // print the definition-so-far
			if int32(prg.curSym) == 0 {
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "File ended" */ 622) /* \xref[!\relax]  */
			} else {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Forbidden token found" */ 623) /* \xref[!\relax]  */
				}
				// \xref[Forbidden token found...]
			}
			prg.print( /* " while scanning " */ 624)
			{
				prg.helpPtr = 4
				prg.helpLine[3] = /* "I suspect you have forgotten an `enddef'," */ 625
				prg.helpLine[2] = /* "causing me to read past where you wanted me to stop." */ 626
				prg.helpLine[1] = /* "I'll try to recover; but if the error is serious," */ 627
				prg.helpLine[0] = /* "you'd better type `E' or `X' now and fix your file." */ 628
			}

			switch prg.scannerStatus {
			case flushing:
				prg.print( /* "to the end of the statement" */ 629)
				prg.helpLine[3] = /* "A previous error seems to have propagated," */ 630
				prg.curSym = uint16(hashBase + hashSize + 6)

			case absorbing:
				prg.print( /* "a text argument" */ 631)
				prg.helpLine[3] = /* "It seems that a right delimiter was left out," */ 632
				if prg.warningInfo == 0 {
					prg.curSym = uint16(hashBase + hashSize + 10)
				} else {
					prg.curSym = uint16(hashBase + hashSize + 2)
					*prg.eqtb[hashBase+hashSize+2-1].rh() = uint16(prg.warningInfo)
				}

			case varDefining, opDefining:
				prg.print( /* "the definition of " */ 633)
				if int32(prg.scannerStatus) == opDefining {
					prg.slowPrint(int32(*prg.hash[prg.warningInfo-1].rh()))
				} else {
					prg.printVariableName(halfword(prg.warningInfo))
				}
				prg.curSym = uint16(hashBase + hashSize + 8)

			case loopDefining:
				prg.print( /* "the text of a " */ 634)
				prg.slowPrint(int32(*prg.hash[prg.warningInfo-1].rh()))
				prg.print( /* " loop" */ 635)
				prg.helpLine[3] = /* "I suspect you have forgotten an `endfor'," */ 636
				prg.curSym = uint16(hashBase + hashSize + 7)

			} // there are no other cases
			prg.insError()
		} else {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Incomplete if; all text was ignored after line " */ 617) /* \xref[!\relax]  */
			}
			// \xref[Incomplete if...]
			prg.printInt(prg.warningInfo)

			{
				prg.helpPtr = 3
				prg.helpLine[2] = /* "A forbidden `outer' token occurred in skipped text." */ 618
				prg.helpLine[1] = /* "This kind of error happens when you say `if...' and forget" */ 619
				prg.helpLine[0] = /* "the matching `fi'. I've inserted a `fi'; this might work." */ 620
			}
			if int32(prg.curSym) == 0 {
				prg.helpLine[2] =
					/* "The file ended while I was skipping conditional text." */ 621
			}
			prg.curSym = uint16(hashBase + hashSize + 9)
			prg.insError()
		}
		prg.deletionsAllowed = true
		r = false
	}
	return r
} // \2

func (prg *prg) getNext() {
	// go here at crucial stages when scanning a number
	var (
		k/* 0..bufSize */ uint16           // an index into |buffer|
		c                        asciiCode // the current character in the buffer
		class                    asciiCode // its class number
		n, f                     int32     // registers for decimal-to-binary conversion
	)
restart:
	prg.curSym = 0
	if int32(prg.curInput.indexField) <= maxInOpen {
	switch1:
		c = prg.buffer[prg.curInput.locField]
		prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
		class = prg.charClass[c]
		switch class {
		case digitClass:
			goto startNumericToken
		case periodClass:
			class = prg.charClass[prg.buffer[prg.curInput.locField]]
			if int32(class) > periodClass {
				goto switch1
			} else if int32(class) < periodClass {
				n = 0
				goto startDecimalToken
			}
		// \xref[. ][\..\ token]

		case spaceClass:
			goto switch1
		case percentClass:
			if int32(prg.curInput.nameField) > 2 {
				prg.line = prg.line + 1
				prg.first = prg.curInput.startField
				if !prg.forceEof {
					if prg.inputLn(prg.inputFile[prg.curInput.indexField-1], true) {
						prg.firmUpTheLine()
					} else {
						prg.forceEof = true
					}
				}
				if prg.forceEof {
					prg.printChar(asciiCode(')'))
					prg.openParens = byte(int32(prg.openParens) - 1)
					// show user that file has been read
					prg.forceEof = false
					prg.endFileReading() // resume previous level
					if prg.checkOuterValidity() {
						goto restart
					} else {
						goto restart
					}
				}
				prg.buffer[prg.curInput.limitField] = '%'
				prg.first = uint16(int32(prg.curInput.limitField) + 1)
				prg.curInput.locField = prg.curInput.startField // ready to read
			} else {
				if int32(prg.inputPtr) > 0 {
					prg.endFileReading()
					goto restart // resume previous level
				}
				if int32(prg.selector) < logOnly {
					prg.openLogFile()
				}
				if int32(prg.interaction) > nonstopMode {
					if int32(prg.curInput.limitField) == int32(prg.curInput.startField) {
						prg.printNl(strNumber( /* "(Please type a command or say `end')" */ 651))
					}
					// \xref[Please type...]
					prg.printLn()
					prg.first = prg.curInput.startField
					{
						prg.print('*')
						prg.termInput()
					} // input on-line into |buffer|
					// \xref[*\relax]
					prg.curInput.limitField = prg.last
					prg.buffer[prg.curInput.limitField] = '%'
					prg.first = uint16(int32(prg.curInput.limitField) + 1)
					prg.curInput.locField = prg.curInput.startField
				} else {
					prg.fatalError(strNumber( /* "*** (job aborted, no legal end found)" */ 652))
				}
				// \xref[job aborted]
				// nonstop mode, which is intended for overnight batch processing,
				//     never waits for on-line input

			}
			{
				if prg.interrupt != 0 {
					prg.pauseForInstructions()
				}
			}

			goto switch1

		case stringClass:
			// Get a string token and |return|
			if int32(prg.buffer[prg.curInput.locField]) == '"' {
				prg.curMod = /* "" */ 285
			} else {
				k = prg.curInput.locField
				prg.buffer[int32(prg.curInput.limitField)+1] = '"'
				for {
					prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
					if int32(prg.buffer[prg.curInput.locField]) == '"' {
						break
					}
				}
				if int32(prg.curInput.locField) > int32(prg.curInput.limitField) {
					prg.curInput.locField = prg.curInput.limitField // the next character to be read on this line will be |"%"|
					{
						if int32(prg.interaction) == errorStopMode {
						}
						prg.printNl(strNumber( /* "! " */ 261))
						prg.print( /* "Incomplete string token has been flushed" */ 644) /* \xref[!\relax]  */
					}
					// \xref[Incomplete string token...]
					{
						prg.helpPtr = 3
						prg.helpLine[2] = /* "Strings should finish on the same line as they began." */ 645
						prg.helpLine[1] = /* "I've deleted the partial string; you might want to" */ 646
						prg.helpLine[0] = /* "insert another by typing, e.g., `I\"new string\"'." */ 647
					}

					prg.deletionsAllowed = false
					prg.error1()
					prg.deletionsAllowed = true
					goto restart
				}
				if int32(prg.curInput.locField) == int32(k)+1 && int32(prg.strStart[int32(prg.buffer[k])+1])-int32(prg.strStart[prg.buffer[k]]) == 1 {
					prg.curMod = int32(prg.buffer[k])
				} else {
					{
						if int32(prg.poolPtr)+int32(prg.curInput.locField)-int32(k) > int32(prg.maxPoolPtr) {
							if int32(prg.poolPtr)+int32(prg.curInput.locField)-int32(k) > poolSize {
								prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
							} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
							prg.maxPoolPtr = uint16(int32(prg.poolPtr) + int32(prg.curInput.locField) - int32(k))
						}
					}
					for {
						{
							prg.strPool[prg.poolPtr] = prg.buffer[k]
							prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
						}
						k = uint16(int32(k) + 1)
						if int32(k) == int32(prg.curInput.locField) {
							break
						}
					}
					prg.curMod = int32(prg.makeString())
				}
			}
			prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
			prg.curCmd = byte(stringToken)
			goto exit

		case 5, 6, 7, 8:
			k = uint16(int32(prg.curInput.locField) - 1)
			goto found

		case invalidClass:
			// Decry the invalid character and |goto restart|
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Text line contains an invalid character" */ 641) /* \xref[!\relax]  */
			}
			// \xref[Text line contains...]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "A funny symbol that I can't read has just been input." */ 642
				prg.helpLine[0] = /* "Continue, and I'll forget that it ever happened." */ 643
			}

			prg.deletionsAllowed = false
			prg.error1()
			prg.deletionsAllowed = true

			goto restart

		default: // letters, etc.
		}

		k = uint16(int32(prg.curInput.locField) - 1)
		for int32(prg.charClass[prg.buffer[prg.curInput.locField]]) == int32(class) {
			prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
		}

		goto found

	startNumericToken:
		n = int32(c) - '0'
		for int32(prg.charClass[prg.buffer[prg.curInput.locField]]) == digitClass {
			if n < 4096 {
				n = 10*n + int32(prg.buffer[prg.curInput.locField]) - '0'
			}
			prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
		}
		if int32(prg.buffer[prg.curInput.locField]) == '.' {
			if int32(prg.charClass[prg.buffer[int32(prg.curInput.locField)+1]]) == digitClass {
				goto done
			}
		}
		f = 0
		goto finNumericToken

	done:
		prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)

	startDecimalToken:
		k = 0
		for {
			if int32(k) < 17 {
				prg.dig[k] = byte(int32(prg.buffer[prg.curInput.locField]) - '0')
				k = uint16(int32(k) + 1)
			}
			prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
			if int32(prg.charClass[prg.buffer[prg.curInput.locField]]) != digitClass {
				break
			}
		}
		f = prg.roundDecimals(smallNumber(k))
		if f == 0200000 {
			n = n + 1
			f = 0
		}

	finNumericToken:
		if n < 4096 {
			prg.curMod = n*0200000 + f
		} else {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Enormous number has been reduced" */ 648) /* \xref[!\relax]  */
			}
			// \xref[Enormous number...]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I can't handle numbers bigger than about 4095.99998;" */ 649
				prg.helpLine[0] = /* "so I've changed your constant to that maximum amount." */ 650
			}

			prg.deletionsAllowed = false
			prg.error1()
			prg.deletionsAllowed = true
			prg.curMod = 01777777777
		}
		prg.curCmd = byte(numericToken)
		goto exit

	found:
		prg.curSym = prg.idLookup(int32(k), int32(prg.curInput.locField)-int32(k))
	} else if int32(prg.curInput.locField) >= int32(prg.hiMemMin) {
		prg.curSym = *(*prg.mem[prg.curInput.locField].hh()).lh()
		prg.curInput.locField = *(*prg.mem[prg.curInput.locField].hh()).rh() // move to next
		if int32(prg.curSym) >= hashBase+hashSize+12+1 {
			if int32(prg.curSym) >= hashBase+hashSize+12+1+paramSize {
				if int32(prg.curSym) >= hashBase+hashSize+12+1+paramSize+paramSize {
					prg.curSym = uint16(int32(prg.curSym) - paramSize)
				}
				// |param_size=text_base-suffix_base|
				prg.beginTokenList(prg.paramStack[int32(prg.curInput.limitField)+int32(prg.curSym)-(hashBase+hashSize+12+1+paramSize)], quarterword(parameter))

				goto restart
			} else {
				prg.curCmd = byte(capsuleToken)
				prg.curMod = int32(prg.paramStack[int32(prg.curInput.limitField)+int32(prg.curSym)-(hashBase+hashSize+12+1)])
				prg.curSym = 0
				goto exit
			}
		}
	} else if int32(prg.curInput.locField) > memMin {
		if int32(*(*prg.mem[prg.curInput.locField].hh()).b1()) == token {
			prg.curMod = *prg.mem[int32(prg.curInput.locField)+1].int()
			if int32(*(*prg.mem[prg.curInput.locField].hh()).b0()) == known {
				prg.curCmd = byte(numericToken)
			} else {
				prg.curCmd = byte(stringToken)
				{
					if int32(prg.strRef[prg.curMod]) < maxStrRef {
						prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) + 1)
					}
				}
			}
		} else {
			prg.curMod = int32(prg.curInput.locField)
			prg.curCmd = byte(capsuleToken)
		}
		prg.curInput.locField = *(*prg.mem[prg.curInput.locField].hh()).rh()
		goto exit
	} else {
		prg.endTokenList()
		goto restart // resume previous level
	}

	// Finish getting the symbolic token in |cur_sym|; |goto restart| if it is illegal
	prg.curCmd = byte(*prg.eqtb[prg.curSym-1].lh())
	prg.curMod = int32(*prg.eqtb[prg.curSym-1].rh())
	if int32(prg.curCmd) >= outerTag {
		if prg.checkOuterValidity() {
			prg.curCmd = byte(int32(prg.curCmd) - outerTag)
		} else {
			goto restart
		}
	}

exit:
}

// 666.

// tangle:pos ../../mf.web:13950:3:

// We need to mention a procedure that may be called by |get_next|.
func (prg *prg) firmUpTheLine() {
	var (
		k /* 0..bufSize */ uint16 // an index into |buffer|
	)
	prg.curInput.limitField = prg.last
	if prg.internal[pausing-1] > 0 {
		if int32(prg.interaction) > nonstopMode {
			prg.printLn()
			if int32(prg.curInput.startField) < int32(prg.curInput.limitField) {
				for ii := int32(prg.curInput.startField); ii <= int32(prg.curInput.limitField)-1; ii++ {
					k = uint16(ii)
					_ = k
					prg.print(int32(prg.buffer[k]))
				}
			}
			prg.first = prg.curInput.limitField
			{
				prg.print( /* "=>" */ 653)
				prg.termInput()
			} // wait for user response
			// \xref[=>]
			if int32(prg.last) > int32(prg.first) {
				for ii := int32(prg.first); ii <= int32(prg.last)-1; ii++ {
					k = uint16(ii)
					_ = k // move line down in buffer
					prg.buffer[int32(k)+int32(prg.curInput.startField)-int32(prg.first)] = prg.buffer[k]
				}
				prg.curInput.limitField = uint16(int32(prg.curInput.startField) + int32(prg.last) - int32(prg.first))
			}
		}
	}
}

// 685.

// tangle:pos ../../mf.web:14273:3:

// Different macro-absorbing operations have different syntaxes, but they
// also have a lot in common. There is a list of special symbols that are to
// be replaced by parameter tokens; there is a special command code that
// ends the definition; the quotation conventions are identical.  Therefore
// it makes sense to have most of the work done by a single subroutine. That
// subroutine is called |scan_toks|.
//
// The first parameter to |scan_toks| is the command code that will
// terminate scanning (either |macro_def| or |iteration|).
//
// The second parameter, |subst_list|, points to a (possibly empty) list
// of two-word nodes whose |info| and |value| fields specify symbol tokens
// before and after replacement. The list will be returned to free storage
// by |scan_toks|.
//
// The third parameter is simply appended to the token list that is built.
// And the final parameter tells how many of the special operations
// \.[\#\AT!], \.[\AT!], and \.[\AT!\#] are to be replaced by suffix parameters.
// When such parameters are present, they are called \.[(SUFFIX0)],
// \.[(SUFFIX1)], and \.[(SUFFIX2)].
func (prg *prg) scanToks(terminator commandCode,
	substList, tailEnd halfword, suffixCount smallNumber) (r halfword) {
	var (
		p       halfword // tail of the token list being built
		q       halfword // temporary for link management
		balance int32    // left delimiters minus right delimiters
	)
	p = uint16(3000 - 2)
	balance = 1
	*(*prg.mem[3000-2].hh()).rh() = uint16(memMin)
	for true {
		prg.getNext()
		if int32(prg.curSym) > 0 {
			{
				q = substList
				for int32(q) != memMin {
					if int32(*(*prg.mem[q].hh()).lh()) == int32(prg.curSym) {
						prg.curSym = uint16(*prg.mem[int32(q)+1].int())
						prg.curCmd = byte(relax)
						goto found
					}
					q = *(*prg.mem[q].hh()).rh()
				}

			found:
			}
			if int32(prg.curCmd) == int32(terminator) {
				if prg.curMod > 0 {
					balance = balance + 1
				} else {
					balance = balance - 1
					if balance == 0 {
						goto done
					}
				}
			} else if int32(prg.curCmd) == macroSpecial {
				if prg.curMod == quote {
					prg.getNext()
				} else if prg.curMod <= int32(suffixCount) {
					prg.curSym = uint16(hashBase + hashSize + 12 + 1 + paramSize - 1 + prg.curMod)
				}
			}
		}
		*(*prg.mem[p].hh()).rh() = prg.curTok()
		p = *(*prg.mem[p].hh()).rh()
	}

done:
	*(*prg.mem[p].hh()).rh() = tailEnd
	prg.flushNodeList(substList)
	r = *(*prg.mem[3000-2].hh()).rh()
	return r
}

// 691.

// tangle:pos ../../mf.web:14363:3:

// Here is a routine that's used whenever a token will be redefined. If
// the user's token is unredefinable, the `|frozen_inaccessible|' token is
// substituted; the latter is redefinable but essentially impossible to use,
// hence \MF's tables won't get fouled up.
func (prg *prg) getSymbol() {
restart:
	prg.getNext()
	if int32(prg.curSym) == 0 || int32(prg.curSym) > hashBase+hashSize {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Missing symbolic token inserted" */ 665) /* \xref[!\relax]  */
		}
		// \xref[Missing symbolic token...]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "Sorry: You can't redefine a number, string, or expr." */ 666
			prg.helpLine[1] = /* "I've inserted an inaccessible symbol so that your" */ 667
			prg.helpLine[0] = /* "definition will be completed without mixing me up too badly." */ 668
		}
		if int32(prg.curSym) > 0 {
			prg.helpLine[2] = /* "Sorry: You can't redefine my error-recovery tokens." */ 669
		} else if int32(prg.curCmd) == stringToken {
			if int32(prg.strRef[prg.curMod]) < maxStrRef {
				if int32(prg.strRef[prg.curMod]) > 1 {
					prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
				} else {
					prg.flushString(strNumber(prg.curMod))
				}
			}
		}
		prg.curSym = uint16(hashBase + hashSize)
		prg.insError()
		goto restart
	}
}

// 692.

// tangle:pos ../../mf.web:14384:3:

// Before we actually redefine a symbolic token, we need to clear away its
// former value, if it was a variable. The following stronger version of
// |get_symbol| does that.
func (prg *prg) getClearSymbol() {
	prg.getSymbol()
	prg.clearSymbol(prg.curSym, false)
}

// 693.

// tangle:pos ../../mf.web:14392:3:

// Here's another little subroutine; it checks that an equals sign
// or assignment sign comes along at the proper place in a macro definition.
func (prg *prg) checkEquals() {
	if int32(prg.curCmd) != equals {
		if int32(prg.curCmd) != assignment {
			prg.missingErr(strNumber('='))

			// \xref[Missing `=']
			{
				prg.helpPtr = 5
				prg.helpLine[4] = /* "The next thing in this `def' should have been `='," */ 670
				prg.helpLine[3] = /* "because I've already looked at the definition heading." */ 671
				prg.helpLine[2] = /* "But don't worry; I'll pretend that an equals sign" */ 672
				prg.helpLine[1] = /* "was present. Everything from here to `enddef'" */ 673
				prg.helpLine[0] = /* "will be the replacement text of this macro." */ 674
			}
			prg.backError()
		}
	}
}

// 694.

// tangle:pos ../../mf.web:14408:3:

// A \&[primarydef], \&[secondarydef], or \&[tertiarydef] is rather easily
// handled now that we have |scan_toks|.  In this case there are
// two parameters, which will be \.[EXPR0] and \.[EXPR1] (i.e.,
// |expr_base| and |expr_base+1|).
func (prg *prg) makeOpDef() {
	var (
		m        commandCode // the type of definition
		p, q, r1 halfword    // for list manipulation
	)
	m = byte(prg.curMod)

	prg.getSymbol()
	q = prg.getNode(tokenNodeSize)
	*(*prg.mem[q].hh()).lh() = prg.curSym
	*prg.mem[int32(q)+1].int() = hashBase + hashSize + 12 + 1

	prg.getClearSymbol()
	prg.warningInfo = int32(prg.curSym)

	prg.getSymbol()
	p = prg.getNode(tokenNodeSize)
	*(*prg.mem[p].hh()).lh() = prg.curSym
	*prg.mem[int32(p)+1].int() = hashBase + hashSize + 12 + 1 + 1
	*(*prg.mem[p].hh()).rh() = q

	prg.getNext()
	prg.checkEquals()

	prg.scannerStatus = byte(opDefining)
	q = prg.getAvail()
	*(*prg.mem[q].hh()).lh() = uint16(memMin)
	r1 = prg.getAvail()
	*(*prg.mem[q].hh()).rh() = r1
	*(*prg.mem[r1].hh()).lh() = uint16(generalMacro)
	*(*prg.mem[r1].hh()).rh() = prg.scanToks(commandCode(macroDef), p, halfword(memMin), smallNumber(0))
	prg.scannerStatus = byte(normal)
	*prg.eqtb[prg.warningInfo-1].lh() = uint16(m)
	*prg.eqtb[prg.warningInfo-1].rh() = q
	prg.getXNext()
}

// 697.

// tangle:pos ../../mf.web:14456:3:

// Let's turn next to the more complex processing associated with \&[def]
// and \&[vardef]. When the following procedure is called, |cur_mod|
// should be either |start_def| or |var_def|.
// \4
// Declare the procedure called |check_delimiter|
func (prg *prg) checkDelimiter(lDelim, rDelim halfword) {
	if int32(prg.curCmd) == rightDelimiter {
		if prg.curMod == int32(lDelim) {
			goto exit
		}
	}
	if int32(prg.curSym) != int32(rDelim) {
		prg.missingErr(*prg.hash[rDelim-1].rh())

		// \xref[Missing `)']
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "I found no right delimiter to match a left one. So I've" */ 922
			prg.helpLine[0] = /* "put one in, behind the scenes; this may fix the problem." */ 923
		}
		prg.backError()
	} else {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "The token `" */ 924) /* \xref[!\relax]  */
		}
		prg.slowPrint(int32(*prg.hash[rDelim-1].rh()))
		// \xref[The token...delimiter]
		prg.print( /* "' is no longer a right delimiter" */ 925)
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "Strange: This token has lost its former meaning!" */ 926
			prg.helpLine[1] = /* "I'll read it as a right delimiter this time;" */ 927
			prg.helpLine[0] = /* "but watch out, I'll probably miss it later." */ 928
		}
		prg.error1()
	}

exit:
}

// \4
// Declare the function called |scan_declared_variable|
func (prg *prg) scanDeclaredVariable() (r halfword) {
	var (
		x    halfword // hash address of the variable's root
		h, t halfword // head and tail of the token list to be returned
		l    halfword // hash address of left bracket
	)
	prg.getSymbol()
	x = prg.curSym
	if int32(prg.curCmd) != tagToken {
		prg.clearSymbol(x, false)
	}
	h = prg.getAvail()
	*(*prg.mem[h].hh()).lh() = x
	t = h

	for true {
		prg.getXNext()
		if int32(prg.curSym) == 0 {
			goto done
		}
		if int32(prg.curCmd) != tagToken {
			if int32(prg.curCmd) != internalQuantity {
				if int32(prg.curCmd) == leftBracket {
					l = prg.curSym
					prg.getXNext()
					if int32(prg.curCmd) != rightBracket {
						prg.backInput()
						prg.curSym = l
						prg.curCmd = byte(leftBracket)
						goto done
					} else {
						prg.curSym = uint16(collectiveSubscript)
					}
				} else {
					goto done
				}
			}
		}
		*(*prg.mem[t].hh()).rh() = prg.getAvail()
		t = *(*prg.mem[t].hh()).rh()
		*(*prg.mem[t].hh()).lh() = prg.curSym
	}

done:
	if int32(*prg.eqtb[x-1].lh())%outerTag != tagToken {
		prg.clearSymbol(x, false)
	}
	if int32(*prg.eqtb[x-1].rh()) == memMin {
		prg.newRoot(x)
	}
	r = h
	return r
}

func (prg *prg) scanDef() {
	var (
		m/* startDef..varDef */ byte                 // the type of definition
		n/* 0..3 */ byte                             // the number of special suffix parameters
		k/* 0..paramSize */ byte                     // the total number of parameters
		c/* generalMacro..textMacro */ byte          // the kind of macro we're defining
		r1                                  halfword // parameter-substitution list
		q                                   halfword // tail of the macro token list
		p                                   halfword // temporary storage
		base                                halfword // |expr_base|, |suffix_base|, or |text_base|
		lDelim, rDelim                      halfword // matching delimiters
	)
	m = byte(prg.curMod)
	c = byte(generalMacro)
	*(*prg.mem[3000-2].hh()).rh() = uint16(memMin)

	q = prg.getAvail()
	*(*prg.mem[q].hh()).lh() = uint16(memMin)
	r1 = uint16(memMin)

	// Scan the token or variable to be defined; set |n|, |scanner_status|, and |warning_info|
	if int32(m) == startDef {
		prg.getClearSymbol()
		prg.warningInfo = int32(prg.curSym)
		prg.getNext()
		prg.scannerStatus = byte(opDefining)
		n = 0
		*prg.eqtb[prg.warningInfo-1].lh() = uint16(definedMacro)
		*prg.eqtb[prg.warningInfo-1].rh() = q
	} else {
		p = prg.scanDeclaredVariable()
		prg.flushVariable(*prg.eqtb[*(*prg.mem[p].hh()).lh()-1].rh(), *(*prg.mem[p].hh()).rh(), true)
		prg.warningInfo = int32(prg.findVariable(p))
		prg.flushList(p)
		if prg.warningInfo == memMin {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "This variable already starts with a macro" */ 681) /* \xref[!\relax]  */
			}
			// \xref[This variable already...]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "After `vardef a' you can't say `vardef a.b'." */ 682
				prg.helpLine[0] = /* "So I'll have to discard this definition." */ 683
			}
			prg.error1()
			prg.warningInfo = memMin + 3 + 10 + 2 + 2 + 2 + 2
		}
		prg.scannerStatus = byte(varDefining)
		n = 2
		if int32(prg.curCmd) == macroSpecial {
			if prg.curMod == macroSuffix {
				n = 3
				prg.getNext()
			}
		}
		*(*prg.mem[prg.warningInfo].hh()).b0() = byte(unsuffixedMacro - 2 + int32(n))
		*prg.mem[prg.warningInfo+1].int() = int32(q)
	}
	k = n
	if int32(prg.curCmd) == leftDelimiter {
		for {
			lDelim = prg.curSym
			rDelim = uint16(prg.curMod)
			prg.getNext()
			if int32(prg.curCmd) == paramType && prg.curMod >= hashBase+hashSize+12+1 {
				base = uint16(prg.curMod)
			} else {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Missing parameter type; `expr' will be assumed" */ 684) /* \xref[!\relax]  */
				}
				// \xref[Missing parameter type]
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "You should've had `expr' or `suffix' or `text' here." */ 685
				}
				prg.backError()
				base = uint16(hashBase + hashSize + 12 + 1)
			}

			// Absorb parameter tokens for type |base|
			for {
				*(*prg.mem[q].hh()).rh() = prg.getAvail()
				q = *(*prg.mem[q].hh()).rh()
				*(*prg.mem[q].hh()).lh() = uint16(int32(base) + int32(k))

				prg.getSymbol()
				p = prg.getNode(tokenNodeSize)
				*prg.mem[int32(p)+1].int() = int32(base) + int32(k)
				*(*prg.mem[p].hh()).lh() = prg.curSym
				if int32(k) == paramSize {
					prg.overflow(strNumber( /* "parameter stack size" */ 686), paramSize)
				}
				// \xref[METAFONT capacity exceeded parameter stack size][\quad parameter stack size]
				k = byte(int32(k) + 1)
				*(*prg.mem[p].hh()).rh() = r1
				r1 = p
				prg.getNext()
				if int32(prg.curCmd) != comma {
					break
				}
			}
			prg.checkDelimiter(lDelim, rDelim)
			prg.getNext()
			if int32(prg.curCmd) != leftDelimiter {
				break
			}
		}
	}
	if int32(prg.curCmd) == paramType {
		p = prg.getNode(tokenNodeSize)
		if prg.curMod < hashBase+hashSize+12+1 {
			c = byte(prg.curMod)
			*prg.mem[int32(p)+1].int() = hashBase + hashSize + 12 + 1 + int32(k)
		} else {
			*prg.mem[int32(p)+1].int() = prg.curMod + int32(k)
			if prg.curMod == hashBase+hashSize+12+1 {
				c = byte(exprMacro)
			} else if prg.curMod == hashBase+hashSize+12+1+paramSize {
				c = byte(suffixMacro)
			} else {
				c = byte(textMacro)
			}
		}
		if int32(k) == paramSize {
			prg.overflow(strNumber( /* "parameter stack size" */ 686), paramSize)
		}
		k = byte(int32(k) + 1)
		prg.getSymbol()
		*(*prg.mem[p].hh()).lh() = prg.curSym
		*(*prg.mem[p].hh()).rh() = r1
		r1 = p
		prg.getNext()
		if int32(c) == exprMacro {
			if int32(prg.curCmd) == ofToken {
				c = byte(ofMacro)
				p = prg.getNode(tokenNodeSize)
				if int32(k) == paramSize {
					prg.overflow(strNumber( /* "parameter stack size" */ 686), paramSize)
				}
				*prg.mem[int32(p)+1].int() = hashBase + hashSize + 12 + 1 + int32(k)
				prg.getSymbol()
				*(*prg.mem[p].hh()).lh() = prg.curSym
				*(*prg.mem[p].hh()).rh() = r1
				r1 = p
				prg.getNext()
			}
		}
	}
	prg.checkEquals()
	p = prg.getAvail()
	*(*prg.mem[p].hh()).lh() = uint16(c)
	*(*prg.mem[q].hh()).rh() = p

	// Attach the replacement text to the tail of node |p|
	if int32(m) == startDef {
		*(*prg.mem[p].hh()).rh() = prg.scanToks(commandCode(macroDef), r1, halfword(memMin), n)
	} else {
		q = prg.getAvail()
		*(*prg.mem[q].hh()).lh() = prg.bgLoc
		*(*prg.mem[p].hh()).rh() = q
		p = prg.getAvail()
		*(*prg.mem[p].hh()).lh() = prg.egLoc
		*(*prg.mem[q].hh()).rh() = prg.scanToks(commandCode(macroDef), r1, p, n)
	}
	if prg.warningInfo == memMin+3+10+2+2+2+2 {
		prg.flushTokenList(halfword(*prg.mem[memMin+3+10+2+2+2+2+1].int()))
	}
	prg.scannerStatus = byte(normal)
	prg.getXNext()
} // \2

// \4
// Declare the procedure called |macro_call|
// \4
// Declare the procedure called |print_macro_name|
func (prg *prg) printMacroName(a, n halfword) {
	var (
		p, q halfword // they traverse the first part of |a|
	)
	if int32(n) != memMin {
		prg.slowPrint(int32(*prg.hash[n-1].rh()))
	} else {
		p = *(*prg.mem[a].hh()).lh()
		if int32(p) == memMin {
			prg.slowPrint(int32(*prg.hash[*(*prg.mem[*(*prg.mem[*(*prg.mem[a].hh()).rh()].hh()).lh()].hh()).lh()-1].rh()))
		} else {
			q = p
			for int32(*(*prg.mem[q].hh()).rh()) != memMin {
				q = *(*prg.mem[q].hh()).rh()
			}
			*(*prg.mem[q].hh()).rh() = *(*prg.mem[*(*prg.mem[a].hh()).rh()].hh()).lh()
			prg.showTokenList(int32(p), memMin, 1000, 0)
			*(*prg.mem[q].hh()).rh() = uint16(memMin)
		}
	}
}

// \4
// Declare the procedure called |print_arg|
func (prg *prg) printArg(q halfword, n int32, b halfword) {
	if int32(*(*prg.mem[q].hh()).rh()) == memMin+1 {
		prg.printNl(strNumber( /* "(EXPR" */ 498))
	} else if int32(b) < hashBase+hashSize+12+1+paramSize+paramSize && int32(b) != textMacro {
		prg.printNl(strNumber( /* "(SUFFIX" */ 499))
	} else {
		prg.printNl(strNumber( /* "(TEXT" */ 500))
	}
	prg.printInt(n)
	prg.print( /* ")<-" */ 702)
	if int32(*(*prg.mem[q].hh()).rh()) == memMin+1 {
		prg.printExp(q, smallNumber(1))
	} else {
		prg.showTokenList(int32(q), memMin, 1000, 0)
	}
}

// \4
// Declare the procedure called |scan_text_arg|
func (prg *prg) scanTextArg(lDelim, rDelim halfword) {
	var (
		balance int32    // excess of |l_delim| over |r_delim|
		p       halfword // list tail
	)
	prg.warningInfo = int32(lDelim)
	prg.scannerStatus = byte(absorbing)
	p = uint16(3000 - 2)
	balance = 1
	*(*prg.mem[3000-2].hh()).rh() = uint16(memMin)
	for true {
		prg.getNext()
		if int32(lDelim) == 0 {
			if int32(prg.curCmd) > comma {
				if balance == 1 {
					goto done
				} else if int32(prg.curCmd) == endGroup {
					balance = balance - 1
				}
			} else if int32(prg.curCmd) == beginGroup {
				balance = balance + 1
			}
		} else {
			// Adjust the balance for a delimited argument; |goto done| if done
			if int32(prg.curCmd) == rightDelimiter {
				if prg.curMod == int32(lDelim) {
					balance = balance - 1
					if balance == 0 {
						goto done
					}
				}
			} else if int32(prg.curCmd) == leftDelimiter {
				if prg.curMod == int32(rDelim) {
					balance = balance + 1
				}
			}
		}
		*(*prg.mem[p].hh()).rh() = prg.curTok()
		p = *(*prg.mem[p].hh()).rh()
	}

done:
	prg.curExp = int32(*(*prg.mem[3000-2].hh()).rh())
	prg.curType = byte(tokenList)
	prg.scannerStatus = byte(normal)
}

func (prg *prg) macroCall(defRef, argList, macroName halfword) {
	var (
		r1             halfword // current node in the macro's token list
		p, q           halfword // for list manipulation
		n              int32    // the number of arguments
		lDelim, rDelim halfword // a delimiter pair
		tail           halfword // tail of the argument list
	)
	r1 = *(*prg.mem[defRef].hh()).rh()
	*(*prg.mem[defRef].hh()).lh() = uint16(int32(*(*prg.mem[defRef].hh()).lh()) + 1)
	if int32(argList) == memMin {
		n = 0
	} else {
		// Determine the number |n| of arguments already supplied, and set |tail| to the tail of |arg_list|
		n = 1
		tail = argList
		for int32(*(*prg.mem[tail].hh()).rh()) != memMin {
			n = n + 1
			tail = *(*prg.mem[tail].hh()).rh()
		}
	}
	if prg.internal[tracingMacros-1] > 0 {
		prg.beginDiagnostic()
		prg.printLn()
		prg.printMacroName(argList, macroName)
		if n == 3 {
			prg.print( /* "@#" */ 664)
		} // indicate a suffixed macro
		prg.showMacro(defRef, memMin, 100000)
		if int32(argList) != memMin {
			n = 0
			p = argList
			for {
				q = *(*prg.mem[p].hh()).lh()
				prg.printArg(q, n, halfword(0))
				n = n + 1
				p = *(*prg.mem[p].hh()).rh()
				if int32(p) == memMin {
					break
				}
			}
		}
		prg.endDiagnostic(false)
	}

	// Scan the remaining arguments, if any; set |r| to the first token of the replacement text
	prg.curCmd = byte(comma + 1) // anything |<>comma| will do
	for int32(*(*prg.mem[r1].hh()).lh()) >= hashBase+hashSize+12+1 {
		if int32(prg.curCmd) != comma {
			prg.getXNext()
			if int32(prg.curCmd) != leftDelimiter {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Missing argument to " */ 708) /* \xref[!\relax]  */
				}
				// \xref[Missing argument...]
				prg.printMacroName(argList, macroName)
				{
					prg.helpPtr = 3
					prg.helpLine[2] = /* "That macro has more parameters than you thought." */ 709
					prg.helpLine[1] = /* "I'll continue by pretending that each missing argument" */ 710
					prg.helpLine[0] = /* "is either zero or null." */ 711
				}
				if int32(*(*prg.mem[r1].hh()).lh()) >= hashBase+hashSize+12+1+paramSize {
					prg.curExp = memMin
					prg.curType = byte(tokenList)
				} else {
					prg.curExp = 0
					prg.curType = byte(known)
				}
				prg.backError()
				prg.curCmd = byte(rightDelimiter)
				goto found
			}
			lDelim = prg.curSym
			rDelim = uint16(prg.curMod)
		}

		// Scan the argument represented by |info(r)|
		if int32(*(*prg.mem[r1].hh()).lh()) >= hashBase+hashSize+12+1+paramSize+paramSize {
			prg.scanTextArg(lDelim, rDelim)
		} else {
			prg.getXNext()
			if int32(*(*prg.mem[r1].hh()).lh()) >= hashBase+hashSize+12+1+paramSize {
				prg.scanSuffix()
			} else {
				prg.scanExpression()
			}
		}
		if int32(prg.curCmd) != comma {
			if int32(prg.curCmd) != rightDelimiter || prg.curMod != int32(lDelim) {
				if int32(*(*prg.mem[*(*prg.mem[r1].hh()).rh()].hh()).lh()) >= hashBase+hashSize+12+1 {
					prg.missingErr(strNumber(','))
					// \xref[Missing `,']
					{
						prg.helpPtr = 3
						prg.helpLine[2] = /* "I've finished reading a macro argument and am about to" */ 712
						prg.helpLine[1] = /* "read another; the arguments weren't delimited correctly." */ 713
						prg.helpLine[0] = /* "You might want to delete some tokens before continuing." */ 707
					}
					prg.backError()
					prg.curCmd = byte(comma)
				} else {
					prg.missingErr(*prg.hash[rDelim-1].rh())
					// \xref[Missing `)']
					{
						prg.helpPtr = 2
						prg.helpLine[1] = /* "I've gotten to the end of the macro parameter list." */ 714
						prg.helpLine[0] = /* "You might want to delete some tokens before continuing." */ 707
					}
					prg.backError()
				}
			}
		}

	found:
		{
			p = prg.getAvail()
			if int32(prg.curType) == tokenList {
				*(*prg.mem[p].hh()).lh() = uint16(prg.curExp)
			} else {
				*(*prg.mem[p].hh()).lh() = prg.stashCurExp()
			}
			if prg.internal[tracingMacros-1] > 0 {
				prg.beginDiagnostic()
				prg.printArg(*(*prg.mem[p].hh()).lh(), n, *(*prg.mem[r1].hh()).lh())
				prg.endDiagnostic(false)
			}
			if int32(argList) == memMin {
				argList = p
			} else {
				*(*prg.mem[tail].hh()).rh() = p
			}
			tail = p
			n = n + 1
		}
		r1 = *(*prg.mem[r1].hh()).rh()
	}
	if int32(prg.curCmd) == comma {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Too many arguments to " */ 703) /* \xref[!\relax]  */
		}
		// \xref[Too many arguments...]
		prg.printMacroName(argList, macroName)
		prg.printChar(asciiCode(';'))
		prg.printNl(strNumber( /* "  Missing `" */ 704))
		prg.slowPrint(int32(*prg.hash[rDelim-1].rh()))
		// \xref[Missing `)'...]
		prg.print( /* "' has been inserted" */ 300)
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "I'm going to assume that the comma I just read was a" */ 705
			prg.helpLine[1] = /* "right delimiter, and then I'll begin expanding the macro." */ 706
			prg.helpLine[0] = /* "You might want to delete some tokens before continuing." */ 707
		}
		prg.error1()
	}
	if int32(*(*prg.mem[r1].hh()).lh()) != generalMacro {
		if int32(*(*prg.mem[r1].hh()).lh()) < textMacro {
			prg.getXNext()
			if int32(*(*prg.mem[r1].hh()).lh()) != suffixMacro {
				if int32(prg.curCmd) == equals || int32(prg.curCmd) == assignment {
					prg.getXNext()
				}
			}
		}
		switch *(*prg.mem[r1].hh()).lh() {
		case primaryMacro:
			prg.scanPrimary()
		case secondaryMacro:
			prg.scanSecondary()
		case tertiaryMacro:
			prg.scanTertiary()
		case exprMacro:
			prg.scanExpression()
		case ofMacro:
			// Scan an expression followed by `\&[of] $\langle$primary$\rangle$'
			prg.scanExpression()
			p = prg.getAvail()
			*(*prg.mem[p].hh()).lh() = prg.stashCurExp()
			if prg.internal[tracingMacros-1] > 0 {
				prg.beginDiagnostic()
				prg.printArg(*(*prg.mem[p].hh()).lh(), n, halfword(0))
				prg.endDiagnostic(false)
			}
			if int32(argList) == memMin {
				argList = p
			} else {
				*(*prg.mem[tail].hh()).rh() = p
			}
			tail = p
			n = n + 1
			if int32(prg.curCmd) != ofToken {
				prg.missingErr(strNumber( /* "of" */ 479))
				prg.print( /* " for " */ 715)
				// \xref[Missing `of']
				prg.printMacroName(argList, macroName)
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "I've got the first argument; will look now for the other." */ 716
				}
				prg.backError()
			}
			prg.getXNext()
			prg.scanPrimary()

		case suffixMacro:
			// Scan a suffix with optional delimiters
			if int32(prg.curCmd) != leftDelimiter {
				lDelim = uint16(memMin)
			} else {
				lDelim = prg.curSym
				rDelim = uint16(prg.curMod)
				prg.getXNext()
			}
			prg.scanSuffix()
			if int32(lDelim) != memMin {
				if int32(prg.curCmd) != rightDelimiter || prg.curMod != int32(lDelim) {
					prg.missingErr(*prg.hash[rDelim-1].rh())
					// \xref[Missing `)']
					{
						prg.helpPtr = 2
						prg.helpLine[1] = /* "I've gotten to the end of the macro parameter list." */ 714
						prg.helpLine[0] = /* "You might want to delete some tokens before continuing." */ 707
					}
					prg.backError()
				}
				prg.getXNext()
			}

		case textMacro:
			prg.scanTextArg(halfword(0), halfword(0))
		} // there are no other cases
		prg.backInput()
		// Append the current expression to |arg_list|
		{
			p = prg.getAvail()
			if int32(prg.curType) == tokenList {
				*(*prg.mem[p].hh()).lh() = uint16(prg.curExp)
			} else {
				*(*prg.mem[p].hh()).lh() = prg.stashCurExp()
			}
			if prg.internal[tracingMacros-1] > 0 {
				prg.beginDiagnostic()
				prg.printArg(*(*prg.mem[p].hh()).lh(), n, *(*prg.mem[r1].hh()).lh())
				prg.endDiagnostic(false)
			}
			if int32(argList) == memMin {
				argList = p
			} else {
				*(*prg.mem[tail].hh()).rh() = p
			}
			tail = p
			n = n + 1
		}
	}
	r1 = *(*prg.mem[r1].hh()).rh()

	// Feed the arguments and replacement text to the scanner
	for int32(prg.curInput.indexField) > maxInOpen && int32(prg.curInput.locField) == memMin {
		prg.endTokenList()
	} // conserve stack space
	if int32(prg.paramPtr)+n > prg.maxParamStack {
		prg.maxParamStack = int32(prg.paramPtr) + n
		if prg.maxParamStack > paramSize {
			prg.overflow(strNumber( /* "parameter stack size" */ 686), paramSize)
		}
		// \xref[METAFONT capacity exceeded parameter stack size][\quad parameter stack size]
	}
	prg.beginTokenList(defRef, quarterword(macro))
	prg.curInput.nameField = macroName
	prg.curInput.locField = r1
	if n > 0 {
		p = argList
		for {
			prg.paramStack[prg.paramPtr] = *(*prg.mem[p].hh()).lh()
			prg.paramPtr = byte(int32(prg.paramPtr) + 1)
			p = *(*prg.mem[p].hh()).rh()
			if int32(p) == memMin {
				break
			}
		}
		prg.flushList(argList)
	}
} // \2

// 707.

// tangle:pos ../../mf.web:14608:3:

// An auxiliary subroutine called |expand| is used by |get_x_next|
// when it has to do exotic expansion commands.
func (prg *prg) expand() {
	var (
		p halfword    // for list manipulation
		k int32       // something that we hope is |<=buf_size|
		j poolPointer // index into |str_pool|
	)
	if prg.internal[tracingCommands-1] > 0200000 {
		if int32(prg.curCmd) != definedMacro {
			prg.showCmdMod(int32(prg.curCmd), prg.curMod)
		}
	}
	switch prg.curCmd {
	case ifTest:
		prg.conditional() // this procedure is discussed in Part 36 below
	case fiOrElse:
		// Terminate the current conditional and skip to \&[fi]
		if prg.curMod > int32(prg.ifLimit) {
			if int32(prg.ifLimit) == ifCode {
				prg.missingErr(strNumber(':'))
				// \xref[Missing `:']
				prg.backInput()
				prg.curSym = uint16(hashBase + hashSize + 5)
				prg.insError()
			} else {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Extra " */ 723) /* \xref[!\relax]  */
				}
				prg.printCmdMod(fiOrElse, prg.curMod)
				// \xref[Extra else]
				// \xref[Extra elseif]
				// \xref[Extra fi]
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "I'm ignoring this; it doesn't match any if." */ 724
				}
				prg.error1()
			}
		} else {
			for prg.curMod != fiCode {
				prg.passText()
			} // skip to \&[fi]

			// Pop the condition stack
			{
				p = prg.condPtr
				prg.ifLine = *prg.mem[int32(p)+1].int()
				prg.curIf = *(*prg.mem[p].hh()).b1()
				prg.ifLimit = *(*prg.mem[p].hh()).b0()
				prg.condPtr = *(*prg.mem[p].hh()).rh()
				prg.freeNode(p, halfword(ifNodeSize))
			}
		}

	case input:
		// Initiate or terminate input from a file
		if prg.curMod > 0 {
			prg.forceEof = true
		} else {
			prg.startInput()
		}

	case iteration:
		if prg.curMod == endFor {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Extra `endfor'" */ 687) /* \xref[!\relax]  */
			}
			// \xref[Extra `endfor']
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I'm not currently working on a for loop," */ 688
				prg.helpLine[0] = /* "so I had better not try to end anything." */ 689
			}

			prg.error1()
		} else {
			prg.beginIteration()
		} // this procedure is discussed in Part 37 below
	case repeatLoop:
		// Repeat a loop
		for int32(prg.curInput.indexField) > maxInOpen && int32(prg.curInput.locField) == memMin {
			prg.endTokenList()
		} // conserve stack space
		if int32(prg.loopPtr) == memMin {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Lost loop" */ 691) /* \xref[!\relax]  */
			}
			// \xref[Lost loop]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I'm confused; after exiting from a loop, I still seem" */ 692
				prg.helpLine[0] = /* "to want to repeat it. I'll try to forget the problem." */ 693
			}

			prg.error1()
		} else {
			prg.resumeIteration()
		} // this procedure is in Part 37 below

	case exitTest:
		// Exit a loop if the proper time has come
		prg.getBoolean()
		if prg.internal[tracingCommands-1] > 0200000 {
			prg.showCmdMod(nullary, prg.curExp)
		}
		if prg.curExp == trueCode {
			if int32(prg.loopPtr) == memMin {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "No loop is in progress" */ 694) /* \xref[!\relax]  */
				}
				// \xref[No loop is in progress]
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "Why say `exitif' when there's nothing to exit from?" */ 695
				}
				if int32(prg.curCmd) == semicolon {
					prg.error1()
				} else {
					prg.backError()
				}
			} else {
				// Exit prematurely from an iteration
				p = uint16(memMin)
				for {
					if int32(prg.curInput.indexField) <= maxInOpen {
						prg.endFileReading()
					} else {
						if int32(prg.curInput.indexField) <= loopText {
							p = prg.curInput.startField
						}
						prg.endTokenList()
					}
					if int32(p) != memMin {
						break
					}
				}
				if int32(p) != int32(*(*prg.mem[prg.loopPtr].hh()).lh()) {
					prg.fatalError(strNumber( /* "*** (loop confusion)" */ 698))
				}
				// \xref[loop confusion]
				prg.stopIteration() // this procedure is in Part 37 below
			}
		} else if int32(prg.curCmd) != semicolon {
			prg.missingErr(strNumber(';'))

			// \xref[Missing `;']
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "After `exitif <boolean expr>' I expect to see a semicolon." */ 696
				prg.helpLine[0] = /* "I shall pretend that one was there." */ 697
			}
			prg.backError()
		}

	case relax:
	case expandAfter:
		// Expand the token after the next token
		prg.getNext()
		p = prg.curTok()
		prg.getNext()
		if int32(prg.curCmd) < minCommand {
			prg.expand()
		} else {
			prg.backInput()
		}
		prg.beginTokenList(p, quarterword(backedUp))

	case scanTokens:
		// Put a string into the input buffer
		prg.getXNext()
		prg.scanPrimary()
		if int32(prg.curType) != stringType {
			prg.dispErr(halfword(memMin), strNumber( /* "Not a string" */ 699))
			// \xref[Not a string]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I'm going to flush this expression, since" */ 700
				prg.helpLine[0] = /* "scantokens should be followed by a known string." */ 701
			}
			prg.putGetFlushError(scaled(0))
		} else {
			prg.backInput()
			if int32(prg.strStart[prg.curExp+1])-int32(prg.strStart[prg.curExp]) > 0 {
				prg.beginFileReading()
				prg.curInput.nameField = 2
				k = int32(prg.first) + (int32(prg.strStart[prg.curExp+1]) - int32(prg.strStart[prg.curExp]))
				if k >= int32(prg.maxBufStack) {
					if k >= bufSize {
						prg.maxBufStack = uint16(bufSize)
						prg.overflow(strNumber( /* "buffer size" */ 256), bufSize)
						// \xref[METAFONT capacity exceeded buffer size][\quad buffer size]
					}
					prg.maxBufStack = uint16(k + 1)
				}
				j = prg.strStart[prg.curExp]
				prg.curInput.limitField = uint16(k)
				for int32(prg.first) < int32(prg.curInput.limitField) {
					prg.buffer[prg.first] = prg.strPool[j]
					j = uint16(int32(j) + 1)
					prg.first = uint16(int32(prg.first) + 1)
				}
				prg.buffer[prg.curInput.limitField] = '%'
				prg.first = uint16(int32(prg.curInput.limitField) + 1)
				prg.curInput.locField = prg.curInput.startField
				prg.flushCurExp(scaled(0))
			}
		}

	case definedMacro:
		prg.macroCall(halfword(prg.curMod), halfword(memMin), prg.curSym)
	} // there are no other cases
} // \2

func (prg *prg) getXNext() {
	var (
		saveExp halfword // a capsule to save |cur_type| and |cur_exp|
	)
	prg.getNext()
	if int32(prg.curCmd) < minCommand {
		saveExp = prg.stashCurExp()
		for {
			if int32(prg.curCmd) == definedMacro {
				prg.macroCall(halfword(prg.curMod), halfword(memMin), prg.curSym)
			} else {
				prg.expand()
			}
			prg.getNext()
			if int32(prg.curCmd) >= minCommand {
				break
			}
		}
		prg.unstashCurExp(saveExp) // that restores |cur_type| and |cur_exp|
	}
}

// 719.

// tangle:pos ../../mf.web:14767:3:

// Now let's consider the |macro_call| procedure, which is used to start up
// all user-defined macros. Since the arguments to a macro might be expressions,
// |macro_call| is recursive.
// \xref[recursion]
//
// The first parameter to |macro_call| points to the reference count of the
// token list that defines the macro. The second parameter contains any
// arguments that have already been parsed (see below).  The third parameter
// points to the symbolic token that names the macro. If the third parameter
// is |null|, the macro was defined by \&[vardef], so its name can be
// reconstructed from the prefix and ``at'' arguments found within the
// second parameter.
//
// What is this second parameter? It's simply a linked list of one-word items,
// whose |info| fields point to the arguments. In other words, if |arg_list=null|,
// no arguments have been scanned yet; otherwise |info(arg_list)| points to
// the first scanned argument, and |link(arg_list)| points to the list of
// further arguments (if any).
//
// Arguments of type \&[expr] are so-called capsules, which we will
// discuss later when we concentrate on expressions; they can be
// recognized easily because their |link| field is |void|. Arguments of type
// \&[suffix] and \&[text] are token lists without reference counts.

// 737.

// tangle:pos ../../mf.web:15073:3:

// It's sometimes necessary to put a single argument onto |param_stack|.
// The |stack_argument| subroutine does this.
func (prg *prg) stackArgument(p halfword) {
	if int32(prg.paramPtr) == prg.maxParamStack {
		prg.maxParamStack = prg.maxParamStack + 1
		if prg.maxParamStack > paramSize {
			prg.overflow(strNumber( /* "parameter stack size" */ 686), paramSize)
		}
		// \xref[METAFONT capacity exceeded parameter stack size][\quad parameter stack size]
	}
	prg.paramStack[prg.paramPtr] = p
	prg.paramPtr = byte(int32(prg.paramPtr) + 1)
} // \2
func (prg *prg) passText() {
	var (
		l int32
	)
	prg.scannerStatus = byte(skipping)
	l = 0
	prg.warningInfo = prg.line
	for true {
		prg.getNext()
		if int32(prg.curCmd) <= fiOrElse {
			if int32(prg.curCmd) < fiOrElse {
				l = l + 1
			} else {
				if l == 0 {
					goto done
				}
				if prg.curMod == fiCode {
					l = l - 1
				}
			}
		} else if int32(prg.curCmd) == stringToken {
			if int32(prg.strRef[prg.curMod]) < maxStrRef {
				if int32(prg.strRef[prg.curMod]) > 1 {
					prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
				} else {
					prg.flushString(strNumber(prg.curMod))
				}
			}
		}
	}

done:
	prg.scannerStatus = byte(normal)
}

// 746.

// tangle:pos ../../mf.web:15182:3:

// Here's a procedure that changes the |if_limit| code corresponding to
// a given value of |cond_ptr|.
func (prg *prg) changeIfLimit(l smallNumber, p halfword) {
	var (
		q halfword
	)
	if int32(p) == int32(prg.condPtr) {
		prg.ifLimit = l
	} else {
		q = prg.condPtr
		for true {
			if int32(q) == memMin {
				prg.confusion(strNumber( /* "if" */ 717))
			}
			// \xref[this can't happen if][\quad if]
			if int32(*(*prg.mem[q].hh()).rh()) == int32(p) {
				*(*prg.mem[q].hh()).b0() = l
				goto exit
			}
			q = *(*prg.mem[q].hh()).rh()
		}
	}

exit:
}

// 747.

// tangle:pos ../../mf.web:15200:3:

// The user is supposed to put colons into the proper parts of conditional
// statements. Therefore, \MF\ has to check for their presence.
func (prg *prg) checkColon() {
	if int32(prg.curCmd) != colon {
		prg.missingErr(strNumber(':'))

		// \xref[Missing `:']
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "There should've been a colon after the condition." */ 720
			prg.helpLine[0] = /* "I shall pretend that one was there." */ 697
		}
		prg.backError()
	}
} // \2
func (prg *prg) conditional() {
	var (
		saveCondPtr                             halfword // |cond_ptr| corresponding to this conditional
		newIfLimit/* fiCode..elseIfCode */ byte          // future value of |if_limit|
		p                                       halfword // temporary register
	)
	{
		p = prg.getNode(ifNodeSize)
		*(*prg.mem[p].hh()).rh() = prg.condPtr
		*(*prg.mem[p].hh()).b0() = prg.ifLimit
		*(*prg.mem[p].hh()).b1() = prg.curIf
		*prg.mem[int32(p)+1].int() = prg.ifLine
		prg.condPtr = p
		prg.ifLimit = byte(ifCode)
		prg.ifLine = prg.line
		prg.curIf = byte(ifCode)
	}
	saveCondPtr = prg.condPtr

reswitch:
	prg.getBoolean()
	newIfLimit = byte(elseIfCode)
	if prg.internal[tracingCommands-1] > 0200000 {
		prg.beginDiagnostic()
		if prg.curExp == trueCode {
			prg.print( /* "[true]" */ 721)
		} else {
			prg.print( /* "[false]" */ 722)
		}
		prg.endDiagnostic(false)
	}

found:
	prg.checkColon()
	if prg.curExp == trueCode {
		prg.changeIfLimit(newIfLimit, saveCondPtr)

		goto exit // wait for \&[elseif], \&[else], or \&[fi]
	}

	// Skip to \&[elseif] or \&[else] or \&[fi], then |goto done|
	for true {
		prg.passText()
		if int32(prg.condPtr) == int32(saveCondPtr) {
			goto done
		} else if prg.curMod == fiCode {
			p = prg.condPtr
			prg.ifLine = *prg.mem[int32(p)+1].int()
			prg.curIf = *(*prg.mem[p].hh()).b1()
			prg.ifLimit = *(*prg.mem[p].hh()).b0()
			prg.condPtr = *(*prg.mem[p].hh()).rh()
			prg.freeNode(p, halfword(ifNodeSize))
		}
	}

done:
	prg.curIf = byte(prg.curMod)
	prg.ifLine = prg.line
	if prg.curMod == fiCode {
		p = prg.condPtr
		prg.ifLine = *prg.mem[int32(p)+1].int()
		prg.curIf = *(*prg.mem[p].hh()).b1()
		prg.ifLimit = *(*prg.mem[p].hh()).b0()
		prg.condPtr = *(*prg.mem[p].hh()).rh()
		prg.freeNode(p, halfword(ifNodeSize))
	} else if prg.curMod == elseIfCode {
		goto reswitch
	} else {
		prg.curExp = trueCode
		newIfLimit = byte(fiCode)
		prg.getXNext()
		goto found
	}

exit:
}

// 754.

// tangle:pos ../../mf.web:15322:3:

// If the expressions that define an arithmetic progression in
// a \&[for] loop don't have known numeric values, the |bad_for|
// subroutine screams at the user.
func (prg *prg) badFor(s strNumber) {
	prg.dispErr(halfword(memMin), strNumber( /* "Improper " */ 725)) // show the bad expression above the message
	// \xref[Improper...replaced by 0]
	prg.print(int32(s))
	prg.print( /* " has been replaced by 0" */ 307)
	{
		prg.helpPtr = 4
		prg.helpLine[3] = /* "When you say `for x=a step b until c'," */ 726
		prg.helpLine[2] = /* "the initial value `a' and the step size `b'" */ 727
		prg.helpLine[1] = /* "and the final value `c' must have known numeric values." */ 728
		prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
	}
	prg.putGetFlushError(scaled(0))
} // \2
func (prg *prg) beginIteration() {
	var (
		m           halfword // |expr_base| (\&[for]) or |suffix_base| (\&[forsuffixes])
		n           halfword // hash address of the current symbol
		p, q, s, pp halfword // link manipulation registers
	)
	m = uint16(prg.curMod)
	n = prg.curSym
	s = prg.getNode(loopNodeSize)
	if int32(m) == startForever {
		*(*prg.mem[int32(s)+1].hh()).lh() = uint16(memMin + 1)
		p = uint16(memMin)
		prg.getXNext()
		goto found
	}
	prg.getSymbol()
	p = prg.getNode(tokenNodeSize)
	*(*prg.mem[p].hh()).lh() = prg.curSym
	*prg.mem[int32(p)+1].int() = int32(m)

	prg.getXNext()
	if int32(prg.curCmd) != equals && int32(prg.curCmd) != assignment {
		prg.missingErr(strNumber('='))

		// \xref[Missing `=']
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "The next thing in this loop should have been `=' or `:='." */ 729
			prg.helpLine[1] = /* "But don't worry; I'll pretend that an equals sign" */ 672
			prg.helpLine[0] = /* "was present, and I'll look for the values next." */ 730
		}

		prg.backError()
	}

	// Scan the values to be used in the loop
	*(*prg.mem[int32(s)+1].hh()).lh() = uint16(memMin)
	q = uint16(int32(s) + 1)
	*(*prg.mem[q].hh()).rh() = uint16(memMin) // |link(q)=loop_list(s)|
	for {
		prg.getXNext()
		if int32(m) != hashBase+hashSize+12+1 {
			prg.scanSuffix()
		} else {
			if int32(prg.curCmd) >= colon {
				if int32(prg.curCmd) <= comma {
					goto continue1
				}
			}
			prg.scanExpression()
			if int32(prg.curCmd) == stepToken {
				if int32(q) == int32(s)+1 {
					if int32(prg.curType) != known {
						prg.badFor(strNumber( /* "initial value" */ 736))
					}
					pp = prg.getNode(progressionNodeSize)
					*prg.mem[int32(pp)+1].int() = prg.curExp

					prg.getXNext()
					prg.scanExpression()
					if int32(prg.curType) != known {
						prg.badFor(strNumber( /* "step size" */ 737))
					}
					*prg.mem[int32(pp)+2].int() = prg.curExp
					if int32(prg.curCmd) != untilToken {
						prg.missingErr(strNumber( /* "until" */ 490))

						// \xref[Missing `until']
						{
							prg.helpPtr = 2
							prg.helpLine[1] = /* "I assume you meant to say `until' after `step'." */ 738
							prg.helpLine[0] = /* "So I'll look for the final value and colon next." */ 739
						}
						prg.backError()
					}
					prg.getXNext()
					prg.scanExpression()
					if int32(prg.curType) != known {
						prg.badFor(strNumber( /* "final value" */ 740))
					}
					*prg.mem[int32(pp)+3].int() = prg.curExp
					*(*prg.mem[int32(s)+1].hh()).lh() = pp
					goto done
				}
			}
			prg.curExp = int32(prg.stashCurExp())
		}
		*(*prg.mem[q].hh()).rh() = prg.getAvail()
		q = *(*prg.mem[q].hh()).rh()
		*(*prg.mem[q].hh()).lh() = uint16(prg.curExp)
		prg.curType = byte(vacuous)

	continue1:
		;
		if int32(prg.curCmd) != comma {
			break
		}
	}

done:
	;

found:
	if int32(prg.curCmd) != colon {
		prg.missingErr(strNumber(':'))

		// \xref[Missing `:']
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "The next thing in this loop should have been a `:'." */ 731
			prg.helpLine[1] = /* "So I'll pretend that a colon was present;" */ 732
			prg.helpLine[0] = /* "everything from here to `endfor' will be iterated." */ 733
		}
		prg.backError()
	}

	// Scan the loop text and put it on the loop control stack
	q = prg.getAvail()
	*(*prg.mem[q].hh()).lh() = uint16(hashBase + hashSize + 1)
	prg.scannerStatus = byte(loopDefining)
	prg.warningInfo = int32(n)
	*(*prg.mem[s].hh()).lh() = prg.scanToks(commandCode(iteration), p, q, smallNumber(0))
	prg.scannerStatus = byte(normal)

	*(*prg.mem[s].hh()).rh() = prg.loopPtr
	prg.loopPtr = s
	prg.resumeIteration()
} // \2
func (prg *prg) resumeIteration() {
	var (
		p, q halfword // link registers
	)
	p = *(*prg.mem[int32(prg.loopPtr)+1].hh()).lh()
	if int32(p) > memMin+1 {
		prg.curExp = *prg.mem[int32(p)+1].int()
		if *prg.mem[int32(p)+2].int() > 0 && prg.curExp > *prg.mem[int32(p)+3].int() || *prg.mem[int32(p)+2].int() < 0 && prg.curExp < *prg.mem[int32(p)+3].int() {
			// The arithmetic progression has ended
			goto notFound
		}
		prg.curType = byte(known)
		q = prg.stashCurExp()                                                // make |q| an \&[expr] argument
		*prg.mem[int32(p)+1].int() = prg.curExp + *prg.mem[int32(p)+2].int() // set |value(p)| for the next iteration
	} else if int32(p) < memMin+1 {
		p = *(*prg.mem[int32(prg.loopPtr)+1].hh()).rh()
		if int32(p) == memMin {
			goto notFound
		}
		*(*prg.mem[int32(prg.loopPtr)+1].hh()).rh() = *(*prg.mem[p].hh()).rh()
		q = *(*prg.mem[p].hh()).lh()
		{
			*(*prg.mem[p].hh()).rh() = prg.avail
			prg.avail = p
			prg.dynUsed = prg.dynUsed - 1
		}
	} else {
		prg.beginTokenList(*(*prg.mem[prg.loopPtr].hh()).lh(), quarterword(foreverText))
		goto exit
	}
	prg.beginTokenList(*(*prg.mem[prg.loopPtr].hh()).lh(), quarterword(loopText))
	prg.stackArgument(q)
	if prg.internal[tracingCommands-1] > 0200000 {
		prg.beginDiagnostic()
		prg.printNl(strNumber( /* "[loop value=" */ 735))
		// \xref[loop value=n]
		if int32(q) != memMin && int32(*(*prg.mem[q].hh()).rh()) == memMin+1 {
			prg.printExp(q, smallNumber(1))
		} else {
			prg.showTokenList(int32(q), memMin, 50, 0)
		}
		prg.printChar(asciiCode('}'))
		prg.endDiagnostic(false)
	}

	goto exit

notFound:
	prg.stopIteration()

exit:
} // \2
func (prg *prg) stopIteration() {
	var (
		p, q halfword // the usual
	)
	p = *(*prg.mem[int32(prg.loopPtr)+1].hh()).lh()
	if int32(p) > memMin+1 {
		prg.freeNode(p, halfword(progressionNodeSize))
	} else if int32(p) < memMin+1 {
		q = *(*prg.mem[int32(prg.loopPtr)+1].hh()).rh()
		for int32(q) != memMin {
			p = *(*prg.mem[q].hh()).lh()
			if int32(p) != memMin {
				if int32(*(*prg.mem[p].hh()).rh()) == memMin+1 {
					prg.recycleValue(p)
					prg.freeNode(p, halfword(valueNodeSize))
				} else {
					prg.flushTokenList(p)
				}
			} // it's a \&[suffix] or \&[text] parameter
			p = q
			q = *(*prg.mem[q].hh()).rh()
			{
				*(*prg.mem[p].hh()).rh() = prg.avail
				prg.avail = p
				prg.dynUsed = prg.dynUsed - 1
			}
		}
	}
	p = prg.loopPtr
	prg.loopPtr = *(*prg.mem[p].hh()).rh()
	prg.flushTokenList(*(*prg.mem[p].hh()).lh())
	prg.freeNode(p, halfword(loopNodeSize))
}

// 766. \[38] File names

// tangle:pos ../../mf.web:15499:21:

// It's time now to fret about file names.  Besides the fact that different
// operating systems treat files in different ways, we must cope with the
// fact that completely different naming conventions are used by different
// groups of people. The following programs show what is required for one
// particular operating system; similar routines for other systems are not
// difficult to devise.
// \xref[system dependencies]
//
// \MF\ assumes that a file name has three parts: the name proper; its
// ``extension''; and a ``file area'' where it is found in an external file
// system.  The extension of an input file is assumed to be
// `\.[.mf]' unless otherwise specified; it is `\.[.log]' on the
// transcript file that records each run of \MF; it is `\.[.tfm]' on the font
// metric files that describe characters in the fonts \MF\ creates; it is
// `\.[.gf]' on the output files that specify generic font information; and it
// is `\.[.base]' on the base files written by \.[INIMF] to initialize \MF.
// The file area can be arbitrary on input files, but files are usually
// output to the user's current area.  If an input file cannot be
// found on the specified area, \MF\ will look for it on a special system
// area; this special area is intended for commonly used input files.
//
// Simple uses of \MF\ refer only to file names that have no explicit
// extension or area. For example, a person usually says `\.[input] \.[cmr10]'
// instead of `\.[input] \.[cmr10.new]'. Simple file
// names are best, because they make the \MF\ source files portable;
// whenever a file name consists entirely of letters and digits, it should be
// treated in the same way by all implementations of \MF. However, users
// need the ability to refer to other files in their environment, especially
// when responding to error messages concerning unopenable files; therefore
// we want to let them use the syntax that appears in their favorite
// operating system.

// 769.

// tangle:pos ../../mf.web:15579:3:

// Input files that can't be found in the user's area may appear in a standard
// system area called |MF_area|.
// This system area name will, of course, vary from place to place.
// \xref[system dependencies]

// 770.

// tangle:pos ../../mf.web:15587:3:

// Here now is the first of the system-dependent routines for file name scanning.
// \xref[system dependencies]
func (prg *prg) beginName() {
	prg.areaDelimiter = 0
	prg.extDelimiter = 0
}

// 771.

// tangle:pos ../../mf.web:15594:3:

// And here's the second.
// \xref[system dependencies]
func (prg *prg) moreName(c asciiCode) (r bool) {
	if int32(c) == ' ' {
		r = false
	} else {
		if int32(c) == '>' || int32(c) == ':' {
			prg.areaDelimiter = prg.poolPtr
			prg.extDelimiter = 0
		} else if int32(c) == '.' && int32(prg.extDelimiter) == 0 {
			prg.extDelimiter = prg.poolPtr
		}
		{
			if int32(prg.poolPtr)+1 > int32(prg.maxPoolPtr) {
				if int32(prg.poolPtr)+1 > poolSize {
					prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
				} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
				prg.maxPoolPtr = uint16(int32(prg.poolPtr) + 1)
			}
		}
		{
			prg.strPool[prg.poolPtr] = c
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		} // contribute |c| to the current string
		r = true
	}
	return r
}

// 772.

// tangle:pos ../../mf.web:15608:3:

// The third.
// \xref[system dependencies]
func (prg *prg) endName() {
	if int32(prg.strPtr)+3 > int32(prg.maxStrPtr) {
		if int32(prg.strPtr)+3 > maxStrings {
			prg.overflow(strNumber( /* "number of strings" */ 258), maxStrings-int32(prg.initStrPtr))
		}
		// \xref[METAFONT capacity exceeded number of strings][\quad number of strings]
		prg.maxStrPtr = uint16(int32(prg.strPtr) + 3)
	}
	if int32(prg.areaDelimiter) == 0 {
		prg.curArea = /* "" */ 285
	} else {
		prg.curArea = prg.strPtr
		prg.strPtr = uint16(int32(prg.strPtr) + 1)
		prg.strStart[prg.strPtr] = uint16(int32(prg.areaDelimiter) + 1)
	}
	if int32(prg.extDelimiter) == 0 {
		prg.curExt = /* "" */ 285
		prg.curName = prg.makeString()
	} else {
		prg.curName = prg.strPtr
		prg.strPtr = uint16(int32(prg.strPtr) + 1)
		prg.strStart[prg.strPtr] = prg.extDelimiter
		prg.curExt = prg.makeString()
	}
}

// 774.

// tangle:pos ../../mf.web:15640:3:

// Another system-dependent routine is needed to convert three internal
// \MF\ strings
// to the |name_of_file| value that is used to open files. The present code
// allows both lowercase and uppercase letters in the file name.
// \xref[system dependencies]
func (prg *prg) packFileName(n, a, e strNumber) {
	var (
		k int32       // number of positions filled in |name_of_file|
		c asciiCode   // character being packed
		j poolPointer // index into |str_pool|
	)
	k = 0
	for ii := int32(prg.strStart[a]); ii <= int32(prg.strStart[int32(a)+1])-1; ii++ {
		j = poolPointer(ii)
		_ = j
		c = prg.strPool[j]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	for ii := int32(prg.strStart[n]); ii <= int32(prg.strStart[int32(n)+1])-1; ii++ {
		j = poolPointer(ii)
		_ = j
		c = prg.strPool[j]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	for ii := int32(prg.strStart[e]); ii <= int32(prg.strStart[int32(e)+1])-1; ii++ {
		j = poolPointer(ii)
		_ = j
		c = prg.strPool[j]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	if k <= fileNameSize {
		prg.nameLength = byte(k)
	} else {
		prg.nameLength = byte(fileNameSize)
	}
	for ii := int32(prg.nameLength) + 1; ii <= fileNameSize; ii++ {
		k = ii
		_ = k
		prg.nameOfFile[k-1] = ' '
	}
}

// 778.

// tangle:pos ../../mf.web:15685:3:

// Here is the messy routine that was just mentioned. It sets |name_of_file|
// from the first |n| characters of |MF_base_default|, followed by
// |buffer[a..b]|, followed by the last |base_ext_length| characters of
// |MF_base_default|.
//
// We dare not give error messages here, since \MF\ calls this routine before
// the |error| routine is ready to roll. Instead, we simply drop excess characters,
// since the error will be detected in another way when a strange file name
// isn't found.
// \xref[system dependencies]
func (prg *prg) packBufferedName(n smallNumber, a, b int32) {
	var (
		k int32     // number of positions filled in |name_of_file|
		c asciiCode // character being packed
		j int32     // index into |buffer| or |MF_base_default|
	)
	if int32(n)+b-a+1+baseExtLength > fileNameSize {
		b = a + fileNameSize - int32(n) - 1 - baseExtLength
	}
	k = 0
	for ii := int32(1); ii <= int32(n); ii++ {
		j = ii
		_ = j
		c = prg.xord[prg.mfBaseDefault[j-1]]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	for ii := a; ii <= b; ii++ {
		j = ii
		_ = j
		c = prg.buffer[j]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	for ii := int32(baseDefaultLength - baseExtLength + 1); ii <= baseDefaultLength; ii++ {
		j = ii
		_ = j
		c = prg.xord[prg.mfBaseDefault[j-1]]
		k = k + 1
		if k <= fileNameSize {
			prg.nameOfFile[k-1] = prg.xchr[c]
		}
	}
	if k <= fileNameSize {
		prg.nameLength = byte(k)
	} else {
		prg.nameLength = byte(fileNameSize)
	}
	for ii := int32(prg.nameLength) + 1; ii <= fileNameSize; ii++ {
		k = ii
		_ = k
		prg.nameOfFile[k-1] = ' '
	}
}

// 780.

// tangle:pos ../../mf.web:15748:3:

// Operating systems often make it possible to determine the exact name (and
// possible version number) of a file that has been opened. The following routine,
// which simply makes a \MF\ string from the value of |name_of_file|, should
// ideally be changed to deduce the full name of file~|f|, which is the file
// most recently opened, if it is possible to do this in a \PASCAL\ program.
// \xref[system dependencies]
//
// This routine might be called after string memory has overflowed, hence
// we dare not use `|str_room|'.
func (prg *prg) makeNameString() (r strNumber) {
	var (
		k /* 1..fileNameSize */ byte // index into |name_of_file|
	)
	if int32(prg.poolPtr)+int32(prg.nameLength) > poolSize || int32(prg.strPtr) == maxStrings {
		r = '?'
	} else {
		for ii := int32(1); ii <= int32(prg.nameLength); ii++ {
			k = byte(ii)
			_ = k
			prg.strPool[prg.poolPtr] = prg.xord[prg.nameOfFile[k-1]]
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
		r = prg.makeString()
	}
	return r
}
func (prg *prg) aMakeNameString(f alphaFile) (r strNumber) {
	r = prg.makeNameString()
	return r
}
func (prg *prg) bMakeNameString(f byteFile) (r strNumber) {
	r = prg.makeNameString()
	return r
}
func (prg *prg) wMakeNameString(f wordFile) (r strNumber) {
	r = prg.makeNameString()
	return r
}

// 781.

// tangle:pos ../../mf.web:15776:3:

// Now let's consider the ``driver''
// routines by which \MF\ deals with file names
// in a system-independent manner.  First comes a procedure that looks for a
// file name in the input by taking the information from the input buffer.
// (We can't use |get_next|, because the conversion to tokens would
// destroy necessary information.)
//
// This procedure doesn't allow semicolons or percent signs to be part of
// file names, because of other conventions of \MF. The manual doesn't
// use semicolons or percents immediately after file names, but some users
// no doubt will find it natural to do so; therefore system-dependent
// changes to allow such characters in file names should probably
// be made with reluctance, and only when an entire file name that
// includes special characters is ``quoted'' somehow.
// \xref[system dependencies]
func (prg *prg) scanFileName() {
	prg.beginName()
	for int32(prg.buffer[prg.curInput.locField]) == ' ' {
		prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
	}
	for true {
		if int32(prg.buffer[prg.curInput.locField]) == ';' || int32(prg.buffer[prg.curInput.locField]) == '%' {
			goto done
		}
		if !prg.moreName(prg.buffer[prg.curInput.locField]) {
			goto done
		}
		prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
	}

done:
	prg.endName()
}

// 784.

// tangle:pos ../../mf.web:15818:3:

// Here is a routine that manufactures the output file names, assuming that
// |job_name<>0|. It ignores and changes the current settings of |cur_area|
// and |cur_ext|.
func (prg *prg) packJobName(s strNumber) {
	prg.curArea = /* "" */ 285
	prg.curExt = s
	prg.curName = prg.jobName
	prg.packFileName(prg.curName, prg.curArea, prg.curExt)
}

// 786.

// tangle:pos ../../mf.web:15838:3:

// If some trouble arises when \MF\ tries to open a file, the following
// routine calls upon the user to supply another file name. Parameter~|s|
// is used in the error message to identify the type of file; parameter~|e|
// is the default extension if none is given. Upon exit from the routine,
// variables |cur_name|, |cur_area|, |cur_ext|, and |name_of_file| are
// ready for another attempt at file opening.
func (prg *prg) promptFileName(s, e strNumber) {
	var (
		k /* 0..bufSize */ uint16 // index into |buffer|
	)
	if int32(prg.interaction) == scrollMode {
	}
	if int32(s) == 743 {
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "I can't find file `" */ 744) /* \xref[!\relax]  */
	} else {
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "I can't write on file `" */ 745) /* \xref[!\relax]  */
	}
	// \xref[I can't write on file x]
	prg.printFileName(int32(prg.curName), int32(prg.curArea), int32(prg.curExt))
	prg.print( /* "'." */ 746)
	if int32(e) == 747 {
		prg.showContext()
	}
	prg.printNl(strNumber( /* "Please type another " */ 748))
	prg.print(int32(s))
	// \xref[Please type...]
	if int32(prg.interaction) < scrollMode {
		prg.fatalError(strNumber( /* "*** (job aborted, file error in nonstop mode)" */ 749))
	}
	// \xref[job aborted, file error...]
	{
		prg.print( /* ": " */ 750)
		prg.termInput()
	}
	// Scan file name in the buffer
	{
		prg.beginName()
		k = prg.first
		for int32(prg.buffer[k]) == ' ' && int32(k) < int32(prg.last) {
			k = uint16(int32(k) + 1)
		}
		for true {
			if int32(k) == int32(prg.last) {
				goto done
			}
			if !prg.moreName(prg.buffer[k]) {
				goto done
			}
			k = uint16(int32(k) + 1)
		}

	done:
		prg.endName()
	}
	if int32(prg.curExt) == 285 {
		prg.curExt = e
	}
	prg.packFileName(prg.curName, prg.curArea, prg.curExt)
} // \2

func (prg *prg) openLogFile() {
	var (
		oldSetting/* 0..maxSelector */ byte          // previous |selector| setting
		k/* 0..bufSize */ uint16                     // index into |months| and |buffer|
		l/* 0..bufSize */ uint16                     // end of first input line
		months                              [36]char // abbreviations of month names
	)
	oldSetting = prg.selector
	if int32(prg.jobName) == 0 {
		prg.jobName = /* "mfput" */ 751
	}
	// \xref[mfput]
	prg.packJobName(strNumber( /* ".log" */ 752))
	for !prg.aOpenOut(prg.logFile) {
		// Try to get a different log file name
		prg.selector = byte(termOnly)
		prg.promptFileName(strNumber( /* "transcript file name" */ 754), strNumber( /* ".log" */ 752))
	}
	prg.logName = prg.aMakeNameString(prg.logFile)
	prg.selector = byte(logOnly)
	prg.logOpened = true

	// Print the banner line, including the date and time
	{
		prg.logFile.Write("This is METAFONT, Version 2.71828182 (TRAP)")
		prg.slowPrint(int32(prg.baseIdent))
		prg.print( /* "  " */ 755)
		prg.printInt(prg.sysDay)
		prg.printChar(asciiCode(' '))
		strcopy(months[:], "JANFEBMARAPRMAYJUNJULAUGSEPOCTNOVDEC")
		for ii := 3*prg.sysMonth - 2; ii <= 3*prg.sysMonth; ii++ {
			k = uint16(ii)
			_ = k
			prg.logFile.Write(string(rune(months[k-1])))
		}
		prg.printChar(asciiCode(' '))
		prg.printInt(prg.sysYear)
		prg.printChar(asciiCode(' '))
		prg.printDd(prg.sysTime / 60)
		prg.printChar(asciiCode(':'))
		prg.printDd(prg.sysTime % 60)
	}
	prg.inputStack[prg.inputPtr] = prg.curInput // make sure bottom level is in memory
	prg.printNl(strNumber( /* "**" */ 753))
	// \xref[**]
	l = uint16(int32(prg.inputStack[0].limitField) - 1) // last position of first line
	for ii := int32(1); ii <= int32(l); ii++ {
		k = uint16(ii)
		_ = k
		prg.print(int32(prg.buffer[k]))
	}
	prg.printLn()                              // now the transcript file contains the first line of input
	prg.selector = byte(int32(oldSetting) + 2) // |log_only| or |term_and_log|
} // \2
func (prg *prg) startInput() {
	for int32(prg.curInput.indexField) > maxInOpen && int32(prg.curInput.locField) == memMin {
		prg.endTokenList()
	}
	if int32(prg.curInput.indexField) > maxInOpen {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "File names can't appear within macros" */ 757) /* \xref[!\relax]  */
		}
		// \xref[File names can't...]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "Sorry...I've converted what follows to tokens," */ 758
			prg.helpLine[1] = /* "possibly garbaging the name you gave." */ 759
			prg.helpLine[0] = /* "Please delete the tokens and insert the name again." */ 760
		}

		prg.error1()
	}
	if int32(prg.curInput.indexField) <= maxInOpen {
		prg.scanFileName()
	} else {
		prg.curName = /* "" */ 285
		prg.curExt = /* "" */ 285
		prg.curArea = /* "" */ 285
	}
	if int32(prg.curExt) == 285 {
		prg.curExt = /* ".mf" */ 747
	}
	prg.packFileName(prg.curName, prg.curArea, prg.curExt)
	for true {
		prg.beginFileReading() // set up |cur_file| and new level of input
		if prg.aOpenIn(prg.inputFile[prg.curInput.indexField-1]) {
			goto done
		}
		if int32(prg.curArea) == 285 {
			prg.packFileName(prg.curName, strNumber( /* "MFinputs:" */ 741), prg.curExt)
			if prg.aOpenIn(prg.inputFile[prg.curInput.indexField-1]) {
				goto done
			}
		}
		prg.endFileReading() // remove the level that didn't work
		prg.promptFileName(strNumber( /* "input file name" */ 743), strNumber( /* ".mf" */ 747))
	}

done:
	prg.curInput.nameField = prg.aMakeNameString(prg.inputFile[prg.curInput.indexField-1])
	prg.strRef[prg.curName] = byte(maxStrRef)
	if int32(prg.jobName) == 0 {
		prg.jobName = prg.curName
		prg.openLogFile()
	} // |open_log_file| doesn't |show_context|, so |limit|
	//     and |loc| needn't be set to meaningful values yet

	if int32(prg.termOffset)+(int32(prg.strStart[int32(prg.curInput.nameField)+1])-int32(prg.strStart[prg.curInput.nameField])) > maxPrintLine-2 {
		prg.printLn()
	} else if int32(prg.termOffset) > 0 || int32(prg.fileOffset) > 0 {
		prg.printChar(asciiCode(' '))
	}
	prg.printChar(asciiCode('('))
	prg.openParens = byte(int32(prg.openParens) + 1)
	prg.slowPrint(int32(prg.curInput.nameField))
	if int32(prg.curInput.nameField) == int32(prg.strPtr)-1 {
		prg.flushString(prg.curInput.nameField)
		prg.curInput.nameField = prg.curName
	}

	// Read the first line of the new file
	{
		prg.line = 1
		if prg.inputLn(prg.inputFile[prg.curInput.indexField-1], false) {
		}
		prg.firmUpTheLine()
		prg.buffer[prg.curInput.limitField] = '%'
		prg.first = uint16(int32(prg.curInput.limitField) + 1)
		prg.curInput.locField = prg.curInput.startField
	}
}

// 798.

// tangle:pos ../../mf.web:16035:3:

// Many different kinds of expressions are possible, so it is wise to have
// precise descriptions of what |cur_type| and |cur_exp| mean in all cases:
//
// \smallskip\hang
// |cur_type=vacuous| means that this expression didn't turn out to have a
// value at all, because it arose from a \&[begingroup]$\,\ldots\,$\&[endgroup]
// construction in which there was no expression before the \&[endgroup].
// In this case |cur_exp| has some irrelevant value.
//
// \smallskip\hang
// |cur_type=boolean_type| means that |cur_exp| is either |true_code|
// or |false_code|.
//
// \smallskip\hang
// |cur_type=unknown_boolean| means that |cur_exp| points to a capsule
// node that is in
// a ring of equivalent booleans whose value has not yet been defined.
//
// \smallskip\hang
// |cur_type=string_type| means that |cur_exp| is a string number (i.e., an
// integer in the range |0<=cur_exp<str_ptr|). That string's reference count
// includes this particular reference.
//
// \smallskip\hang
// |cur_type=unknown_string| means that |cur_exp| points to a capsule
// node that is in
// a ring of equivalent strings whose value has not yet been defined.
//
// \smallskip\hang
// |cur_type=pen_type| means that |cur_exp| points to a pen header node. This
// node contains a reference count, which takes account of this particular
// reference.
//
// \smallskip\hang
// |cur_type=unknown_pen| means that |cur_exp| points to a capsule
// node that is in
// a ring of equivalent pens whose value has not yet been defined.
//
// \smallskip\hang
// |cur_type=future_pen| means that |cur_exp| points to a knot list that
// should eventually be made into a pen. Nobody else points to this particular
// knot list. The |future_pen| option occurs only as an output of |scan_primary|
// and |scan_secondary|, not as an output of |scan_tertiary| or |scan_expression|.
//
// \smallskip\hang
// |cur_type=path_type| means that |cur_exp| points to the first node of
// a path; nobody else points to this particular path. The control points of
// the path will have been chosen.
//
// \smallskip\hang
// |cur_type=unknown_path| means that |cur_exp| points to a capsule
// node that is in
// a ring of equivalent paths whose value has not yet been defined.
//
// \smallskip\hang
// |cur_type=picture_type| means that |cur_exp| points to an edges header node.
// Nobody else points to this particular set of edges.
//
// \smallskip\hang
// |cur_type=unknown_picture| means that |cur_exp| points to a capsule
// node that is in
// a ring of equivalent pictures whose value has not yet been defined.
//
// \smallskip\hang
// |cur_type=transform_type| means that |cur_exp| points to a |transform_type|
// capsule node. The |value| part of this capsule
// points to a transform node that contains six numeric values,
// each of which is |independent|, |dependent|, |proto_dependent|, or |known|.
//
// \smallskip\hang
// |cur_type=pair_type| means that |cur_exp| points to a capsule
// node whose type is |pair_type|. The |value| part of this capsule
// points to a pair node that contains two numeric values,
// each of which is |independent|, |dependent|, |proto_dependent|, or |known|.
//
// \smallskip\hang
// |cur_type=known| means that |cur_exp| is a |scaled| value.
//
// \smallskip\hang
// |cur_type=dependent| means that |cur_exp| points to a capsule node whose type
// is |dependent|. The |dep_list| field in this capsule points to the associated
// dependency list.
//
// \smallskip\hang
// |cur_type=proto_dependent| means that |cur_exp| points to a |proto_dependent|
// capsule node. The |dep_list| field in this capsule
// points to the associated dependency list.
//
// \smallskip\hang
// |cur_type=independent| means that |cur_exp| points to a capsule node
// whose type is |independent|. This somewhat unusual case can arise, for
// example, in the expression
// `$x+\&[begingroup]\penalty0\,\&[string]\,x; 0\,\&[endgroup]$'.
//
// \smallskip\hang
// |cur_type=token_list| means that |cur_exp| points to a linked list of
// tokens.
//
// \smallskip\noindent
// The possible settings of |cur_type| have been listed here in increasing
// numerical order. Notice that |cur_type| will never be |numeric_type| or
// |suffixed_macro| or |unsuffixed_macro|, although variables of those types
// are allowed.  Conversely, \MF\ has no variables of type |vacuous| or
// |token_list|.

// 824.

// tangle:pos ../../mf.web:16652:3:

// Errors at the beginning of expressions are flagged by |bad_exp|.
func (prg *prg) badExp(s strNumber) {
	var (
		saveFlag /* 0..maxCommandCode */ byte
	)
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print(int32(s)) /* \xref[!\relax]  */
	}
	prg.print( /* " expression can't begin with `" */ 770)
	prg.printCmdMod(int32(prg.curCmd), prg.curMod)
	prg.printChar(asciiCode('\''))
	{
		prg.helpPtr = 4
		prg.helpLine[3] = /* "I'm afraid I need some sort of value in order to continue," */ 771
		prg.helpLine[2] = /* "so I've tentatively inserted `0'. You may want to" */ 772
		prg.helpLine[1] = /* "delete this zero and insert something else;" */ 773
		prg.helpLine[0] = /* "see Chapter 27 of The METAFONTbook for an example." */ 774
	}
	// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]
	prg.backInput()
	prg.curSym = 0
	prg.curCmd = byte(numericToken)
	prg.curMod = 0
	prg.insError()

	saveFlag = prg.varFlag
	prg.varFlag = 0
	prg.getXNext()
	prg.varFlag = saveFlag
}

// 827.

// tangle:pos ../../mf.web:16681:3:

// The |stash_in| subroutine puts the current (numeric) expression into a field
// within a ``big node.''
func (prg *prg) stashIn(p halfword) {
	var (
		q halfword // temporary register
	)
	*(*prg.mem[p].hh()).b0() = prg.curType
	if int32(prg.curType) == known {
		*prg.mem[int32(p)+1].int() = prg.curExp
	} else {
		if int32(prg.curType) == independent {
			q = prg.singleDependency(halfword(prg.curExp))
			if int32(q) == int32(prg.depFinal) {
				*(*prg.mem[p].hh()).b0() = byte(known)
				*prg.mem[int32(p)+1].int() = 0
				prg.freeNode(q, halfword(depNodeSize))
			} else {
				*(*prg.mem[p].hh()).b0() = byte(dependent)
				prg.newDep(p, q)
			}
			prg.recycleValue(halfword(prg.curExp))
		} else {
			prg.mem[int32(p)+1] = prg.mem[prg.curExp+1]
			// |dep_list(p):=dep_list(cur_exp)| and |prev_dep(p):=prev_dep(cur_exp)|
			*(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh() = p
		}
		prg.freeNode(halfword(prg.curExp), halfword(valueNodeSize))
	}
	prg.curType = byte(vacuous)
}

// 828.

// tangle:pos ../../mf.web:16699:3:

// In rare cases the current expression can become |independent|. There
// may be many dependency lists pointing to such an independent capsule,
// so we can't simply move it into place within a big node. Instead,
// we copy it, then recycle it.

// 842.

// tangle:pos ../../mf.web:16865:3:

// The most difficult part of |scan_primary| has been saved for last, since
// it was necessary to build up some confidence first. We can now face the task
// of scanning a variable.
//
// As we scan a variable, we build a token list containing the relevant
// names and subscript values, simultaneously following along in the
// ``collective'' structure to see if we are actually dealing with a macro
// instead of a value.
//
// The local variables |pre_head| and |post_head| will point to the beginning
// of the prefix and suffix lists; |tail| will point to the end of the list
// that is currently growing.
//
// Another local variable, |tt|, contains partial information about the
// declared type of the variable-so-far. If |tt>=unsuffixed_macro|, the
// relation |tt=type(q)| will always hold. If |tt=undefined|, the routine
// doesn't bother to update its information about type. And if
// |undefined<tt<unsuffixed_macro|, the precise value of |tt| isn't critical.

// 848.

// tangle:pos ../../mf.web:16939:3:

// Here's a routine that puts the current expression back to be read again.
func (prg *prg) backExpr() {
	var (
		p halfword // capsule token
	)
	p = prg.stashCurExp()
	*(*prg.mem[p].hh()).rh() = uint16(memMin)
	prg.beginTokenList(p, quarterword(backedUp))
}

// 849.

// tangle:pos ../../mf.web:16946:3:

// Unknown subscripts lead to the following error message.
func (prg *prg) badSubscript() {
	prg.dispErr(halfword(memMin), strNumber( /* "Improper subscript has been replaced by zero" */ 786))
	// \xref[Improper subscript...]
	{
		prg.helpPtr = 3
		prg.helpLine[2] = /* "A bracketed subscript must have a known numeric value;" */ 787
		prg.helpLine[1] = /* "unfortunately, what I found was the value that appears just" */ 788
		prg.helpLine[0] = /* "above this error message. So I'll try a zero subscript." */ 789
	}
	prg.flushError(scaled(0))
}

// 851.

// tangle:pos ../../mf.web:16982:3:

// How do things stand now? Well, we have scanned an entire variable name,
// including possible subscripts and/or attributes; |cur_cmd|, |cur_mod|, and
// |cur_sym| represent the token that follows. If |post_head=null|, a
// token list for this variable name starts at |link(pre_head)|, with all
// subscripts evaluated. But if |post_head<>null|, the variable turned out
// to be a suffixed macro; |pre_head| is the head of the prefix list, while
// |post_head| is the head of a token list containing both `\.[\AT!]' and
// the suffix.
//
// Our immediate problem is to see if this variable still exists. (Variable
// structures can change drastically whenever we call |get_x_next|; users
// aren't supposed to do this, but the fact that it is possible means that
// we must be cautious.)
//
// The following procedure prints an error message when a variable
// unexpectedly disappears. Its help message isn't quite right for
// our present purposes, but we'll be able to fix that up.
func (prg *prg) obliterated(q halfword) {
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "Variable " */ 790) /* \xref[!\relax]  */
	}
	prg.showTokenList(int32(q), memMin, 1000, 0)
	prg.print( /* " has been obliterated" */ 791)
	// \xref[Variable...obliterated]
	{
		prg.helpPtr = 5
		prg.helpLine[4] = /* "It seems you did a nasty thing---probably by accident," */ 792
		prg.helpLine[3] = /* "but nevertheless you nearly hornswoggled me..." */ 793
		prg.helpLine[2] = /* "While I was evaluating the right-hand side of this" */ 794
		prg.helpLine[1] = /* "command, something happened, and the left-hand side" */ 795
		prg.helpLine[0] = /* "is no longer a variable! So I won't change anything." */ 796
	}
}

// 863.

// tangle:pos ../../mf.web:17227:3:

// The following procedure calls a macro that has two parameters,
// |p| and |cur_exp|.
func (prg *prg) binaryMac(p, c, n halfword) {
	var (
		q, r1 halfword // nodes in the parameter list
	)
	q = prg.getAvail()
	r1 = prg.getAvail()
	*(*prg.mem[q].hh()).rh() = r1

	*(*prg.mem[q].hh()).lh() = p
	*(*prg.mem[r1].hh()).lh() = prg.stashCurExp()

	prg.macroCall(c, q, n)
}

// 865.

// tangle:pos ../../mf.web:17266:3:

// A |future_pen| becomes a full-fledged pen here.
func (prg *prg) materializePen() {
	var (
		aMinusB, aPlusB, majorAxis, minorAxis scaled   // ellipse variables
		theta                                 angle    // amount by which the ellipse has been rotated
		p                                     halfword // path traverser
		q                                     halfword // the knot list to be made into a pen
	)
	q = uint16(prg.curExp)
	if int32(*(*prg.mem[q].hh()).b0()) == endpoint {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Pen path must be a cycle" */ 806) /* \xref[!\relax]  */
		}
		// \xref[Pen path must be a cycle]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "I can't make a pen from the given path." */ 807
			prg.helpLine[0] = /* "So I've replaced it by the trivial path `(0,0)..cycle'." */ 575
		}
		prg.putGetError()
		prg.curExp = memMin + 3
		goto commonEnding
	} else if int32(*(*prg.mem[q].hh()).b0()) == open {
		prg.tx = *prg.mem[int32(q)+1].int()
		prg.ty = *prg.mem[int32(q)+2].int()
		prg.txx = *prg.mem[int32(q)+3].int() - prg.tx
		prg.tyx = *prg.mem[int32(q)+4].int() - prg.ty
		prg.txy = *prg.mem[int32(q)+5].int() - prg.tx
		prg.tyy = *prg.mem[int32(q)+6].int() - prg.ty
		aMinusB = prg.pythAdd(prg.txx-prg.tyy, prg.tyx+prg.txy)
		aPlusB = prg.pythAdd(prg.txx+prg.tyy, prg.tyx-prg.txy)
		majorAxis = (aMinusB + aPlusB) / 2
		minorAxis = abs(aPlusB-aMinusB) / 2
		if majorAxis == minorAxis {
			theta = 0
		} else {
			theta = (prg.nArg(prg.txx-prg.tyy, prg.tyx+prg.txy) + prg.nArg(prg.txx+prg.tyy, prg.tyx-prg.txy)) / 2
		}
		prg.freeNode(q, halfword(knotNodeSize))
		q = prg.makeEllipse(majorAxis, minorAxis, theta)
		if prg.tx != 0 || prg.ty != 0 {
			p = q
			for {
				*prg.mem[int32(p)+1].int() = *prg.mem[int32(p)+1].int() + prg.tx
				*prg.mem[int32(p)+2].int() = *prg.mem[int32(p)+2].int() + prg.ty
				p = *(*prg.mem[p].hh()).rh()
				if int32(p) == int32(q) {
					break
				}
			}
		}
	}
	prg.curExp = int32(prg.makePen(q))

commonEnding:
	prg.tossKnotList(q)
	prg.curType = byte(penType)
}

// 871.

// tangle:pos ../../mf.web:17413:3:

// A pair of numeric values is changed into a knot node for a one-point path
// when \MF\ discovers that the pair is part of a path.
// \4
// Declare the procedure called |known_pair|
func (prg *prg) knownPair() {
	var (
		p halfword // the pair node
	)
	if int32(prg.curType) != pairType {
		prg.dispErr(halfword(memMin), strNumber( /* "Undefined coordinates have been replaced by (0,0)" */ 809))
		// \xref[Undefined coordinates...]
		{
			prg.helpPtr = 5
			prg.helpLine[4] = /* "I need x and y numbers for this part of the path." */ 810
			prg.helpLine[3] = /* "The value I found (see above) was no good;" */ 811
			prg.helpLine[2] = /* "so I'll try to keep going by using zero instead." */ 812
			prg.helpLine[1] = /* "(Chapter 27 of The METAFONTbook explains that" */ 813
			prg.helpLine[0] = /* "you might want to type `I ???' now.)" */ 814
		}
		prg.putGetFlushError(scaled(0))
		prg.curX = 0
		prg.curY = 0
	} else {
		p = uint16(*prg.mem[prg.curExp+1].int())

		// Make sure that both |x| and |y| parts of |p| are known; copy them into |cur_x| and |cur_y|
		if int32(*(*prg.mem[p].hh()).b0()) == known {
			prg.curX = *prg.mem[int32(p)+1].int()
		} else {
			prg.dispErr(p, strNumber(
				/* "Undefined x coordinate has been replaced by 0" */ 815))
			// \xref[Undefined coordinates...]
			{
				prg.helpPtr = 5
				prg.helpLine[4] = /* "I need a `known' x value for this part of the path." */ 816
				prg.helpLine[3] = /* "The value I found (see above) was no good;" */ 811
				prg.helpLine[2] = /* "so I'll try to keep going by using zero instead." */ 812
				prg.helpLine[1] = /* "(Chapter 27 of The METAFONTbook explains that" */ 813
				prg.helpLine[0] = /* "you might want to type `I ???' now.)" */ 814
			}
			prg.putGetError()
			prg.recycleValue(p)
			prg.curX = 0
		}
		if int32(*(*prg.mem[int32(p)+2].hh()).b0()) == known {
			prg.curY = *prg.mem[int32(p)+2+1].int()
		} else {
			prg.dispErr(halfword(int32(p)+2), strNumber(
				/* "Undefined y coordinate has been replaced by 0" */ 817))
			{
				prg.helpPtr = 5
				prg.helpLine[4] = /* "I need a `known' y value for this part of the path." */ 818
				prg.helpLine[3] = /* "The value I found (see above) was no good;" */ 811
				prg.helpLine[2] = /* "so I'll try to keep going by using zero instead." */ 812
				prg.helpLine[1] = /* "(Chapter 27 of The METAFONTbook explains that" */ 813
				prg.helpLine[0] = /* "you might want to type `I ???' now.)" */ 814
			}
			prg.putGetError()
			prg.recycleValue(halfword(int32(p) + 2))
			prg.curY = 0
		}
		prg.flushCurExp(scaled(0))
	}
}

func (prg *prg) newKnot() (r halfword) { // convert a pair to a knot with two endpoints
	var (
		q halfword // the new node
	)
	q = prg.getNode(knotNodeSize)
	*(*prg.mem[q].hh()).b0() = byte(endpoint)
	*(*prg.mem[q].hh()).b1() = byte(endpoint)
	*(*prg.mem[q].hh()).rh() = q

	prg.knownPair()
	*prg.mem[int32(q)+1].int() = prg.curX
	*prg.mem[int32(q)+2].int() = prg.curY
	r = q
	return r
}

// 875.

// tangle:pos ../../mf.web:17490:3:

// The |scan_direction| subroutine looks at the directional information
// that is enclosed in braces, and also scans ahead to the following character.
// A type code is returned, either |open| (if the direction was $(0,0)$),
// or |curl| (if the direction was a curl of known value |cur_exp|), or
// |given| (if the direction is given by the |angle| value that now
// appears in |cur_exp|).
//
// There's nothing difficult about this subroutine, but the program is rather
// lengthy because a variety of potential errors need to be nipped in the bud.
func (prg *prg) scanDirection() (r smallNumber) {
	var (
		t/* given..open */ byte        // the type of information found
		x                       scaled // an |x| coordinate
	)
	prg.getXNext()
	if int32(prg.curCmd) == curlCommand {
		prg.getXNext()
		prg.scanExpression()
		if int32(prg.curType) != known || prg.curExp < 0 {
			prg.dispErr(halfword(memMin), strNumber( /* "Improper curl has been replaced by 1" */ 821))
			// \xref[Improper curl]
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "A curl must be a known, nonnegative number." */ 822
			}
			prg.putGetFlushError(scaled(0200000))
		}
		t = byte(curl)
	} else {
		// Scan a given direction
		prg.scanExpression()
		if int32(prg.curType) > pairType {
			if int32(prg.curType) != known {
				prg.dispErr(halfword(memMin), strNumber( /* "Undefined x coordinate has been replaced by 0" */ 815))
				// \xref[Undefined coordinates...]
				{
					prg.helpPtr = 5
					prg.helpLine[4] = /* "I need a `known' x value for this part of the path." */ 816
					prg.helpLine[3] = /* "The value I found (see above) was no good;" */ 811
					prg.helpLine[2] = /* "so I'll try to keep going by using zero instead." */ 812
					prg.helpLine[1] = /* "(Chapter 27 of The METAFONTbook explains that" */ 813
					prg.helpLine[0] = /* "you might want to type `I ???' now.)" */ 814
				}
				prg.putGetFlushError(scaled(0))
			}
			x = prg.curExp
			if int32(prg.curCmd) != comma {
				prg.missingErr(strNumber(','))

				// \xref[Missing `,']
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "I've got the x coordinate of a path direction;" */ 823
					prg.helpLine[0] = /* "will look for the y coordinate next." */ 824
				}
				prg.backError()
			}
			prg.getXNext()
			prg.scanExpression()
			if int32(prg.curType) != known {
				prg.dispErr(halfword(memMin), strNumber( /* "Undefined y coordinate has been replaced by 0" */ 817))
				{
					prg.helpPtr = 5
					prg.helpLine[4] = /* "I need a `known' y value for this part of the path." */ 818
					prg.helpLine[3] = /* "The value I found (see above) was no good;" */ 811
					prg.helpLine[2] = /* "so I'll try to keep going by using zero instead." */ 812
					prg.helpLine[1] = /* "(Chapter 27 of The METAFONTbook explains that" */ 813
					prg.helpLine[0] = /* "you might want to type `I ???' now.)" */ 814
				}
				prg.putGetFlushError(scaled(0))
			}
			prg.curY = prg.curExp
			prg.curX = x
		} else {
			prg.knownPair()
		}
		if prg.curX == 0 && prg.curY == 0 {
			t = byte(open)
		} else {
			t = byte(given)
			prg.curExp = prg.nArg(prg.curX, prg.curY)
		}
	}
	if int32(prg.curCmd) != rightBrace {
		prg.missingErr(strNumber('}'))

		// \xref[Missing `\char`\]']
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "I've scanned a direction spec for part of a path," */ 819
			prg.helpLine[1] = /* "so a right brace should have come next." */ 820
			prg.helpLine[0] = /* "I shall pretend that one was there." */ 697
		}

		prg.backError()
	}
	prg.getXNext()
	r = t
	return r
}

// 895.

// tangle:pos ../../mf.web:17914:3:

// OK, let's look at the simplest \\[do] procedure first.
func (prg *prg) doNullary(c quarterword) {
	var (
		k int32 // all-purpose loop index
	)
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
	if prg.internal[tracingCommands-1] > 0400000 {
		prg.showCmdMod(nullary, int32(c))
	}
	switch c {
	case trueCode, falseCode:
		prg.curType = byte(booleanType)
		prg.curExp = int32(c)

	case nullPictureCode:
		prg.curType = byte(pictureType)
		prg.curExp = int32(prg.getNode(edgeHeaderSize))
		prg.initEdges(halfword(prg.curExp))

	case nullPenCode:
		prg.curType = byte(penType)
		prg.curExp = memMin + 3

	case normalDeviate:
		prg.curType = byte(known)
		prg.curExp = prg.normRand()

	case penCircle:
		// Make a special knot node for \&[pencircle]
		prg.curType = byte(futurePen)
		prg.curExp = int32(prg.getNode(knotNodeSize))
		*(*prg.mem[prg.curExp].hh()).b0() = byte(open)
		*(*prg.mem[prg.curExp].hh()).b1() = byte(open)
		*(*prg.mem[prg.curExp].hh()).rh() = uint16(prg.curExp)

		*prg.mem[prg.curExp+1].int() = 0
		*prg.mem[prg.curExp+2].int() = 0

		*prg.mem[prg.curExp+3].int() = 0200000
		*prg.mem[prg.curExp+4].int() = 0

		*prg.mem[prg.curExp+5].int() = 0
		*prg.mem[prg.curExp+6].int() = 0200000

	case jobNameOp:
		if int32(prg.jobName) == 0 {
			prg.openLogFile()
		}
		prg.curType = byte(stringType)
		prg.curExp = int32(prg.jobName)

	case readStringOp:
		// Read a string from the terminal
		if int32(prg.interaction) <= nonstopMode {
			prg.fatalError(strNumber( /* "*** (cannot readstring in nonstop modes)" */ 835))
		}
		prg.beginFileReading()
		prg.curInput.nameField = 1
		{
			prg.print( /* "" */ 285)
			prg.termInput()
		}
		{
			if int32(prg.poolPtr)+int32(prg.last)-int32(prg.curInput.startField) > int32(prg.maxPoolPtr) {
				if int32(prg.poolPtr)+int32(prg.last)-int32(prg.curInput.startField) > poolSize {
					prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
				} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
				prg.maxPoolPtr = uint16(int32(prg.poolPtr) + int32(prg.last) - int32(prg.curInput.startField))
			}
		}
		for ii := int32(prg.curInput.startField); ii <= int32(prg.last)-1; ii++ {
			k = ii
			_ = k
			prg.strPool[prg.poolPtr] = prg.buffer[k]
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
		prg.endFileReading()
		prg.curType = byte(stringType)
		prg.curExp = int32(prg.makeString())

	} // there are no other cases
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
}

// 898.

// tangle:pos ../../mf.web:17958:3:

// Things get a bit more interesting when there's an operand. The
// operand to |do_unary| appears in |cur_type| and |cur_exp|.
// \4
// Declare unary action procedures
func (prg *prg) nicePair(p int32, t quarterword) (r bool) {
	if int32(t) == pairType {
		p = *prg.mem[p+1].int()
		if int32(*(*prg.mem[p].hh()).b0()) == known {
			if int32(*(*prg.mem[p+2].hh()).b0()) == known {
				r = true
				goto exit
			}
		}
	}
	r = false

exit:
	;
	return r
}

func (prg *prg) printKnownOrUnknownType(t smallNumber, v int32) {
	prg.printChar(asciiCode('('))
	if int32(t) < dependent {
		if int32(t) != pairType {
			prg.printType(t)
		} else if prg.nicePair(v, quarterword(pairType)) {
			prg.print( /* "pair" */ 337)
		} else {
			prg.print( /* "unknown pair" */ 836)
		}
	} else {
		prg.print( /* "unknown numeric" */ 837)
	}
	prg.printChar(asciiCode(')'))
}

func (prg *prg) badUnary(c quarterword) {
	prg.dispErr(halfword(memMin), strNumber( /* "Not implemented: " */ 838))
	prg.printOp(c)
	// \xref[Not implemented...]
	prg.printKnownOrUnknownType(prg.curType, prg.curExp)
	{
		prg.helpPtr = 3
		prg.helpLine[2] = /* "I'm afraid I don't know how to apply that operation to that" */ 839
		prg.helpLine[1] = /* "particular type. Continue, and I'll simply return the" */ 840
		prg.helpLine[0] = /* "argument (shown above) as the result of the operation." */ 841
	}
	prg.putGetError()
}

func (prg *prg) negateDepList(p halfword) {
	for true {
		*prg.mem[int32(p)+1].int() = -*prg.mem[int32(p)+1].int()
		if int32(*(*prg.mem[p].hh()).lh()) == memMin {
			goto exit
		}
		p = *(*prg.mem[p].hh()).rh()
	}

exit:
}

func (prg *prg) pairToPath() {
	prg.curExp = int32(prg.newKnot())
	prg.curType = byte(pathType)
}

func (prg *prg) takePart(c quarterword) {
	var (
		p halfword // the big node
	)
	p = uint16(*prg.mem[prg.curExp+1].int())
	*prg.mem[memMin+3+10+2+2+1].int() = int32(p)
	*(*prg.mem[memMin+3+10+2+2].hh()).b0() = prg.curType
	*(*prg.mem[p].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2)
	prg.freeNode(halfword(prg.curExp), halfword(valueNodeSize))
	prg.makeExpCopy(halfword(int32(p) + 2*(int32(c)-xPart)))
	prg.recycleValue(halfword(memMin + 3 + 10 + 2 + 2))
}

func (prg *prg) strToNum(c quarterword) { // converts a string to a number
	var (
		n                 int32       // accumulator
		m                 asciiCode   // current character
		k                 poolPointer // index into |str_pool|
		b/* 8..16 */ byte             // radix of conversion
		badChar           bool        // did the string contain an invalid digit?
	)
	if int32(c) == asciiOp {
		if int32(prg.strStart[prg.curExp+1])-int32(prg.strStart[prg.curExp]) == 0 {
			n = -1
		} else {
			n = int32(prg.strPool[prg.strStart[prg.curExp]])
		}
	} else {
		if int32(c) == octOp {
			b = 8
		} else {
			b = 16
		}
		n = 0
		badChar = false
		for ii := int32(prg.strStart[prg.curExp]); ii <= int32(prg.strStart[prg.curExp+1])-1; ii++ {
			k = poolPointer(ii)
			_ = k
			m = prg.strPool[k]
			if int32(m) >= '0' && int32(m) <= '9' {
				m = byte(int32(m) - '0')
			} else if int32(m) >= 'A' && int32(m) <= 'F' {
				m = byte(int32(m) - 'A' + 10)
			} else if int32(m) >= 'a' && int32(m) <= 'f' {
				m = byte(int32(m) - 'a' + 10)
			} else {
				badChar = true
				m = 0
			}
			if int32(m) >= int32(b) {
				badChar = true
				m = 0
			}
			if n < 32768/int32(b) {
				n = n*int32(b) + int32(m)
			} else {
				n = 32767
			}
		}

		// Give error messages if |bad_char| or |n>=4096|
		if badChar {
			prg.dispErr(halfword(memMin), strNumber( /* "String contains illegal digits" */ 843))
			// \xref[String contains illegal digits]
			if int32(c) == octOp {
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I zeroed out characters that weren't in the range 0..7." */ 844
			} else {
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I zeroed out characters that weren't hex digits." */ 845
			}
			prg.putGetError()
		}
		if n > 4095 {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Number too large (" */ 846) /* \xref[!\relax]  */
			}
			prg.printInt(n)
			prg.printChar(asciiCode(')'))
			// \xref[Number too large]
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I have trouble with numbers greater than 4095; watch out." */ 847
			}
			prg.putGetError()
		}
	}
	prg.flushCurExp(n * 0200000)
}

func (prg *prg) pathLength() (r scaled) { // computes the length of the current path
	var (
		n scaled   // the path length so far
		p halfword // traverser
	)
	p = uint16(prg.curExp)
	if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
		n = -0200000
	} else {
		n = 0
	}
	for {
		p = *(*prg.mem[p].hh()).rh()
		n = n + 0200000
		if int32(p) == prg.curExp {
			break
		}
	}
	r = n
	return r
}

func (prg *prg) testKnown(c quarterword) {
	var (
		b/* trueCode..falseCode */ byte          // is the current expression known?
		p, q                            halfword // locations in a big node
	)
	b = byte(falseCode)
	switch prg.curType {
	case vacuous, booleanType, stringType, penType,
		futurePen, pathType, pictureType, known:
		b = byte(trueCode)
	case transformType, pairType:
		p = uint16(*prg.mem[prg.curExp+1].int())
		q = uint16(int32(p) + int32(prg.bigNodeSize[prg.curType-13]))
		for {
			q = uint16(int32(q) - 2)
			if int32(*(*prg.mem[q].hh()).b0()) != known {
				goto done
			}
			if int32(q) == int32(p) {
				break
			}
		}
		b = byte(trueCode)

	done:
		;

	default:
	}
	if int32(c) == knownOp {
		prg.flushCurExp(scaled(b))
	} else {
		prg.flushCurExp(trueCode + falseCode - int32(b))
	}
	prg.curType = byte(booleanType)
}

func (prg *prg) doUnary(c quarterword) {
	var (
		p, q halfword // for list manipulation
		x    int32    // a temporary register
	)
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
	if prg.internal[tracingCommands-1] > 0400000 {
		prg.beginDiagnostic()
		prg.printNl(strNumber('{'))
		prg.printOp(c)
		prg.printChar(asciiCode('('))

		prg.printExp(halfword(memMin), smallNumber(0)) // show the operand, but not verbosely
		prg.print( /* ")]" */ 842)
		prg.endDiagnostic(false)
	}
	switch c {
	case plus:
		if int32(prg.curType) < pairType {
			if int32(prg.curType) != pictureType {
				prg.badUnary(quarterword(plus))
			}
		}
	case minus:
		// Negate the current expression
		switch prg.curType {
		case pairType, independent:
			q = uint16(prg.curExp)
			prg.makeExpCopy(q)
			if int32(prg.curType) == dependent {
				prg.negateDepList(*(*prg.mem[prg.curExp+1].hh()).rh())
			} else if int32(prg.curType) == pairType {
				p = uint16(*prg.mem[prg.curExp+1].int())
				if int32(*(*prg.mem[p].hh()).b0()) == known {
					*prg.mem[int32(p)+1].int() = -*prg.mem[int32(p)+1].int()
				} else {
					prg.negateDepList(*(*prg.mem[int32(p)+1].hh()).rh())
				}
				if int32(*(*prg.mem[int32(p)+2].hh()).b0()) == known {
					*prg.mem[int32(p)+2+1].int() = -*prg.mem[int32(p)+2+1].int()
				} else {
					prg.negateDepList(*(*prg.mem[int32(p)+2+1].hh()).rh())
				}
			} // if |cur_type=known| then |cur_exp=0|
			prg.recycleValue(q)
			prg.freeNode(q, halfword(valueNodeSize))

		case dependent, protoDependent:
			prg.negateDepList(*(*prg.mem[prg.curExp+1].hh()).rh())
		case known:
			prg.curExp = -prg.curExp
		case pictureType:
			prg.negateEdges(halfword(prg.curExp))

		default:
			prg.badUnary(quarterword(minus))
		}

	// \4
	// Additional cases of unary operators
	case notOp:
		if int32(prg.curType) != booleanType {
			prg.badUnary(quarterword(notOp))
		} else {
			prg.curExp = trueCode + falseCode - prg.curExp
		}

	case sqrtOp, mExpOp, mLogOp, sinDOp,
		cosDOp, floorOp, uniformDeviate, oddOp,
		charExistsOp: //

		if int32(prg.curType) != known {
			prg.badUnary(c)
		} else {
			switch c {
			case sqrtOp:
				prg.curExp = prg.squareRt(prg.curExp)
			case mExpOp:
				prg.curExp = prg.mExp(prg.curExp)
			case mLogOp:
				prg.curExp = prg.mLog(prg.curExp)
			case sinDOp, cosDOp:
				prg.nSinCos(prg.curExp % 23592960 * 16)
				if int32(c) == sinDOp {
					prg.curExp = prg.roundFraction(prg.nSin)
				} else {
					prg.curExp = prg.roundFraction(prg.nCos)
				}

			case floorOp:
				prg.curExp = prg.floorScaled(prg.curExp)
			case uniformDeviate:
				prg.curExp = prg.unifRand(prg.curExp)
			case oddOp:
				if prg.roundUnscaled(prg.curExp)&1 != 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
				prg.curType = byte(booleanType)

			case charExistsOp:
				// Determine if a character has been shipped out
				prg.curExp = prg.roundUnscaled(prg.curExp) % 256
				if prg.curExp < 0 {
					prg.curExp = prg.curExp + 256
				}
				if prg.charExists[prg.curExp] {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
				prg.curType = byte(booleanType)

			}
		} // there are no other cases

	case angleOp:
		if prg.nicePair(prg.curExp, prg.curType) {
			p = uint16(*prg.mem[prg.curExp+1].int())
			x = prg.nArg(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2+1].int())
			if x >= 0 {
				prg.flushCurExp((x + 8) / 16)
			} else {
				prg.flushCurExp(-((-x + 8) / 16))
			}
		} else {
			prg.badUnary(quarterword(angleOp))
		}

	case xPart, yPart:
		if int32(prg.curType) <= pairType && int32(prg.curType) >= transformType {
			prg.takePart(c)
		} else {
			prg.badUnary(c)
		}
	case xxPart, xyPart, yxPart, yyPart:
		if int32(prg.curType) == transformType {
			prg.takePart(c)
		} else {
			prg.badUnary(c)
		}

	case charOp:
		if int32(prg.curType) != known {
			prg.badUnary(quarterword(charOp))
		} else {
			prg.curExp = prg.roundUnscaled(prg.curExp) % 256
			prg.curType = byte(stringType)
			if prg.curExp < 0 {
				prg.curExp = prg.curExp + 256
			}
			if int32(prg.strStart[prg.curExp+1])-int32(prg.strStart[prg.curExp]) != 1 {
				{
					if int32(prg.poolPtr)+1 > int32(prg.maxPoolPtr) {
						if int32(prg.poolPtr)+1 > poolSize {
							prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
						} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
						prg.maxPoolPtr = uint16(int32(prg.poolPtr) + 1)
					}
				}
				{
					prg.strPool[prg.poolPtr] = byte(prg.curExp)
					prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
				}
				prg.curExp = int32(prg.makeString())
			}
		}
	case decimal:
		if int32(prg.curType) != known {
			prg.badUnary(quarterword(decimal))
		} else {
			prg.oldSetting = prg.selector
			prg.selector = byte(newString)
			prg.printScaled(prg.curExp)
			prg.curExp = int32(prg.makeString())
			prg.selector = prg.oldSetting
			prg.curType = byte(stringType)
		}
	case octOp, hexOp, asciiOp:
		if int32(prg.curType) != stringType {
			prg.badUnary(c)
		} else {
			prg.strToNum(c)
		}

	case lengthOp:
		if int32(prg.curType) == stringType {
			prg.flushCurExp((int32(prg.strStart[prg.curExp+1]) - int32(prg.strStart[prg.curExp])) * 0200000)
		} else if int32(prg.curType) == pathType {
			prg.flushCurExp(prg.pathLength())
		} else if int32(prg.curType) == known {
			prg.curExp = abs(prg.curExp)
		} else if prg.nicePair(prg.curExp, prg.curType) {
			prg.flushCurExp(prg.pythAdd(*prg.mem[*prg.mem[prg.curExp+1].int()+1].int(), *prg.mem[*prg.mem[prg.curExp+1].int()+2+1].int()))
		} else {
			prg.badUnary(c)
		}

	case turningOp:
		if int32(prg.curType) == pairType {
			prg.flushCurExp(scaled(0))
		} else if int32(prg.curType) != pathType {
			prg.badUnary(quarterword(turningOp))
		} else if int32(*(*prg.mem[prg.curExp].hh()).b0()) == endpoint {
			prg.flushCurExp(scaled(0))
		} else {
			prg.curPen = uint16(memMin + 3)
			prg.curPathType = byte(contourCode)
			prg.curExp = int32(prg.makeSpec(halfword(prg.curExp),
				02000000000-0100000-1-017777777777, 0))
			prg.flushCurExp(prg.turningNumber * 0200000) // convert to |scaled|
		}

	case booleanType:
		if int32(prg.curType) >= booleanType && int32(prg.curType) <= unknownBoolean {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case stringType:
		if int32(prg.curType) >= stringType && int32(prg.curType) <= unknownString {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case penType:
		if int32(prg.curType) >= penType && int32(prg.curType) <= futurePen {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case pathType:
		if int32(prg.curType) >= pathType && int32(prg.curType) <= unknownPath {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case pictureType:
		if int32(prg.curType) >= pictureType && int32(prg.curType) <= unknownPicture {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case transformType, pairType:
		if int32(prg.curType) == int32(c) {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case numericType:
		if int32(prg.curType) >= known && int32(prg.curType) <= independent {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)
	case knownOp, unknownOp:
		prg.testKnown(c)

	case cycleOp:
		if int32(prg.curType) != pathType {
			prg.flushCurExp(falseCode)
		} else if int32(*(*prg.mem[prg.curExp].hh()).b0()) != endpoint {
			prg.flushCurExp(trueCode)
		} else {
			prg.flushCurExp(falseCode)
		}
		prg.curType = byte(booleanType)

	case makePenOp:
		if int32(prg.curType) == pairType {
			prg.pairToPath()
		}
		if int32(prg.curType) == pathType {
			prg.curType = byte(futurePen)
		} else {
			prg.badUnary(quarterword(makePenOp))
		}

	case makePathOp:
		if int32(prg.curType) == futurePen {
			prg.materializePen()
		}
		if int32(prg.curType) != penType {
			prg.badUnary(quarterword(makePathOp))
		} else {
			prg.flushCurExp(scaled(prg.makePath(halfword(prg.curExp))))
			prg.curType = byte(pathType)
		}

	case totalWeightOp:
		if int32(prg.curType) != pictureType {
			prg.badUnary(quarterword(totalWeightOp))
		} else {
			prg.flushCurExp(prg.totalWeight(halfword(prg.curExp)))
		}
	case reverse:
		if int32(prg.curType) == pathType {
			p = prg.htapYpoc(halfword(prg.curExp))
			if int32(*(*prg.mem[p].hh()).b1()) == endpoint {
				p = *(*prg.mem[p].hh()).rh()
			}
			prg.tossKnotList(halfword(prg.curExp))
			prg.curExp = int32(p)
		} else if int32(prg.curType) == pairType {
			prg.pairToPath()
		} else {
			prg.badUnary(quarterword(reverse))
		}

	} // there are no other cases
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
}

// 922.

// tangle:pos ../../mf.web:18295:3:

// Finally, we have the operations that combine a capsule~|p|
// with the current expression.
// \4
// Declare binary action procedures
func (prg *prg) badBinary(p halfword, c quarterword) {
	prg.dispErr(p, strNumber( /* "" */ 285))
	prg.dispErr(halfword(memMin), strNumber( /* "Not implemented: " */ 838))
	// \xref[Not implemented...]
	if int32(c) >= minOf {
		prg.printOp(c)
	}
	prg.printKnownOrUnknownType(*(*prg.mem[p].hh()).b0(), int32(p))
	if int32(c) >= minOf {
		prg.print( /* "of" */ 479)
	} else {
		prg.printOp(c)
	}
	prg.printKnownOrUnknownType(prg.curType, prg.curExp)

	{
		prg.helpPtr = 3
		prg.helpLine[2] = /* "I'm afraid I don't know how to apply that operation to that" */ 839
		prg.helpLine[1] = /* "combination of types. Continue, and I'll return the second" */ 848
		prg.helpLine[0] = /* "argument (see above) as the result of the operation." */ 849
	}
	prg.putGetError()
}

func (prg *prg) tarnished(p halfword) (r halfword) {
	var (
		q  halfword // beginning of the big node
		r1 halfword // current position in the big node
	)
	q = uint16(*prg.mem[int32(p)+1].int())
	r1 = uint16(int32(q) + int32(prg.bigNodeSize[*(*prg.mem[p].hh()).b0()-13]))
	for {
		r1 = uint16(int32(r1) - 2)
		if int32(*(*prg.mem[r1].hh()).b0()) == independent {
			r = uint16(memMin + 1)
			goto exit
		}
		if int32(r1) == int32(q) {
			break
		}
	}
	r = uint16(memMin)

exit:
	;
	return r
}

// \4
// Declare the procedure called |dep_finish|
func (prg *prg) depFinish(v, q halfword, t smallNumber) {
	var (
		p  halfword // the destination
		vv scaled   // the value, if it is |known|
	)
	if int32(q) == memMin {
		p = uint16(prg.curExp)
	} else {
		p = q
	}
	*(*prg.mem[int32(p)+1].hh()).rh() = v
	*(*prg.mem[p].hh()).b0() = t
	if int32(*(*prg.mem[v].hh()).lh()) == memMin {
		vv = *prg.mem[int32(v)+1].int()
		if int32(q) == memMin {
			prg.flushCurExp(vv)
		} else {
			prg.recycleValue(p)
			*(*prg.mem[q].hh()).b0() = byte(known)
			*prg.mem[int32(q)+1].int() = vv
		}
	} else if int32(q) == memMin {
		prg.curType = t
	}
	if prg.fixNeeded {
		prg.fixDependencies()
	}
}

func (prg *prg) addOrSubtract(p, q halfword, c quarterword) {
	var (
		s, t smallNumber // operand types
		r1   halfword    // list traverser
		v    int32       // second operand value
	)
	if int32(q) == memMin {
		t = prg.curType
		if int32(t) < dependent {
			v = prg.curExp
		} else {
			v = int32(*(*prg.mem[prg.curExp+1].hh()).rh())
		}
	} else {
		t = *(*prg.mem[q].hh()).b0()
		if int32(t) < dependent {
			v = *prg.mem[int32(q)+1].int()
		} else {
			v = int32(*(*prg.mem[int32(q)+1].hh()).rh())
		}
	}
	if int32(t) == known {
		if int32(c) == minus {
			v = -v
		}
		if int32(*(*prg.mem[p].hh()).b0()) == known {
			v = prg.slowAdd(*prg.mem[int32(p)+1].int(), v)
			if int32(q) == memMin {
				prg.curExp = v
			} else {
				*prg.mem[int32(q)+1].int() = v
			}

			goto exit
		}

		// Add a known value to the constant term of |dep_list(p)|
		r1 = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[r1].hh()).lh()) != memMin {
			r1 = *(*prg.mem[r1].hh()).rh()
		}
		*prg.mem[int32(r1)+1].int() = prg.slowAdd(*prg.mem[int32(r1)+1].int(), v)
		if int32(q) == memMin {
			q = prg.getNode(valueNodeSize)
			prg.curExp = int32(q)
			prg.curType = *(*prg.mem[p].hh()).b0()
			*(*prg.mem[q].hh()).b1() = byte(capsule)
		}
		*(*prg.mem[int32(q)+1].hh()).rh() = *(*prg.mem[int32(p)+1].hh()).rh()
		*(*prg.mem[q].hh()).b0() = *(*prg.mem[p].hh()).b0()
		*(*prg.mem[int32(q)+1].hh()).lh() = *(*prg.mem[int32(p)+1].hh()).lh()
		*(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh() = q
		*(*prg.mem[p].hh()).b0() = byte(known) // this will keep the recycler from collecting non-garbage

	} else {
		if int32(c) == minus {
			prg.negateDepList(halfword(v))
		}

		// Add operand |p| to the dependency list |v|
		if int32(*(*prg.mem[p].hh()).b0()) == known {
			for int32(*(*prg.mem[v].hh()).lh()) != memMin {
				v = int32(*(*prg.mem[v].hh()).rh())
			}
			*prg.mem[v+1].int() = prg.slowAdd(*prg.mem[int32(p)+1].int(), *prg.mem[v+1].int())
		} else {
			s = *(*prg.mem[p].hh()).b0()
			r1 = *(*prg.mem[int32(p)+1].hh()).rh()
			if int32(t) == dependent {
				if int32(s) == dependent {
					if prg.maxCoef(r1)+prg.maxCoef(halfword(v)) < 04525252525 {
						v = int32(prg.pPlusQ(halfword(v), r1, smallNumber(dependent)))
						goto done
					}
				} // |fix_needed| will necessarily be false
				t = byte(protoDependent)
				v = int32(prg.pOverV(halfword(v), scaled(0200000), smallNumber(dependent), smallNumber(protoDependent)))
			}
			if int32(s) == protoDependent {
				v = int32(prg.pPlusQ(halfword(v), r1, smallNumber(protoDependent)))
			} else {
				v = int32(prg.pPlusFq(halfword(v), 0200000, r1, smallNumber(protoDependent), smallNumber(dependent)))
			}

		done:
			if int32(q) != memMin {
				prg.depFinish(halfword(v), q, t)
			} else {
				prg.curType = t
				prg.depFinish(halfword(v), halfword(memMin), t)
			}
		}
	}

exit:
}

func (prg *prg) depMult(p halfword, v int32, vIsScaled bool) {
	var (
		q    halfword    // the dependency list being multiplied by |v|
		s, t smallNumber // its type, before and after
	)
	if int32(p) == memMin {
		q = uint16(prg.curExp)
	} else if int32(*(*prg.mem[p].hh()).b0()) != known {
		q = p
	} else {
		if vIsScaled {
			*prg.mem[int32(p)+1].int() = prg.takeScaled(*prg.mem[int32(p)+1].int(), v)
		} else {
			*prg.mem[int32(p)+1].int() = prg.takeFraction(*prg.mem[int32(p)+1].int(), v)
		}

		goto exit
	}
	t = *(*prg.mem[q].hh()).b0()
	q = *(*prg.mem[int32(q)+1].hh()).rh()
	s = t
	if int32(t) == dependent {
		if vIsScaled {
			if prg.abVsCd(prg.maxCoef(q), abs(v), 04525252525-1, 0200000) >= 0 {
				t = byte(protoDependent)
			}
		}
	}
	q = prg.pTimesV(q, v, s, t, vIsScaled)
	prg.depFinish(q, p, t)

exit:
}

func (prg *prg) hardTimes(p halfword) {
	var (
		q    halfword // a copy of the dependent variable |p|
		r1   halfword // the big node for the nice pair
		u, v scaled   // the known values of the nice pair
	)
	if int32(*(*prg.mem[p].hh()).b0()) == pairType {
		q = prg.stashCurExp()
		prg.unstashCurExp(p)
		p = q
	} // now |cur_type=pair_type|
	r1 = uint16(*prg.mem[prg.curExp+1].int())
	u = *prg.mem[int32(r1)+1].int()
	v = *prg.mem[int32(r1)+2+1].int()

	// Move the dependent variable |p| into both parts of the pair node |r|
	*(*prg.mem[int32(r1)+2].hh()).b0() = *(*prg.mem[p].hh()).b0()
	prg.newDep(halfword(int32(r1)+2), prg.copyDepList(*(*prg.mem[int32(p)+1].hh()).rh()))

	*(*prg.mem[r1].hh()).b0() = *(*prg.mem[p].hh()).b0()
	prg.mem[int32(r1)+1] = prg.mem[int32(p)+1]
	*(*prg.mem[*(*prg.mem[int32(p)+1].hh()).lh()].hh()).rh() = r1
	prg.freeNode(p, halfword(valueNodeSize))
	prg.depMult(r1, u, true)
	prg.depMult(halfword(int32(r1)+2), v, true)
}

func (prg *prg) depDiv(p halfword, v scaled) {
	var (
		q    halfword    // the dependency list being divided by |v|
		s, t smallNumber // its type, before and after
	)
	if int32(p) == memMin {
		q = uint16(prg.curExp)
	} else if int32(*(*prg.mem[p].hh()).b0()) != known {
		q = p
	} else {
		*prg.mem[int32(p)+1].int() = prg.makeScaled(*prg.mem[int32(p)+1].int(), v)
		goto exit
	}
	t = *(*prg.mem[q].hh()).b0()
	q = *(*prg.mem[int32(q)+1].hh()).rh()
	s = t
	if int32(t) == dependent {
		if prg.abVsCd(prg.maxCoef(q), 0200000, 04525252525-1, abs(v)) >= 0 {
			t = byte(protoDependent)
		}
	}
	q = prg.pOverV(q, v, s, t)
	prg.depFinish(q, p, t)

exit:
}

func (prg *prg) setUpTrans(c quarterword) {
	var (
		p, q, r1 halfword // list manipulation registers
	)
	if int32(c) != transformedBy || int32(prg.curType) != transformType {
		p = prg.stashCurExp()
		prg.curExp = int32(prg.idTransform())
		prg.curType = byte(transformType)
		q = uint16(*prg.mem[prg.curExp+1].int())
		switch c {
		case rotatedBy:
			if int32(*(*prg.mem[p].hh()).b0()) == known {
				prg.nSinCos(*prg.mem[int32(p)+1].int() % 23592960 * 16)
				*prg.mem[int32(q)+4+1].int() = prg.roundFraction(prg.nCos)
				*prg.mem[int32(q)+8+1].int() = prg.roundFraction(prg.nSin)
				*prg.mem[int32(q)+6+1].int() = -*prg.mem[int32(q)+8+1].int()
				*prg.mem[int32(q)+10+1].int() = *prg.mem[int32(q)+4+1].int()

				goto done
			}

		case slantedBy:
			if int32(*(*prg.mem[p].hh()).b0()) > pairType {
				prg.install(halfword(int32(q)+6), p)
				goto done
			}
		case scaledBy:
			if int32(*(*prg.mem[p].hh()).b0()) > pairType {
				prg.install(halfword(int32(q)+4), p)
				prg.install(halfword(int32(q)+10), p)
				goto done
			}
		case shiftedBy:
			if int32(*(*prg.mem[p].hh()).b0()) == pairType {
				r1 = uint16(*prg.mem[int32(p)+1].int())
				prg.install(q, r1)
				prg.install(halfword(int32(q)+2), halfword(int32(r1)+2))
				goto done
			}
		case xScaled:
			if int32(*(*prg.mem[p].hh()).b0()) > pairType {
				prg.install(halfword(int32(q)+4), p)
				goto done
			}
		case yScaled:
			if int32(*(*prg.mem[p].hh()).b0()) > pairType {
				prg.install(halfword(int32(q)+10), p)
				goto done
			}
		case zScaled:
			if int32(*(*prg.mem[p].hh()).b0()) == pairType {
				r1 = uint16(*prg.mem[int32(p)+1].int())
				prg.install(halfword(int32(q)+4), r1)
				prg.install(halfword(int32(q)+10), r1)
				prg.install(halfword(int32(q)+8), halfword(int32(r1)+2))
				if int32(*(*prg.mem[int32(r1)+2].hh()).b0()) == known {
					*prg.mem[int32(r1)+2+1].int() = -*prg.mem[int32(r1)+2+1].int()
				} else {
					prg.negateDepList(*(*prg.mem[int32(r1)+2+1].hh()).rh())
				}
				prg.install(halfword(int32(q)+6), halfword(int32(r1)+2))

				goto done
			}

		case transformedBy:

		} // there are no other cases
		prg.dispErr(p, strNumber( /* "Improper transformation argument" */ 858))
		// \xref[Improper transformation argument]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "The expression shown above has the wrong type," */ 859
			prg.helpLine[1] = /* "so I can't transform anything using it." */ 860
			prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
		}
		prg.putGetError()

	done:
		prg.recycleValue(p)
		prg.freeNode(p, halfword(valueNodeSize))
	}

	// If the current transform is entirely known, stash it in global variables; otherwise |return|
	q = uint16(*prg.mem[prg.curExp+1].int())
	r1 = uint16(int32(q) + transformNodeSize)
	for {
		r1 = uint16(int32(r1) - 2)
		if int32(*(*prg.mem[r1].hh()).b0()) != known {
			goto exit
		}
		if int32(r1) == int32(q) {
			break
		}
	}
	prg.txx = *prg.mem[int32(q)+4+1].int()
	prg.txy = *prg.mem[int32(q)+6+1].int()
	prg.tyx = *prg.mem[int32(q)+8+1].int()
	prg.tyy = *prg.mem[int32(q)+10+1].int()
	prg.tx = *prg.mem[int32(q)+1].int()
	prg.ty = *prg.mem[int32(q)+2+1].int()
	prg.flushCurExp(scaled(0))

exit:
}

func (prg *prg) setUpKnownTrans(c quarterword) {
	prg.setUpTrans(c)
	if int32(prg.curType) != known {
		prg.dispErr(halfword(memMin), strNumber( /* "Transform components aren't all known" */ 861))
		// \xref[Transform components...]
		{
			prg.helpPtr = 3
			prg.helpLine[2] = /* "I'm unable to apply a partially specified transformation" */ 862
			prg.helpLine[1] = /* "except to a fully known pair or transform." */ 863
			prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
		}
		prg.putGetFlushError(scaled(0))
		prg.txx = 0200000
		prg.txy = 0
		prg.tyx = 0
		prg.tyy = 0200000
		prg.tx = 0
		prg.ty = 0
	}
}

func (prg *prg) trans(p, q halfword) {
	var (
		v scaled // the new |x| value
	)
	v = prg.takeScaled(*prg.mem[p].int(), prg.txx) + prg.takeScaled(*prg.mem[q].int(), prg.txy) + prg.tx
	*prg.mem[q].int() = prg.takeScaled(*prg.mem[p].int(), prg.tyx) + prg.takeScaled(*prg.mem[q].int(), prg.tyy) + prg.ty
	*prg.mem[p].int() = v
}

func (prg *prg) pathTrans(p halfword, c quarterword) {
	var (
		q halfword // list traverser
	)
	prg.setUpKnownTrans(c)
	prg.unstashCurExp(p)
	if int32(prg.curType) == penType {
		if *prg.mem[prg.curExp+9].int() == 0 {
			if prg.tx == 0 {
				if prg.ty == 0 {
					goto exit
				}
			}
		}
		prg.flushCurExp(scaled(prg.makePath(halfword(prg.curExp))))
		prg.curType = byte(futurePen)
	}
	q = uint16(prg.curExp)
	for {
		if int32(*(*prg.mem[q].hh()).b0()) != endpoint {
			prg.trans(halfword(int32(q)+3), halfword(int32(q)+4))
		} // that's |left_x| and |left_y|
		prg.trans(halfword(int32(q)+1), halfword(int32(q)+2)) // that's |x_coord| and |y_coord|
		if int32(*(*prg.mem[q].hh()).b1()) != endpoint {
			prg.trans(halfword(int32(q)+5), halfword(int32(q)+6))
		} // that's |right_x| and |right_y|
		q = *(*prg.mem[q].hh()).rh()
		if int32(q) == prg.curExp {
			break
		}
	}

exit:
}

func (prg *prg) edgesTrans(p halfword, c quarterword) {
	prg.setUpKnownTrans(c)
	prg.unstashCurExp(p)
	prg.curEdges = uint16(prg.curExp)
	if int32(*(*prg.mem[prg.curEdges].hh()).rh()) == int32(prg.curEdges) {
		goto exit
	} // the empty set is easy to transform
	if prg.txx == 0 {
		if prg.tyy == 0 {
			if prg.txy%0200000 == 0 {
				if prg.tyx%0200000 == 0 {
					prg.xySwapEdges()
					prg.txx = prg.txy
					prg.tyy = prg.tyx
					prg.txy = 0
					prg.tyx = 0
					if int32(*(*prg.mem[prg.curEdges].hh()).rh()) == int32(prg.curEdges) {
						goto exit
					}
				}
			}
		}
	}
	if prg.txy == 0 {
		if prg.tyx == 0 {
			if prg.txx%0200000 == 0 {
				if prg.tyy%0200000 == 0 {
					if prg.txx == 0 || prg.tyy == 0 {
						prg.tossEdges(prg.curEdges)
						prg.curExp = int32(prg.getNode(edgeHeaderSize))
						prg.initEdges(halfword(prg.curExp))
					} else {
						if prg.txx < 0 {
							prg.xReflectEdges()
							prg.txx = -prg.txx
						}
						if prg.tyy < 0 {
							prg.yReflectEdges()
							prg.tyy = -prg.tyy
						}
						if prg.txx != 0200000 {
							prg.xScaleEdges(prg.txx / 0200000)
						}
						if prg.tyy != 0200000 {
							prg.yScaleEdges(prg.tyy / 0200000)
						}

						// Shift the edges by |(tx,ty)|, rounded
						prg.tx = prg.roundUnscaled(prg.tx)
						prg.ty = prg.roundUnscaled(prg.ty)
						if int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())+prg.tx <= 0 || int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh())+prg.tx >= 8192 || int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh())+prg.ty <= 0 || int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh())+prg.ty >= 8191 || abs(prg.tx) >= 4096 || abs(prg.ty) >= 4096 {
							{
								if int32(prg.interaction) == errorStopMode {
								}
								prg.printNl(strNumber( /* "! " */ 261))
								prg.print( /* "Too far to shift" */ 867) /* \xref[!\relax]  */
							}
							// \xref[Too far to shift]
							{
								prg.helpPtr = 3
								prg.helpLine[2] = /* "I can't shift the picture as requested---it would" */ 868
								prg.helpLine[1] = /* "make some coordinates too large or too small." */ 537
								prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
							}
							prg.putGetError()
						} else {
							if prg.tx != 0 {
								if !(abs(int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())-prg.tx-4096) < 4096) {
									prg.fixOffset()
								}
								*(*prg.mem[int32(prg.curEdges)+2].hh()).lh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) + prg.tx)
								*(*prg.mem[int32(prg.curEdges)+2].hh()).rh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh()) + prg.tx)
								*(*prg.mem[int32(prg.curEdges)+3].hh()).lh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) - prg.tx)
								*prg.mem[int32(prg.curEdges)+4].int() = 0
							}
							if prg.ty != 0 {
								*(*prg.mem[int32(prg.curEdges)+1].hh()).lh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh()) + prg.ty)
								*(*prg.mem[int32(prg.curEdges)+1].hh()).rh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) + prg.ty)
								*(*prg.mem[int32(prg.curEdges)+5].hh()).lh() = uint16(int32(*(*prg.mem[int32(prg.curEdges)+5].hh()).lh()) + prg.ty)
								*prg.mem[int32(prg.curEdges)+4].int() = 0
							}
						}
					}

					goto exit
				}
			}
		}
	}
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "That transformation is too hard" */ 864) /* \xref[!\relax]  */
	}
	// \xref[That transformation...]
	{
		prg.helpPtr = 3
		prg.helpLine[2] = /* "I can apply complicated transformations to paths," */ 865
		prg.helpLine[1] = /* "but I can only do integer operations on pictures." */ 866
		prg.helpLine[0] = /* "Proceed, and I'll omit the transformation." */ 538
	}
	prg.putGetError()

exit:
}

// \4
// Declare subroutines needed by |big_trans|
func (prg *prg) bilin1(p halfword, t scaled, q halfword, u, delta scaled) {
	var (
		r1 halfword // list traverser
	)
	if t != 0200000 {
		prg.depMult(p, t, true)
	}
	if u != 0 {
		if int32(*(*prg.mem[q].hh()).b0()) == known {
			delta = delta + prg.takeScaled(*prg.mem[int32(q)+1].int(), u)
		} else {
			if int32(*(*prg.mem[p].hh()).b0()) != protoDependent {
				if int32(*(*prg.mem[p].hh()).b0()) == known {
					prg.newDep(p, prg.constDependency(*prg.mem[int32(p)+1].int()))
				} else {
					*(*prg.mem[int32(p)+1].hh()).rh() = prg.pTimesV(*(*prg.mem[int32(p)+1].hh()).rh(), 0200000, smallNumber(dependent), smallNumber(protoDependent), true)
				}
				*(*prg.mem[p].hh()).b0() = byte(protoDependent)
			}
			*(*prg.mem[int32(p)+1].hh()).rh() = prg.pPlusFq(*(*prg.mem[int32(p)+1].hh()).rh(), u, *(*prg.mem[int32(q)+1].hh()).rh(), smallNumber(protoDependent), *(*prg.mem[q].hh()).b0())
		}
	}
	if int32(*(*prg.mem[p].hh()).b0()) == known {
		*prg.mem[int32(p)+1].int() = *prg.mem[int32(p)+1].int() + delta
	} else {
		r1 = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[r1].hh()).lh()) != memMin {
			r1 = *(*prg.mem[r1].hh()).rh()
		}
		delta = *prg.mem[int32(r1)+1].int() + delta
		if int32(r1) != int32(*(*prg.mem[int32(p)+1].hh()).rh()) {
			*prg.mem[int32(r1)+1].int() = delta
		} else {
			prg.recycleValue(p)
			*(*prg.mem[p].hh()).b0() = byte(known)
			*prg.mem[int32(p)+1].int() = delta
		}
	}
	if prg.fixNeeded {
		prg.fixDependencies()
	}
}

func (prg *prg) addMultDep(p halfword, v scaled, r1 halfword) {
	if int32(*(*prg.mem[r1].hh()).b0()) == known {
		*prg.mem[int32(prg.depFinal)+1].int() = *prg.mem[int32(prg.depFinal)+1].int() + prg.takeScaled(*prg.mem[int32(r1)+1].int(), v)
	} else {
		*(*prg.mem[int32(p)+1].hh()).rh() = prg.pPlusFq(*(*prg.mem[int32(p)+1].hh()).rh(), v, *(*prg.mem[int32(r1)+1].hh()).rh(), smallNumber(protoDependent), *(*prg.mem[r1].hh()).b0())
		if prg.fixNeeded {
			prg.fixDependencies()
		}
	}
}

func (prg *prg) bilin2(p, t halfword, v scaled, u, q halfword) {
	var (
		vv scaled // temporary storage for |value(p)|
	)
	vv = *prg.mem[int32(p)+1].int()
	*(*prg.mem[p].hh()).b0() = byte(protoDependent)
	prg.newDep(p, prg.constDependency(scaled(0))) // this sets |dep_final|
	if vv != 0 {
		prg.addMultDep(p, vv, t)
	} // |dep_final| doesn't change
	if v != 0 {
		prg.addMultDep(p, v, u)
	}
	if int32(q) != memMin {
		prg.addMultDep(p, scaled(0200000), q)
	}
	if int32(*(*prg.mem[int32(p)+1].hh()).rh()) == int32(prg.depFinal) {
		vv = *prg.mem[int32(prg.depFinal)+1].int()
		prg.recycleValue(p)
		*(*prg.mem[p].hh()).b0() = byte(known)
		*prg.mem[int32(p)+1].int() = vv
	}
}

func (prg *prg) bilin3(p halfword, t, v, u, delta scaled) {
	if t != 0200000 {
		delta = delta + prg.takeScaled(*prg.mem[int32(p)+1].int(), t)
	} else {
		delta = delta + *prg.mem[int32(p)+1].int()
	}
	if u != 0 {
		*prg.mem[int32(p)+1].int() = delta + prg.takeScaled(v, u)
	} else {
		*prg.mem[int32(p)+1].int() = delta
	}
}

func (prg *prg) bigTrans(p halfword, c quarterword) {
	var (
		q, r1, pp, qq halfword    // list manipulation registers
		s             smallNumber // size of a big node
	)
	s = prg.bigNodeSize[*(*prg.mem[p].hh()).b0()-13]
	q = uint16(*prg.mem[int32(p)+1].int())
	r1 = uint16(int32(q) + int32(s))
	for {
		r1 = uint16(int32(r1) - 2)
		if int32(*(*prg.mem[r1].hh()).b0()) != known {
			prg.setUpKnownTrans(c)
			prg.makeExpCopy(p)
			r1 = uint16(*prg.mem[prg.curExp+1].int())
			if int32(prg.curType) == transformType {
				prg.bilin1(halfword(int32(r1)+10), prg.tyy, halfword(int32(q)+6), prg.tyx, scaled(0))
				prg.bilin1(halfword(int32(r1)+8), prg.tyy, halfword(int32(q)+4), prg.tyx, scaled(0))
				prg.bilin1(halfword(int32(r1)+6), prg.txx, halfword(int32(q)+10), prg.txy, scaled(0))
				prg.bilin1(halfword(int32(r1)+4), prg.txx, halfword(int32(q)+8), prg.txy, scaled(0))
			}
			prg.bilin1(halfword(int32(r1)+2), prg.tyy, q, prg.tyx, prg.ty)
			prg.bilin1(r1, prg.txx, halfword(int32(q)+2), prg.txy, prg.tx)

			goto exit
		}
		if int32(r1) == int32(q) {
			break
		}
	}

	// Transform a known big node
	prg.setUpTrans(c)
	if int32(prg.curType) == known {
		prg.makeExpCopy(p)
		r1 = uint16(*prg.mem[prg.curExp+1].int())
		if int32(prg.curType) == transformType {
			prg.bilin3(halfword(int32(r1)+10), prg.tyy, *prg.mem[int32(q)+6+1].int(), prg.tyx, scaled(0))
			prg.bilin3(halfword(int32(r1)+8), prg.tyy, *prg.mem[int32(q)+4+1].int(), prg.tyx, scaled(0))
			prg.bilin3(halfword(int32(r1)+6), prg.txx, *prg.mem[int32(q)+10+1].int(), prg.txy, scaled(0))
			prg.bilin3(halfword(int32(r1)+4), prg.txx, *prg.mem[int32(q)+8+1].int(), prg.txy, scaled(0))
		}
		prg.bilin3(halfword(int32(r1)+2), prg.tyy, *prg.mem[int32(q)+1].int(), prg.tyx, prg.ty)
		prg.bilin3(r1, prg.txx, *prg.mem[int32(q)+2+1].int(), prg.txy, prg.tx)
	} else {
		pp = prg.stashCurExp()
		qq = uint16(*prg.mem[int32(pp)+1].int())
		prg.makeExpCopy(p)
		r1 = uint16(*prg.mem[prg.curExp+1].int())
		if int32(prg.curType) == transformType {
			prg.bilin2(halfword(int32(r1)+10), halfword(int32(qq)+10), *prg.mem[int32(q)+6+1].int(), halfword(int32(qq)+8), halfword(memMin))
			prg.bilin2(halfword(int32(r1)+8), halfword(int32(qq)+10), *prg.mem[int32(q)+4+1].int(), halfword(int32(qq)+8), halfword(memMin))
			prg.bilin2(halfword(int32(r1)+6), halfword(int32(qq)+4), *prg.mem[int32(q)+10+1].int(), halfword(int32(qq)+6), halfword(memMin))
			prg.bilin2(halfword(int32(r1)+4), halfword(int32(qq)+4), *prg.mem[int32(q)+8+1].int(), halfword(int32(qq)+6), halfword(memMin))
		}
		prg.bilin2(halfword(int32(r1)+2), halfword(int32(qq)+10), *prg.mem[int32(q)+1].int(), halfword(int32(qq)+8), halfword(int32(qq)+2))
		prg.bilin2(r1, halfword(int32(qq)+4), *prg.mem[int32(q)+2+1].int(), halfword(int32(qq)+6), qq)
		prg.recycleValue(pp)
		prg.freeNode(pp, halfword(valueNodeSize))
	}

exit:
} // node |p| will now be recycled by |do_binary|

func (prg *prg) cat(p halfword) {
	var (
		a, b strNumber   // the strings being concatenated
		k    poolPointer // index into |str_pool|
	)
	a = uint16(*prg.mem[int32(p)+1].int())
	b = uint16(prg.curExp)
	{
		if int32(prg.poolPtr)+(int32(prg.strStart[int32(a)+1])-int32(prg.strStart[a]))+(int32(prg.strStart[int32(b)+1])-int32(prg.strStart[b])) > int32(prg.maxPoolPtr) {
			if int32(prg.poolPtr)+(int32(prg.strStart[int32(a)+1])-int32(prg.strStart[a]))+(int32(prg.strStart[int32(b)+1])-int32(prg.strStart[b])) > poolSize {
				prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
			} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
			prg.maxPoolPtr = uint16(int32(prg.poolPtr) + (int32(prg.strStart[int32(a)+1]) - int32(prg.strStart[a])) + (int32(prg.strStart[int32(b)+1]) - int32(prg.strStart[b])))
		}
	}
	for ii := int32(prg.strStart[a]); ii <= int32(prg.strStart[int32(a)+1])-1; ii++ {
		k = poolPointer(ii)
		_ = k
		prg.strPool[prg.poolPtr] = prg.strPool[k]
		prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
	}
	for ii := int32(prg.strStart[b]); ii <= int32(prg.strStart[int32(b)+1])-1; ii++ {
		k = poolPointer(ii)
		_ = k
		prg.strPool[prg.poolPtr] = prg.strPool[k]
		prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
	}
	prg.curExp = int32(prg.makeString())
	{
		if int32(prg.strRef[b]) < maxStrRef {
			if int32(prg.strRef[b]) > 1 {
				prg.strRef[b] = byte(int32(prg.strRef[b]) - 1)
			} else {
				prg.flushString(b)
			}
		}
	}
}

func (prg *prg) chopString(p halfword) {
	var (
		a, b     int32     // start and stop points
		l        int32     // length of the original string
		k        int32     // runs from |a| to |b|
		s        strNumber // the original string
		reversed bool      // was |a>b|?
	)
	a = prg.roundUnscaled(*prg.mem[int32(p)+1].int())
	b = prg.roundUnscaled(*prg.mem[int32(p)+2+1].int())
	if a <= b {
		reversed = false
	} else {
		reversed = true
		k = a
		a = b
		b = k
	}
	s = uint16(prg.curExp)
	l = int32(prg.strStart[int32(s)+1]) - int32(prg.strStart[s])
	if a < 0 {
		a = 0
		if b < 0 {
			b = 0
		}
	}
	if b > l {
		b = l
		if a > l {
			a = l
		}
	}
	{
		if int32(prg.poolPtr)+b-a > int32(prg.maxPoolPtr) {
			if int32(prg.poolPtr)+b-a > poolSize {
				prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
			} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
			prg.maxPoolPtr = uint16(int32(prg.poolPtr) + b - a)
		}
	}
	if reversed {
		for ii := int32(prg.strStart[s]) + b - 1; ii >= int32(prg.strStart[s])+a; ii-- {
			k = ii
			_ = k
			prg.strPool[prg.poolPtr] = prg.strPool[k]
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
	} else {
		for ii := int32(prg.strStart[s]) + a; ii <= int32(prg.strStart[s])+b-1; ii++ {
			k = ii
			_ = k
			prg.strPool[prg.poolPtr] = prg.strPool[k]
			prg.poolPtr = uint16(int32(prg.poolPtr) + 1)
		}
	}
	prg.curExp = int32(prg.makeString())
	{
		if int32(prg.strRef[s]) < maxStrRef {
			if int32(prg.strRef[s]) > 1 {
				prg.strRef[s] = byte(int32(prg.strRef[s]) - 1)
			} else {
				prg.flushString(s)
			}
		}
	}
}

func (prg *prg) chopPath(p halfword) {
	var (
		q              halfword // a knot in the original path
		pp, qq, rr, ss halfword // link variables for copies of path nodes
		a, b, k, l     scaled   // indices for chopping
		reversed       bool     // was |a>b|?
	)
	l = prg.pathLength()
	a = *prg.mem[int32(p)+1].int()
	b = *prg.mem[int32(p)+2+1].int()
	if a <= b {
		reversed = false
	} else {
		reversed = true
		k = a
		a = b
		b = k
	}

	// Dispense with the cases |a<0| and/or |b>l|
	if a < 0 {
		if int32(*(*prg.mem[prg.curExp].hh()).b0()) == endpoint {
			a = 0
			if b < 0 {
				b = 0
			}
		} else {
			for {
				a = a + l
				b = b + l
				if a >= 0 {
					break
				}
			}
		}
	} // a cycle always has length |l>0|
	if b > l {
		if int32(*(*prg.mem[prg.curExp].hh()).b0()) == endpoint {
			b = l
			if a > l {
				a = l
			}
		} else {
			for a >= l {
				a = a - l
				b = b - l
			}
		}
	}
	q = uint16(prg.curExp)
	for a >= 0200000 {
		q = *(*prg.mem[q].hh()).rh()
		a = a - 0200000
		b = b - 0200000
	}
	if b == a {
		if a > 0 {
			qq = *(*prg.mem[q].hh()).rh()
			prg.splitCubic(q, a*010000, *prg.mem[int32(qq)+1].int(), *prg.mem[int32(qq)+2].int())
			q = *(*prg.mem[q].hh()).rh()
		}
		pp = prg.copyKnot(q)
		qq = pp
	} else {
		// Construct a path from |pp| to |qq| of length $\lceil b\rceil$
		pp = prg.copyKnot(q)
		qq = pp
		for {
			q = *(*prg.mem[q].hh()).rh()
			rr = qq
			qq = prg.copyKnot(q)
			*(*prg.mem[rr].hh()).rh() = qq
			b = b - 0200000
			if b <= 0 {
				break
			}
		}
		if a > 0 {
			ss = pp
			pp = *(*prg.mem[pp].hh()).rh()
			prg.splitCubic(ss, a*010000, *prg.mem[int32(pp)+1].int(), *prg.mem[int32(pp)+2].int())
			pp = *(*prg.mem[ss].hh()).rh()
			prg.freeNode(ss, halfword(knotNodeSize))
			if int32(rr) == int32(ss) {
				b = prg.makeScaled(b, 0200000-a)
				rr = pp
			}
		}
		if b < 0 {
			prg.splitCubic(rr, (b+0200000)*010000, *prg.mem[int32(qq)+1].int(), *prg.mem[int32(qq)+2].int())
			prg.freeNode(qq, halfword(knotNodeSize))
			qq = *(*prg.mem[rr].hh()).rh()
		}
	}
	*(*prg.mem[pp].hh()).b0() = byte(endpoint)
	*(*prg.mem[qq].hh()).b1() = byte(endpoint)
	*(*prg.mem[qq].hh()).rh() = pp
	prg.tossKnotList(halfword(prg.curExp))
	if reversed {
		prg.curExp = int32(*(*prg.mem[prg.htapYpoc(pp)].hh()).rh())
		prg.tossKnotList(pp)
	} else {
		prg.curExp = int32(pp)
	}
}

func (prg *prg) pairValue(x, y scaled) {
	var (
		p halfword // a pair node
	)
	p = prg.getNode(valueNodeSize)
	prg.flushCurExp(scaled(p))
	prg.curType = byte(pairType)
	*(*prg.mem[p].hh()).b0() = byte(pairType)
	*(*prg.mem[p].hh()).b1() = byte(capsule)
	prg.initBigNode(p)
	p = uint16(*prg.mem[int32(p)+1].int())

	*(*prg.mem[p].hh()).b0() = byte(known)
	*prg.mem[int32(p)+1].int() = x

	*(*prg.mem[int32(p)+2].hh()).b0() = byte(known)
	*prg.mem[int32(p)+2+1].int() = y

}

func (prg *prg) setUpOffset(p halfword) {
	prg.findOffset(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2+1].int(), halfword(prg.curExp))
	prg.pairValue(prg.curX, prg.curY)
}

func (prg *prg) setUpDirectionTime(p halfword) {
	prg.flushCurExp(prg.findDirectionTime(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2+1].int(), halfword(prg.curExp)))
}

func (prg *prg) findPoint(v scaled, c quarterword) {
	var (
		p halfword // the path
		n scaled   // its length
		q halfword // successor of |p|
	)
	p = uint16(prg.curExp)

	if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
		n = -0200000
	} else {
		n = 0
	}
	for {
		p = *(*prg.mem[p].hh()).rh()
		n = n + 0200000
		if int32(p) == prg.curExp {
			break
		}
	}
	if n == 0 {
		v = 0
	} else if v < 0 {
		if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
			v = 0
		} else {
			v = n - 1 - (-v-1)%n
		}
	} else if v > n {
		if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
			v = n
		} else {
			v = v % n
		}
	}
	p = uint16(prg.curExp)
	for v >= 0200000 {
		p = *(*prg.mem[p].hh()).rh()
		v = v - 0200000
	}
	if v != 0 {
		q = *(*prg.mem[p].hh()).rh()
		prg.splitCubic(p, v*010000, *prg.mem[int32(q)+1].int(), *prg.mem[int32(q)+2].int())
		p = *(*prg.mem[p].hh()).rh()
	}

	// Set the current expression to the desired path coordinates
	switch c {
	case pointOf:
		prg.pairValue(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2].int())
	case precontrolOf:
		if int32(*(*prg.mem[p].hh()).b0()) == endpoint {
			prg.pairValue(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2].int())
		} else {
			prg.pairValue(*prg.mem[int32(p)+3].int(), *prg.mem[int32(p)+4].int())
		}
	case postcontrolOf:
		if int32(*(*prg.mem[p].hh()).b1()) == endpoint {
			prg.pairValue(*prg.mem[int32(p)+1].int(), *prg.mem[int32(p)+2].int())
		} else {
			prg.pairValue(*prg.mem[int32(p)+5].int(), *prg.mem[int32(p)+6].int())
		}
	}
}

func (prg *prg) doBinary(p halfword, c quarterword) {
	var (
		q, r1, rr    halfword // for list manipulation
		oldP, oldExp halfword // capsules to recycle
		v            int32    // for numeric manipulation
	)
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
	if prg.internal[tracingCommands-1] > 0400000 {
		prg.beginDiagnostic()
		prg.printNl(strNumber( /* "[(" */ 850))
		prg.printExp(p, smallNumber(0)) // show the operand, but not verbosely
		prg.printChar(asciiCode(')'))
		prg.printOp(c)
		prg.printChar(asciiCode('('))

		prg.printExp(halfword(memMin), smallNumber(0))
		prg.print( /* ")]" */ 842)
		prg.endDiagnostic(false)
	}

	// Sidestep |independent| cases in capsule |p|
	switch *(*prg.mem[p].hh()).b0() {
	case transformType, pairType:
		oldP = prg.tarnished(p)
	case independent:
		oldP = uint16(memMin + 1)

	default:
		oldP = uint16(memMin)
	}
	if int32(oldP) != memMin {
		q = prg.stashCurExp()
		oldP = p
		prg.makeExpCopy(oldP)
		p = prg.stashCurExp()
		prg.unstashCurExp(q)
	}

	// Sidestep |independent| cases in the current expression
	switch prg.curType {
	case transformType, pairType:
		oldExp = prg.tarnished(halfword(prg.curExp))
	case independent:
		oldExp = uint16(memMin + 1)

	default:
		oldExp = uint16(memMin)
	}
	if int32(oldExp) != memMin {
		oldExp = uint16(prg.curExp)
		prg.makeExpCopy(oldExp)
	}
	switch c {
	case plus, minus:
		// Add or subtract the current expression from |p|
		if int32(prg.curType) < pairType || int32(*(*prg.mem[p].hh()).b0()) < pairType {
			if int32(prg.curType) == pictureType && int32(*(*prg.mem[p].hh()).b0()) == pictureType {
				if int32(c) == minus {
					prg.negateEdges(halfword(prg.curExp))
				}
				prg.curEdges = uint16(prg.curExp)
				prg.mergeEdges(halfword(*prg.mem[int32(p)+1].int()))
			} else {
				prg.badBinary(p, c)
			}
		} else if int32(prg.curType) == pairType {
			if int32(*(*prg.mem[p].hh()).b0()) != pairType {
				prg.badBinary(p, c)
			} else {
				q = uint16(*prg.mem[int32(p)+1].int())
				r1 = uint16(*prg.mem[prg.curExp+1].int())
				prg.addOrSubtract(q, r1, c)
				prg.addOrSubtract(halfword(int32(q)+2), halfword(int32(r1)+2), c)
			}
		} else if int32(*(*prg.mem[p].hh()).b0()) == pairType {
			prg.badBinary(p, c)
		} else {
			prg.addOrSubtract(p, halfword(memMin), c)
		}

	// \4
	// Additional cases of binary operators
	case lessThan, lessOrEqual, greaterThan, greaterOrEqual,
		equalTo, unequalTo:
		if int32(prg.curType) > pairType && int32(*(*prg.mem[p].hh()).b0()) > pairType {
			prg.addOrSubtract(p, halfword(memMin), quarterword(minus))
		} else if int32(prg.curType) != int32(*(*prg.mem[p].hh()).b0()) {
			prg.badBinary(p, c)
			goto done
		} else if int32(prg.curType) == stringType {
			prg.flushCurExp(prg.strVsStr(strNumber(*prg.mem[int32(p)+1].int()), strNumber(prg.curExp)))
		} else if int32(prg.curType) == unknownString || int32(prg.curType) == unknownBoolean {
			q = uint16(*prg.mem[prg.curExp+1].int())
			for int32(q) != prg.curExp && int32(q) != int32(p) {
				q = uint16(*prg.mem[int32(q)+1].int())
			}
			if int32(q) == int32(p) {
				prg.flushCurExp(scaled(0))
			}
		} else if int32(prg.curType) == pairType || int32(prg.curType) == transformType {
			q = uint16(*prg.mem[int32(p)+1].int())
			r1 = uint16(*prg.mem[prg.curExp+1].int())
			rr = uint16(int32(r1) + int32(prg.bigNodeSize[prg.curType-13]) - 2)
			for true {
				prg.addOrSubtract(q, r1, quarterword(minus))
				if int32(*(*prg.mem[r1].hh()).b0()) != known {
					goto done1
				}
				if *prg.mem[int32(r1)+1].int() != 0 {
					goto done1
				}
				if int32(r1) == int32(rr) {
					goto done1
				}
				q = uint16(int32(q) + 2)
				r1 = uint16(int32(r1) + 2)
			}

		done1:
			prg.takePart(quarterword(xPart + (int32(r1)-*prg.mem[prg.curExp+1].int())/2))
		} else if int32(prg.curType) == booleanType {
			prg.flushCurExp(prg.curExp - *prg.mem[int32(p)+1].int())
		} else {
			prg.badBinary(p, c)
			goto done
		}

		// Compare the current expression with zero
		if int32(prg.curType) != known {
			if int32(prg.curType) < known {
				prg.dispErr(p, strNumber( /* "" */ 285))
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "The quantities shown above have not been equated." */ 851
				}
			} else {
				prg.helpPtr = 2
				prg.helpLine[1] = /* "Oh dear. I can't decide if the expression above is positive," */ 852
				prg.helpLine[0] = /* "negative, or zero. So this comparison test won't be `true'." */ 853
			}
			prg.dispErr(halfword(memMin), strNumber( /* "Unknown relation will be considered false" */ 854))
			// \xref[Unknown relation...]
			prg.putGetFlushError(falseCode)
		} else {
			switch c {
			case lessThan:
				if prg.curExp < 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			case lessOrEqual:
				if prg.curExp <= 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			case greaterThan:
				if prg.curExp > 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			case greaterOrEqual:
				if prg.curExp >= 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			case equalTo:
				if prg.curExp == 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			case unequalTo:
				if prg.curExp != 0 {
					prg.curExp = trueCode
				} else {
					prg.curExp = falseCode
				}
			}
		} // there are no other cases
		prg.curType = byte(booleanType)

	done:
		;

	case andOp, orOp:
		if int32(*(*prg.mem[p].hh()).b0()) != booleanType || int32(prg.curType) != booleanType {
			prg.badBinary(p, c)
		} else if *prg.mem[int32(p)+1].int() == int32(c)+falseCode-andOp {
			prg.curExp = *prg.mem[int32(p)+1].int()
		}

	case times:
		if int32(prg.curType) < pairType || int32(*(*prg.mem[p].hh()).b0()) < pairType {
			prg.badBinary(p, quarterword(times))
		} else if int32(prg.curType) == known || int32(*(*prg.mem[p].hh()).b0()) == known {
			if int32(*(*prg.mem[p].hh()).b0()) == known {
				v = *prg.mem[int32(p)+1].int()
				prg.freeNode(p, halfword(valueNodeSize))
			} else {
				v = prg.curExp
				prg.unstashCurExp(p)
			}
			if int32(prg.curType) == known {
				prg.curExp = prg.takeScaled(prg.curExp, v)
			} else if int32(prg.curType) == pairType {
				p = uint16(*prg.mem[prg.curExp+1].int())
				prg.depMult(p, v, true)
				prg.depMult(halfword(int32(p)+2), v, true)
			} else {
				prg.depMult(halfword(memMin), v, true)
			}

			goto exit
		} else if prg.nicePair(int32(p), *(*prg.mem[p].hh()).b0()) && int32(prg.curType) > pairType || prg.nicePair(prg.curExp, prg.curType) && int32(*(*prg.mem[p].hh()).b0()) > pairType {
			prg.hardTimes(p)
			goto exit
		} else {
			prg.badBinary(p, quarterword(times))
		}

	case over:
		if int32(prg.curType) != known || int32(*(*prg.mem[p].hh()).b0()) < pairType {
			prg.badBinary(p, quarterword(over))
		} else {
			v = prg.curExp
			prg.unstashCurExp(p)
			if v == 0 {
				prg.dispErr(halfword(memMin), strNumber( /* "Division by zero" */ 784))
				// \xref[Division by zero]
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "You're trying to divide the quantity shown above the error" */ 856
					prg.helpLine[0] = /* "message by zero. I'm going to divide it by one instead." */ 857
				}
				prg.putGetError()
			} else {
				if int32(prg.curType) == known {
					prg.curExp = prg.makeScaled(prg.curExp, v)
				} else if int32(prg.curType) == pairType {
					p = uint16(*prg.mem[prg.curExp+1].int())
					prg.depDiv(p, v)
					prg.depDiv(halfword(int32(p)+2), v)
				} else {
					prg.depDiv(halfword(memMin), v)
				}
			}

			goto exit
		}

	case pythagAdd, pythagSub:
		if int32(prg.curType) == known && int32(*(*prg.mem[p].hh()).b0()) == known {
			if int32(c) == pythagAdd {
				prg.curExp = prg.pythAdd(*prg.mem[int32(p)+1].int(), prg.curExp)
			} else {
				prg.curExp = prg.pythSub(*prg.mem[int32(p)+1].int(), prg.curExp)
			}
		} else {
			prg.badBinary(p, c)
		}

	case rotatedBy, slantedBy, scaledBy, shiftedBy,
		transformedBy, xScaled, yScaled, zScaled: //

		if int32(*(*prg.mem[p].hh()).b0()) == pathType || int32(*(*prg.mem[p].hh()).b0()) == futurePen || int32(*(*prg.mem[p].hh()).b0()) == penType {
			prg.pathTrans(p, c)
			goto exit
		} else if int32(*(*prg.mem[p].hh()).b0()) == pairType || int32(*(*prg.mem[p].hh()).b0()) == transformType {
			prg.bigTrans(p, c)
		} else if int32(*(*prg.mem[p].hh()).b0()) == pictureType {
			prg.edgesTrans(p, c)
			goto exit
		} else {
			prg.badBinary(p, c)
		}

	case concatenate:
		if int32(prg.curType) == stringType && int32(*(*prg.mem[p].hh()).b0()) == stringType {
			prg.cat(p)
		} else {
			prg.badBinary(p, quarterword(concatenate))
		}
	case substringOf:
		if prg.nicePair(int32(p), *(*prg.mem[p].hh()).b0()) && int32(prg.curType) == stringType {
			prg.chopString(halfword(*prg.mem[int32(p)+1].int()))
		} else {
			prg.badBinary(p, quarterword(substringOf))
		}
	case subpathOf:
		if int32(prg.curType) == pairType {
			prg.pairToPath()
		}
		if prg.nicePair(int32(p), *(*prg.mem[p].hh()).b0()) && int32(prg.curType) == pathType {
			prg.chopPath(halfword(*prg.mem[int32(p)+1].int()))
		} else {
			prg.badBinary(p, quarterword(subpathOf))
		}

	case pointOf, precontrolOf, postcontrolOf:
		if int32(prg.curType) == pairType {
			prg.pairToPath()
		}
		if int32(prg.curType) == pathType && int32(*(*prg.mem[p].hh()).b0()) == known {
			prg.findPoint(*prg.mem[int32(p)+1].int(), c)
		} else {
			prg.badBinary(p, c)
		}

	case penOffsetOf:
		if int32(prg.curType) == futurePen {
			prg.materializePen()
		}
		if int32(prg.curType) == penType && prg.nicePair(int32(p), *(*prg.mem[p].hh()).b0()) {
			prg.setUpOffset(halfword(*prg.mem[int32(p)+1].int()))
		} else {
			prg.badBinary(p, quarterword(penOffsetOf))
		}

	case directionTimeOf:
		if int32(prg.curType) == pairType {
			prg.pairToPath()
		}
		if int32(prg.curType) == pathType && prg.nicePair(int32(p), *(*prg.mem[p].hh()).b0()) {
			prg.setUpDirectionTime(halfword(*prg.mem[int32(p)+1].int()))
		} else {
			prg.badBinary(p, quarterword(directionTimeOf))
		}

	case intersect:
		if int32(*(*prg.mem[p].hh()).b0()) == pairType {
			q = prg.stashCurExp()
			prg.unstashCurExp(p)
			prg.pairToPath()
			p = prg.stashCurExp()
			prg.unstashCurExp(q)
		}
		if int32(prg.curType) == pairType {
			prg.pairToPath()
		}
		if int32(prg.curType) == pathType && int32(*(*prg.mem[p].hh()).b0()) == pathType {
			prg.pathIntersection(halfword(*prg.mem[int32(p)+1].int()), halfword(prg.curExp))
			prg.pairValue(prg.curT, prg.curTt)
		} else {
			prg.badBinary(p, quarterword(intersect))
		}

	} // there are no other cases
	prg.recycleValue(p)
	prg.freeNode(p, halfword(valueNodeSize)) // |return| to avoid this
	// |return| to avoid this
exit:
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
	// Recycle any sidestepped |independent| capsules
	if int32(oldP) != memMin {
		prg.recycleValue(oldP)
		prg.freeNode(oldP, halfword(valueNodeSize))
	}
	if int32(oldExp) != memMin {
		prg.recycleValue(oldExp)
		prg.freeNode(oldExp, halfword(valueNodeSize))
	}
}

// 944.

// tangle:pos ../../mf.web:18630:3:

// Here is a routine that is similar to |times|; but it is invoked only
// internally, when |v| is a |fraction| whose magnitude is at most~1,
// and when |cur_type>=pair_type|.
func (prg *prg) fracMult(n, d scaled) { // multiplies |cur_exp| by |n/d|
	var (
		p      halfword // a pair node
		oldExp halfword // a capsule to recycle
		v      fraction // |n/d|
	)
	if prg.internal[tracingCommands-1] > 0400000 {
		prg.beginDiagnostic()
		prg.printNl(strNumber( /* "[(" */ 850))
		prg.printScaled(n)
		prg.printChar(asciiCode('/'))
		prg.printScaled(d)
		prg.print( /* ")*(" */ 855)
		prg.printExp(halfword(memMin), smallNumber(0))
		prg.print( /* ")]" */ 842)
		prg.endDiagnostic(false)
	}
	switch prg.curType {
	case transformType, pairType:
		oldExp = prg.tarnished(halfword(prg.curExp))
	case independent:
		oldExp = uint16(memMin + 1)

	default:
		oldExp = uint16(memMin)
	}
	if int32(oldExp) != memMin {
		oldExp = uint16(prg.curExp)
		prg.makeExpCopy(oldExp)
	}
	v = prg.makeFraction(n, d)
	if int32(prg.curType) == known {
		prg.curExp = prg.takeFraction(prg.curExp, v)
	} else if int32(prg.curType) == pairType {
		p = uint16(*prg.mem[prg.curExp+1].int())
		prg.depMult(p, v, false)
		prg.depMult(halfword(int32(p)+2), v, false)
	} else {
		prg.depMult(halfword(memMin), v, false)
	}
	if int32(oldExp) != memMin {
		prg.recycleValue(oldExp)
		prg.freeNode(oldExp, halfword(valueNodeSize))
	}
}

// 989. \[43] Statements and commands

// tangle:pos ../../mf.web:19313:34:

// The chief executive of \MF\ is the |do_statement| routine, which
// contains the master switch that causes all the various pieces of \MF\
// to do their things, in the right order.
//
// In a sense, this is the grand climax of the program: It applies all the
// tools that we have worked so hard to construct. In another sense, this is
// the messiest part of the program: It necessarily refers to other pieces
// of code all over the place, so that a person can't fully understand what is
// going on without paging back and forth to be reminded of conventions that
// are defined elsewhere. We are now at the hub of the web.
//
// The structure of |do_statement| itself is quite simple.  The first token
// of the statement is fetched using |get_x_next|.  If it can be the first
// token of an expression, we look for an equation, an assignment, or a
// title. Otherwise we use a \&[case] construction to branch at high speed to
// the appropriate routine for various and sundry other types of commands,
// each of which has an “action procedure” that does the necessary work.
//
// The program uses the fact that
// $$\hbox[|min_primary_command=max_statement_command=type_name|]$$
// to interpret a statement that starts with, e.g., `\&[string]',
// as a type declaration rather than a boolean expression.
// \4
// Declare generic font output procedures
func (prg *prg) writeGf(a, b gfIndex) {
	var (
		k gfIndex
	)
	for ii := int32(a); ii <= int32(b); ii++ {
		k = gfIndex(ii)
		_ = k
		prg.gfFile.Write(prg.gfBuf[k])
	}
}

func (prg *prg) gfSwap() {
	if int32(prg.gfLimit) == gfBufSize {
		prg.writeGf(gfIndex(0), gfIndex(int32(prg.halfBuf)-1))
		prg.gfLimit = prg.halfBuf
		prg.gfOffset = prg.gfOffset + gfBufSize
		prg.gfPtr = 0
	} else {
		prg.writeGf(prg.halfBuf, gfIndex(gfBufSize-1))
		prg.gfLimit = byte(gfBufSize)
	}
}

func (prg *prg) gfFour(x int32) {
	if x >= 0 {
		prg.gfBuf[prg.gfPtr] = byte(x / 0100000000)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	} else {
		x = x + 010000000000
		x = x + 010000000000
		{
			prg.gfBuf[prg.gfPtr] = byte(x/0100000000 + 128)
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
	}
	x = x % 0100000000
	{
		prg.gfBuf[prg.gfPtr] = byte(x / 0200000)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	x = x % 0200000
	{
		prg.gfBuf[prg.gfPtr] = byte(x / 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(x % 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
}

func (prg *prg) gfTwo(x int32) {
	{
		prg.gfBuf[prg.gfPtr] = byte(x / 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(x % 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
}

func (prg *prg) gfThree(x int32) {
	{
		prg.gfBuf[prg.gfPtr] = byte(x / 0200000)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(x % 0200000 / 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(x % 0400)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
}

func (prg *prg) gfPaint(d int32) {
	if d < 64 {
		prg.gfBuf[prg.gfPtr] = byte(paint0 + d)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	} else if d < 256 {
		{
			prg.gfBuf[prg.gfPtr] = byte(paint1)
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
		{
			prg.gfBuf[prg.gfPtr] = byte(d)
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
	} else {
		{
			prg.gfBuf[prg.gfPtr] = byte(paint1 + 1)
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
		prg.gfTwo(d)
	}
}

func (prg *prg) gfString(s, t strNumber) {
	var (
		k poolPointer
		l int32 // length of the strings to output
	)
	if int32(s) != 0 {
		l = int32(prg.strStart[int32(s)+1]) - int32(prg.strStart[s])
		if int32(t) != 0 {
			l = l + (int32(prg.strStart[int32(t)+1]) - int32(prg.strStart[t]))
		}
		if l <= 255 {
			{
				prg.gfBuf[prg.gfPtr] = byte(xxx1)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
			{
				prg.gfBuf[prg.gfPtr] = byte(l)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
		} else {
			{
				prg.gfBuf[prg.gfPtr] = byte(xxx3)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
			prg.gfThree(l)
		}
		for ii := int32(prg.strStart[s]); ii <= int32(prg.strStart[int32(s)+1])-1; ii++ {
			k = poolPointer(ii)
			_ = k
			prg.gfBuf[prg.gfPtr] = prg.strPool[k]
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
	}
	if int32(t) != 0 {
		for ii := int32(prg.strStart[t]); ii <= int32(prg.strStart[int32(t)+1])-1; ii++ {
			k = poolPointer(ii)
			_ = k
			prg.gfBuf[prg.gfPtr] = prg.strPool[k]
			prg.gfPtr = byte(int32(prg.gfPtr) + 1)
			if int32(prg.gfPtr) == int32(prg.gfLimit) {
				prg.gfSwap()
			}
		}
	}
}

func (prg *prg) gfBoc(minM, maxM, minN, maxN int32) {
	if minM < prg.gfMinM {
		prg.gfMinM = minM
	}
	if maxN > prg.gfMaxN {
		prg.gfMaxN = maxN
	}
	if prg.bocP == -1 {
		if prg.bocC >= 0 {
			if prg.bocC < 256 {
				if maxM-minM >= 0 {
					if maxM-minM < 256 {
						if maxM >= 0 {
							if maxM < 256 {
								if maxN-minN >= 0 {
									if maxN-minN < 256 {
										if maxN >= 0 {
											if maxN < 256 {
												{
													prg.gfBuf[prg.gfPtr] = byte(boc1)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}
												{
													prg.gfBuf[prg.gfPtr] = byte(prg.bocC)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}

												{
													prg.gfBuf[prg.gfPtr] = byte(maxM - minM)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}
												{
													prg.gfBuf[prg.gfPtr] = byte(maxM)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}
												{
													prg.gfBuf[prg.gfPtr] = byte(maxN - minN)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}
												{
													prg.gfBuf[prg.gfPtr] = byte(maxN)
													prg.gfPtr = byte(int32(prg.gfPtr) + 1)
													if int32(prg.gfPtr) == int32(prg.gfLimit) {
														prg.gfSwap()
													}
												}
												goto exit
											}
										}
									}
								}
							}
						}
					}
				}
			}
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(boc)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	prg.gfFour(prg.bocC)
	prg.gfFour(prg.bocP)

	prg.gfFour(minM)
	prg.gfFour(maxM)
	prg.gfFour(minN)
	prg.gfFour(maxN)

exit:
}

func (prg *prg) initGf() {
	var (
		k eightBits // runs through all possible character codes
		t int32     // the time of this run
	)
	prg.gfMinM = 4096
	prg.gfMaxM = -4096
	prg.gfMinN = 4096
	prg.gfMaxN = -4096
	for ii := int32(0); ii <= 255; ii++ {
		k = eightBits(ii)
		_ = k
		prg.charPtr[k] = -1
	}

	// Determine the file extension, |gf_ext|
	if prg.internal[hppp-1] <= 0 {
		prg.gfExt = /* ".gf" */ 1054
	} else {
		prg.oldSetting = prg.selector
		prg.selector = byte(newString)
		prg.printChar(asciiCode('.'))
		prg.printInt(prg.makeScaled(prg.internal[hppp-1], 59429463))
		// $2^[32]/72.27\approx59429463.07$
		prg.print( /* "gf" */ 1055)
		prg.gfExt = prg.makeString()
		prg.selector = prg.oldSetting
	}
	{
		if int32(prg.jobName) == 0 {
			prg.openLogFile()
		}
		prg.packJobName(prg.gfExt)
		for !prg.bOpenOut(prg.gfFile) {
			prg.promptFileName(strNumber( /* "file name for output" */ 756), prg.gfExt)
		}
		prg.outputFileName = prg.bMakeNameString(prg.gfFile)
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(pre)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(gfIdByte)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	} // begin to output the preamble
	prg.oldSetting = prg.selector
	prg.selector = byte(newString)
	prg.print( /* " METAFONT output " */ 1053)
	prg.printInt(prg.roundUnscaled(prg.internal[year-1]))
	prg.printChar(asciiCode('.'))
	prg.printDd(prg.roundUnscaled(prg.internal[month-1]))
	prg.printChar(asciiCode('.'))
	prg.printDd(prg.roundUnscaled(prg.internal[day-1]))
	prg.printChar(asciiCode(':'))

	t = prg.roundUnscaled(prg.internal[time-1])
	prg.printDd(t / 60)
	prg.printDd(t % 60)

	prg.selector = prg.oldSetting
	{
		prg.gfBuf[prg.gfPtr] = byte(int32(prg.poolPtr) - int32(prg.strStart[prg.strPtr]))
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	prg.gfString(strNumber(0), prg.makeString())
	prg.strPtr = uint16(int32(prg.strPtr) - 1)
	prg.poolPtr = prg.strStart[prg.strPtr] // flush that string from memory
	prg.gfPrevPtr = prg.gfOffset + int32(prg.gfPtr)
}

func (prg *prg) shipOut(c eightBits) {
	var (
		f            int32    // current character extension
		prevM, m, mm int32    // previous and current pixel column numbers
		prevN, n     int32    // previous and current pixel row numbers
		p, q         halfword // for list traversal
		prevW, w, ww int32    // old and new weights
		d            int32    // data from edge-weight node
		delta        int32    // number of rows to skip
		curMinM      int32    // starting column, relative to the current offset
		xOff, yOff   int32    // offsets, rounded to integers
	)
	if int32(prg.outputFileName) == 0 {
		prg.initGf()
	}
	f = prg.roundUnscaled(prg.internal[charExt-1])

	xOff = prg.roundUnscaled(prg.internal[xOffset-1])
	yOff = prg.roundUnscaled(prg.internal[yOffset-1])
	if int32(prg.termOffset) > maxPrintLine-9 {
		prg.printLn()
	} else if int32(prg.termOffset) > 0 || int32(prg.fileOffset) > 0 {
		prg.printChar(asciiCode(' '))
	}
	prg.printChar(asciiCode('['))
	prg.printInt(int32(c))
	if f != 0 {
		prg.printChar(asciiCode('.'))
		prg.printInt(f)
	}

	prg.bocC = 256*f + int32(c)
	prg.bocP = prg.charPtr[c]
	prg.charPtr[c] = prg.gfPrevPtr

	if prg.internal[proofing-1] > 0 {
		if xOff != 0 {
			prg.gfString(strNumber( /* "xoffset" */ 438), strNumber(0))
			{
				prg.gfBuf[prg.gfPtr] = byte(yyy)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
			prg.gfFour(xOff * 0200000)
		}
		if yOff != 0 {
			prg.gfString(strNumber( /* "yoffset" */ 439), strNumber(0))
			{
				prg.gfBuf[prg.gfPtr] = byte(yyy)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
			prg.gfFour(yOff * 0200000)
		}
	}

	// Output the character represented in |cur_edges|
	prevN = 4096
	p = *(*prg.mem[prg.curEdges].hh()).lh()
	n = int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).rh()) - zeroField
	for int32(p) != int32(prg.curEdges) {
		if int32(*(*prg.mem[int32(p)+1].hh()).lh()) > memMin+1 {
			prg.sortEdges(p)
		}
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		w = 0
		prevM = -02000000000 // $|fraction_one|\approx\infty$
		ww = 0
		prevW = 0
		m = prevM
		for {
			if int32(q) == 3000 {
				mm = 02000000000
			} else {
				d = int32(*(*prg.mem[q].hh()).lh()) - 0
				mm = d / 8
				ww = ww + d%8 - zeroW
			}
			if mm != m {
				if prevW <= 0 {
					if w > 0 {
						if prevM == -02000000000 {
							if prevN == 4096 {
								prg.gfBoc(int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh())+xOff-zeroField, int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).rh())+xOff-zeroField, int32(*(*prg.mem[int32(prg.curEdges)+1].hh()).lh())+yOff-zeroField, n+yOff)
								curMinM = int32(*(*prg.mem[int32(prg.curEdges)+2].hh()).lh()) - zeroField + int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())
							} else if prevN > n+1 {
								delta = prevN - n - 1
								if delta < 0400 {
									{
										prg.gfBuf[prg.gfPtr] = byte(skip1)
										prg.gfPtr = byte(int32(prg.gfPtr) + 1)
										if int32(prg.gfPtr) == int32(prg.gfLimit) {
											prg.gfSwap()
										}
									}
									{
										prg.gfBuf[prg.gfPtr] = byte(delta)
										prg.gfPtr = byte(int32(prg.gfPtr) + 1)
										if int32(prg.gfPtr) == int32(prg.gfLimit) {
											prg.gfSwap()
										}
									}
								} else {
									{
										prg.gfBuf[prg.gfPtr] = byte(skip1 + 1)
										prg.gfPtr = byte(int32(prg.gfPtr) + 1)
										if int32(prg.gfPtr) == int32(prg.gfLimit) {
											prg.gfSwap()
										}
									}
									prg.gfTwo(delta)
								}
							} else {
								// Skip to column $m$ in the next row and |goto done|, or skip zero rows
								delta = m - curMinM
								if delta > maxNewRow {
									prg.gfBuf[prg.gfPtr] = byte(skip0)
									prg.gfPtr = byte(int32(prg.gfPtr) + 1)
									if int32(prg.gfPtr) == int32(prg.gfLimit) {
										prg.gfSwap()
									}
								} else {
									{
										prg.gfBuf[prg.gfPtr] = byte(newRow0 + delta)
										prg.gfPtr = byte(int32(prg.gfPtr) + 1)
										if int32(prg.gfPtr) == int32(prg.gfLimit) {
											prg.gfSwap()
										}
									}
									goto done
								}
							}
							prg.gfPaint(m - curMinM) // skip to column $m$, painting white
							// skip to column $m$, painting white
						done:
							prevN = n
						} else {
							prg.gfPaint(m - prevM)
						}
						prevM = m
						prevW = w
					}
				} else if w <= 0 {
					prg.gfPaint(m - prevM)
					prevM = m
					prevW = w
				}
				m = mm
			}
			w = ww
			q = *(*prg.mem[q].hh()).rh()
			if mm == 02000000000 {
				break
			}
		}
		if w != 0 {
			prg.printNl(strNumber( /* "(There's unbounded black in character shipped out!)" */ 1057))
		}
		// \xref[There's unbounded black...]
		if prevM-int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh())+xOff > prg.gfMaxM {
			prg.gfMaxM = prevM - int32(*(*prg.mem[int32(prg.curEdges)+3].hh()).lh()) + xOff
		}
		p = *(*prg.mem[p].hh()).lh()
		n = n - 1
	}
	if prevN == 4096 {
		prg.gfBoc(0, 0, 0, 0)
		if prg.gfMaxM < 0 {
			prg.gfMaxM = 0
		}
		if prg.gfMinN > 0 {
			prg.gfMinN = 0
		}
	} else if prevN+yOff < prg.gfMinN {
		prg.gfMinN = prevN + yOff
	}
	{
		prg.gfBuf[prg.gfPtr] = byte(eoc)
		prg.gfPtr = byte(int32(prg.gfPtr) + 1)
		if int32(prg.gfPtr) == int32(prg.gfLimit) {
			prg.gfSwap()
		}
	}
	prg.gfPrevPtr = prg.gfOffset + int32(prg.gfPtr)
	prg.totalChars = prg.totalChars + 1
	prg.printChar(asciiCode(']')) // progress report
	if prg.internal[tracingOutput-1] > 0 {
		prg.printEdges(strNumber( /* " (just shipped out)" */ 1056), true, xOff, yOff)
	}
}

// \4
// Declare action procedures for use by |do_statement|
// \4
// Declare the procedure called |try_eq|
func (prg *prg) tryEq(l, r1 halfword) {
	var (
		p                                   halfword // dependency list for right operand minus left operand
		t/* known..independent */ byte               // the type of list |p|
		q                                   halfword // the constant term of |p| is here
		pp                                  halfword // dependency list for right operand
		tt/* dependent..independent */ byte          // the type of list |pp|
		copied                              bool     // have we copied a list that ought to be recycled?
	)
	t = *(*prg.mem[l].hh()).b0()
	if int32(t) == known {
		t = byte(dependent)
		p = prg.constDependency(-*prg.mem[int32(l)+1].int())
		q = p
	} else if int32(t) == independent {
		t = byte(dependent)
		p = prg.singleDependency(l)
		*prg.mem[int32(p)+1].int() = -*prg.mem[int32(p)+1].int()
		q = prg.depFinal
	} else {
		p = *(*prg.mem[int32(l)+1].hh()).rh()
		q = p
		for true {
			*prg.mem[int32(q)+1].int() = -*prg.mem[int32(q)+1].int()
			if int32(*(*prg.mem[q].hh()).lh()) == memMin {
				goto done
			}
			q = *(*prg.mem[q].hh()).rh()
		}

	done:
		*(*prg.mem[*(*prg.mem[int32(l)+1].hh()).lh()].hh()).rh() = *(*prg.mem[q].hh()).rh()
		*(*prg.mem[int32(*(*prg.mem[q].hh()).rh())+1].hh()).lh() = *(*prg.mem[int32(l)+1].hh()).lh()
		*(*prg.mem[l].hh()).b0() = byte(known)
	}

	// Add the right operand to list |p|
	if int32(r1) == memMin {
		if int32(prg.curType) == known {
			*prg.mem[int32(q)+1].int() = *prg.mem[int32(q)+1].int() + prg.curExp
			goto done1
		} else {
			tt = prg.curType
			if int32(tt) == independent {
				pp = prg.singleDependency(halfword(prg.curExp))
			} else {
				pp = *(*prg.mem[prg.curExp+1].hh()).rh()
			}
		}
	} else if int32(*(*prg.mem[r1].hh()).b0()) == known {
		*prg.mem[int32(q)+1].int() = *prg.mem[int32(q)+1].int() + *prg.mem[int32(r1)+1].int()
		goto done1
	} else {
		tt = *(*prg.mem[r1].hh()).b0()
		if int32(tt) == independent {
			pp = prg.singleDependency(r1)
		} else {
			pp = *(*prg.mem[int32(r1)+1].hh()).rh()
		}
	}
	if int32(tt) != independent {
		copied = false
	} else {
		copied = true
		tt = byte(dependent)
	}

	// Add dependency list |pp| of type |tt| to dependency list~|p| of type~|t|
	prg.watchCoefs = false
	if int32(t) == int32(tt) {
		p = prg.pPlusQ(p, pp, t)
	} else if int32(t) == protoDependent {
		p = prg.pPlusFq(p, 0200000, pp, smallNumber(protoDependent), smallNumber(dependent))
	} else {
		q = p
		for int32(*(*prg.mem[q].hh()).lh()) != memMin {
			*prg.mem[int32(q)+1].int() = prg.roundFraction(*prg.mem[int32(q)+1].int())
			q = *(*prg.mem[q].hh()).rh()
		}
		t = byte(protoDependent)
		p = prg.pPlusQ(p, pp, t)
	}
	prg.watchCoefs = true

	if copied {
		prg.flushNodeList(pp)
	}

done1:
	;
	if int32(*(*prg.mem[p].hh()).lh()) == memMin {
		if abs(*prg.mem[int32(p)+1].int()) > 64 {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Inconsistent equation" */ 897) /* \xref[!\relax]  */
			}

			// \xref[Inconsistent equation]
			prg.print( /* " (off by " */ 899)
			prg.printScaled(*prg.mem[int32(p)+1].int())
			prg.printChar(asciiCode(')'))
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "The equation I just read contradicts what was said before." */ 898
				prg.helpLine[0] = /* "But don't worry; continue and I'll just ignore it." */ 896
			}
			prg.putGetError()
		} else if int32(r1) == memMin {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Redundant equation" */ 599) /* \xref[!\relax]  */
			}

			// \xref[Redundant equation]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I already knew that this equation was true." */ 600
				prg.helpLine[0] = /* "But perhaps no harm has been done; let's continue." */ 601
			}

			prg.putGetError()
		}
		prg.freeNode(p, halfword(depNodeSize))
	} else {
		prg.linearEq(p, t)
		if int32(r1) == memMin {
			if int32(prg.curType) != known {
				if int32(*(*prg.mem[prg.curExp].hh()).b0()) == known {
					pp = uint16(prg.curExp)
					prg.curExp = *prg.mem[prg.curExp+1].int()
					prg.curType = byte(known)
					prg.freeNode(pp, halfword(valueNodeSize))
				}
			}
		}
	}
}

// \4
// Declare the procedure called |make_eq|
func (prg *prg) makeEq(lhs halfword) {
	var (
		t    smallNumber // type of the left-hand side
		v    int32       // value of the left-hand side
		p, q halfword    // pointers inside of big nodes
	)
restart:
	t = *(*prg.mem[lhs].hh()).b0()
	if int32(t) <= pairType {
		v = *prg.mem[int32(lhs)+1].int()
	}
	switch t {
	case booleanType, stringType, penType, pathType,
		pictureType:
		if int32(prg.curType) == int32(t)+unknownTag {
			prg.nonlinearEq(v, halfword(prg.curExp), false)
			prg.unstashCurExp(halfword(prg.curExp))
			goto done
		} else if int32(prg.curType) == int32(t) {
			if int32(prg.curType) <= stringType {
				if int32(prg.curType) == stringType {
					if prg.strVsStr(strNumber(v), strNumber(prg.curExp)) != 0 {
						goto notFound
					}
				} else if v != prg.curExp {
					goto notFound
				}

				// Exclaim about a redundant equation
				{
					{
						if int32(prg.interaction) == errorStopMode {
						}
						prg.printNl(strNumber( /* "! " */ 261))
						prg.print( /* "Redundant equation" */ 599) /* \xref[!\relax]  */
					}

					// \xref[Redundant equation]
					{
						prg.helpPtr = 2
						prg.helpLine[1] = /* "I already knew that this equation was true." */ 600
						prg.helpLine[0] = /* "But perhaps no harm has been done; let's continue." */ 601
					}

					prg.putGetError()
				}
				goto done
			}
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Redundant or inconsistent equation" */ 894) /* \xref[!\relax]  */
			}
			// \xref[Redundant or inconsistent equation]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "An equation between already-known quantities can't help." */ 895
				prg.helpLine[0] = /* "But don't worry; continue and I'll just ignore it." */ 896
			}
			prg.putGetError()
			goto done

		notFound:
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Inconsistent equation" */ 897) /* \xref[!\relax]  */
			}
			// \xref[Inconsistent equation]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "The equation I just read contradicts what was said before." */ 898
				prg.helpLine[0] = /* "But don't worry; continue and I'll just ignore it." */ 896
			}
			prg.putGetError()
			goto done
		}

	case unknownBoolean, unknownString, unknownPen, unknownPicture,
		unknownPath:
		if int32(prg.curType) == int32(t)-unknownTag {
			prg.nonlinearEq(prg.curExp, lhs, true)
			goto done
		} else if int32(prg.curType) == int32(t) {
			prg.ringMerge(lhs, halfword(prg.curExp))
			goto done
		} else if int32(prg.curType) == pairType {
			if int32(t) == unknownPath {
				prg.pairToPath()
				goto restart
			}
		}
	case transformType, pairType:
		if int32(prg.curType) == int32(t) {
			p = uint16(v + int32(prg.bigNodeSize[t-13]))
			q = uint16(*prg.mem[prg.curExp+1].int() + int32(prg.bigNodeSize[t-13]))
			for {
				p = uint16(int32(p) - 2)
				q = uint16(int32(q) - 2)
				prg.tryEq(p, q)
				if int32(p) == v {
					break
				}
			}

			goto done
		}

	case known, dependent, protoDependent, independent:
		if int32(prg.curType) >= known {
			prg.tryEq(lhs, halfword(memMin))
			goto done
		}
	case vacuous:

	} // all cases have been listed

	// Announce that the equation cannot be performed
	prg.dispErr(lhs, strNumber( /* "" */ 285))
	prg.dispErr(halfword(memMin), strNumber( /* "Equation cannot be performed (" */ 891))
	// \xref[Equation cannot be performed]
	if int32(*(*prg.mem[lhs].hh()).b0()) <= pairType {
		prg.printType(*(*prg.mem[lhs].hh()).b0())
	} else {
		prg.print( /* "numeric" */ 341)
	}
	prg.printChar(asciiCode('='))
	if int32(prg.curType) <= pairType {
		prg.printType(prg.curType)
	} else {
		prg.print( /* "numeric" */ 341)
	}
	prg.printChar(asciiCode(')'))

	{
		prg.helpPtr = 2
		prg.helpLine[1] = /* "I'm sorry, but I don't know how to make such things equal." */ 892
		prg.helpLine[0] = /* "(See the two expressions just above the error message.)" */ 893
	}
	prg.putGetError()

done:
	{
		if prg.arithError {
			prg.clearArith()
		}
	}
	prg.recycleValue(lhs)
	prg.freeNode(lhs, halfword(valueNodeSize))
} // \2

func (prg *prg) doEquation() {
	var (
		lhs halfword // capsule for the left-hand side
		p   halfword // temporary register
	)
	lhs = prg.stashCurExp()
	prg.getXNext()
	prg.varFlag = byte(assignment)
	prg.scanExpression()
	if int32(prg.curCmd) == equals {
		prg.doEquation()
	} else if int32(prg.curCmd) == assignment {
		prg.doAssignment()
	}
	if prg.internal[tracingCommands-1] > 0400000 {
		prg.beginDiagnostic()
		prg.printNl(strNumber( /* "[(" */ 850))
		prg.printExp(lhs, smallNumber(0))
		prg.print( /* ")=(" */ 886)
		prg.printExp(halfword(memMin), smallNumber(0))
		prg.print( /* ")]" */ 842)
		prg.endDiagnostic(false)
	}
	if int32(prg.curType) == unknownPath {
		if int32(*(*prg.mem[lhs].hh()).b0()) == pairType {
			p = prg.stashCurExp()
			prg.unstashCurExp(lhs)
			lhs = p
		}
	} // in this case |make_eq| will change the pair to a path
	prg.makeEq(lhs) // equate |lhs| to |(cur_type,cur_exp)|
}

func (prg *prg) doAssignment() {
	var (
		lhs halfword // token list for the left-hand side
		p   halfword // where the left-hand value is stored
		q   halfword // temporary capsule for the right-hand value
	)
	if int32(prg.curType) != tokenList {
		prg.dispErr(halfword(memMin), strNumber( /* "Improper `:=' will be changed to `='" */ 883))
		// \xref[Improper `:=']
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "I didn't find a variable name at the left of the `:='," */ 884
			prg.helpLine[0] = /* "so I'm going to pretend that you said `=' instead." */ 885
		}

		prg.error1()
		prg.doEquation()
	} else {
		lhs = uint16(prg.curExp)
		prg.curType = byte(vacuous)

		prg.getXNext()
		prg.varFlag = byte(assignment)
		prg.scanExpression()
		if int32(prg.curCmd) == equals {
			prg.doEquation()
		} else if int32(prg.curCmd) == assignment {
			prg.doAssignment()
		}
		if prg.internal[tracingCommands-1] > 0400000 {
			prg.beginDiagnostic()
			prg.printNl(strNumber('{'))
			if int32(*(*prg.mem[lhs].hh()).lh()) > hashBase+hashSize+12 {
				prg.slowPrint(int32(prg.intName[int32(*(*prg.mem[lhs].hh()).lh())-(hashBase+hashSize+12)-1]))
			} else {
				prg.showTokenList(int32(lhs), memMin, 1000, 0)
			}
			prg.print( /* ":=" */ 461)
			prg.printExp(halfword(memMin), smallNumber(0))
			prg.printChar(asciiCode('}'))
			prg.endDiagnostic(false)
		}
		if int32(*(*prg.mem[lhs].hh()).lh()) > hashBase+hashSize+12 {
			if int32(prg.curType) == known {
				prg.internal[int32(*(*prg.mem[lhs].hh()).lh())-(hashBase+hashSize+12)-1] = prg.curExp
			} else {
				prg.dispErr(halfword(memMin), strNumber( /* "Internal quantity `" */ 887))
				// \xref[Internal quantity...]
				prg.slowPrint(int32(prg.intName[int32(*(*prg.mem[lhs].hh()).lh())-(hashBase+hashSize+12)-1]))
				prg.print( /* "' must receive a known value" */ 888)
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "I can't set an internal quantity to anything but a known" */ 889
					prg.helpLine[0] = /* "numeric value, so I'll have to ignore this assignment." */ 890
				}
				prg.putGetError()
			}
		} else {
			// Assign the current expression to the variable |lhs|
			p = prg.findVariable(lhs)
			if int32(p) != memMin {
				q = prg.stashCurExp()
				prg.curType = prg.undType(p)
				prg.recycleValue(p)
				*(*prg.mem[p].hh()).b0() = prg.curType
				*prg.mem[int32(p)+1].int() = memMin
				prg.makeExpCopy(p)
				p = prg.stashCurExp()
				prg.unstashCurExp(q)
				prg.makeEq(p)
			} else {
				prg.obliterated(lhs)
				prg.putGetError()
			}
		}
		prg.flushNodeList(lhs)
	}
}

func (prg *prg) doTypeDeclaration() {
	var (
		t smallNumber // the type being declared
		p halfword    // token list for a declared variable
		q halfword    // value node for the variable
	)
	if prg.curMod >= transformType {
		t = byte(prg.curMod)
	} else {
		t = byte(prg.curMod + unknownTag)
	}
	for {
		p = prg.scanDeclaredVariable()
		prg.flushVariable(*prg.eqtb[*(*prg.mem[p].hh()).lh()-1].rh(), *(*prg.mem[p].hh()).rh(), false)

		q = prg.findVariable(p)
		if int32(q) != memMin {
			*(*prg.mem[q].hh()).b0() = t
			*prg.mem[int32(q)+1].int() = memMin
		} else {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Declared variable conflicts with previous vardef" */ 900) /* \xref[!\relax]  */
			}
			// \xref[Declared variable conflicts...]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "You can't use, e.g., `numeric foo[]' after `vardef foo'." */ 901
				prg.helpLine[0] = /* "Proceed, and I'll ignore the illegal redeclaration." */ 902
			}
			prg.putGetError()
		}
		prg.flushList(p)
		if int32(prg.curCmd) < comma {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Illegal suffix of declared variable will be flushed" */ 903) /* \xref[!\relax]  */
			}
			// \xref[Illegal suffix...flushed]
			{
				prg.helpPtr = 5
				prg.helpLine[4] = /* "Variables in declarations must consist entirely of" */ 904
				prg.helpLine[3] = /* "names and collective subscripts, e.g., `x[]a'." */ 905
				prg.helpLine[2] = /* "Are you trying to use a reserved word in a variable name?" */ 906
				prg.helpLine[1] = /* "I'm going to discard the junk I found here," */ 907
				prg.helpLine[0] = /* "up to the next comma or the end of the declaration." */ 908
			}
			if int32(prg.curCmd) == numericToken {
				prg.helpLine[2] = /* "Explicit subscripts like `x15a' aren't permitted." */ 909
			}
			prg.putGetError()
			prg.scannerStatus = byte(flushing)
			for {
				prg.getNext()

				// Decrease the string reference count...
				if int32(prg.curCmd) == stringToken {
					if int32(prg.strRef[prg.curMod]) < maxStrRef {
						if int32(prg.strRef[prg.curMod]) > 1 {
							prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
						} else {
							prg.flushString(strNumber(prg.curMod))
						}
					}
				}
				if int32(prg.curCmd) >= comma {
					break
				}
			} // either |end_of_statement| or |cur_cmd=comma|
			prg.scannerStatus = byte(normal)
		}
		if int32(prg.curCmd) > comma {
			break
		}
	}
}

func (prg *prg) doRandomSeed() {
	prg.getXNext()
	if int32(prg.curCmd) != assignment {
		prg.missingErr(strNumber( /* ":=" */ 461))
		// \xref[Missing `:=']
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "Always say `randomseed:=<numeric expression>'." */ 914
		}
		prg.backError()
	}
	prg.getXNext()
	prg.scanExpression()
	if int32(prg.curType) != known {
		prg.dispErr(halfword(memMin), strNumber( /* "Unknown value will be ignored" */ 915))
		// \xref[Unknown value...ignored]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "Your expression was too random for me to handle," */ 916
			prg.helpLine[0] = /* "so I won't change the random seed just now." */ 917
		}

		prg.putGetFlushError(scaled(0))
	} else {
		// Initialize the random seed to |cur_exp|
		prg.initRandoms(prg.curExp)
		if int32(prg.selector) >= logOnly {
			prg.oldSetting = prg.selector
			prg.selector = byte(logOnly)
			prg.printNl(strNumber( /* "[randomseed:=" */ 918))
			prg.printScaled(prg.curExp)
			prg.printChar(asciiCode('}'))
			prg.printNl(strNumber( /* "" */ 285))
			prg.selector = prg.oldSetting
		}
	}
}

func (prg *prg) doProtection() {
	var (
		m/* 0..1 */ byte          // 0 to unprotect, 1 to protect
		t                halfword // the |eq_type| before we change it
	)
	m = byte(prg.curMod)
	for {
		prg.getSymbol()
		t = *prg.eqtb[prg.curSym-1].lh()
		if int32(m) == 0 {
			if int32(t) >= outerTag {
				*prg.eqtb[prg.curSym-1].lh() = uint16(int32(t) - outerTag)
			}
		} else if int32(t) < outerTag {
			*prg.eqtb[prg.curSym-1].lh() = uint16(int32(t) + outerTag)
		}
		prg.getXNext()
		if int32(prg.curCmd) != comma {
			break
		}
	}
}

func (prg *prg) defDelims() {
	var (
		lDelim, rDelim halfword // the new delimiter pair
	)
	prg.getClearSymbol()
	lDelim = prg.curSym

	prg.getClearSymbol()
	rDelim = prg.curSym

	*prg.eqtb[lDelim-1].lh() = uint16(leftDelimiter)
	*prg.eqtb[lDelim-1].rh() = rDelim

	*prg.eqtb[rDelim-1].lh() = uint16(rightDelimiter)
	*prg.eqtb[rDelim-1].rh() = lDelim

	prg.getXNext()
} // \2

func (prg *prg) doInterim() {
	prg.getXNext()
	if int32(prg.curCmd) != internalQuantity {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "The token `" */ 924) /* \xref[!\relax]  */
		}
		// \xref[The token...quantity]
		if int32(prg.curSym) == 0 {
			prg.print( /* "(%CAPSULE)" */ 929)
		} else {
			prg.slowPrint(int32(*prg.hash[prg.curSym-1].rh()))
		}
		prg.print( /* "' isn't an internal quantity" */ 930)
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "Something like `tracingonline' should follow `interim'." */ 931
		}
		prg.backError()
	} else {
		prg.saveInternal(halfword(prg.curMod))
		prg.backInput()
	}
	prg.doStatement()
}

func (prg *prg) doLet() {
	var (
		l halfword // hash location of the left-hand symbol
	)
	prg.getSymbol()
	l = prg.curSym
	prg.getXNext()
	if int32(prg.curCmd) != equals {
		if int32(prg.curCmd) != assignment {
			prg.missingErr(strNumber('='))
			// \xref[Missing `=']
			{
				prg.helpPtr = 3
				prg.helpLine[2] = /* "You should have said `let symbol = something'." */ 932
				prg.helpLine[1] = /* "But don't worry; I'll pretend that an equals sign" */ 672
				prg.helpLine[0] = /* "was present. The next token I read will be `something'." */ 933
			}
			prg.backError()
		}
	}
	prg.getSymbol()
	switch prg.curCmd {
	case definedMacro, secondaryPrimaryMacro, tertiarySecondaryMacro, expressionTertiaryMacro:
		*(*prg.mem[prg.curMod].hh()).lh() = uint16(int32(*(*prg.mem[prg.curMod].hh()).lh()) + 1)

	default:
	}

	prg.clearSymbol(l, false)
	*prg.eqtb[l-1].lh() = uint16(prg.curCmd)
	if int32(prg.curCmd) == tagToken {
		*prg.eqtb[l-1].rh() = uint16(memMin)
	} else {
		*prg.eqtb[l-1].rh() = uint16(prg.curMod)
	}
	prg.getXNext()
}

func (prg *prg) doNewInternal() {
	for {
		if int32(prg.intPtr) == maxInternal {
			prg.overflow(strNumber( /* "number of internals" */ 934), maxInternal)
		}
		// \xref[METAFONT capacity exceeded number of int][\quad number of internals]
		prg.getClearSymbol()
		prg.intPtr = byte(int32(prg.intPtr) + 1)
		*prg.eqtb[prg.curSym-1].lh() = uint16(internalQuantity)
		*prg.eqtb[prg.curSym-1].rh() = uint16(prg.intPtr)
		prg.intName[prg.intPtr-1] = *prg.hash[prg.curSym-1].rh()
		prg.internal[prg.intPtr-1] = 0
		prg.getXNext()
		if int32(prg.curCmd) != comma {
			break
		}
	}
}

func (prg *prg) doShow() {
	for {
		prg.getXNext()
		prg.scanExpression()
		prg.printNl(strNumber( /* ">> " */ 765))
		// \xref[>>]
		prg.printExp(halfword(memMin), smallNumber(2))
		prg.flushCurExp(scaled(0))
		if int32(prg.curCmd) != comma {
			break
		}
	}
}

func (prg *prg) dispToken() {
	prg.printNl(strNumber( /* "> " */ 940))
	// \xref[>\relax]
	if int32(prg.curSym) == 0 {
		if int32(prg.curCmd) == numericToken {
			prg.printScaled(prg.curMod)
		} else if int32(prg.curCmd) == capsuleToken {
			prg.gPointer = uint16(prg.curMod)
			prg.printCapsule()
		} else {
			prg.printChar(asciiCode('"'))
			prg.slowPrint(prg.curMod)
			prg.printChar(asciiCode('"'))
			{
				if int32(prg.strRef[prg.curMod]) < maxStrRef {
					if int32(prg.strRef[prg.curMod]) > 1 {
						prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
					} else {
						prg.flushString(strNumber(prg.curMod))
					}
				}
			}
		}
	} else {
		prg.slowPrint(int32(*prg.hash[prg.curSym-1].rh()))
		prg.printChar(asciiCode('='))
		if int32(*prg.eqtb[prg.curSym-1].lh()) >= outerTag {
			prg.print( /* "(outer) " */ 941)
		}
		prg.printCmdMod(int32(prg.curCmd), prg.curMod)
		if int32(prg.curCmd) == definedMacro {
			prg.printLn()
			prg.showMacro(halfword(prg.curMod), memMin, 100000)
		} // this avoids recursion between |show_macro| and |print_cmd_mod|
		// \xref[recursion]
	}
}

func (prg *prg) doShowToken() {
	for {
		prg.getNext()
		prg.dispToken()
		prg.getXNext()
		if int32(prg.curCmd) != comma {
			break
		}
	}
}

func (prg *prg) doShowStats() {
	prg.printNl(strNumber( /* "Memory usage " */ 950))
	// \xref[Memory usage...]
	prg.printInt(prg.varUsed)
	prg.printChar(asciiCode('&'))
	prg.printInt(prg.dynUsed)
	if false {
		prg.print( /* "unknown" */ 358)
	}
	prg.print( /* " (" */ 558)
	prg.printInt(int32(prg.hiMemMin) - int32(prg.loMemMax) - 1)
	prg.print( /* " still untouched)" */ 951)
	prg.printLn()
	prg.printNl(strNumber( /* "String usage " */ 952))
	prg.printInt(int32(prg.strPtr) - int32(prg.initStrPtr))
	prg.printChar(asciiCode('&'))
	prg.printInt(int32(prg.poolPtr) - int32(prg.initPoolPtr))
	prg.print( /* " (" */ 558)
	prg.printInt(maxStrings - int32(prg.maxStrPtr))
	prg.printChar(asciiCode('&'))
	prg.printInt(poolSize - int32(prg.maxPoolPtr))
	prg.print( /* " still untouched)" */ 951)
	prg.printLn()
	prg.getXNext()
}

func (prg *prg) dispVar(p halfword) {
	var (
		q                           halfword // traverses attributes and subscripts
		n/* 0..maxPrintLine */ byte          // amount of macro text to show
	)
	if int32(*(*prg.mem[p].hh()).b0()) == structured {
		q = *(*prg.mem[int32(p)+1].hh()).lh()
		for {
			prg.dispVar(q)
			q = *(*prg.mem[q].hh()).rh()
			if int32(q) == memMin+3+10+2+2 {
				break
			}
		}
		q = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[q].hh()).b1()) == subscr {
			prg.dispVar(q)
			q = *(*prg.mem[q].hh()).rh()
		}
	} else if int32(*(*prg.mem[p].hh()).b0()) >= unsuffixedMacro {
		prg.printNl(strNumber( /* "" */ 285))
		prg.printVariableName(p)
		if int32(*(*prg.mem[p].hh()).b0()) > unsuffixedMacro {
			prg.print( /* "@#" */ 664)
		} // |suffixed_macro|
		prg.print( /* "=macro:" */ 953)
		if int32(prg.fileOffset) >= maxPrintLine-20 {
			n = 5
		} else {
			n = byte(maxPrintLine - int32(prg.fileOffset) - 15)
		}
		prg.showMacro(halfword(*prg.mem[int32(p)+1].int()), memMin, int32(n))
	} else if int32(*(*prg.mem[p].hh()).b0()) != undefined {
		prg.printNl(strNumber( /* "" */ 285))
		prg.printVariableName(p)
		prg.printChar(asciiCode('='))
		prg.printExp(p, smallNumber(0))
	}
}

func (prg *prg) doShowVar() {
	for {
		prg.getNext()
		if int32(prg.curSym) > 0 {
			if int32(prg.curSym) <= hashBase+hashSize+12 {
				if int32(prg.curCmd) == tagToken {
					if prg.curMod != memMin {
						prg.dispVar(halfword(prg.curMod))
						goto done
					}
				}
			}
		}
		prg.dispToken()

	done:
		prg.getXNext()
		if int32(prg.curCmd) != comma {
			break
		}
	}
}

func (prg *prg) doShowDependencies() {
	var (
		p halfword // link that runs through all dependencies
	)
	p = *(*prg.mem[memMin+3+10].hh()).rh()
	for int32(p) != memMin+3+10 {
		if prg.interesting(p) {
			prg.printNl(strNumber( /* "" */ 285))
			prg.printVariableName(p)
			if int32(*(*prg.mem[p].hh()).b0()) == dependent {
				prg.printChar(asciiCode('='))
			} else {
				prg.print( /* " = " */ 768)
			} // extra spaces imply proto-dependency
			prg.printDependency(*(*prg.mem[int32(p)+1].hh()).rh(), *(*prg.mem[p].hh()).b0())
		}
		p = *(*prg.mem[int32(p)+1].hh()).rh()
		for int32(*(*prg.mem[p].hh()).lh()) != memMin {
			p = *(*prg.mem[p].hh()).rh()
		}
		p = *(*prg.mem[p].hh()).rh()
	}
	prg.getXNext()
}

func (prg *prg) doShowWhatever() {
	if int32(prg.interaction) == errorStopMode {
	}
	switch prg.curMod {
	case showTokenCode:
		prg.doShowToken()
	case showStatsCode:
		prg.doShowStats()
	case showCode:
		prg.doShow()
	case showVarCode:
		prg.doShowVar()
	case showDependenciesCode:
		prg.doShowDependencies()
	} // there are no other cases
	if prg.internal[showstopping-1] > 0 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "OK" */ 954) /* \xref[!\relax]  */
		}
		// \xref[OK]
		if int32(prg.interaction) < errorStopMode {
			prg.helpPtr = 0
			prg.errorCount = int8(int32(prg.errorCount) - 1)
		} else {
			prg.helpPtr = 1
			prg.helpLine[0] = /* "This isn't an error message; I'm just showing something." */ 955
		}
		if int32(prg.curCmd) == semicolon {
			prg.error1()
		} else {
			prg.putGetError()
		}
	}
}

func (prg *prg) scanWith() (r bool) {
	var (
		t      smallNumber // |known| or |pen_type|
		result bool        // the value to return
	)
	t = byte(prg.curMod)
	prg.curType = byte(vacuous)
	prg.getXNext()
	prg.scanExpression()
	result = false
	if int32(prg.curType) != int32(t) {
		prg.dispErr(halfword(memMin), strNumber( /* "Improper type" */ 963))
		// \xref[Improper type]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "Next time say `withweight <known numeric expression>';" */ 964
			prg.helpLine[0] = /* "I'll ignore the bad `with' clause and look for another." */ 965
		}
		if int32(t) == penType {
			prg.helpLine[1] = /* "Next time say `withpen <known pen expression>';" */ 966
		}
		prg.putGetFlushError(scaled(0))
	} else if int32(prg.curType) == penType {
		result = true
	} else {
		// Check the tentative weight
		prg.curExp = prg.roundUnscaled(prg.curExp)
		if abs(prg.curExp) < 4 && prg.curExp != 0 {
			result = true
		} else {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Weight must be -3, -2, -1, +1, +2, or +3" */ 967) /* \xref[!\relax]  */
			}
			// \xref[Weight must be...]
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I'll ignore the bad `with' clause and look for another." */ 965
			}
			prg.putGetFlushError(scaled(0))
		}
	}
	r = result
	return r
}

func (prg *prg) findEdgesVar(t halfword) {
	var (
		p halfword
	)
	p = prg.findVariable(t)
	prg.curEdges = uint16(memMin)
	if int32(p) == memMin {
		prg.obliterated(t)
		prg.putGetError()
	} else if int32(*(*prg.mem[p].hh()).b0()) != pictureType {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Variable " */ 790) /* \xref[!\relax]  */
		}
		prg.showTokenList(int32(t), memMin, 1000, 0)
		// \xref[Variable x is the wrong type]
		prg.print( /* " is the wrong type (" */ 968)
		prg.printType(*(*prg.mem[p].hh()).b0())
		prg.printChar(asciiCode(')'))
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "I was looking for a \"known\" picture variable." */ 969
			prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
		}
		prg.putGetError()
	} else {
		prg.curEdges = uint16(*prg.mem[int32(p)+1].int())
	}
	prg.flushNodeList(t)
}

func (prg *prg) doAddTo() {
	var (
		lhs, rhs                                     halfword // variable on left, path on right
		w                                            int32    // tentative weight
		p                                            halfword // list manipulation register
		q                                            halfword // beginning of second half of doubled path
		addToType/* doublePathCode..alsoCode */ byte          // modifier of \&[addto]
	)
	prg.getXNext()
	prg.varFlag = byte(thingToAdd)
	prg.scanPrimary()
	if int32(prg.curType) != tokenList {
		prg.dispErr(halfword(memMin), strNumber( /* "Not a suitable variable" */ 971))
		// \xref[Not a suitable variable]
		{
			prg.helpPtr = 4
			prg.helpLine[3] = /* "At this point I needed to see the name of a picture variable." */ 972
			prg.helpLine[2] = /* "(Or perhaps you have indeed presented me with one; I might" */ 973
			prg.helpLine[1] = /* "have missed it, if it wasn't followed by the proper token.)" */ 974
			prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
		}
		prg.putGetFlushError(scaled(0))
	} else {
		lhs = uint16(prg.curExp)
		addToType = byte(prg.curMod)

		prg.curType = byte(vacuous)
		prg.getXNext()
		prg.scanExpression()
		if int32(addToType) == alsoCode {
			prg.findEdgesVar(lhs)
			if int32(prg.curEdges) == memMin {
				prg.flushCurExp(scaled(0))
			} else if int32(prg.curType) != pictureType {
				prg.dispErr(halfword(memMin), strNumber( /* "Improper `addto'" */ 975))
				// \xref[Improper `addto']
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "This expression should have specified a known picture." */ 976
					prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
				}
				prg.putGetFlushError(scaled(0))
			} else {
				prg.mergeEdges(halfword(prg.curExp))
				prg.flushCurExp(scaled(0))
			}
		} else {
			// Get ready to fill a contour, and fill it
			if int32(prg.curType) == pairType {
				prg.pairToPath()
			}
			if int32(prg.curType) != pathType {
				prg.dispErr(halfword(memMin), strNumber( /* "Improper `addto'" */ 975))
				// \xref[Improper `addto']
				{
					prg.helpPtr = 2
					prg.helpLine[1] = /* "This expression should have been a known path." */ 977
					prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
				}
				prg.putGetFlushError(scaled(0))
				prg.flushTokenList(lhs)
			} else {
				rhs = uint16(prg.curExp)
				w = 1
				prg.curPen = uint16(memMin + 3)
				for int32(prg.curCmd) == withOption {
					if prg.scanWith() {
						if int32(prg.curType) == known {
							w = prg.curExp
						} else {
							// Change the tentative pen
							if int32(*(*prg.mem[prg.curPen].hh()).lh()) == memMin {
								prg.tossPen(prg.curPen)
							} else {
								*(*prg.mem[prg.curPen].hh()).lh() = uint16(int32(*(*prg.mem[prg.curPen].hh()).lh()) - 1)
							}
							prg.curPen = uint16(prg.curExp)
						}
					}
				}

				// Complete the contour filling operation
				prg.findEdgesVar(lhs)
				if int32(prg.curEdges) == memMin {
					prg.tossKnotList(rhs)
				} else {
					lhs = uint16(memMin)
					prg.curPathType = addToType
					if int32(*(*prg.mem[rhs].hh()).b0()) == endpoint {
						if int32(prg.curPathType) == doublePathCode {
							if int32(*(*prg.mem[rhs].hh()).rh()) == int32(rhs) {
								*prg.mem[int32(rhs)+5].int() = *prg.mem[int32(rhs)+1].int()
								*prg.mem[int32(rhs)+6].int() = *prg.mem[int32(rhs)+2].int()
								*prg.mem[int32(rhs)+3].int() = *prg.mem[int32(rhs)+1].int()
								*prg.mem[int32(rhs)+4].int() = *prg.mem[int32(rhs)+2].int()
								*(*prg.mem[rhs].hh()).b0() = byte(explicit)
								*(*prg.mem[rhs].hh()).b1() = byte(explicit)
							} else {
								p = prg.htapYpoc(rhs)
								q = *(*prg.mem[p].hh()).rh()

								*prg.mem[int32(prg.pathTail)+5].int() = *prg.mem[int32(q)+5].int()
								*prg.mem[int32(prg.pathTail)+6].int() = *prg.mem[int32(q)+6].int()
								*(*prg.mem[prg.pathTail].hh()).b1() = *(*prg.mem[q].hh()).b1()
								*(*prg.mem[prg.pathTail].hh()).rh() = *(*prg.mem[q].hh()).rh()
								prg.freeNode(q, halfword(knotNodeSize))

								*prg.mem[int32(p)+5].int() = *prg.mem[int32(rhs)+5].int()
								*prg.mem[int32(p)+6].int() = *prg.mem[int32(rhs)+6].int()
								*(*prg.mem[p].hh()).b1() = *(*prg.mem[rhs].hh()).b1()
								*(*prg.mem[p].hh()).rh() = *(*prg.mem[rhs].hh()).rh()
								prg.freeNode(rhs, halfword(knotNodeSize))

								rhs = p
							}
						} else {
							// Complain about non-cycle and |goto not_found|
							{
								if int32(prg.interaction) == errorStopMode {
								}
								prg.printNl(strNumber( /* "! " */ 261))
								prg.print( /* "Not a cycle" */ 978) /* \xref[!\relax]  */
							}
							// \xref[Not a cycle]
							{
								prg.helpPtr = 2
								prg.helpLine[1] = /* "That contour should have ended with `..cycle' or `&cycle'." */ 979
								prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
							}
							prg.putGetError()
							prg.tossKnotList(rhs)
							goto notFound
						}
					} else if int32(prg.curPathType) == doublePathCode {
						lhs = prg.htapYpoc(rhs)
					}
					prg.curWt = w
					rhs = prg.makeSpec(rhs, *prg.mem[int32(prg.curPen)+9].int(), prg.internal[tracingSpecs-1])

					// Check the turning number
					if prg.turningNumber <= 0 {
						if int32(prg.curPathType) != doublePathCode {
							if prg.internal[turningCheck-1] > 0 {
								if prg.turningNumber < 0 && int32(*(*prg.mem[prg.curPen].hh()).rh()) == memMin {
									prg.curWt = -prg.curWt
								} else {
									if prg.turningNumber == 0 {
										if prg.internal[turningCheck-1] <= 0200000 && int32(*(*prg.mem[prg.curPen].hh()).rh()) == memMin {
											goto done
										} else {
											prg.printStrange(strNumber( /* "Strange path (turning number is zero)" */ 980))
										}
									} else {
										prg.printStrange(strNumber( /* "Backwards path (turning number is negative)" */ 981))
									}
									// \xref[Backwards path...]
									{
										prg.helpPtr = 3
										prg.helpLine[2] = /* "The path doesn't have a counterclockwise orientation," */ 982
										prg.helpLine[1] = /* "so I'll probably have trouble drawing it." */ 983
										prg.helpLine[0] = /* "(See Chapter 27 of The METAFONTbook for more help.)" */ 984
									}
									// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]
									prg.putGetError()
								}
							}
						}
					}

				done:
					;
					if *prg.mem[int32(prg.curPen)+9].int() == 0 {
						prg.fillSpec(rhs)
					} else {
						prg.fillEnvelope(rhs)
					}
					if int32(lhs) != memMin {
						prg.revTurns = true
						lhs = prg.makeSpec(lhs, *prg.mem[int32(prg.curPen)+9].int(), prg.internal[tracingSpecs-1])
						prg.revTurns = false
						if *prg.mem[int32(prg.curPen)+9].int() == 0 {
							prg.fillSpec(lhs)
						} else {
							prg.fillEnvelope(lhs)
						}
					}

				notFound:
				}
				if int32(*(*prg.mem[prg.curPen].hh()).lh()) == memMin {
					prg.tossPen(prg.curPen)
				} else {
					*(*prg.mem[prg.curPen].hh()).lh() = uint16(int32(*(*prg.mem[prg.curPen].hh()).lh()) - 1)
				}
			}
		}
	}
}

// \4
// Declare the function called |tfm_check|
func (prg *prg) tfmCheck(m smallNumber) (r scaled) {
	if abs(prg.internal[m-1]) >= 01000000000 {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Enormous " */ 1001) /* \xref[!\relax]  */
		}
		prg.print(int32(prg.intName[m-1]))
		// \xref[Enormous charwd...]
		// \xref[Enormous chardp...]
		// \xref[Enormous charht...]
		// \xref[Enormous charic...]
		// \xref[Enormous designsize...]
		prg.print( /* " has been reduced" */ 1002)
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "Font metric dimensions must be less than 2048pt." */ 1003
		}
		prg.putGetError()
		if prg.internal[m-1] > 0 {
			r = 01000000000 - 1
		} else {
			r = 1 - 01000000000
		}
	} else {
		r = prg.internal[m-1]
	}
	return r
}

func (prg *prg) doShipOut() {
	var (
		c int32 // the character code
	)
	prg.getXNext()
	prg.varFlag = byte(semicolon)
	prg.scanExpression()
	if int32(prg.curType) != tokenList {
		if int32(prg.curType) == pictureType {
			prg.curEdges = uint16(prg.curExp)
		} else {
			{
				prg.dispErr(halfword(memMin), strNumber( /* "Not a suitable variable" */ 971))
				// \xref[Not a suitable variable]
				{
					prg.helpPtr = 4
					prg.helpLine[3] = /* "At this point I needed to see the name of a picture variable." */ 972
					prg.helpLine[2] = /* "(Or perhaps you have indeed presented me with one; I might" */ 973
					prg.helpLine[1] = /* "have missed it, if it wasn't followed by the proper token.)" */ 974
					prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
				}
				prg.putGetFlushError(scaled(0))
			}

			goto exit
		}
	} else {
		prg.findEdgesVar(halfword(prg.curExp))
		prg.curType = byte(vacuous)
	}
	if int32(prg.curEdges) != memMin {
		c = prg.roundUnscaled(prg.internal[charCode-1]) % 256
		if c < 0 {
			c = c + 256
		}

		// Store the width information for character code~|c|
		if c < int32(prg.bc) {
			prg.bc = byte(c)
		}
		if c > int32(prg.ec) {
			prg.ec = byte(c)
		}
		prg.charExists[c] = true
		prg.gfDx[c] = prg.internal[charDx-1]
		prg.gfDy[c] = prg.internal[charDy-1]
		prg.tfmWidth[c] = prg.tfmCheck(smallNumber(charWd))
		prg.tfmHeight[c] = prg.tfmCheck(smallNumber(charHt))
		prg.tfmDepth[c] = prg.tfmCheck(smallNumber(charDp))
		prg.tfmItalCorr[c] = prg.tfmCheck(smallNumber(charIc))
		if prg.internal[proofing-1] >= 0 {
			prg.shipOut(eightBits(c))
		}
	}
	prg.flushCurExp(scaled(0))

exit:
}

func (prg *prg) doDisplay() {
	var (
		e halfword // token list for a picture variable
	)
	prg.getXNext()
	prg.varFlag = byte(inWindow)
	prg.scanPrimary()
	if int32(prg.curType) != tokenList {
		prg.dispErr(halfword(memMin), strNumber( /* "Not a suitable variable" */ 971))
		// \xref[Not a suitable variable]
		{
			prg.helpPtr = 4
			prg.helpLine[3] = /* "At this point I needed to see the name of a picture variable." */ 972
			prg.helpLine[2] = /* "(Or perhaps you have indeed presented me with one; I might" */ 973
			prg.helpLine[1] = /* "have missed it, if it wasn't followed by the proper token.)" */ 974
			prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
		}
		prg.putGetFlushError(scaled(0))
	} else {
		e = uint16(prg.curExp)
		prg.curType = byte(vacuous)
		prg.getXNext()
		prg.scanExpression()
		if int32(prg.curType) != known {
			goto commonEnding
		}
		prg.curExp = prg.roundUnscaled(prg.curExp)
		if prg.curExp < 0 {
			goto notFound
		}
		if prg.curExp > 15 {
			goto notFound
		}
		if !prg.windowOpen[prg.curExp] {
			goto notFound
		}
		prg.findEdgesVar(e)
		if int32(prg.curEdges) != memMin {
			prg.dispEdges(windowNumber(prg.curExp))
		}

		goto exit

	notFound:
		prg.curExp = prg.curExp * 0200000

	commonEnding:
		prg.dispErr(halfword(memMin), strNumber( /* "Bad window number" */ 985))
		// \xref[Bad window number]
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "It should be the number of an open window." */ 986
		}
		prg.putGetFlushError(scaled(0))
		prg.flushTokenList(e)
	}

exit:
}

func (prg *prg) getPair(c commandCode) (r bool) {
	var (
		p halfword // a pair of values that are known (we hope)
		b bool     // did we find such a pair?
	)
	if int32(prg.curCmd) != int32(c) {
		r = false
	} else {
		prg.getXNext()
		prg.scanExpression()
		if prg.nicePair(prg.curExp, prg.curType) {
			p = uint16(*prg.mem[prg.curExp+1].int())
			prg.curX = *prg.mem[int32(p)+1].int()
			prg.curY = *prg.mem[int32(p)+2+1].int()
			b = true
		} else {
			b = false
		}
		prg.flushCurExp(scaled(0))
		r = b
	}
	return r
}

func (prg *prg) doOpenWindow() {
	var (
		k               int32  // the window number in question
		r0, c0, r11, c1 scaled // window coordinates
	)
	prg.getXNext()
	prg.scanExpression()
	if int32(prg.curType) != known {
		goto notFound
	}
	k = prg.roundUnscaled(prg.curExp)
	if k < 0 {
		goto notFound
	}
	if k > 15 {
		goto notFound
	}
	if !prg.getPair(commandCode(fromToken)) {
		goto notFound
	}
	r0 = prg.curX
	c0 = prg.curY
	if !prg.getPair(commandCode(toToken)) {
		goto notFound
	}
	r11 = prg.curX
	c1 = prg.curY
	if !prg.getPair(commandCode(atToken)) {
		goto notFound
	}
	prg.openAWindow(windowNumber(k), r0, c0, r11, c1, prg.curX, prg.curY)
	goto exit

notFound:
	{
		if int32(prg.interaction) == errorStopMode {
		}
		prg.printNl(strNumber( /* "! " */ 261))
		prg.print( /* "Improper `openwindow'" */ 987) /* \xref[!\relax]  */
	}
	// \xref[Improper `openwindow']
	{
		prg.helpPtr = 2
		prg.helpLine[1] = /* "Say `openwindow k from (r0,c0) to (r1,c1) at (x,y)'," */ 988
		prg.helpLine[0] = /* "where all quantities are known and k is between 0 and 15." */ 989
	}
	prg.putGetError()

exit:
}

func (prg *prg) doCull() {
	var (
		e                                    halfword // token list for a picture variable
		keeping/* dropCode..keepCode */ byte          // modifier of |cull_op|
		w, wIn, wOut                         int32    // culling weights
	)
	w = 1
	prg.getXNext()
	prg.varFlag = byte(cullOp)
	prg.scanPrimary()
	if int32(prg.curType) != tokenList {
		prg.dispErr(halfword(memMin), strNumber( /* "Not a suitable variable" */ 971))
		// \xref[Not a suitable variable]
		{
			prg.helpPtr = 4
			prg.helpLine[3] = /* "At this point I needed to see the name of a picture variable." */ 972
			prg.helpLine[2] = /* "(Or perhaps you have indeed presented me with one; I might" */ 973
			prg.helpLine[1] = /* "have missed it, if it wasn't followed by the proper token.)" */ 974
			prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
		}
		prg.putGetFlushError(scaled(0))
	} else {
		e = uint16(prg.curExp)
		prg.curType = byte(vacuous)
		keeping = byte(prg.curMod)
		if !prg.getPair(commandCode(cullOp)) {
			goto notFound
		}
		for int32(prg.curCmd) == withOption && prg.curMod == known {
			if prg.scanWith() {
				w = prg.curExp
			}
		}

		// Set up the culling weights, or |goto not_found| if the thresholds are bad
		if prg.curX > prg.curY {
			goto notFound
		}
		if int32(keeping) == dropCode {
			if prg.curX > 0 || prg.curY < 0 {
				goto notFound
			}
			wOut = w
			wIn = 0
		} else {
			if prg.curX <= 0 && prg.curY >= 0 {
				goto notFound
			}
			wOut = 0
			wIn = w
		}
		prg.findEdgesVar(e)
		if int32(prg.curEdges) != memMin {
			prg.cullEdges(prg.floorUnscaled(prg.curX+0200000-1), prg.floorUnscaled(prg.curY), wOut, wIn)
		}

		goto exit

	notFound:
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Bad culling amounts" */ 990) /* \xref[!\relax]  */
		}
		// \xref[Bad culling amounts]
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "Always cull by known amounts that exclude 0." */ 991
		}
		prg.putGetError()
		prg.flushTokenList(e)
	}

exit:
}

func (prg *prg) doMessage() {
	var (
		m /* messageCode..errHelpCode */ byte // the type of message
	)
	m = byte(prg.curMod)
	prg.getXNext()
	prg.scanExpression()
	if int32(prg.curType) != stringType {
		prg.dispErr(halfword(memMin), strNumber( /* "Not a string" */ 699))
		// \xref[Not a string]
		{
			prg.helpPtr = 1
			prg.helpLine[0] = /* "A message should be a known string expression." */ 995
		}
		prg.putGetError()
	} else {
		switch m {
		case messageCode:
			prg.printNl(strNumber( /* "" */ 285))
			prg.slowPrint(prg.curExp)

		case errMessageCode:
			// Print string |cur_exp| as an error message
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "" */ 285) /* \xref[!\relax]  */
			}
			prg.slowPrint(prg.curExp)
			if int32(prg.errHelp) != 0 {
				prg.useErrHelp = true
			} else if prg.longHelpSeen {
				prg.helpPtr = 1
				prg.helpLine[0] = /* "(That was another `errmessage'.)" */ 996
			} else {
				if int32(prg.interaction) < errorStopMode {
					prg.longHelpSeen = true
				}
				{
					prg.helpPtr = 4
					prg.helpLine[3] = /* "This error message was generated by an `errmessage'" */ 997
					prg.helpLine[2] = /* "command, so I can't give any explicit help." */ 998
					prg.helpLine[1] = /* "Pretend that you're Miss Marple: Examine all clues," */ 999
					prg.helpLine[0] = /* "and deduce the truth by inspired guesses." */ 1000
				}
			}
			prg.putGetError()
			prg.useErrHelp = false

		case errHelpCode:
			// Save string |cur_exp| as the |err_help|
			if int32(prg.errHelp) != 0 {
				if int32(prg.strRef[prg.errHelp]) < maxStrRef {
					if int32(prg.strRef[prg.errHelp]) > 1 {
						prg.strRef[prg.errHelp] = byte(int32(prg.strRef[prg.errHelp]) - 1)
					} else {
						prg.flushString(prg.errHelp)
					}
				}
			}
			if int32(prg.strStart[prg.curExp+1])-int32(prg.strStart[prg.curExp]) == 0 {
				prg.errHelp = 0
			} else {
				prg.errHelp = uint16(prg.curExp)
				{
					if int32(prg.strRef[prg.errHelp]) < maxStrRef {
						prg.strRef[prg.errHelp] = byte(int32(prg.strRef[prg.errHelp]) + 1)
					}
				}
			}

		}
	} // there are no other cases
	prg.flushCurExp(scaled(0))
}

func (prg *prg) getCode() (r eightBits) {
	var (
		c int32 // the code value found
	)
	prg.getXNext()
	prg.scanExpression()
	if int32(prg.curType) == known {
		c = prg.roundUnscaled(prg.curExp)
		if c >= 0 {
			if c < 256 {
				goto found
			}
		}
	} else if int32(prg.curType) == stringType {
		if int32(prg.strStart[prg.curExp+1])-int32(prg.strStart[prg.curExp]) == 1 {
			c = int32(prg.strPool[prg.strStart[prg.curExp]])
			goto found
		}
	}
	prg.dispErr(halfword(memMin), strNumber( /* "Invalid code has been replaced by 0" */ 1009))
	// \xref[Invalid code...]
	{
		prg.helpPtr = 2
		prg.helpLine[1] = /* "I was looking for a number between 0 and 255, or for a" */ 1010
		prg.helpLine[0] = /* "string of length 1. Didn't find it; will use 0 instead." */ 1011
	}
	prg.putGetFlushError(scaled(0))
	c = 0

found:
	r = byte(c)
	return r
}

func (prg *prg) setTag(c halfword, t smallNumber, r1 halfword) {
	if int32(prg.charTag[c]) == noTag {
		prg.charTag[c] = t
		prg.charRemainder[c] = r1
		if int32(t) == ligTag {
			prg.labelPtr = uint16(int32(prg.labelPtr) + 1)
			prg.labelLoc[prg.labelPtr] = int16(r1)
			prg.labelChar[prg.labelPtr-1] = byte(c)
		}
	} else {
		// Complain about a character tag conflict
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Character " */ 1012) /* \xref[!\relax]  */
		}
		if int32(c) > ' ' && int32(c) < 127 {
			prg.print(int32(c))
		} else if int32(c) == 256 {
			prg.print( /* "||" */ 1013)
		} else {
			prg.print( /* "code " */ 1014)
			prg.printInt(int32(c))
		}
		prg.print( /* " is already " */ 1015)
		// \xref[Character c is already...]
		switch prg.charTag[c] {
		case ligTag:
			prg.print( /* "in a ligtable" */ 1016)
		case listTag:
			prg.print( /* "in a charlist" */ 1017)
		case extTag:
			prg.print( /* "extensible" */ 1006)
		} // there are no other cases
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "It's not legal to label a character more than once." */ 1018
			prg.helpLine[0] = /* "So I'll not change anything just now." */ 970
		}
		prg.putGetError()
	}
}

func (prg *prg) doTfmCommand() {
	var (
		c, cc/* 0..256 */ uint16        // character codes
		k/* 0..maxKerns */ uint16       // index into the |kern| array
		j                         int32 // index into |header_byte| or |param|
	)
	switch prg.curMod {
	case charListCode:
		c = uint16(prg.getCode())
		// we will store a list of character successors
		for int32(prg.curCmd) == colon {
			cc = uint16(prg.getCode())
			prg.setTag(c, smallNumber(listTag), cc)
			c = cc
		}

	case ligTableCode:
		// Store a list of ligature/kern steps
		prg.lkStarted = false

	continue1:
		prg.getXNext()
		if int32(prg.curCmd) == skipTo && prg.lkStarted {
			c = uint16(prg.getCode())
			if int32(prg.nl)-int32(prg.skipTable[c]) > 128 {
				{
					{
						if int32(prg.interaction) == errorStopMode {
						}
						prg.printNl(strNumber( /* "! " */ 261))
						prg.print( /* "Too far to skip" */ 1035) /* \xref[!\relax]  */
					} /* \xref[Too far to skip]  */
					{
						prg.helpPtr = 1
						prg.helpLine[0] = /* "At most 127 lig/kern steps can separate skipto1 from 1::." */ 1036
					}
					prg.error1()
					prg.ll = prg.skipTable[c]
					for {
						prg.lll = uint16(int32(prg.ligKern[prg.ll].b0) - minQuarterword)
						prg.ligKern[prg.ll].b0 = byte(stopFlag)
						prg.ll = uint16(int32(prg.ll) - int32(prg.lll))
						if int32(prg.lll) == 0 {
							break
						}
					}
				}
				prg.skipTable[c] = uint16(ligTableSize)
			}
			if int32(prg.skipTable[c]) == ligTableSize {
				prg.ligKern[int32(prg.nl)-1].b0 = byte(0 + minQuarterword)
			} else {
				prg.ligKern[int32(prg.nl)-1].b0 = byte(int32(prg.nl) - int32(prg.skipTable[c]) - 1 + minQuarterword)
			}
			prg.skipTable[c] = uint16(int32(prg.nl) - 1)
			goto done
		}
		if int32(prg.curCmd) == bcharLabel {
			c = 256
			prg.curCmd = byte(colon)
		} else {
			prg.backInput()
			c = uint16(prg.getCode())
		}
		if int32(prg.curCmd) == colon || int32(prg.curCmd) == doubleColon {
			if int32(prg.curCmd) == colon {
				if int32(c) == 256 {
					prg.bchLabel = prg.nl
				} else {
					prg.setTag(c, smallNumber(ligTag), prg.nl)
				}
			} else if int32(prg.skipTable[c]) < ligTableSize {
				prg.ll = prg.skipTable[c]
				prg.skipTable[c] = uint16(ligTableSize)
				for {
					prg.lll = uint16(int32(prg.ligKern[prg.ll].b0) - minQuarterword)
					if int32(prg.nl)-int32(prg.ll) > 128 {
						{
							{
								if int32(prg.interaction) == errorStopMode {
								}
								prg.printNl(strNumber( /* "! " */ 261))
								prg.print( /* "Too far to skip" */ 1035) /* \xref[!\relax]  */
							} /* \xref[Too far to skip]  */
							{
								prg.helpPtr = 1
								prg.helpLine[0] = /* "At most 127 lig/kern steps can separate skipto1 from 1::." */ 1036
							}
							prg.error1()
							prg.ll = prg.ll
							for {
								prg.lll = uint16(int32(prg.ligKern[prg.ll].b0) - minQuarterword)
								prg.ligKern[prg.ll].b0 = byte(stopFlag)
								prg.ll = uint16(int32(prg.ll) - int32(prg.lll))
								if int32(prg.lll) == 0 {
									break
								}
							}
						}
						goto continue1
					}
					prg.ligKern[prg.ll].b0 = byte(int32(prg.nl) - int32(prg.ll) - 1 + minQuarterword)
					prg.ll = uint16(int32(prg.ll) - int32(prg.lll))
					if int32(prg.lll) == 0 {
						break
					}
				}
			}

			goto continue1
		}
		if int32(prg.curCmd) == ligKernToken {
			prg.ligKern[prg.nl].b1 = byte(int32(c) + minQuarterword)
			prg.ligKern[prg.nl].b0 = byte(0 + minQuarterword)
			if prg.curMod < 128 {
				prg.ligKern[prg.nl].b2 = byte(prg.curMod + minQuarterword)
				prg.ligKern[prg.nl].b3 = byte(int32(prg.getCode()) + minQuarterword)
			} else {
				prg.getXNext()
				prg.scanExpression()
				if int32(prg.curType) != known {
					prg.dispErr(halfword(memMin), strNumber( /* "Improper kern" */ 1037))
					// \xref[Improper kern]
					{
						prg.helpPtr = 2
						prg.helpLine[1] = /* "The amount of kern should be a known numeric value." */ 1038
						prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
					}
					prg.putGetFlushError(scaled(0))
				}
				prg.kern[prg.nk] = prg.curExp
				k = 0
				for prg.kern[k] != prg.curExp {
					k = uint16(int32(k) + 1)
				}
				if int32(k) == int32(prg.nk) {
					if int32(prg.nk) == maxKerns {
						prg.overflow(strNumber( /* "kern" */ 1034), maxKerns)
					}
					// \xref[METAFONT capacity exceeded kern][\quad kern]
					prg.nk = uint16(int32(prg.nk) + 1)
				}
				prg.ligKern[prg.nl].b2 = byte(kernFlag + int32(k)/256)
				prg.ligKern[prg.nl].b3 = byte(int32(k)%256 + minQuarterword)
			}
			prg.lkStarted = true
		} else {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Illegal ligtable step" */ 1023) /* \xref[!\relax]  */
			}
			// \xref[Illegal ligtable step]
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I was looking for `=:' or `kern' here." */ 1024
			}
			prg.backError()
			prg.ligKern[prg.nl].b1 = byte(0 + minQuarterword)
			prg.ligKern[prg.nl].b2 = byte(0 + minQuarterword)
			prg.ligKern[prg.nl].b3 = byte(0 + minQuarterword)

			prg.ligKern[prg.nl].b0 = byte(stopFlag + 1) // this specifies an unconditional stop
		}
		if int32(prg.nl) == ligTableSize {
			prg.overflow(strNumber( /* "ligtable size" */ 1025), ligTableSize)
		}
		// \xref[METAFONT capacity exceeded ligtable size][\quad ligtable size]
		prg.nl = uint16(int32(prg.nl) + 1)
		if int32(prg.curCmd) == comma {
			goto continue1
		}
		if int32(prg.ligKern[int32(prg.nl)-1].b0) < stopFlag {
			prg.ligKern[int32(prg.nl)-1].b0 = byte(stopFlag)
		}

	done:
		;

	case extensibleCode:
		// Define an extensible recipe
		if int32(prg.ne) == 256 {
			prg.overflow(strNumber( /* "extensible" */ 1006), 256)
		}
		// \xref[METAFONT capacity exceeded extensible][\quad extensible]
		c = uint16(prg.getCode())
		prg.setTag(c, smallNumber(extTag), prg.ne)
		if int32(prg.curCmd) != colon {
			prg.missingErr(strNumber(':')) /* \xref[Missing `\char`\#']  */
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I'm processing `extensible c: t,m,b,r'." */ 1039
			}
			prg.backError()
		}
		prg.exten[prg.ne].b0 = byte(int32(prg.getCode()) + minQuarterword)
		if int32(prg.curCmd) != comma {
			prg.missingErr(strNumber(',')) /* \xref[Missing `\char`\#']  */
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I'm processing `extensible c: t,m,b,r'." */ 1039
			}
			prg.backError()
		}
		prg.exten[prg.ne].b1 = byte(int32(prg.getCode()) + minQuarterword)
		if int32(prg.curCmd) != comma {
			prg.missingErr(strNumber(',')) /* \xref[Missing `\char`\#']  */
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I'm processing `extensible c: t,m,b,r'." */ 1039
			}
			prg.backError()
		}
		prg.exten[prg.ne].b2 = byte(int32(prg.getCode()) + minQuarterword)
		if int32(prg.curCmd) != comma {
			prg.missingErr(strNumber(',')) /* \xref[Missing `\char`\#']  */
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I'm processing `extensible c: t,m,b,r'." */ 1039
			}
			prg.backError()
		}
		prg.exten[prg.ne].b3 = byte(int32(prg.getCode()) + minQuarterword)
		prg.ne = uint16(int32(prg.ne) + 1)

	case headerByteCode, fontDimenCode:
		c = uint16(prg.curMod)
		prg.getXNext()
		prg.scanExpression()
		if int32(prg.curType) != known || prg.curExp < 0100000 {
			prg.dispErr(halfword(memMin), strNumber( /* "Improper location" */ 1019))
			// \xref[Improper location]
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I was looking for a known, positive number." */ 1020
				prg.helpLine[0] = /* "For safety's sake I'll ignore the present command." */ 1021
			}
			prg.putGetError()
		} else {
			j = prg.roundUnscaled(prg.curExp)
			if int32(prg.curCmd) != colon {
				prg.missingErr(strNumber(':'))
				// \xref[Missing `:']
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "A colon should follow a headerbyte or fontdimen location." */ 1022
				}
				prg.backError()
			}
			if int32(c) == headerByteCode {
				for {
					if j > headerSize {
						prg.overflow(strNumber( /* "headerbyte" */ 1007), headerSize)
					}
					// \xref[METAFONT capacity exceeded headerbyte][\quad headerbyte]
					prg.headerByte[j-1] = int16(prg.getCode())
					j = j + 1
					if int32(prg.curCmd) != comma {
						break
					}
				}
			} else {
				// Store a list of font dimensions
				for {
					if j > maxFontDimen {
						prg.overflow(strNumber( /* "fontdimen" */ 1008), maxFontDimen)
					}
					// \xref[METAFONT capacity exceeded fontdimen][\quad fontdimen]
					for j > int32(prg.np) {
						prg.np = byte(int32(prg.np) + 1)
						prg.param[prg.np-1] = 0
					}
					prg.getXNext()
					prg.scanExpression()
					if int32(prg.curType) != known {
						prg.dispErr(halfword(memMin), strNumber( /* "Improper font parameter" */ 1040))
						// \xref[Improper font parameter]
						{
							prg.helpPtr = 1
							prg.helpLine[0] = /* "I'm zeroing this one. Proceed, with fingers crossed." */ 309
						}
						prg.putGetFlushError(scaled(0))
					}
					prg.param[j-1] = prg.curExp
					j = j + 1
					if int32(prg.curCmd) != comma {
						break
					}
				}
			}
		}

	} // there are no other cases
}

func (prg *prg) doSpecial() {
	var (
		m smallNumber // either |string_type| or |known|
	)
	m = byte(prg.curMod)
	prg.getXNext()
	prg.scanExpression()
	if prg.internal[proofing-1] >= 0 {
		if int32(prg.curType) != int32(m) {
			prg.dispErr(halfword(memMin), strNumber( /* "Unsuitable expression" */ 1060))
			// \xref[Unsuitable expression]
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "The expression shown above has the wrong type to be output." */ 1061
			}
			prg.putGetError()
		} else {
			if int32(prg.outputFileName) == 0 {
				prg.initGf()
			}
			if int32(m) == stringType {
				prg.gfString(strNumber(prg.curExp), strNumber(0))
			} else {
				{
					prg.gfBuf[prg.gfPtr] = byte(yyy)
					prg.gfPtr = byte(int32(prg.gfPtr) + 1)
					if int32(prg.gfPtr) == int32(prg.gfLimit) {
						prg.gfSwap()
					}
				}
				prg.gfFour(prg.curExp)
			}
		}
	}
	prg.flushCurExp(scaled(0))
}

func (prg *prg) storeBaseFile() {
	var (
		k    int32        // all-purpose index
		p, q halfword     // all-purpose pointers
		x    int32        // something to dump
		w    fourQuarters // four ASCII codes
	)
	prg.selector = byte(newString)
	prg.print( /* " (preloaded base=" */ 1071)
	prg.print(int32(prg.jobName))
	prg.printChar(asciiCode(' '))
	prg.printInt(prg.roundUnscaled(prg.internal[year-1]))
	prg.printChar(asciiCode('.'))
	prg.printInt(prg.roundUnscaled(prg.internal[month-1]))
	prg.printChar(asciiCode('.'))
	prg.printInt(prg.roundUnscaled(prg.internal[day-1]))
	prg.printChar(asciiCode(')'))
	if int32(prg.interaction) == batchMode {
		prg.selector = byte(logOnly)
	} else {
		prg.selector = byte(termAndLog)
	}
	{
		if int32(prg.poolPtr)+1 > int32(prg.maxPoolPtr) {
			if int32(prg.poolPtr)+1 > poolSize {
				prg.overflow(strNumber( /* "pool size" */ 257), poolSize-int32(prg.initPoolPtr))
			} /* \xref[METAFONT capacity exceeded pool size][\quad pool size]  */
			prg.maxPoolPtr = uint16(int32(prg.poolPtr) + 1)
		}
	}
	prg.baseIdent = prg.makeString()
	prg.strRef[prg.baseIdent] = byte(maxStrRef)

	prg.packJobName(strNumber(baseExtension))
	for !prg.wOpenOut(prg.baseFile) {
		prg.promptFileName(strNumber( /* "base file name" */ 1072), strNumber(baseExtension))
	}
	prg.printNl(strNumber( /* "Beginning to dump on file " */ 1073))
	// \xref[Beginning to dump...]
	prg.slowPrint(int32(prg.wMakeNameString(prg.baseFile)))
	prg.flushString(strNumber(int32(prg.strPtr) - 1))
	prg.printNl(strNumber( /* "" */ 285))
	prg.slowPrint(int32(prg.baseIdent))

	// Dump constants for consistency check
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = 461259239
		prg.baseFile.Put()
	}

	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = memMin
		prg.baseFile.Put()
	}

	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = 3000
		prg.baseFile.Put()
	}

	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = hashSize
		prg.baseFile.Put()
	}

	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = hashPrime
		prg.baseFile.Put()
	}

	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = maxInOpen
		prg.baseFile.Put()
	}

	// Dump the string pool
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.poolPtr)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.strPtr)
		prg.baseFile.Put()
	}
	for ii := int32(0); ii <= int32(prg.strPtr); ii++ {
		k = ii
		_ = k
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.strStart[k])
		prg.baseFile.Put()
	}
	k = 0
	for k+4 < int32(prg.poolPtr) {
		w.b0 = byte(int32(prg.strPool[k]) + minQuarterword)
		w.b1 = byte(int32(prg.strPool[k+1]) + minQuarterword)
		w.b2 = byte(int32(prg.strPool[k+2]) + minQuarterword)
		w.b3 = byte(int32(prg.strPool[k+3]) + minQuarterword)
		{
			*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).qqqq() = w
			prg.baseFile.Put()
		}
		k = k + 4
	}
	k = int32(prg.poolPtr) - 4
	w.b0 = byte(int32(prg.strPool[k]) + minQuarterword)
	w.b1 = byte(int32(prg.strPool[k+1]) + minQuarterword)
	w.b2 = byte(int32(prg.strPool[k+2]) + minQuarterword)
	w.b3 = byte(int32(prg.strPool[k+3]) + minQuarterword)
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).qqqq() = w
		prg.baseFile.Put()
	}
	prg.printLn()
	prg.printInt(int32(prg.strPtr))
	prg.print( /* " strings of total length " */ 1068)
	prg.printInt(int32(prg.poolPtr))

	// Dump the dynamic memory
	prg.sortAvail()
	prg.varUsed = 0
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.loMemMax)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.rover)
		prg.baseFile.Put()
	}
	p = uint16(memMin)
	q = prg.rover
	x = 0
	for {
		for ii := int32(p); ii <= int32(q)+1; ii++ {
			k = ii
			_ = k
			*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P())) = prg.mem[k]
			prg.baseFile.Put()
		}
		x = x + int32(q) + 2 - int32(p)
		prg.varUsed = prg.varUsed + int32(q) - int32(p)
		p = uint16(int32(q) + int32(*(*prg.mem[q].hh()).lh()))
		q = *(*prg.mem[int32(q)+1].hh()).rh()
		if int32(q) == int32(prg.rover) {
			break
		}
	}
	prg.varUsed = prg.varUsed + int32(prg.loMemMax) - int32(p)
	prg.dynUsed = int32(prg.memEnd) + 1 - int32(prg.hiMemMin)

	for ii := int32(p); ii <= int32(prg.loMemMax); ii++ {
		k = ii
		_ = k
		*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P())) = prg.mem[k]
		prg.baseFile.Put()
	}
	x = x + int32(prg.loMemMax) + 1 - int32(p)
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.hiMemMin)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.avail)
		prg.baseFile.Put()
	}
	for ii := int32(prg.hiMemMin); ii <= int32(prg.memEnd); ii++ {
		k = ii
		_ = k
		*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P())) = prg.mem[k]
		prg.baseFile.Put()
	}
	x = x + int32(prg.memEnd) + 1 - int32(prg.hiMemMin)
	p = prg.avail
	for int32(p) != memMin {
		prg.dynUsed = prg.dynUsed - 1
		p = *(*prg.mem[p].hh()).rh()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = prg.varUsed
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = prg.dynUsed
		prg.baseFile.Put()
	}
	prg.printLn()
	prg.printInt(x)
	prg.print( /* " memory locations dumped; current usage is " */ 1069)
	prg.printInt(prg.varUsed)
	prg.printChar(asciiCode('&'))
	prg.printInt(prg.dynUsed)

	// Dump the table of equivalents and the hash table
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.hashUsed)
		prg.baseFile.Put()
	}
	prg.stCount = hashBase + hashSize - 1 - int32(prg.hashUsed)
	for ii := int32(1); ii <= int32(prg.hashUsed); ii++ {
		p = halfword(ii)
		_ = p
		if int32(*prg.hash[p-1].rh()) != 0 {
			{
				*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(p)
				prg.baseFile.Put()
			}
			{
				*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh() = prg.hash[p-1]
				prg.baseFile.Put()
			}
			{
				*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh() = prg.eqtb[p-1]
				prg.baseFile.Put()
			}
			prg.stCount = prg.stCount + 1
		}
	}
	for ii := int32(prg.hashUsed) + 1; ii <= hashBase+hashSize+12; ii++ {
		p = halfword(ii)
		_ = p
		{
			*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh() = prg.hash[p-1]
			prg.baseFile.Put()
		}
		{
			*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh() = prg.eqtb[p-1]
			prg.baseFile.Put()
		}
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = prg.stCount
		prg.baseFile.Put()
	}

	prg.printLn()
	prg.printInt(prg.stCount)
	prg.print( /* " symbolic tokens" */ 1070)

	// Dump a few more things and the closing check word
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.intPtr)
		prg.baseFile.Put()
	}
	for ii := int32(1); ii <= int32(prg.intPtr); ii++ {
		k = ii
		_ = k
		{
			*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = prg.internal[k-1]
			prg.baseFile.Put()
		}
		{
			*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.intName[k-1])
			prg.baseFile.Put()
		}
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.startSym)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.interaction)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.baseIdent)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.bgLoc)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = int32(prg.egLoc)
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = prg.serialNo
		prg.baseFile.Put()
	}
	{
		*(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int() = 69069
		prg.baseFile.Put()
	}
	prg.internal[tracingStats-1] = 0

	// Close the base file
	prg.wClose(prg.baseFile)
}

func (prg *prg) doStatement() {
	prg.curType = byte(vacuous)
	prg.getXNext()
	if int32(prg.curCmd) > maxPrimaryCommand {
		if int32(prg.curCmd) < semicolon {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "A statement can't begin with `" */ 869) /* \xref[!\relax]  */
			}
			// \xref[A statement can't begin with x]
			prg.printCmdMod(int32(prg.curCmd), prg.curMod)
			prg.printChar(asciiCode('\''))
			{
				prg.helpPtr = 5
				prg.helpLine[4] = /* "I was looking for the beginning of a new statement." */ 870
				prg.helpLine[3] = /* "If you just proceed without changing anything, I'll ignore" */ 871
				prg.helpLine[2] = /* "everything up to the next `;'. Please insert a semicolon" */ 872
				prg.helpLine[1] = /* "now in front of anything that you don't want me to delete." */ 873
				prg.helpLine[0] = /* "(See Chapter 27 of The METAFONTbook for an example.)" */ 874
			}

			// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]
			prg.backError()
			prg.getXNext()
		}
	} else if int32(prg.curCmd) > maxStatementCommand {
		prg.varFlag = byte(assignment)
		prg.scanExpression()
		if int32(prg.curCmd) < endGroup {
			if int32(prg.curCmd) == equals {
				prg.doEquation()
			} else if int32(prg.curCmd) == assignment {
				prg.doAssignment()
			} else if int32(prg.curType) == stringType {
				if prg.internal[tracingTitles-1] > 0 {
					prg.printNl(strNumber( /* "" */ 285))
					prg.slowPrint(prg.curExp)
				}
				if prg.internal[proofing-1] > 0 {
					if int32(prg.outputFileName) == 0 {
						prg.initGf()
					}
					prg.gfString(strNumber( /* "title " */ 1062), strNumber(prg.curExp))
					// \xref[title]
				}
			} else if int32(prg.curType) != vacuous {
				prg.dispErr(halfword(memMin), strNumber( /* "Isolated expression" */ 879))
				// \xref[Isolated expression]
				{
					prg.helpPtr = 3
					prg.helpLine[2] = /* "I couldn't find an `=' or `:=' after the" */ 880
					prg.helpLine[1] = /* "expression that is shown above this error message," */ 881
					prg.helpLine[0] = /* "so I guess I'll just ignore it and carry on." */ 882
				}
				prg.putGetError()
			}
			prg.flushCurExp(scaled(0))
			prg.curType = byte(vacuous)
		}
	} else {
		// Do a statement that doesn't begin with an expression
		if prg.internal[tracingCommands-1] > 0 {
			prg.showCmdMod(int32(prg.curCmd), prg.curMod)
		}
		switch prg.curCmd {
		case typeName:
			prg.doTypeDeclaration()
		case macroDef:
			if prg.curMod > varDef {
				prg.makeOpDef()
			} else if prg.curMod > endDef {
				prg.scanDef()
			}
		// \4
		// Cases of |do_statement| that invoke particular commands
		case randomSeed:
			prg.doRandomSeed()

		case modeCommand:
			prg.printLn()
			prg.interaction = byte(prg.curMod)

			// Initialize the print |selector| based on |interaction|
			if int32(prg.interaction) == batchMode {
				prg.selector = byte(noPrint)
			} else {
				prg.selector = byte(termOnly)
			}
			if prg.logOpened {
				prg.selector = byte(int32(prg.selector) + 2)
			}
			prg.getXNext()

		case protectionCommand:
			prg.doProtection()

		case delimiters:
			prg.defDelims()

		case saveCommand:
			for {
				prg.getSymbol()
				prg.saveVariable(prg.curSym)
				prg.getXNext()
				if int32(prg.curCmd) != comma {
					break
				}
			}
		case interimCommand:
			prg.doInterim()
		case letCommand:
			prg.doLet()
		case newInternal:
			prg.doNewInternal()

		case showCommand:
			prg.doShowWhatever()

		case addToCommand:
			prg.doAddTo()

		case shipOutCommand:
			prg.doShipOut()
		case displayCommand:
			prg.doDisplay()
		case openWindow:
			prg.doOpenWindow()
		case cullCommand:
			prg.doCull()

		case everyJobCommand:
			prg.getSymbol()
			prg.startSym = prg.curSym
			prg.getXNext()

		case messageCommand:
			prg.doMessage()

		case tfmCommand:
			prg.doTfmCommand()

		case specialCommand:
			prg.doSpecial()

		} // there are no other cases
		prg.curType = byte(vacuous)
	}
	if int32(prg.curCmd) < semicolon {
		{
			if int32(prg.interaction) == errorStopMode {
			}
			prg.printNl(strNumber( /* "! " */ 261))
			prg.print( /* "Extra tokens will be flushed" */ 875) /* \xref[!\relax]  */
		}
		// \xref[Extra tokens will be flushed]
		{
			prg.helpPtr = 6
			prg.helpLine[5] = /* "I've just read as much of that statement as I could fathom," */ 876
			prg.helpLine[4] = /* "so a semicolon should have been next. It's very puzzling..." */ 877
			prg.helpLine[3] = /* "but I'll try to get myself back together, by ignoring" */ 878
			prg.helpLine[2] = /* "everything up to the next `;'. Please insert a semicolon" */ 872
			prg.helpLine[1] = /* "now in front of anything that you don't want me to delete." */ 873
			prg.helpLine[0] = /* "(See Chapter 27 of The METAFONTbook for an example.)" */ 874
		}

		// \xref[METAFONTbook][\sl The [\logos METAFONT\/]book]
		prg.backError()
		prg.scannerStatus = byte(flushing)
		for {
			prg.getNext()

			// Decrease the string reference count...
			if int32(prg.curCmd) == stringToken {
				if int32(prg.strRef[prg.curMod]) < maxStrRef {
					if int32(prg.strRef[prg.curMod]) > 1 {
						prg.strRef[prg.curMod] = byte(int32(prg.strRef[prg.curMod]) - 1)
					} else {
						prg.flushString(strNumber(prg.curMod))
					}
				}
			}
			if int32(prg.curCmd) > comma {
				break
			}
		} // |cur_cmd=semicolon|, |end_group|, or |stop|
		prg.scannerStatus = byte(normal)
	}
	prg.errorCount = 0
}

// 1017.

// tangle:pos ../../mf.web:19802:3:

// \MF's |main_control| procedure just calls |do_statement| repeatedly
// until coming to the end of the user's program.
// Each execution of |do_statement| concludes with
// |cur_cmd=semicolon|, |end_group|, or |stop|.
func (prg *prg) mainControl() {
	for {
		prg.doStatement()
		if int32(prg.curCmd) == endGroup {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "Extra `endgroup'" */ 910) /* \xref[!\relax]  */
			}
			// \xref[Extra `endgroup']
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I'm not currently working on a `begingroup'," */ 911
				prg.helpLine[0] = /* "so I had better not try to end anything." */ 689
			}
			prg.flushError(scaled(0))
		}
		if int32(prg.curCmd) == stop {
			break
		}
	}
}

// 1088.

// tangle:pos ../../mf.web:20697:3:

// The first 24 bytes (6 words) of a \.[TFM] file contain twelve 16-bit
// integers that give the lengths of the various subsequent portions
// of the file. These twelve integers are, in order:
// $$\vbox[\halign[\hfil#&$\null=\null$#\hfil\cr
// |lf|&length of the entire file, in words;\cr
// |lh|&length of the header data, in words;\cr
// |bc|&smallest character code in the font;\cr
// |ec|&largest character code in the font;\cr
// |nw|&number of words in the width table;\cr
// |nh|&number of words in the height table;\cr
// |nd|&number of words in the depth table;\cr
// |ni|&number of words in the italic correction table;\cr
// |nl|&number of words in the lig/kern table;\cr
// |nk|&number of words in the kern table;\cr
// |ne|&number of words in the extensible character table;\cr
// |np|&number of font parameter words.\cr]]$$
// They are all nonnegative and less than $2^[15]$. We must have |bc-1<=ec<=255|,
// |ne<=256|, and
// $$\hbox[|lf=6+lh+(ec-bc+1)+nw+nh+nd+ni+nl+nk+ne+np|.]$$
// Note that a font may contain as many as 256 characters (if |bc=0| and |ec=255|),
// and as few as 0 characters (if |bc=ec+1|).
//
// Incidentally, when two or more 8-bit bytes are combined to form an integer of
// 16 or more bits, the most significant bytes appear first in the file.
// This is called BigEndian order.
//  \xref[BigEndian order]

// 1089.

// tangle:pos ../../mf.web:20724:3:

// The rest of the \.[TFM] file may be regarded as a sequence of ten data
// arrays having the informal specification
// $$\def\arr$[#1]#2$[\&[array] $[#1]$ \&[of] #2]
// \tabskip\centering
// \halign to\displaywidth[\hfil\\[#]\tabskip=0pt&$\,:\,$\arr#\hfil
//  \tabskip\centering\cr
// header&|[0..lh-1]\\[stuff]|\cr
// char\_info&|[bc..ec]char_info_word|\cr
// width&|[0..nw-1]fix_word|\cr
// height&|[0..nh-1]fix_word|\cr
// depth&|[0..nd-1]fix_word|\cr
// italic&|[0..ni-1]fix_word|\cr
// lig\_kern&|[0..nl-1]lig_kern_command|\cr
// kern&|[0..nk-1]fix_word|\cr
// exten&|[0..ne-1]extensible_recipe|\cr
// param&|[1..np]fix_word|\cr]$$
// The most important data type used here is a | fix_word|, which is
// a 32-bit representation of a binary fraction. A |fix_word| is a signed
// quantity, with the two's complement of the entire word used to represent
// negation. Of the 32 bits in a |fix_word|, exactly 12 are to the left of the
// binary point; thus, the largest |fix_word| value is $2048-2^[-20]$, and
// the smallest is $-2048$. We will see below, however, that all but two of
// the |fix_word| values must lie between $-16$ and $+16$.

// 1090.

// tangle:pos ../../mf.web:20748:3:

// The first data array is a block of header information, which contains
// general facts about the font. The header must contain at least two words,
// |header[0]| and |header[1]|, whose meaning is explained below.  Additional
// header information of use to other software routines might also be
// included, and \MF\ will generate it if the \.[headerbyte] command occurs.
// For example, 16 more words of header information are in use at the Xerox
// Palo Alto Research Center; the first ten specify the character coding
// scheme used (e.g., `\.[XEROX TEXT]' or `\.[TEX MATHSY]'), the next five
// give the font family name (e.g., `\.[HELVETICA]' or `\.[CMSY]'), and the
// last gives the ``face byte.''
//
// \yskip\hang|header[0]| is a 32-bit check sum that \MF\ will copy into
// the \.[GF] output file. This helps ensure consistency between files,
// since \TeX\ records the check sums from the \.[TFM]'s it reads, and these
// should match the check sums on actual fonts that are used.  The actual
// relation between this check sum and the rest of the \.[TFM] file is not
// important; the check sum is simply an identification number with the
// property that incompatible fonts almost always have distinct check sums.
// \xref[check sum]
//
// \yskip\hang|header[1]| is a |fix_word| containing the design size of the
// font, in units of \TeX\ points. This number must be at least 1.0; it is
// fairly arbitrary, but usually the design size is 10.0 for a ``10 point''
// font, i.e., a font that was designed to look best at a 10-point size,
// whatever that really means. When a \TeX\ user asks for a font `\.[at]
// $\delta$ \.[pt]', the effect is to override the design size and replace it
// by $\delta$, and to multiply the $x$ and~$y$ coordinates of the points in
// the font image by a factor of $\delta$ divided by the design size.  [\sl
// All other dimensions in the\/ \.[TFM] file are |fix_word|\kern-1pt\
// numbers in design-size units.] Thus, for example, the value of |param[6]|,
// which defines the \.[em] unit, is often the |fix_word| value $2^[20]=1.0$,
// since many fonts have a design size equal to one em.  The other dimensions
// must be less than 16 design-size units in absolute value; thus,
// |header[1]| and |param[1]| are the only |fix_word| entries in the whole
// \.[TFM] file whose first byte might be something besides 0 or 255.
// \xref[design size]

// 1091.

// tangle:pos ../../mf.web:20785:3:

// Next comes the |char_info| array, which contains one | char_info_word|
// per character. Each word in this part of the file contains six fields
// packed into four bytes as follows.
//
// \yskip\hang first byte: | width_index| (8 bits)\par
// \hang second byte: | height_index| (4 bits) times 16, plus | depth_index|
//   (4~bits)\par
// \hang third byte: | italic_index| (6 bits) times 4, plus | tag|
//   (2~bits)\par
// \hang fourth byte: | remainder| (8 bits)\par
// \yskip\noindent
// The actual width of a character is \\[width]|[width_index]|, in design-size
// units; this is a device for compressing information, since many characters
// have the same width. Since it is quite common for many characters
// to have the same height, depth, or italic correction, the \.[TFM] format
// imposes a limit of 16 different heights, 16 different depths, and
// 64 different italic corrections.
//
// Incidentally, the relation $\\[width][0]=\\[height][0]=\\[depth][0]=
// \\[italic][0]=0$ should always hold, so that an index of zero implies a
// value of zero.  The |width_index| should never be zero unless the
// character does not exist in the font, since a character is valid if and
// only if it lies between |bc| and |ec| and has a nonzero |width_index|.

// 1092.

// tangle:pos ../../mf.web:20809:3:

// The |tag| field in a |char_info_word| has four values that explain how to
// interpret the |remainder| field.
//
// \def\hangg#1 [\hang\hbox[#1 ]]
// \yskip\hangg|tag=0| (|no_tag|) means that |remainder| is unused.\par
// \hangg|tag=1| (|lig_tag|) means that this character has a ligature/kerning
// program starting at location |remainder| in the |lig_kern| array.\par
// \hangg|tag=2| (|list_tag|) means that this character is part of a chain of
// characters of ascending sizes, and not the largest in the chain.  The
// |remainder| field gives the character code of the next larger character.\par
// \hangg|tag=3| (|ext_tag|) means that this character code represents an
// extensible character, i.e., a character that is built up of smaller pieces
// so that it can be made arbitrarily large. The pieces are specified in
// | exten[remainder]|.\par
// \yskip\noindent
// Characters with |tag=2| and |tag=3| are treated as characters with |tag=0|
// unless they are used in special circumstances in math formulas. For example,
// \TeX's \.[\\sum] operation looks for a |list_tag|, and the \.[\\left]
// operation looks for both |list_tag| and |ext_tag|.

// 1093.

// tangle:pos ../../mf.web:20834:3:

// The |lig_kern| array contains instructions in a simple programming language
// that explains what to do for special letter pairs. Each word in this array is a
// | lig_kern_command| of four bytes.
//
// \yskip\hang first byte: |skip_byte|, indicates that this is the final program
//   step if the byte is 128 or more, otherwise the next step is obtained by
//   skipping this number of intervening steps.\par
// \hang second byte: |next_char|, ``if |next_char| follows the current character,
//   then perform the operation and stop, otherwise continue.''\par
// \hang third byte: |op_byte|, indicates a ligature step if less than~128,
//   a kern step otherwise.\par
// \hang fourth byte: |remainder|.\par
// \yskip\noindent
// In a kern step, an
// additional space equal to |kern[256*(op_byte-128)+remainder]| is inserted
// between the current character and |next_char|. This amount is
// often negative, so that the characters are brought closer together
// by kerning; but it might be positive.
//
// There are eight kinds of ligature steps, having |op_byte| codes $4a+2b+c$ where
// $0\le a\le b+c$ and $0\le b,c\le1$. The character whose code is
// |remainder| is inserted between the current character and |next_char|;
// then the current character is deleted if $b=0$, and |next_char| is
// deleted if $c=0$; then we pass over $a$~characters to reach the next
// current character (which may have a ligature/kerning program of its own).
//
// If the very first instruction of the |lig_kern| array has |skip_byte=255|,
// the |next_char| byte is the so-called boundary character of this font;
// the value of |next_char| need not lie between |bc| and~|ec|.
// If the very last instruction of the |lig_kern| array has |skip_byte=255|,
// there is a special ligature/kerning program for a boundary character at the
// left, beginning at location |256*op_byte+remainder|.
// The interpretation is that \TeX\ puts implicit boundary characters
// before and after each consecutive string of characters from the same font.
// These implicit characters do not appear in the output, but they can affect
// ligatures and kerning.
//
// If the very first instruction of a character's |lig_kern| program has
// |skip_byte>128|, the program actually begins in location
// |256*op_byte+remainder|. This feature allows access to large |lig_kern|
// arrays, because the first instruction must otherwise
// appear in a location |<=255|.
//
// Any instruction with |skip_byte>128| in the |lig_kern| array must satisfy
// the condition
// $$\hbox[|256*op_byte+remainder<nl|.]$$
// If such an instruction is encountered during
// normal program execution, it denotes an unconditional halt; no ligature
// or kerning command is performed.

// 1094.

// tangle:pos ../../mf.web:20892:3:

// Extensible characters are specified by an | extensible_recipe|, which
// consists of four bytes called | top|, | mid|, | bot|, and | rep| (in this
// order). These bytes are the character codes of individual pieces used to
// build up a large symbol.  If |top|, |mid|, or |bot| are zero, they are not
// present in the built-up result. For example, an extensible vertical line is
// like an extensible bracket, except that the top and bottom pieces are missing.
//
// Let $T$, $M$, $B$, and $R$ denote the respective pieces, or an empty box
// if the piece isn't present. Then the extensible characters have the form
// $TR^kMR^kB$ from top to bottom, for some |k>=0|, unless $M$ is absent;
// in the latter case we can have $TR^kB$ for both even and odd values of~|k|.
// The width of the extensible character is the width of $R$; and the
// height-plus-depth is the sum of the individual height-plus-depths of the
// components used, since the pieces are butted together in a vertical list.

// 1095.

// tangle:pos ../../mf.web:20912:3:

// The final portion of a \.[TFM] file is the |param| array, which is another
// sequence of |fix_word| values.
//
// \yskip\hang|param[1]=slant| is the amount of italic slant, which is used
// to help position accents. For example, |slant=.25| means that when you go
// up one unit, you also go .25 units to the right. The |slant| is a pure
// number; it is the only |fix_word| other than the design size itself that is
// not scaled by the design size.
// \xref[design size]
//
// \hang|param[2]=space| is the normal spacing between words in text.
// Note that character @'40 in the font need not have anything to do with
// blank spaces.
//
// \hang|param[3]=space_stretch| is the amount of glue stretching between words.
//
// \hang|param[4]=space_shrink| is the amount of glue shrinking between words.
//
// \hang|param[5]=x_height| is the size of one ex in the font; it is also
// the height of letters for which accents don't have to be raised or lowered.
//
// \hang|param[6]=quad| is the size of one em in the font.
//
// \hang|param[7]=extra_space| is the amount added to |param[2]| at the
// ends of sentences.
//
// \yskip\noindent
// If fewer than seven parameters are present, \TeX\ sets the missing parameters
// to zero.

// 1117.

// tangle:pos ../../mf.web:21341:3:

// Straight linear insertion is good enough for sorting, since the lists
// are usually not terribly long. As we work on the data, the current list
// will start at |link(temp_head)| and end at |inf_val|; the nodes in this
// list will be in increasing order of their |value| fields.
//
// Given such a list, the |sort_in| function takes a value and returns a pointer
// to where that value can be found in the list. The value is inserted in
// the proper place, if necessary.
//
// At the time we need to do these operations, most of \MF's work has been
// completed, so we will have plenty of memory to play with. The value nodes
// that are allocated for sorting will never be returned to free storage.
func (prg *prg) sortIn(v scaled) (r halfword) {
	var (
		p, q, r1 halfword // list manipulation registers
	)
	p = uint16(3000 - 1)
	for true {
		q = *(*prg.mem[p].hh()).rh()
		if v <= *prg.mem[int32(q)+1].int() {
			goto found
		}
		p = q
	}

found:
	if v < *prg.mem[int32(q)+1].int() {
		r1 = prg.getNode(valueNodeSize)
		*prg.mem[int32(r1)+1].int() = v
		*(*prg.mem[r1].hh()).rh() = q
		*(*prg.mem[p].hh()).rh() = r1
	}
	r = *(*prg.mem[p].hh()).rh()
	return r
}

// 1118.

// tangle:pos ../../mf.web:21370:3:

// Now we come to the interesting part, where we reduce the list if necessary
// until it has the required size. The |min_cover| routine is basic to this
// process; it computes the minimum number~|m| such that the values of the
// current sorted list can be covered by |m|~intervals of width~|d|. It
// also sets the global value |perturbation| to the smallest value $d'>d$
// such that the covering found by this algorithm would be different.
//
// In particular, |min_cover(0)| returns the number of distinct values in the
// current list and sets |perturbation| to the minimum distance between
// adjacent values.
func (prg *prg) minCover(d scaled) (r int32) {
	var (
		p halfword // runs through the current list
		l scaled   // the least element covered by the current interval
		m int32    // lower bound on the size of the minimum cover
	)
	m = 0
	p = *(*prg.mem[3000-1].hh()).rh()
	prg.perturbation = 017777777777
	for int32(p) != memMin+3+10+2+2+2 {
		m = m + 1
		l = *prg.mem[int32(p)+1].int()
		for {
			p = *(*prg.mem[p].hh()).rh()
			if *prg.mem[int32(p)+1].int() > l+d {
				break
			}
		}
		if *prg.mem[int32(p)+1].int()-l < prg.perturbation {
			prg.perturbation = *prg.mem[int32(p)+1].int() - l
		}
	}
	r = m
	return r
}

// 1120.

// tangle:pos ../../mf.web:21399:3:

// The smallest |d| such that a given list can be covered with |m| intervals
// is determined by the |threshold| routine, which is sort of an inverse
// to |min_cover|. The idea is to increase the interval size rapidly until
// finding the range, then to go sequentially until the exact borderline has
// been discovered.
func (prg *prg) threshold(m int32) (r scaled) {
	var (
		d scaled // lower bound on the smallest interval size
	)
	prg.excess = prg.minCover(scaled(0)) - m
	if prg.excess <= 0 {
		r = 0
	} else {
		for {
			d = prg.perturbation
			if prg.minCover(d+d) <= m {
				break
			}
		}
		for prg.minCover(d) > m {
			d = prg.perturbation
		}
		r = d
	}
	return r
}

// 1121.

// tangle:pos ../../mf.web:21416:3:

// The |skimp| procedure reduces the current list to at most |m| entries,
// by changing values if necessary. It also sets |info(p):=k| if |value(p)|
// is the |k|th distinct value on the resulting list, and it sets
// |perturbation| to the maximum amount by which a |value| field has
// been changed. The size of the resulting list is returned as the
// value of |skimp|.
func (prg *prg) skimp(m int32) (r int32) {
	var (
		d        scaled   // the size of intervals being coalesced
		p, q, r1 halfword // list manipulation registers
		l        scaled   // the least value in the current interval
		v        scaled   // a compromise value
	)
	d = prg.threshold(m)
	prg.perturbation = 0
	q = uint16(3000 - 1)
	m = 0
	p = *(*prg.mem[3000-1].hh()).rh()
	for int32(p) != memMin+3+10+2+2+2 {
		m = m + 1
		l = *prg.mem[int32(p)+1].int()
		*(*prg.mem[p].hh()).lh() = uint16(m)
		if *prg.mem[int32(*(*prg.mem[p].hh()).rh())+1].int() <= l+d {
			for {
				p = *(*prg.mem[p].hh()).rh()
				*(*prg.mem[p].hh()).lh() = uint16(m)
				prg.excess = prg.excess - 1
				if prg.excess == 0 {
					d = 0
				}
				if *prg.mem[int32(*(*prg.mem[p].hh()).rh())+1].int() > l+d {
					break
				}
			}
			v = l + (*prg.mem[int32(p)+1].int()-l)/2
			if *prg.mem[int32(p)+1].int()-v > prg.perturbation {
				prg.perturbation = *prg.mem[int32(p)+1].int() - v
			}
			r1 = q
			for {
				r1 = *(*prg.mem[r1].hh()).rh()
				*prg.mem[int32(r1)+1].int() = v
				if int32(r1) == int32(p) {
					break
				}
			}
			*(*prg.mem[q].hh()).rh() = p // remove duplicate values from the current list
		}
		q = p
		p = *(*prg.mem[p].hh()).rh()
	}
	r = m
	return r
}

// 1123.

// tangle:pos ../../mf.web:21451:3:

// A warning message is issued whenever something is perturbed by
// more than 1/16\thinspace pt.
func (prg *prg) tfmWarning(m smallNumber) {
	prg.printNl(strNumber( /* "(some " */ 1041))
	prg.print(int32(prg.intName[m-1]))
	// \xref[some charwds...]
	// \xref[some chardps...]
	// \xref[some charhts...]
	// \xref[some charics...]
	prg.print( /* " values had to be adjusted by as much as " */ 1042)
	prg.printScaled(prg.perturbation)
	prg.print( /* "pt)" */ 1043)
}

// 1128.

// tangle:pos ../../mf.web:21510:3:

// Bytes 5--8 of the header are set to the design size, unless the user has
// some crazy reason for specifying them differently.
// \xref[design size]
//
// Error messages are not allowed at the time this procedure is called,
// so a warning is printed instead.
//
// The value of |max_tfm_dimen| is calculated so that
// $$\hbox[|make_scaled(16*max_tfm_dimen,internal[design_size])|]
//  < \\[three\_bytes].$$
func (prg *prg) fixDesignSize() {
	var (
		d scaled // the design size
	)
	d = prg.internal[designSize-1]
	if d < 0200000 || d >= 01000000000 {
		if d != 0 {
			prg.printNl(strNumber( /* "(illegal design size has been changed to 128pt)" */ 1044))
		}
		// \xref[illegal design size...]
		d = 040000000
		prg.internal[designSize-1] = d
	}
	if int32(prg.headerByte[5-1]) < 0 {
		if int32(prg.headerByte[6-1]) < 0 {
			if int32(prg.headerByte[7-1]) < 0 {
				if int32(prg.headerByte[8-1]) < 0 {
					prg.headerByte[5-1] = int16(d / 04000000)
					prg.headerByte[6-1] = int16(d / 4096 % 256)
					prg.headerByte[7-1] = int16(d / 16 % 256)
					prg.headerByte[8-1] = int16(d % 16 * 16)
				}
			}
		}
	}
	prg.maxTfmDimen = 16*prg.internal[designSize-1] - 1 - prg.internal[designSize-1]/010000000
	if prg.maxTfmDimen >= 01000000000 {
		prg.maxTfmDimen = 01000000000 - 1
	}
}

// 1129.

// tangle:pos ../../mf.web:21543:3:

// The |dimen_out| procedure computes a |fix_word| relative to the
// design size. If the data was out of range, it is corrected and the
// global variable |tfm_changed| is increased by~one.
func (prg *prg) dimenOut(x scaled) (r int32) {
	if abs(x) > prg.maxTfmDimen {
		prg.tfmChanged = prg.tfmChanged + 1
		if x > 0 {
			x = prg.maxTfmDimen
		} else {
			x = -prg.maxTfmDimen
		}
	}
	x = prg.makeScaled(x*16, prg.internal[designSize-1])
	r = x
	return r
}

// 1131.

// tangle:pos ../../mf.web:21560:3:

// If the user has not specified any of the first four header bytes,
// the |fix_check_sum| procedure replaces them by a ``check sum'' computed
// from the |tfm_width| data relative to the design size.
// \xref[check sum]
func (prg *prg) fixCheckSum() {
	var (
		k              eightBits // runs through character codes
		b1, b2, b3, b4 eightBits // bytes of the check sum
		x              int32     // hash value used in check sum computation
	)
	if int32(prg.headerByte[1-1]) < 0 {
		if int32(prg.headerByte[2-1]) < 0 {
			if int32(prg.headerByte[3-1]) < 0 {
				if int32(prg.headerByte[4-1]) < 0 {
					b1 = prg.bc
					b2 = prg.ec
					b3 = prg.bc
					b4 = prg.ec
					prg.tfmChanged = 0
					for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
						k = eightBits(ii)
						_ = k
						if prg.charExists[k] {
							x = prg.dimenOut(*prg.mem[prg.tfmWidth[k]+1].int()) + (int32(k)+4)*020000000 // this is positive
							b1 = byte((int32(b1) + int32(b1) + x) % 255)
							b2 = byte((int32(b2) + int32(b2) + x) % 253)
							b3 = byte((int32(b3) + int32(b3) + x) % 251)
							b4 = byte((int32(b4) + int32(b4) + x) % 247)
						}
					}
					prg.headerByte[1-1] = int16(b1)
					prg.headerByte[2-1] = int16(b2)
					prg.headerByte[3-1] = int16(b3)
					prg.headerByte[4-1] = int16(b4)
					goto exit
				}
			}
		}
	}
	for ii := int32(1); ii <= 4; ii++ {
		k = eightBits(ii)
		_ = k
		if int32(prg.headerByte[k-1]) < 0 {
			prg.headerByte[k-1] = 0
		}
	}

exit:
}

// 1133.

// tangle:pos ../../mf.web:21589:3:

// Finally we're ready to actually write the \.[TFM] information.
// Here are some utility routines for this purpose.
func (prg *prg) tfmTwo(x int32) {
	prg.tfmFile.Write(x / 256)
	prg.tfmFile.Write(x % 256)
}

func (prg *prg) tfmFour(x int32) {
	if x >= 0 {
		prg.tfmFile.Write(x / 0100000000)
	} else {
		x = x + 010000000000 // use two's complement for negative values
		x = x + 010000000000
		prg.tfmFile.Write(x/0100000000 + 128)
	}
	x = x % 0100000000
	prg.tfmFile.Write(x / 0200000)
	x = x % 0200000
	prg.tfmFile.Write(x / 0400)
	prg.tfmFile.Write(x % 0400)
}

func (prg *prg) tfmQqqq(x fourQuarters) {
	prg.tfmFile.Write(int32(x.b0) - minQuarterword)
	prg.tfmFile.Write(int32(x.b1) - minQuarterword)
	prg.tfmFile.Write(int32(x.b2) - minQuarterword)
	prg.tfmFile.Write(int32(x.b3) - minQuarterword)
}

// 1142. \[46] Generic font file format

// tangle:pos ../../mf.web:21761:35:

// The most important output produced by a typical run of \MF\ is the
// ``generic font'' (\.[GF]) file that specifies the bit patterns of the
// characters that have been drawn. The term [\sl generic\/] indicates that
// this file format doesn't match the conventions of any name-brand manufacturer;
// but it is easy to convert \.[GF] files to the special format required by
// almost all digital phototypesetting equipment. There's a strong analogy
// between the \.[DVI] files written by \TeX\ and the \.[GF] files written
// by \MF; and, in fact, the file formats have a lot in common.
//
// A \.[GF] file is a stream of 8-bit bytes that may be
// regarded as a series of commands in a machine-like language. The first
// byte of each command is the operation code, and this code is followed by
// zero or more bytes that provide parameters to the command. The parameters
// themselves may consist of several consecutive bytes; for example, the
// `|boc|' (beginning of character) command has six parameters, each of
// which is four bytes long. Parameters are usually regarded as nonnegative
// integers; but four-byte-long parameters can be either positive or
// negative, hence they range in value from $-2^[31]$ to $2^[31]-1$.
// As in \.[TFM] files, numbers that occupy
// more than one byte position appear in BigEndian order,
// and negative numbers appear in two's complement notation.
//
// A \.[GF] file consists of a ``preamble,'' followed by a sequence of one or
// more ``characters,'' followed by a ``postamble.'' The preamble is simply a
// |pre| command, with its parameters that introduce the file; this must come
// first.  Each ``character'' consists of a |boc| command, followed by any
// number of other commands that specify ``black'' pixels,
// followed by an |eoc| command. The characters appear in the order that \MF\
// generated them. If we ignore no-op commands (which are allowed between any
// two commands in the file), each |eoc| command is immediately followed by a
// |boc| command, or by a |post| command; in the latter case, there are no
// more characters in the file, and the remaining bytes form the postamble.
// Further details about the postamble will be explained later.
//
// Some parameters in \.[GF] commands are ``pointers.'' These are four-byte
// quantities that give the location number of some other byte in the file;
// the first file byte is number~0, then comes number~1, and so on.

// 1143.

// tangle:pos ../../mf.web:21800:3:

// The \.[GF] format is intended to be both compact and easily interpreted
// by a machine. Compactness is achieved by making most of the information
// relative instead of absolute. When a \.[GF]-reading program reads the
// commands for a character, it keeps track of two quantities: (a)~the current
// column number,~|m|; and (b)~the current row number,~|n|.  These are 32-bit
// signed integers, although most actual font formats produced from \.[GF]
// files will need to curtail this vast range because of practical
// limitations. (\MF\ output will never allow $\vert m\vert$ or $\vert
// n\vert$ to get extremely large, but the \.[GF] format tries to be more general.)
//
// How do \.[GF]'s row and column numbers correspond to the conventions
// of \TeX\ and \MF? Well, the ``reference point'' of a character, in \TeX's
// view, is considered to be at the lower left corner of the pixel in row~0
// and column~0. This point is the intersection of the baseline with the left
// edge of the type; it corresponds to location $(0,0)$ in \MF\ programs.
// Thus the pixel in \.[GF] row~0 and column~0 is \MF's unit square, comprising the
// region of the plane whose coordinates both lie between 0 and~1. The
// pixel in \.[GF] row~|n| and column~|m| consists of the points whose \MF\
// coordinates |(x,y)| satisfy |m<=x<=m+1| and |n<=y<=n+1|.  Negative values of
// |m| and~|x| correspond to columns of pixels [\sl left\/] of the reference
// point; negative values of |n| and~|y| correspond to rows of pixels [\sl
// below\/] the baseline.
//
// Besides |m| and |n|, there's also a third aspect of the current
// state, namely the  |paint_switch|, which is always either |black| or
// |white|. Each \\[paint] command advances |m| by a specified amount~|d|,
// and blackens the intervening pixels if |paint_switch=black|; then
// the |paint_switch| changes to the opposite state. \.[GF]'s commands are
// designed so that |m| will never decrease within a row, and |n| will never
// increase within a character; hence there is no way to whiten a pixel that
// has been blackened.

// 1144.

// tangle:pos ../../mf.web:21832:3:

// Here is a list of all the commands that may appear in a \.[GF] file. Each
// command is specified by its symbolic name (e.g., |boc|), its opcode byte
// (e.g., 67), and its parameters (if any). The parameters are followed
// by a bracketed number telling how many bytes they occupy; for example,
// `|d[2]|' means that parameter |d| is two bytes long.
//
// \yskip\hang|paint_0| 0. This is a \\[paint] command with |d=0|; it does
// nothing but change the |paint_switch| from \\[black] to \\[white] or vice~versa.
//
// \yskip\hang\\[paint\_1] through \\[paint\_63] (opcodes 1 to 63).
// These are \\[paint] commands with |d=1| to~63, defined as follows: If
// |paint_switch=black|, blacken |d|~pixels of the current row~|n|,
// in columns |m| through |m+d-1| inclusive. Then, in any case,
// complement the |paint_switch| and advance |m| by~|d|.
//
// \yskip\hang|paint1| 64 |d[1]|. This is a \\[paint] command with a specified
// value of~|d|; \MF\ uses it to paint when |64<=d<256|.
//
// \yskip\hang| paint2| 65 |d[2]|. Same as |paint1|, but |d|~can be as high
// as~65535.
//
// \yskip\hang| paint3| 66 |d[3]|. Same as |paint1|, but |d|~can be as high
// as $2^[24]-1$. \MF\ never needs this command, and it is hard to imagine
// anybody making practical use of it; surely a more compact encoding will be
// desirable when characters can be this large. But the command is there,
// anyway, just in case.
//
// \yskip\hang|boc| 67 |c[4]| |p[4]| |min_m[4]| |max_m[4]| |min_n[4]|
// |max_n[4]|. Beginning of a character:  Here |c| is the character code, and
// |p| points to the previous character beginning (if any) for characters having
// this code number modulo 256.  (The pointer |p| is |-1| if there was no
// prior character with an equivalent code.) The values of registers |m| and |n|
// defined by the instructions that follow for this character must
// satisfy |min_m<=m<=max_m| and |min_n<=n<=max_n|.  (The values of |max_m| and
// |min_n| need not be the tightest bounds possible.)  When a \.[GF]-reading
// program sees a |boc|, it can use |min_m|, |max_m|, |min_n|, and |max_n| to
// initialize the bounds of an array. Then it sets |m:=min_m|, |n:=max_n|, and
// |paint_switch:=white|.
//
// \yskip\hang|boc1| 68 |c[1]| | del_m[1]| |max_m[1]| | del_n[1]| |max_n[1]|.
// Same as |boc|, but |p| is assumed to be~$-1$; also |del_m=max_m-min_m|
// and |del_n=max_n-min_n| are given instead of |min_m| and |min_n|.
// The one-byte parameters must be between 0 and 255, inclusive.
// \ (This abbreviated |boc| saves 19~bytes per character, in common cases.)
//
// \yskip\hang|eoc| 69. End of character: All pixels blackened so far
// constitute the pattern for this character. In particular, a completely
// blank character might have |eoc| immediately following |boc|.
//
// \yskip\hang|skip0| 70. Decrease |n| by 1 and set |m:=min_m|,
// |paint_switch:=white|. \ (This finishes one row and begins another,
// ready to whiten the leftmost pixel in the new row.)
//
// \yskip\hang|skip1| 71 |d[1]|. Decrease |n| by |d+1|, set |m:=min_m|, and set
// |paint_switch:=white|. This is a way to produce |d| all-white rows.
//
// \yskip\hang| skip2| 72 |d[2]|. Same as |skip1|, but |d| can be as large
// as 65535.
//
// \yskip\hang| skip3| 73 |d[3]|. Same as |skip1|, but |d| can be as large
// as $2^[24]-1$. \MF\ obviously never needs this command.
//
// \yskip\hang|new_row_0| 74. Decrease |n| by 1 and set |m:=min_m|,
// |paint_switch:=black|. \ (This finishes one row and begins another,
// ready to [\sl blacken\/] the leftmost pixel in the new row.)
//
// \yskip\hang| new_row_1| through | new_row_164| (opcodes 75 to 238). Same as
// |new_row_0|, but with |m:=min_m+1| through |min_m+164|, respectively.
//
// \yskip\hang|xxx1| 239 |k[1]| |x[k]|. This command is undefined in
// general; it functions as a $(k+2)$-byte |no_op| unless special \.[GF]-reading
// programs are being used. \MF\ generates \\[xxx] commands when encountering
// a \&[special] string; this occurs in the \.[GF] file only between
// characters, after the preamble, and before the postamble. However,
// \\[xxx] commands might appear within characters,
// in \.[GF] files generated by other
// processors. It is recommended that |x| be a string having the form of a
// keyword followed by possible parameters relevant to that keyword.
//
// \yskip\hang| xxx2| 240 |k[2]| |x[k]|. Like |xxx1|, but |0<=k<65536|.
//
// \yskip\hang|xxx3| 241 |k[3]| |x[k]|. Like |xxx1|, but |0<=k<$2^[24]$|.
// \MF\ uses this when sending a \&[special] string whose length exceeds~255.
//
// \yskip\hang| xxx4| 242 |k[4]| |x[k]|. Like |xxx1|, but |k| can be
// ridiculously large; |k| mustn't be negative.
//
// \yskip\hang|yyy| 243 |y[4]|. This command is undefined in general;
// it functions as a 5-byte |no_op| unless special \.[GF]-reading programs
// are being used. \MF\ puts |scaled| numbers into |yyy|'s, as a
// result of \&[numspecial] commands; the intent is to provide numeric
// parameters to \\[xxx] commands that immediately precede.
//
// \yskip\hang| no_op| 244. No operation, do nothing. Any number of |no_op|'s
// may occur between \.[GF] commands, but a |no_op| cannot be inserted between
// a command and its parameters or between two parameters.
//
// \yskip\hang|char_loc| 245 |c[1]| |dx[4]| |dy[4]| |w[4]| |p[4]|.
// This command will appear only in the postamble, which will be explained shortly.
//
// \yskip\hang| char_loc0| 246 |c[1]| | dm[1]| |w[4]| |p[4]|.
// Same as |char_loc|, except that |dy| is assumed to be zero, and the value
// of~|dx| is taken to be |65536*dm|, where |0<=dm<256|.
//
// \yskip\hang|pre| 247 |i[1]| |k[1]| |x[k]|.
// Beginning of the preamble; this must come at the very beginning of the
// file. Parameter |i| is an identifying number for \.[GF] format, currently
// 131. The other information is merely commentary; it is not given
// special interpretation like \\[xxx] commands are. (Note that \\[xxx]
// commands may immediately follow the preamble, before the first |boc|.)
//
// \yskip\hang|post| 248. Beginning of the postamble, see below.
//
// \yskip\hang|post_post| 249. Ending of the postamble, see below.
//
// \yskip\noindent Commands 250--255 are undefined at the present time.

// 1145.

// tangle:pos ../../mf.web:21951:3:

// \MF\ refers to the following opcodes explicitly.

// 1146.

// tangle:pos ../../mf.web:21971:3:

// The last character in a \.[GF] file is followed by `|post|'; this command
// introduces the postamble, which summarizes important facts that \MF\ has
// accumulated. The postamble has the form
// $$\vbox[\halign[\hbox[#\hfil]\cr
//   |post| |p[4]| | ds[4]| | cs[4]| | hppp[4]| | vppp[4]|
//    | min_m[4]| | max_m[4]| | min_n[4]| | max_n[4]|\cr
//   $\langle\,$character locators$\,\rangle$\cr
//   |post_post| |q[4]| |i[1]| 223's$[[\G]4]$\cr]]$$
// Here |p| is a pointer to the byte following the final |eoc| in the file
// (or to the byte following the preamble, if there are no characters);
// it can be used to locate the beginning of \\[xxx] commands
// that might have preceded the postamble. The |ds| and |cs| parameters
// \xref[design size] \xref[check sum]
// give the design size and check sum, respectively, which are exactly the
// values put into the header of the \.[TFM] file that \MF\ produces (or
// would produce) on this run. Parameters |hppp| and |vppp| are the ratios of
// pixels per point, horizontally and vertically, expressed as |scaled| integers
// (i.e., multiplied by $2^[16]$); they can be used to correlate the font
// with specific device resolutions, magnifications, and ``at sizes.''  Then
// come |min_m|, |max_m|, |min_n|, and |max_n|, which bound the values that
// registers |m| and~|n| assume in all characters in this \.[GF] file.
// (These bounds need not be the best possible; |max_m| and |min_n| may, on the
// other hand, be tighter than the similar bounds in |boc| commands. For
// example, some character may have |min_n=-100| in its |boc|, but it might
// turn out that |n| never gets lower than |-50| in any character; then
// |min_n| can have any value |<=-50|. If there are no characters in the file,
// it's possible to have |min_m>max_m| and/or |min_n>max_n|.)

// 1147.

// tangle:pos ../../mf.web:21999:3:

// Character locators are introduced by |char_loc| commands,
// which specify a character residue~|c|, character escapements (|dx,dy|),
// a character width~|w|, and a pointer~|p|
// to the beginning of that character. (If two or more characters have the
// same code~|c| modulo 256, only the last will be indicated; the others can be
// located by following backpointers. Characters whose codes differ by a
// multiple of 256 are assumed to share the same font metric information,
// hence the \.[TFM] file contains only residues of character codes modulo~256.
// This convention is intended for oriental languages, when there are many
// character shapes but few distinct widths.)
// \xref[oriental characters]\xref[Chinese characters]\xref[Japanese characters]
//
// The character escapements (|dx,dy|) are the values of \MF's \&[chardx]
// and \&[chardy] parameters; they are in units of |scaled| pixels;
// i.e., |dx| is in horizontal pixel units times $2^[16]$, and |dy| is in
// vertical pixel units times $2^[16]$.  This is the intended amount of
// displacement after typesetting the character; for \.[DVI] files, |dy|
// should be zero, but other document file formats allow nonzero vertical
// escapement.
//
// The character width~|w| duplicates the information in the \.[TFM] file; it
// is a |fix_word| value relative to the design size, and it should be
// independent of magnification.
//
// The backpointer |p| points to the character's |boc|, or to the first of
// a sequence of consecutive \\[xxx] or |yyy| or |no_op| commands that
// immediately precede the |boc|, if such commands exist; such ``special''
// commands essentially belong to the characters, while the special commands
// after the final character belong to the postamble (i.e., to the font
// as a whole). This convention about |p| applies also to the backpointers
// in |boc| commands, even though it wasn't explained in the description
// of~|boc|. \xref[backpointers]
//
// Pointer |p| might be |-1| if the character exists in the \.[TFM] file
// but not in the \.[GF] file. This unusual situation can arise in \MF\ output
// if the user had |proofing<0| when the character was being shipped out,
// but then made |proofing>=0| in order to get a \.[GF] file.

// 1148.

// tangle:pos ../../mf.web:22037:3:

// The last part of the postamble, following the |post_post| byte that
// signifies the end of the character locators, contains |q|, a pointer to the
// |post| command that started the postamble.  An identification byte, |i|,
// comes next; this currently equals~131, as in the preamble.
//
// The |i| byte is followed by four or more bytes that are all equal to
// the decimal number 223 (i.e., @'337 in octal). \MF\ puts out four to seven of
// these trailing bytes, until the total length of the file is a multiple of
// four bytes, since this works out best on machines that pack four bytes per
// word; but any number of 223's is allowed, as long as there are at least four
// of them. In effect, 223 is a sort of signature that is added at the very end.
// \xref[Fuchs, David Raymond]
//
// This curious way to finish off a \.[GF] file makes it feasible for
// \.[GF]-reading programs to find the postamble first, on most computers,
// even though \MF\ wants to write the postamble last. Most operating
// systems permit random access to individual words or bytes of a file, so
// the \.[GF] reader can start at the end and skip backwards over the 223's
// until finding the identification byte. Then it can back up four bytes, read
// |q|, and move to byte |q| of the file. This byte should, of course,
// contain the value 248 (|post|); now the postamble can be read, so the
// \.[GF] reader can discover all the information needed for individual characters.
//
// Unfortunately, however, standard \PASCAL\ does not include the ability to
// \xref[system dependencies]
// access a random position in a file, or even to determine the length of a file.
// Almost all systems nowadays provide the necessary capabilities, so \.[GF]
// format has been designed to work most efficiently with modern operating systems.
// But if \.[GF] files have to be processed under the restrictions of standard
// \PASCAL, one can simply read them from front to back. This will
// be adequate for most applications. However, the postamble-first approach
// would facilitate a program that merges two \.[GF] files, replacing data
// from one that is overridden by corresponding data in the other.

// 1187.

// tangle:pos ../../mf.web:22552:3:

// Corresponding to the procedure that dumps a base file, we also have a function
// that reads~one~in. The function returns |false| if the dumped base is
// incompatible with the present \MF\ table sizes, etc.
// \4
// Declare the function called |open_base_file|
func (prg *prg) openBaseFile() (r bool) {
	var (
		j /* 0..bufSize */ uint16 // the first space after the file name
	)
	j = prg.curInput.locField
	if int32(prg.buffer[prg.curInput.locField]) == '&' {
		prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
		j = prg.curInput.locField
		prg.buffer[prg.last] = ' '
		for int32(prg.buffer[j]) != ' ' {
			j = uint16(int32(j) + 1)
		}
		prg.packBufferedName(smallNumber(0), int32(prg.curInput.locField), int32(j)-1) // try first without the system file area
		if prg.wOpenIn(prg.baseFile) {
			goto found
		}
		prg.packBufferedName(smallNumber(baseAreaLength), int32(prg.curInput.locField), int32(j)-1)
		// now try the system base file area
		if prg.wOpenIn(prg.baseFile) {
			goto found
		}

		prg.termOut.Writeln("Sorry, I can't find that base;", " will try PLAIN.")
		// \xref[Sorry, I can't find...]

	}
	// now pull out all the stops: try for the system \.[plain] file
	prg.packBufferedName(smallNumber(baseDefaultLength-baseExtLength), 1, 0)
	if !prg.wOpenIn(prg.baseFile) {
		prg.termOut.Writeln("I can't find the PLAIN base file!")
		// \xref[I can't find PLAIN...]
		// \xref[plain]
		r = false
		goto exit
	}

found:
	prg.curInput.locField = j
	r = true

exit:
	;
	return r
}

func (prg *prg) loadBaseFile() (r bool) {
	var (
		k    int32        // all-purpose index
		p, q halfword     // all-purpose pointers
		x    int32        // something undumped
		w    fourQuarters // four ASCII codes
	)
	x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	if x != 461259239 {
		goto offBase
	} // check that strings are the same
	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != memMin {
		goto offBase
	}
	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != 3000 {
		goto offBase
	}
	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != hashSize {
		goto offBase
	}
	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != hashPrime {
		goto offBase
	}
	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != maxInOpen {
		goto offBase
	}

	// Undump the string pool
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 0 {
			goto offBase
		}
		if x > poolSize {
			prg.termOut.Writeln("---! Must increase the ", "string pool size") /* \xref[Must increase the x]  */ /* \xref[Must increase the x]  */
			goto offBase
		} else {
			prg.poolPtr = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 0 {
			goto offBase
		}
		if x > maxStrings {
			prg.termOut.Writeln("---! Must increase the ", "max strings") /* \xref[Must increase the x]  */ /* \xref[Must increase the x]  */
			goto offBase
		} else {
			prg.strPtr = uint16(x)
		}
	}
	for ii := int32(0); ii <= int32(prg.strPtr); ii++ {
		k = ii
		_ = k
		{
			{
				prg.baseFile.Get()
				x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
			}
			if x < 0 || x > int32(prg.poolPtr) {
				goto offBase
			} else {
				prg.strStart[k] = uint16(x)
			}
		}
		prg.strRef[k] = byte(maxStrRef)
	}
	k = 0
	for k+4 < int32(prg.poolPtr) {
		{
			prg.baseFile.Get()
			w = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).qqqq()
		}
		prg.strPool[k] = byte(int32(w.b0) - minQuarterword)
		prg.strPool[k+1] = byte(int32(w.b1) - minQuarterword)
		prg.strPool[k+2] = byte(int32(w.b2) - minQuarterword)
		prg.strPool[k+3] = byte(int32(w.b3) - minQuarterword)
		k = k + 4
	}
	k = int32(prg.poolPtr) - 4
	{
		prg.baseFile.Get()
		w = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).qqqq()
	}
	prg.strPool[k] = byte(int32(w.b0) - minQuarterword)
	prg.strPool[k+1] = byte(int32(w.b1) - minQuarterword)
	prg.strPool[k+2] = byte(int32(w.b2) - minQuarterword)
	prg.strPool[k+3] = byte(int32(w.b3) - minQuarterword)
	prg.initStrPtr = prg.strPtr
	prg.initPoolPtr = prg.poolPtr
	prg.maxStrPtr = prg.strPtr
	prg.maxPoolPtr = prg.poolPtr

	// Undump the dynamic memory
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < memMin+3+10+2+2+2+2+1+1000 || x > 3000-2-1 {
			goto offBase
		} else {
			prg.loMemMax = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < memMin+3+10+2+2+2+2+1+1 || x > int32(prg.loMemMax) {
			goto offBase
		} else {
			prg.rover = uint16(x)
		}
	}
	p = uint16(memMin)
	q = prg.rover
	for {
		for ii := int32(p); ii <= int32(q)+1; ii++ {
			k = ii
			_ = k
			prg.baseFile.Get()
			prg.mem[k] = *(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))
		}
		p = uint16(int32(q) + int32(*(*prg.mem[q].hh()).lh()))
		if int32(p) > int32(prg.loMemMax) || int32(q) >= int32(*(*prg.mem[int32(q)+1].hh()).rh()) && int32(*(*prg.mem[int32(q)+1].hh()).rh()) != int32(prg.rover) {
			goto offBase
		}
		q = *(*prg.mem[int32(q)+1].hh()).rh()
		if int32(q) == int32(prg.rover) {
			break
		}
	}
	for ii := int32(p); ii <= int32(prg.loMemMax); ii++ {
		k = ii
		_ = k
		prg.baseFile.Get()
		prg.mem[k] = *(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < int32(prg.loMemMax)+1 || x > 3000-2 {
			goto offBase
		} else {
			prg.hiMemMin = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < memMin || x > 3000 {
			goto offBase
		} else {
			prg.avail = uint16(x)
		}
	}
	prg.memEnd = 3000
	for ii := int32(prg.hiMemMin); ii <= int32(prg.memEnd); ii++ {
		k = ii
		_ = k
		prg.baseFile.Get()
		prg.mem[k] = *(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))
	}
	{
		prg.baseFile.Get()
		prg.varUsed = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	{
		prg.baseFile.Get()
		prg.dynUsed = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}

	// Undump the table of equivalents and the hash table
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 1 || x > hashBase+hashSize {
			goto offBase
		} else {
			prg.hashUsed = uint16(x)
		}
	}
	p = 0
	for {
		{
			{
				prg.baseFile.Get()
				x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
			}
			if x < int32(p)+1 || x > int32(prg.hashUsed) {
				goto offBase
			} else {
				p = uint16(x)
			}
		}
		{
			prg.baseFile.Get()
			prg.hash[p-1] = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh()
		}
		{
			prg.baseFile.Get()
			prg.eqtb[p-1] = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh()
		}
		if int32(p) == int32(prg.hashUsed) {
			break
		}
	}
	for ii := int32(prg.hashUsed) + 1; ii <= hashBase+hashSize+12; ii++ {
		p = halfword(ii)
		_ = p
		{
			prg.baseFile.Get()
			prg.hash[p-1] = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh()
		}
		{
			prg.baseFile.Get()
			prg.eqtb[p-1] = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).hh()
		}
	}
	{
		prg.baseFile.Get()
		prg.stCount = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}

	// Undump a few more things and the closing check word
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < maxGivenInternal || x > maxInternal {
			goto offBase
		} else {
			prg.intPtr = byte(x)
		}
	}
	for ii := int32(1); ii <= int32(prg.intPtr); ii++ {
		k = ii
		_ = k
		{
			prg.baseFile.Get()
			prg.internal[k-1] = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		{
			{
				prg.baseFile.Get()
				x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
			}
			if x < 0 || x > int32(prg.strPtr) {
				goto offBase
			} else {
				prg.intName[k-1] = uint16(x)
			}
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 0 || x > hashBase+hashSize {
			goto offBase
		} else {
			prg.startSym = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < batchMode || x > errorStopMode {
			goto offBase
		} else {
			prg.interaction = byte(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 0 || x > int32(prg.strPtr) {
			goto offBase
		} else {
			prg.baseIdent = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 1 || x > hashBase+hashSize+12 {
			goto offBase
		} else {
			prg.bgLoc = uint16(x)
		}
	}
	{
		{
			prg.baseFile.Get()
			x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
		}
		if x < 1 || x > hashBase+hashSize+12 {
			goto offBase
		} else {
			prg.egLoc = uint16(x)
		}
	}
	{
		prg.baseFile.Get()
		prg.serialNo = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}

	{
		prg.baseFile.Get()
		x = *(*(*memoryWord)(unsafe.Pointer(prg.baseFile.Data4P()))).int()
	}
	if x != 69069 || prg.baseFile.EOF() {
		goto offBase
	}
	r = true
	goto exit // it worked!
	// it worked!
offBase:
	;
	prg.termOut.Writeln("(Fatal base file error; I'm stymied)")
	// \xref[Fatal base file error]
	r = false

exit:
	;
	return r
}

// 706. \[35] Expanding the next token

// tangle:pos ../../mf.web:14572:35:

// Only a few command codes |<min_command| can possibly be returned by
// |get_next|; in increasing order, they are
// |if_test|, |fi_or_else|, |input|, |iteration|, |repeat_loop|,
// |exit_test|, |relax|, |scan_tokens|, |expand_after|, and |defined_macro|.
//
// \MF\ usually gets the next token of input by saying |get_x_next|. This is
// like |get_next| except that it keeps getting more tokens until
// finding |cur_cmd>=min_command|. In other words, |get_x_next| expands
// macros and removes conditionals or iterations or input instructions that
// might be present.
//
// It follows that |get_x_next| might invoke itself recursively. In fact,
// there is massive recursion, since macro expansion can involve the
// scanning of arbitrarily complex expressions, which in turn involve
// macro expansion and conditionals, etc.
// \xref[recursion]
//
// Therefore it's necessary to declare a whole bunch of |forward|
// procedures at this point, and to insert some other procedures
// that will be invoked by |get_x_next|.
func (prg *prg) scanPrimary() {
	var (
		p, q, r1                              halfword    // for list manipulation
		c                                     quarterword // a primitive operation code
		myVarFlag/* 0..maxCommandCode */ byte             // initial value of |var_flag|
		lDelim, rDelim                        halfword    // hash addresses of a delimiter pair

		// Other local variables for |scan_primary|
		groupLine int32 // where a group began

		num, denom scaled // for primaries that are fractions, like `1/2'

		preHead, postHead, tail halfword
		// prefix and suffix list variables
		tt       smallNumber // approximation to the type of the variable-so-far
		t        halfword    // a token
		macroRef halfword    // reference count for a suffixed macro
	)
	myVarFlag = prg.varFlag
	prg.varFlag = 0

restart:
	{
		if prg.arithError {
			prg.clearArith()
		}
	}

	// Supply diagnostic information, if requested
	//  if panicking then check_mem(false); [  ]

	if prg.interrupt != 0 {
		if prg.okToInterrupt {
			prg.backInput()
			{
				if prg.interrupt != 0 {
					prg.pauseForInstructions()
				}
			}
			prg.getXNext()
		}
	}
	switch prg.curCmd {
	case leftDelimiter:
		// Scan a delimited primary
		lDelim = prg.curSym
		rDelim = uint16(prg.curMod)
		prg.getXNext()
		prg.scanExpression()
		if int32(prg.curCmd) == comma && int32(prg.curType) >= known {
			p = prg.getNode(valueNodeSize)
			*(*prg.mem[p].hh()).b0() = byte(pairType)
			*(*prg.mem[p].hh()).b1() = byte(capsule)
			prg.initBigNode(p)
			q = uint16(*prg.mem[int32(p)+1].int())
			prg.stashIn(q)

			prg.getXNext()
			prg.scanExpression()
			if int32(prg.curType) < known {
				prg.dispErr(halfword(memMin), strNumber( /* "Nonnumeric ypart has been replaced by 0" */ 775))
				// \xref[Nonnumeric...replaced by 0]
				{
					prg.helpPtr = 4
					prg.helpLine[3] = /* "I thought you were giving me a pair `(x,y)'; but" */ 776
					prg.helpLine[2] = /* "after finding a nice xpart `x' I found a ypart `y'" */ 777
					prg.helpLine[1] = /* "that isn't of numeric type. So I've changed y to zero." */ 778
					prg.helpLine[0] = /* "(The y that I didn't like appears above the error message.)" */ 779
				}
				prg.putGetFlushError(scaled(0))
			}
			prg.stashIn(halfword(int32(q) + 2))
			prg.checkDelimiter(lDelim, rDelim)
			prg.curType = byte(pairType)
			prg.curExp = int32(p)
		} else {
			prg.checkDelimiter(lDelim, rDelim)
		}

	case beginGroup:
		// Scan a grouped primary
		groupLine = prg.line
		if prg.internal[tracingCommands-1] > 0 {
			prg.showCmdMod(int32(prg.curCmd), prg.curMod)
		}
		{
			p = prg.getAvail()
			*(*prg.mem[p].hh()).lh() = 0
			*(*prg.mem[p].hh()).rh() = prg.savePtr
			prg.savePtr = p
		}
		for {
			prg.doStatement() // ends with |cur_cmd>=semicolon|
			if int32(prg.curCmd) != semicolon {
				break
			}
		}
		if int32(prg.curCmd) != endGroup {
			{
				if int32(prg.interaction) == errorStopMode {
				}
				prg.printNl(strNumber( /* "! " */ 261))
				prg.print( /* "A group begun on line " */ 780) /* \xref[!\relax]  */
			}
			// \xref[A group...never ended]
			prg.printInt(groupLine)
			prg.print( /* " never ended" */ 781)
			{
				prg.helpPtr = 2
				prg.helpLine[1] = /* "I saw a `begingroup' back there that hasn't been matched" */ 782
				prg.helpLine[0] = /* "by `endgroup'. So I've inserted `endgroup' now." */ 783
			}
			prg.backError()
			prg.curCmd = byte(endGroup)
		}
		prg.unsave() // this might change |cur_type|, if independent variables are recycled
		if prg.internal[tracingCommands-1] > 0 {
			prg.showCmdMod(int32(prg.curCmd), prg.curMod)
		}

	case stringToken:
		// Scan a string constant
		prg.curType = byte(stringType)
		prg.curExp = prg.curMod

	case numericToken:
		// Scan a primary that starts with a numeric token
		prg.curExp = prg.curMod
		prg.curType = byte(known)
		prg.getXNext()
		if int32(prg.curCmd) != slash {
			num = 0
			denom = 0
		} else {
			prg.getXNext()
			if int32(prg.curCmd) != numericToken {
				prg.backInput()
				prg.curCmd = byte(slash)
				prg.curMod = over
				prg.curSym = uint16(hashBase + hashSize + 4)

				goto done
			}
			num = prg.curExp
			denom = prg.curMod
			if denom == 0 {
				{
					if int32(prg.interaction) == errorStopMode {
					}
					prg.printNl(strNumber( /* "! " */ 261))
					prg.print( /* "Division by zero" */ 784) /* \xref[!\relax]  */
				}
				// \xref[Division by zero]
				{
					prg.helpPtr = 1
					prg.helpLine[0] = /* "I'll pretend that you meant to divide by 1." */ 785
				}
				prg.error1()
			} else {
				prg.curExp = prg.makeScaled(num, denom)
			}
			{
				if prg.arithError {
					prg.clearArith()
				}
			}
			prg.getXNext()
		}
		if int32(prg.curCmd) >= minPrimaryCommand {
			if int32(prg.curCmd) < numericToken {
				p = prg.stashCurExp()
				prg.scanPrimary()
				if abs(num) >= abs(denom) || int32(prg.curType) < pairType {
					prg.doBinary(p, quarterword(times))
				} else {
					prg.fracMult(num, denom)
					prg.freeNode(p, halfword(valueNodeSize))
				}
			}
		}

		goto done

	case nullary:
		// Scan a nullary operation
		prg.doNullary(quarterword(prg.curMod))

	case unary, typeName, cycle, plusOrMinus:
		// Scan a unary operation
		c = byte(prg.curMod)
		prg.getXNext()
		prg.scanPrimary()
		prg.doUnary(c)
		goto done

	case primaryBinary:
		// Scan a binary operation with `\&[of]' between its operands
		c = byte(prg.curMod)
		prg.getXNext()
		prg.scanExpression()
		if int32(prg.curCmd) != ofToken {
			prg.missingErr(strNumber( /* "of" */ 479))
			prg.print( /* " for " */ 715)
			prg.printCmdMod(primaryBinary, int32(c))
			// \xref[Missing `of']
			{
				prg.helpPtr = 1
				prg.helpLine[0] = /* "I've got the first argument; will look now for the other." */ 716
			}
			prg.backError()
		}
		p = prg.stashCurExp()
		prg.getXNext()
		prg.scanPrimary()
		prg.doBinary(p, c)
		goto done

	case strOp:
		// Convert a suffix to a string
		prg.getXNext()
		prg.scanSuffix()
		prg.oldSetting = prg.selector
		prg.selector = byte(newString)
		prg.showTokenList(prg.curExp, memMin, 100000, 0)
		prg.flushTokenList(halfword(prg.curExp))
		prg.curExp = int32(prg.makeString())
		prg.selector = prg.oldSetting
		prg.curType = byte(stringType)

		goto done

	case internalQuantity:
		// Scan an internal numeric quantity
		q = uint16(prg.curMod)
		if int32(myVarFlag) == assignment {
			prg.getXNext()
			if int32(prg.curCmd) == assignment {
				prg.curExp = int32(prg.getAvail())
				*(*prg.mem[prg.curExp].hh()).lh() = uint16(int32(q) + hashBase + hashSize + 12)
				prg.curType = byte(tokenList)
				goto done
			}
			prg.backInput()
		}
		prg.curType = byte(known)
		prg.curExp = prg.internal[q-1]

	case capsuleToken:
		prg.makeExpCopy(halfword(prg.curMod))
	case tagToken:
		// Scan a variable primary; |goto restart| if it turns out to be a macro
		{
			preHead = prg.avail
			if int32(preHead) == memMin {
				preHead = prg.getAvail()
			} else {
				prg.avail = *(*prg.mem[preHead].hh()).rh()
				*(*prg.mem[preHead].hh()).rh() = uint16(memMin)
				prg.dynUsed = prg.dynUsed + 1
			}
		}
		tail = preHead
		postHead = uint16(memMin)
		tt = byte(vacuous)
		for true {
			t = prg.curTok()
			*(*prg.mem[tail].hh()).rh() = t
			if int32(tt) != undefined {
				{
					p = *(*prg.mem[preHead].hh()).rh()
					q = *(*prg.mem[p].hh()).lh()
					tt = byte(undefined)
					if int32(*prg.eqtb[q-1].lh())%outerTag == tagToken {
						q = *prg.eqtb[q-1].rh()
						if int32(q) == memMin {
							goto done2
						}
						for true {
							p = *(*prg.mem[p].hh()).rh()
							if int32(p) == memMin {
								tt = *(*prg.mem[q].hh()).b0()
								goto done2
							}
							if int32(*(*prg.mem[q].hh()).b0()) != structured {
								goto done2
							}
							q = *(*prg.mem[*(*prg.mem[int32(q)+1].hh()).lh()].hh()).rh() // the |collective_subscript| attribute
							if int32(p) >= int32(prg.hiMemMin) {
								for {
									q = *(*prg.mem[q].hh()).rh()
									if int32(*(*prg.mem[int32(q)+2].hh()).lh()) >= int32(*(*prg.mem[p].hh()).lh()) {
										break
									}
								}
								if int32(*(*prg.mem[int32(q)+2].hh()).lh()) > int32(*(*prg.mem[p].hh()).lh()) {
									goto done2
								}
							}
						}
					}

				done2:
				}
				if int32(tt) >= unsuffixedMacro {
					*(*prg.mem[tail].hh()).rh() = uint16(memMin)
					if int32(tt) > unsuffixedMacro {
						postHead = prg.getAvail()
						tail = postHead
						*(*prg.mem[tail].hh()).rh() = t

						tt = byte(undefined)
						macroRef = uint16(*prg.mem[int32(q)+1].int())
						*(*prg.mem[macroRef].hh()).lh() = uint16(int32(*(*prg.mem[macroRef].hh()).lh()) + 1)
					} else {
						// Set up unsuffixed macro call and |goto restart|
						p = prg.getAvail()
						*(*prg.mem[preHead].hh()).lh() = *(*prg.mem[preHead].hh()).rh()
						*(*prg.mem[preHead].hh()).rh() = p
						*(*prg.mem[p].hh()).lh() = t
						prg.macroCall(halfword(*prg.mem[int32(q)+1].int()), preHead, halfword(memMin))
						prg.getXNext()
						goto restart
					}
				}
			}
			prg.getXNext()
			tail = t
			if int32(prg.curCmd) == leftBracket {
				prg.getXNext()
				prg.scanExpression()
				if int32(prg.curCmd) != rightBracket {
					prg.backInput() // that was the token following the current expression
					prg.backExpr()
					prg.curCmd = byte(leftBracket)
					prg.curMod = 0
					prg.curSym = uint16(hashBase + hashSize + 3)
				} else {
					if int32(prg.curType) != known {
						prg.badSubscript()
					}
					prg.curCmd = byte(numericToken)
					prg.curMod = prg.curExp
					prg.curSym = 0
				}
			}
			if int32(prg.curCmd) > maxSuffixToken {
				goto done1
			}
			if int32(prg.curCmd) < minSuffixToken {
				goto done1
			}
		} // now |cur_cmd| is |internal_quantity|, |tag_token|, or |numeric_token|
		// now |cur_cmd| is |internal_quantity|, |tag_token|, or |numeric_token|
	done1:
		if int32(postHead) != memMin {
			prg.backInput()
			p = prg.getAvail()
			q = *(*prg.mem[postHead].hh()).rh()
			*(*prg.mem[preHead].hh()).lh() = *(*prg.mem[preHead].hh()).rh()
			*(*prg.mem[preHead].hh()).rh() = postHead
			*(*prg.mem[postHead].hh()).lh() = q
			*(*prg.mem[postHead].hh()).rh() = p
			*(*prg.mem[p].hh()).lh() = *(*prg.mem[q].hh()).rh()
			*(*prg.mem[q].hh()).rh() = uint16(memMin)
			prg.macroCall(macroRef, preHead, halfword(memMin))
			*(*prg.mem[macroRef].hh()).lh() = uint16(int32(*(*prg.mem[macroRef].hh()).lh()) - 1)
			prg.getXNext()
			goto restart
		}
		q = *(*prg.mem[preHead].hh()).rh()
		{
			*(*prg.mem[preHead].hh()).rh() = prg.avail
			prg.avail = preHead
			prg.dynUsed = prg.dynUsed - 1
		}
		if int32(prg.curCmd) == int32(myVarFlag) {
			prg.curType = byte(tokenList)
			prg.curExp = int32(q)
			goto done
		}
		p = prg.findVariable(q)
		if int32(p) != memMin {
			prg.makeExpCopy(p)
		} else {
			prg.obliterated(q)

			prg.helpLine[2] = /* "While I was evaluating the suffix of this variable," */ 797
			prg.helpLine[1] = /* "something was redefined, and it's no longer a variable!" */ 798
			prg.helpLine[0] = /* "In order to get back on my feet, I've inserted `0' instead." */ 799
			prg.putGetFlushError(scaled(0))
		}
		prg.flushNodeList(q)
		goto done

	default:
		prg.badExp(strNumber( /* "A primary" */ 769))
		goto restart
		// \xref[A primary expression...]

	}

	prg.getXNext() // the routines |goto done| if they don't want this
	// the routines |goto done| if they don't want this
done:
	if int32(prg.curCmd) == leftBracket {
		if int32(prg.curType) >= known {
			p = prg.stashCurExp()
			prg.getXNext()
			prg.scanExpression()
			if int32(prg.curCmd) != comma {
				{
					prg.backInput() // that was the token following the current expression
					prg.backExpr()
					prg.curCmd = byte(leftBracket)
					prg.curMod = 0
					prg.curSym = uint16(hashBase + hashSize + 3)
				}
				prg.unstashCurExp(p)
			} else {
				q = prg.stashCurExp()
				prg.getXNext()
				prg.scanExpression()
				if int32(prg.curCmd) != rightBracket {
					prg.missingErr(strNumber(']'))

					// \xref[Missing `]']
					{
						prg.helpPtr = 3
						prg.helpLine[2] = /* "I've scanned an expression of the form `a[b,c'," */ 801
						prg.helpLine[1] = /* "so a right bracket should have come next." */ 802
						prg.helpLine[0] = /* "I shall pretend that one was there." */ 697
					}

					prg.backError()
				}
				r1 = prg.stashCurExp()
				prg.makeExpCopy(q)

				prg.doBinary(r1, quarterword(minus))
				prg.doBinary(p, quarterword(times))
				prg.doBinary(q, quarterword(plus))
				prg.getXNext()
			}
		}
	}
} // \2
func (prg *prg) scanSuffix() {
	var (
		h, t halfword // head and tail of the list being built
		p    halfword // temporary register
	)
	h = prg.getAvail()
	t = h
	for true {
		if int32(prg.curCmd) == leftBracket {
			prg.getXNext()
			prg.scanExpression()
			if int32(prg.curType) != known {
				prg.badSubscript()
			}
			if int32(prg.curCmd) != rightBracket {
				prg.missingErr(strNumber(']'))

				// \xref[Missing `]']
				{
					prg.helpPtr = 3
					prg.helpLine[2] = /* "I've seen a `[' and a subscript value, in a suffix," */ 803
					prg.helpLine[1] = /* "so a right bracket should have come next." */ 802
					prg.helpLine[0] = /* "I shall pretend that one was there." */ 697
				}

				prg.backError()
			}
			prg.curCmd = byte(numericToken)
			prg.curMod = prg.curExp
		}
		if int32(prg.curCmd) == numericToken {
			p = prg.newNumTok(prg.curMod)
		} else if int32(prg.curCmd) == tagToken || int32(prg.curCmd) == internalQuantity {
			p = prg.getAvail()
			*(*prg.mem[p].hh()).lh() = prg.curSym
		} else {
			goto done
		}
		*(*prg.mem[t].hh()).rh() = p
		t = p
		prg.getXNext()
	}

done:
	prg.curExp = int32(*(*prg.mem[h].hh()).rh())
	{
		*(*prg.mem[h].hh()).rh() = prg.avail
		prg.avail = h
		prg.dynUsed = prg.dynUsed - 1
	}
	prg.curType = byte(tokenList)
} // \2
func (prg *prg) scanSecondary() {
	var (
		p       halfword // for list manipulation
		c, d    halfword // operation codes or modifiers
		macName halfword // token defined with \&[primarydef]
	)
restart:
	if int32(prg.curCmd) < minPrimaryCommand || int32(prg.curCmd) > maxPrimaryCommand {
		prg.badExp(strNumber( /* "A secondary" */ 804))
	}
	// \xref[A secondary expression...]
	prg.scanPrimary()

continue1:
	if int32(prg.curCmd) <= maxSecondaryCommand {
		if int32(prg.curCmd) >= minSecondaryCommand {
			p = prg.stashCurExp()
			c = uint16(prg.curMod)
			d = uint16(prg.curCmd)
			if int32(d) == secondaryPrimaryMacro {
				macName = prg.curSym
				*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) + 1)
			}
			prg.getXNext()
			prg.scanPrimary()
			if int32(d) != secondaryPrimaryMacro {
				prg.doBinary(p, quarterword(c))
			} else {
				prg.backInput()
				prg.binaryMac(p, c, macName)
				*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) - 1)
				prg.getXNext()
				goto restart
			}

			goto continue1
		}
	}
} // \2
func (prg *prg) scanTertiary() {
	var (
		p       halfword // for list manipulation
		c, d    halfword // operation codes or modifiers
		macName halfword // token defined with \&[secondarydef]
	)
restart:
	if int32(prg.curCmd) < minPrimaryCommand || int32(prg.curCmd) > maxPrimaryCommand {
		prg.badExp(strNumber( /* "A tertiary" */ 805))
	}
	// \xref[A tertiary expression...]
	prg.scanSecondary()
	if int32(prg.curType) == futurePen {
		prg.materializePen()
	}

continue1:
	if int32(prg.curCmd) <= maxTertiaryCommand {
		if int32(prg.curCmd) >= minTertiaryCommand {
			p = prg.stashCurExp()
			c = uint16(prg.curMod)
			d = uint16(prg.curCmd)
			if int32(d) == tertiarySecondaryMacro {
				macName = prg.curSym
				*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) + 1)
			}
			prg.getXNext()
			prg.scanSecondary()
			if int32(d) != tertiarySecondaryMacro {
				prg.doBinary(p, quarterword(c))
			} else {
				prg.backInput()
				prg.binaryMac(p, c, macName)
				*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) - 1)
				prg.getXNext()
				goto restart
			}

			goto continue1
		}
	}
} // \2
func (prg *prg) scanExpression() {
	var (
		p, q, r1, pp, qq                      halfword // for list manipulation
		c, d                                  halfword // operation codes or modifiers
		myVarFlag/* 0..maxCommandCode */ byte          // initial value of |var_flag|
		macName                               halfword // token defined with \&[tertiarydef]
		cycleHit                              bool     // did a path expression just end with `\&[cycle]'?
		x, y                                  scaled   // explicit coordinates or tension at a path join
		t/* endpoint..open */ byte                     // knot type following a path join
	)
	myVarFlag = prg.varFlag

restart:
	if int32(prg.curCmd) < minPrimaryCommand || int32(prg.curCmd) > maxPrimaryCommand {
		prg.badExp(strNumber( /* "An" */ 808))
	}
	// \xref[An expression...]
	prg.scanTertiary()

continue1:
	if int32(prg.curCmd) <= maxExpressionCommand {
		if int32(prg.curCmd) >= minExpressionCommand {
			if int32(prg.curCmd) != equals || int32(myVarFlag) != assignment {
				p = prg.stashCurExp()
				c = uint16(prg.curMod)
				d = uint16(prg.curCmd)
				if int32(d) == expressionTertiaryMacro {
					macName = prg.curSym
					*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) + 1)
				}
				if int32(d) < ampersand || int32(d) == ampersand && (int32(*(*prg.mem[p].hh()).b0()) == pairType || int32(*(*prg.mem[p].hh()).b0()) == pathType) {
					cycleHit = false

					// Convert the left operand, |p|, into a partial path ending at~|q|; but |return| if |p| doesn't have a suitable type
					{
						prg.unstashCurExp(p)
						if int32(prg.curType) == pairType {
							p = prg.newKnot()
						} else if int32(prg.curType) == pathType {
							p = uint16(prg.curExp)
						} else {
							goto exit
						}
						q = p
						for int32(*(*prg.mem[q].hh()).rh()) != int32(p) {
							q = *(*prg.mem[q].hh()).rh()
						}
						if int32(*(*prg.mem[p].hh()).b0()) != endpoint {
							r1 = prg.copyKnot(p)
							*(*prg.mem[q].hh()).rh() = r1
							q = r1
						}
						*(*prg.mem[p].hh()).b0() = byte(open)
						*(*prg.mem[q].hh()).b1() = byte(open)
					}

				continuePath:
					if int32(prg.curCmd) == leftBrace {
						t = prg.scanDirection()
						if int32(t) != open {
							*(*prg.mem[q].hh()).b1() = t
							*prg.mem[int32(q)+5].int() = prg.curExp
							if int32(*(*prg.mem[q].hh()).b0()) == open {
								*(*prg.mem[q].hh()).b0() = t
								*prg.mem[int32(q)+3].int() = prg.curExp
							} // note that |left_given(q)=left_curl(q)|
						}
					}
					d = uint16(prg.curCmd)
					if int32(d) == pathJoin {
						prg.getXNext()
						if int32(prg.curCmd) == tension {
							prg.getXNext()
							y = int32(prg.curCmd)
							if int32(prg.curCmd) == atLeast {
								prg.getXNext()
							}
							prg.scanPrimary()

							// Make sure that the current expression is a valid tension setting
							if int32(prg.curType) != known || prg.curExp < 0140000 {
								prg.dispErr(halfword(memMin), strNumber( /* "Improper tension has been set to 1" */ 826))
								// \xref[Improper tension]
								{
									prg.helpPtr = 1
									prg.helpLine[0] = /* "The expression above should have been a number >=3/4." */ 827
								}
								prg.putGetFlushError(scaled(0200000))
							}
							if y == atLeast {
								prg.curExp = -prg.curExp
							}
							*prg.mem[int32(q)+6].int() = prg.curExp
							if int32(prg.curCmd) == andCommand {
								prg.getXNext()
								y = int32(prg.curCmd)
								if int32(prg.curCmd) == atLeast {
									prg.getXNext()
								}
								prg.scanPrimary()

								// Make sure that the current expression is a valid tension setting
								if int32(prg.curType) != known || prg.curExp < 0140000 {
									prg.dispErr(halfword(memMin), strNumber( /* "Improper tension has been set to 1" */ 826))
									// \xref[Improper tension]
									{
										prg.helpPtr = 1
										prg.helpLine[0] = /* "The expression above should have been a number >=3/4." */ 827
									}
									prg.putGetFlushError(scaled(0200000))
								}
								if y == atLeast {
									prg.curExp = -prg.curExp
								}
							}
							y = prg.curExp
						} else if int32(prg.curCmd) == controls {
							*(*prg.mem[q].hh()).b1() = byte(explicit)
							t = byte(explicit)
							prg.getXNext()
							prg.scanPrimary()

							prg.knownPair()
							*prg.mem[int32(q)+5].int() = prg.curX
							*prg.mem[int32(q)+6].int() = prg.curY
							if int32(prg.curCmd) != andCommand {
								x = *prg.mem[int32(q)+5].int()
								y = *prg.mem[int32(q)+6].int()
							} else {
								prg.getXNext()
								prg.scanPrimary()

								prg.knownPair()
								x = prg.curX
								y = prg.curY
							}
						} else {
							*prg.mem[int32(q)+6].int() = 0200000
							y = 0200000
							prg.backInput() // default tension
							// default tension
							goto done
						}
						if int32(prg.curCmd) != pathJoin {
							prg.missingErr(strNumber( /* ".." */ 409))

							// \xref[Missing `..']
							{
								prg.helpPtr = 1
								prg.helpLine[0] = /* "A path join command should end with two dots." */ 825
							}
							prg.backError()
						}

					done:
					} else if int32(d) != ampersand {
						goto finishPath
					}
					prg.getXNext()
					if int32(prg.curCmd) == leftBrace {
						t = prg.scanDirection()
						if int32(*(*prg.mem[q].hh()).b1()) != explicit {
							x = prg.curExp
						} else {
							t = byte(explicit)
						} // the direction information is superfluous
					} else if int32(*(*prg.mem[q].hh()).b1()) != explicit {
						t = byte(open)
						x = 0
					}
					if int32(prg.curCmd) == cycle {
						cycleHit = true
						prg.getXNext()
						pp = p
						qq = p
						if int32(d) == ampersand {
							if int32(p) == int32(q) {
								d = uint16(pathJoin)
								*prg.mem[int32(q)+6].int() = 0200000
								y = 0200000
							}
						}
					} else {
						prg.scanTertiary()

						// Convert the right operand, |cur_exp|, into a partial path from |pp| to~|qq|
						{
							if int32(prg.curType) != pathType {
								pp = prg.newKnot()
							} else {
								pp = uint16(prg.curExp)
							}
							qq = pp
							for int32(*(*prg.mem[qq].hh()).rh()) != int32(pp) {
								qq = *(*prg.mem[qq].hh()).rh()
							}
							if int32(*(*prg.mem[pp].hh()).b0()) != endpoint {
								r1 = prg.copyKnot(pp)
								*(*prg.mem[qq].hh()).rh() = r1
								qq = r1
							}
							*(*prg.mem[pp].hh()).b0() = byte(open)
							*(*prg.mem[qq].hh()).b1() = byte(open)
						}
					}

					// Join the partial paths and reset |p| and |q| to the head and tail of the result
					{
						if int32(d) == ampersand {
							if *prg.mem[int32(q)+1].int() != *prg.mem[int32(pp)+1].int() || *prg.mem[int32(q)+2].int() != *prg.mem[int32(pp)+2].int() {
								{
									if int32(prg.interaction) == errorStopMode {
									}
									prg.printNl(strNumber( /* "! " */ 261))
									prg.print( /* "Paths don't touch; `&' will be changed to `..'" */ 828) /* \xref[!\relax]  */
								}
								// \xref[Paths don't touch]
								{
									prg.helpPtr = 3
									prg.helpLine[2] = /* "When you join paths `p&q', the ending point of p" */ 829
									prg.helpLine[1] = /* "must be exactly equal to the starting point of q." */ 830
									prg.helpLine[0] = /* "So I'm going to pretend that you said `p..q' instead." */ 831
								}
								prg.putGetError()
								d = uint16(pathJoin)
								*prg.mem[int32(q)+6].int() = 0200000
								y = 0200000
							}
						}

						// Plug an opening in |right_type(pp)|, if possible
						if int32(*(*prg.mem[pp].hh()).b1()) == open {
							if int32(t) == curl || int32(t) == given {
								*(*prg.mem[pp].hh()).b1() = t
								*prg.mem[int32(pp)+5].int() = x
							}
						}
						if int32(d) == ampersand {
							if int32(*(*prg.mem[q].hh()).b0()) == open {
								if int32(*(*prg.mem[q].hh()).b1()) == open {
									*(*prg.mem[q].hh()).b0() = byte(curl)
									*prg.mem[int32(q)+3].int() = 0200000
								}
							}
							if int32(*(*prg.mem[pp].hh()).b1()) == open {
								if int32(t) == open {
									*(*prg.mem[pp].hh()).b1() = byte(curl)
									*prg.mem[int32(pp)+5].int() = 0200000
								}
							}
							*(*prg.mem[q].hh()).b1() = *(*prg.mem[pp].hh()).b1()
							*(*prg.mem[q].hh()).rh() = *(*prg.mem[pp].hh()).rh()

							*prg.mem[int32(q)+5].int() = *prg.mem[int32(pp)+5].int()
							*prg.mem[int32(q)+6].int() = *prg.mem[int32(pp)+6].int()
							prg.freeNode(pp, halfword(knotNodeSize))
							if int32(qq) == int32(pp) {
								qq = q
							}
						} else {
							if int32(*(*prg.mem[q].hh()).b1()) == open {
								if int32(*(*prg.mem[q].hh()).b0()) == curl || int32(*(*prg.mem[q].hh()).b0()) == given {
									*(*prg.mem[q].hh()).b1() = *(*prg.mem[q].hh()).b0()
									*prg.mem[int32(q)+5].int() = *prg.mem[int32(q)+3].int()
								}
							}
							*(*prg.mem[q].hh()).rh() = pp
							*prg.mem[int32(pp)+4].int() = y
							if int32(t) != open {
								*prg.mem[int32(pp)+3].int() = x
								*(*prg.mem[pp].hh()).b0() = t
							}
						}
						q = qq
					}
					if int32(prg.curCmd) >= minExpressionCommand {
						if int32(prg.curCmd) <= ampersand {
							if !cycleHit {
								goto continuePath
							}
						}
					}

				finishPath:
					if cycleHit {
						if int32(d) == ampersand {
							p = q
						}
					} else {
						*(*prg.mem[p].hh()).b0() = byte(endpoint)
						if int32(*(*prg.mem[p].hh()).b1()) == open {
							*(*prg.mem[p].hh()).b1() = byte(curl)
							*prg.mem[int32(p)+5].int() = 0200000
						}
						*(*prg.mem[q].hh()).b1() = byte(endpoint)
						if int32(*(*prg.mem[q].hh()).b0()) == open {
							*(*prg.mem[q].hh()).b0() = byte(curl)
							*prg.mem[int32(q)+3].int() = 0200000
						}
						*(*prg.mem[q].hh()).rh() = p
					}
					prg.makeChoices(p)
					prg.curType = byte(pathType)
					prg.curExp = int32(p)
				} else {
					prg.getXNext()
					prg.scanTertiary()
					if int32(d) != expressionTertiaryMacro {
						prg.doBinary(p, quarterword(c))
					} else {
						prg.backInput()
						prg.binaryMac(p, c, macName)
						*(*prg.mem[c].hh()).lh() = uint16(int32(*(*prg.mem[c].hh()).lh()) - 1)
						prg.getXNext()
						goto restart
					}
				}

				goto continue1
			}
		}
	}

exit:
}

func (prg *prg) getBoolean() {
	prg.getXNext()
	prg.scanExpression()
	if int32(prg.curType) != booleanType {
		prg.dispErr(halfword(memMin), strNumber( /* "Undefined condition will be treated as `false'" */ 832))
		// \xref[Undefined condition...]
		{
			prg.helpPtr = 2
			prg.helpLine[1] = /* "The expression shown above should have had a definite" */ 833
			prg.helpLine[0] = /* "true-or-false value. I'm changing it to `false'." */ 834
		}

		prg.putGetFlushError(falseCode)
		prg.curType = byte(booleanType)
	}
}

// 153. \[9] Packed data

// tangle:pos ../../mf.web:3103:21:

// In order to make efficient use of storage space, \MF\ bases its major data
// structures on a |memory_word|, which contains either a (signed) integer,
// possibly scaled, or a small number of fields that are one half or one
// quarter of the size used for storing integers.
//
// If |x| is a variable of type |memory_word|, it contains up to four
// fields that can be referred to as follows:
// $$\vbox[\halign[\hfil#&#\hfil&#\hfil\cr
// |x|&.|int|&(an |integer|)\cr
// |x|&.|sc|\qquad&(a |scaled| integer)\cr
// |x.hh.lh|, |x.hh|&.|rh|&(two halfword fields)\cr
// |x.hh.b0|, |x.hh.b1|, |x.hh|&.|rh|&(two quarterword fields, one halfword
//   field)\cr
// |x.qqqq.b0|, |x.qqqq.b1|, |x.qqqq|&.|b2|, |x.qqqq.b3|\hskip-100pt
//   &\qquad\qquad\qquad(four quarterword fields)\cr]]$$
// This is somewhat cumbersome to write, and not very readable either, but
// macros will be used to make the notation shorter and more transparent.
// The \PASCAL\ code below gives a formal definition of |memory_word| and
// its subsidiary types, using packed variant records. \MF\ makes no
// assumptions about the relative positions of the fields within a word.
//
// Since we are assuming 32-bit integers, a halfword must contain at least
// 16 bits, and a quarterword must contain at least 8 bits.
// \xref[system dependencies]
// But it doesn't hurt to have more bits; for example, with enough 36-bit
// words you might be able to have |mem_max| as large as 262142.
//
// N.B.: Valuable memory space will be dreadfully wasted unless \MF\ is compiled
// by a \PASCAL\ that packs all of the |memory_word| variants into
// the space of a single integer. Some \PASCAL\ compilers will pack an
// integer whose subrange is `|0..255|' into an eight-bit field, but others
// insist on allocating space for an additional sign bit; on such systems you
// can get 256 values into a quarterword only if the subrange is `|-128..127|'.
//
// The present implementation tries to accommodate as many variations as possible,
// so it makes few assumptions. If integers having the subrange
// `|min_quarterword..max_quarterword|' can be packed into a quarterword,
// and if integers having the subrange `|min_halfword..max_halfword|'
// can be packed into a halfword, everything should work satisfactorily.
//
// It is usually most efficient to have |min_quarterword=min_halfword=0|,
// so one should try to achieve this unless it causes a severe problem.
// The values defined here are recommended for most 32-bit computers.

// 155.

// tangle:pos ../../mf.web:3169:3:

// The operation of subtracting |min_halfword| occurs rather frequently in
// \MF, so it is convenient to abbreviate this operation by using the macro
// |ho| defined here.  \MF\ will run faster with respect to compilers that
// don't optimize the expression `|x-0|', if this macro is simplified in the
// obvious way when |min_halfword=0|. Similarly, |qi| and |qo| are used for
// input to and output from quarterwords.
// \xref[system dependencies]

// 157.

// tangle:pos ../../mf.web:3212:3:

// When debugging, we may want to print a |memory_word| without knowing
// what type it is; so we print it in all modes.
// \xref[dirty \PASCAL]\xref[debugging]
//  procedure print_word( w:memory_word);
//   [prints |w| in all ways]
// begin print_int(w.int); print_char([" "=]32);
//
// print_scaled(w.int ); print_char([" "=]32); print_scaled(w.int  div [010000=]4096); print_ln;
//
// print_int(w.hh.lh); print_char(["="=]61); print_int(w.hh.b0); print_char([":"=]58);
// print_int(w.hh.b1); print_char([";"=]59); print_int(w.hh.rh); print_char([" "=]32);
//
// print_int(w.qqqq.b0); print_char([":"=]58); print_int(w.qqqq.b1); print_char([":"=]58);
// print_int(w.qqqq.b2); print_char([":"=]58); print_int(w.qqqq.b3);
// end;
// [  ]

// 158. \[10] Dynamic memory allocation

// tangle:pos ../../mf.web:3227:36:

// The \MF\ system does nearly all of its own memory allocation, so that it
// can readily be transported into environments that do not have automatic
// facilities for strings, garbage collection, etc., and so that it can be in
// control of what error messages the user receives. The dynamic storage
// requirements of \MF\ are handled by providing a large array |mem| in
// which consecutive blocks of words are used as nodes by the \MF\ routines.
//
// Pointer variables are indices into this array, or into another array
// called |eqtb| that will be explained later. A pointer variable might
// also be a special flag that lies outside the bounds of |mem|, so we
// allow pointers to assume any |halfword| value. The minimum memory
// index represents a null pointer.

// 162.

// tangle:pos ../../mf.web:3297:3:

// If one-word memory is exhausted, it might mean that the user has forgotten
// a token like `\&[enddef]' or `\&[endfor]'. We will define some procedures
// later that try to help pinpoint the trouble.
// \4
// Declare the procedure called |show_token_list|
func (prg *prg) printCapsule() {
	prg.printChar(asciiCode('('))
	prg.printExp(prg.gPointer, smallNumber(0))
	prg.printChar(asciiCode(')'))
}

// 216.

// tangle:pos ../../mf.web:4772:3:

// A token list is a singly linked list of nodes in |mem|, where
// each node contains a token and a link.  Here's a subroutine that gets rid
// of a token list when it is no longer needed.
func (prg *prg) tokenRecycle() {
	prg.recycleValue(prg.gPointer)
} // \2

func (prg *prg) closeFilesAndTerminate() {
	var (
		k                           int32    // all-purpose index
		lh                          int32    // the length of the \.[TFM] header, in words
		lkOffset/* 0..256 */ uint16          // extra words inserted at beginning of |lig_kern| array
		p                           halfword // runs through a list of \.[TFM] dimensions
		x                           scaled   // a |tfm_width| value being output to the \.[GF] file
	)
	if prg.internal[tracingStats-1] > 0 {
		if prg.logOpened {
			prg.logFile.Writeln(" ")
			prg.logFile.Writeln("Here is how much of METAFONT's memory", " you used:")
			// \xref[Here is how much...]
			prg.logFile.Write(" ", int32(prg.maxStrPtr)-int32(prg.initStrPtr), knuth.WriteWidth(1), " string")
			if int32(prg.maxStrPtr) != int32(prg.initStrPtr)+1 {
				prg.logFile.Write("s")
			}
			prg.logFile.Writeln(" out of ", maxStrings-int32(prg.initStrPtr), knuth.WriteWidth(1))

			prg.logFile.Writeln(" ", int32(prg.maxPoolPtr)-int32(prg.initPoolPtr), knuth.WriteWidth(1), " string characters out of ", poolSize-int32(prg.initPoolPtr), knuth.WriteWidth(1))

			prg.logFile.Writeln(" ", int32(prg.loMemMax)-memMin+int32(prg.memEnd)-int32(prg.hiMemMin)+2, knuth.WriteWidth(1),
				" words of memory out of ", int32(prg.memEnd)+1-memMin, knuth.WriteWidth(1))

			prg.logFile.Writeln(" ", prg.stCount, knuth.WriteWidth(1), " symbolic tokens out of ", hashSize, knuth.WriteWidth(1))

			prg.logFile.Writeln(" ", prg.maxInStack, knuth.WriteWidth(1), "i,", prg.intPtr, knuth.WriteWidth(1), "n,", prg.maxRoundingPtr, knuth.WriteWidth(1), "r,", prg.maxParamStack, knuth.WriteWidth(1), "p,", int32(prg.maxBufStack)+1, knuth.WriteWidth(1), "b stack positions out of ", stackSize, knuth.WriteWidth(1), "i,", maxInternal, knuth.WriteWidth(1), "n,", maxWiggle, knuth.WriteWidth(1), "r,", paramSize, knuth.WriteWidth(1), "p,", bufSize, knuth.WriteWidth(1), "b")
		}
	}

	// Finish the \.[TFM] and \.[GF] files
	if prg.gfPrevPtr > 0 || prg.internal[fontmaking-1] > 0 {
		prg.rover = uint16(memMin + 3 + 10 + 2 + 2 + 2 + 2 + 1 + 1)
		*(*prg.mem[prg.rover].hh()).rh() = 65535
		prg.loMemMax = uint16(int32(prg.hiMemMin) - 1)
		if int32(prg.loMemMax)-int32(prg.rover) > 65535 {
			prg.loMemMax = uint16(65535 + int32(prg.rover))
		}
		*(*prg.mem[prg.rover].hh()).lh() = uint16(int32(prg.loMemMax) - int32(prg.rover))
		*(*prg.mem[int32(prg.rover)+1].hh()).lh() = prg.rover
		*(*prg.mem[int32(prg.rover)+1].hh()).rh() = prg.rover
		*(*prg.mem[prg.loMemMax].hh()).rh() = uint16(memMin)
		*(*prg.mem[prg.loMemMax].hh()).lh() = uint16(memMin)

		// Massage the \.[TFM] widths
		*(*prg.mem[3000-1].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2 + 2)
		for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
			k = ii
			_ = k
			if prg.charExists[k] {
				prg.tfmWidth[k] = int32(prg.sortIn(prg.tfmWidth[k]))
			}
		}
		prg.nw = uint16(prg.skimp(255) + 1)
		prg.dimenHead[1-1] = *(*prg.mem[3000-1].hh()).rh()
		if prg.perturbation >= 010000 {
			prg.tfmWarning(smallNumber(charWd))
		}
		prg.fixDesignSize()
		prg.fixCheckSum()
		if prg.internal[fontmaking-1] > 0 {
			*(*prg.mem[3000-1].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2 + 2)
			for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
				k = ii
				_ = k
				if prg.charExists[k] {
					if prg.tfmHeight[k] == 0 {
						prg.tfmHeight[k] = memMin + 3 + 10 + 2
					} else {
						prg.tfmHeight[k] = int32(prg.sortIn(prg.tfmHeight[k]))
					}
				}
			}
			prg.nh = uint16(prg.skimp(15) + 1)
			prg.dimenHead[2-1] = *(*prg.mem[3000-1].hh()).rh()
			if prg.perturbation >= 010000 {
				prg.tfmWarning(smallNumber(charHt))
			}
			*(*prg.mem[3000-1].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2 + 2)
			for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
				k = ii
				_ = k
				if prg.charExists[k] {
					if prg.tfmDepth[k] == 0 {
						prg.tfmDepth[k] = memMin + 3 + 10 + 2
					} else {
						prg.tfmDepth[k] = int32(prg.sortIn(prg.tfmDepth[k]))
					}
				}
			}
			prg.nd = uint16(prg.skimp(15) + 1)
			prg.dimenHead[3-1] = *(*prg.mem[3000-1].hh()).rh()
			if prg.perturbation >= 010000 {
				prg.tfmWarning(smallNumber(charDp))
			}
			*(*prg.mem[3000-1].hh()).rh() = uint16(memMin + 3 + 10 + 2 + 2 + 2)
			for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
				k = ii
				_ = k
				if prg.charExists[k] {
					if prg.tfmItalCorr[k] == 0 {
						prg.tfmItalCorr[k] = memMin + 3 + 10 + 2
					} else {
						prg.tfmItalCorr[k] = int32(prg.sortIn(prg.tfmItalCorr[k]))
					}
				}
			}
			prg.ni = uint16(prg.skimp(63) + 1)
			prg.dimenHead[4-1] = *(*prg.mem[3000-1].hh()).rh()
			if prg.perturbation >= 010000 {
				prg.tfmWarning(smallNumber(charIc))
			}
			prg.internal[fontmaking-1] = 0 // avoid loop in case of fatal error

			// Finish the \.[TFM] file
			if int32(prg.jobName) == 0 {
				prg.openLogFile()
			}
			prg.packJobName(strNumber( /* ".tfm" */ 1045))
			for !prg.bOpenOut(prg.tfmFile) {
				prg.promptFileName(strNumber( /* "file name for font metrics" */ 1046), strNumber( /* ".tfm" */ 1045))
			}
			prg.metricFileName = prg.bMakeNameString(prg.tfmFile)

			// Output the subfile sizes and header bytes
			k = headerSize
			for int32(prg.headerByte[k-1]) < 0 {
				k = k - 1
			}
			lh = (k + 3) / 4 // this is the number of header words
			if int32(prg.bc) > int32(prg.ec) {
				prg.bc = 1
			} // if there are no characters, |ec=0| and |bc=1|

			// Compute the ligature/kern program offset and implant the left boundary label
			prg.bchar = prg.roundUnscaled(prg.internal[boundaryChar-1])
			if prg.bchar < 0 || prg.bchar > 255 {
				prg.bchar = -1
				prg.lkStarted = false
				lkOffset = 0
			} else {
				prg.lkStarted = true
				lkOffset = 1
			}

			// Find the minimum |lk_offset| and adjust all remainders
			k = int32(prg.labelPtr) // pointer to the largest unallocated label
			if int32(prg.labelLoc[k])+int32(lkOffset) > 255 {
				lkOffset = 0
				prg.lkStarted = false // location 0 can do double duty
				for {
					prg.charRemainder[prg.labelChar[k-1]] = lkOffset
					for int32(prg.labelLoc[k-1]) == int32(prg.labelLoc[k]) {
						k = k - 1
						prg.charRemainder[prg.labelChar[k-1]] = lkOffset
					}
					lkOffset = uint16(int32(lkOffset) + 1)
					k = k - 1
					if int32(lkOffset)+int32(prg.labelLoc[k]) < 256 {
						break
					}
				}
				// N.B.: |lk_offset=256| satisfies this when |k=0|
			}
			if int32(lkOffset) > 0 {
				for k > 0 {
					prg.charRemainder[prg.labelChar[k-1]] = uint16(int32(prg.charRemainder[prg.labelChar[k-1]]) + int32(lkOffset))
					k = k - 1
				}
			}
			if int32(prg.bchLabel) < ligTableSize {
				prg.ligKern[prg.nl].b0 = byte(255 + minQuarterword)
				prg.ligKern[prg.nl].b1 = byte(0 + minQuarterword)
				prg.ligKern[prg.nl].b2 = byte((int32(prg.bchLabel)+int32(lkOffset))/256 + minQuarterword)
				prg.ligKern[prg.nl].b3 = byte((int32(prg.bchLabel)+int32(lkOffset))%256 + minQuarterword)
				prg.nl = uint16(int32(prg.nl) + 1) // possibly |nl=lig_table_size+1|
			}
			prg.tfmTwo(6 + lh + (int32(prg.ec) - int32(prg.bc) + 1) + int32(prg.nw) + int32(prg.nh) + int32(prg.nd) + int32(prg.ni) + int32(prg.nl) + int32(lkOffset) + int32(prg.nk) + int32(prg.ne) + int32(prg.np))
			// this is the total number of file words that will be output
			prg.tfmTwo(lh)
			prg.tfmTwo(int32(prg.bc))
			prg.tfmTwo(int32(prg.ec))
			prg.tfmTwo(int32(prg.nw))
			prg.tfmTwo(int32(prg.nh))
			prg.tfmTwo(int32(prg.nd))
			prg.tfmTwo(int32(prg.ni))
			prg.tfmTwo(int32(prg.nl) + int32(lkOffset))
			prg.tfmTwo(int32(prg.nk))
			prg.tfmTwo(int32(prg.ne))
			prg.tfmTwo(int32(prg.np))
			for ii := int32(1); ii <= 4*lh; ii++ {
				k = ii
				_ = k
				if int32(prg.headerByte[k-1]) < 0 {
					prg.headerByte[k-1] = 0
				}
				prg.tfmFile.Write(prg.headerByte[k-1])
			}

			// Output the character information bytes, then output the dimensions themselves
			for ii := int32(prg.bc); ii <= int32(prg.ec); ii++ {
				k = ii
				_ = k
				if !prg.charExists[k] {
					prg.tfmFour(0)
				} else {
					prg.tfmFile.Write(*(*prg.mem[prg.tfmWidth[k]].hh()).lh()) // the width index
					prg.tfmFile.Write(int32(*(*prg.mem[prg.tfmHeight[k]].hh()).lh())*16 + int32(*(*prg.mem[prg.tfmDepth[k]].hh()).lh()))
					prg.tfmFile.Write(int32(*(*prg.mem[prg.tfmItalCorr[k]].hh()).lh())*4 + int32(prg.charTag[k]))
					prg.tfmFile.Write(prg.charRemainder[k])
				}
			}
			prg.tfmChanged = 0
			for ii := int32(1); ii <= 4; ii++ {
				k = ii
				_ = k
				prg.tfmFour(0)
				p = prg.dimenHead[k-1]
				for int32(p) != memMin+3+10+2+2+2 {
					prg.tfmFour(prg.dimenOut(*prg.mem[int32(p)+1].int()))
					p = *(*prg.mem[p].hh()).rh()
				}
			}

			// Output the ligature/kern program
			for ii := int32(0); ii <= 255; ii++ {
				k = ii
				_ = k
				if int32(prg.skipTable[k]) < ligTableSize {
					prg.printNl(strNumber( /* "(local label " */ 1048))
					prg.printInt(k)
					prg.print( /* ":: was missing)" */ 1049)
					// \xref[local label l:: was missing]
					prg.ll = prg.skipTable[k]
					for {
						prg.lll = uint16(int32(prg.ligKern[prg.ll].b0) - minQuarterword)
						prg.ligKern[prg.ll].b0 = byte(stopFlag)
						prg.ll = uint16(int32(prg.ll) - int32(prg.lll))
						if int32(prg.lll) == 0 {
							break
						}
					}
				}
			}
			if prg.lkStarted {
				prg.tfmFile.Write(255)
				prg.tfmFile.Write(prg.bchar)
				prg.tfmTwo(0)
			} else {
				for ii := int32(1); ii <= int32(lkOffset); ii++ {
					k = ii
					_ = k // output the redirection specs
					prg.ll = uint16(prg.labelLoc[prg.labelPtr])
					if prg.bchar < 0 {
						prg.tfmFile.Write(254)
						prg.tfmFile.Write(0)
					} else {
						prg.tfmFile.Write(255)
						prg.tfmFile.Write(prg.bchar)
					}
					prg.tfmTwo(int32(prg.ll) + int32(lkOffset))
					for {
						prg.labelPtr = uint16(int32(prg.labelPtr) - 1)
						if int32(prg.labelLoc[prg.labelPtr]) < int32(prg.ll) {
							break
						}
					}
				}
			}
			for ii := int32(0); ii <= int32(prg.nl)-1; ii++ {
				k = ii
				_ = k
				prg.tfmQqqq(prg.ligKern[k])
			}
			for ii := int32(0); ii <= int32(prg.nk)-1; ii++ {
				k = ii
				_ = k
				prg.tfmFour(prg.dimenOut(prg.kern[k]))
			}

			// Output the extensible character recipes and the font metric parameters
			for ii := int32(0); ii <= int32(prg.ne)-1; ii++ {
				k = ii
				_ = k
				prg.tfmQqqq(prg.exten[k])
			}
			for ii := int32(1); ii <= int32(prg.np); ii++ {
				k = ii
				_ = k
				if k == 1 {
					if abs(prg.param[1-1]) < 01000000000 {
						prg.tfmFour(prg.param[1-1] * 16)
					} else {
						prg.tfmChanged = prg.tfmChanged + 1
						if prg.param[1-1] > 0 {
							prg.tfmFour(017777777777)
						} else {
							prg.tfmFour(-017777777777)
						}
					}
				} else {
					prg.tfmFour(prg.dimenOut(prg.param[k-1]))
				}
			}
			if prg.tfmChanged > 0 {
				if prg.tfmChanged == 1 {
					prg.printNl(strNumber( /* "(a font metric dimension" */ 1050))
				} else {
					prg.printNl(strNumber('('))
					prg.printInt(prg.tfmChanged)
					// \xref[font metric dimensions...]
					prg.print( /* " font metric dimensions" */ 1051)
				}
				prg.print( /* " had to be decreased)" */ 1052)
			}
			if prg.internal[tracingStats-1] > 0 {
				prg.logFile.Writeln(" ")
				if int32(prg.bchLabel) < ligTableSize {
					prg.nl = uint16(int32(prg.nl) - 1)
				}
				prg.logFile.Writeln("(You used ", prg.nw, knuth.WriteWidth(1), "w,", prg.nh, knuth.WriteWidth(1), "h,", prg.nd, knuth.WriteWidth(1), "d,", prg.ni, knuth.WriteWidth(1), "i,", prg.nl, knuth.WriteWidth(1), "l,", prg.nk, knuth.WriteWidth(1), "k,", prg.ne, knuth.WriteWidth(1), "e,", prg.np, knuth.WriteWidth(1), "p metric file positions")
				prg.logFile.Writeln("  out of ", "256w,16h,16d,64i,", ligTableSize, knuth.WriteWidth(1), "l,", maxKerns, knuth.WriteWidth(1), "k,256e,", maxFontDimen, knuth.WriteWidth(1), "p)")
			}

			prg.printNl(strNumber( /* "Font metrics written on " */ 1047))
			prg.slowPrint(int32(prg.metricFileName))
			prg.printChar(asciiCode('.'))
			// \xref[Font metrics written...]
			prg.bClose(prg.tfmFile)
		}
		if prg.gfPrevPtr > 0 {
			{
				prg.gfBuf[prg.gfPtr] = byte(post)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			} // beginning of the postamble
			prg.gfFour(prg.gfPrevPtr)
			prg.gfPrevPtr = prg.gfOffset + int32(prg.gfPtr) - 5 // |post| location
			prg.gfFour(prg.internal[designSize-1] * 16)
			for ii := int32(1); ii <= 4; ii++ {
				k = ii
				_ = k
				prg.gfBuf[prg.gfPtr] = byte(prg.headerByte[k-1])
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			} // the check sum
			prg.gfFour(prg.internal[hppp-1])
			prg.gfFour(prg.internal[vppp-1])

			prg.gfFour(prg.gfMinM)
			prg.gfFour(prg.gfMaxM)
			prg.gfFour(prg.gfMinN)
			prg.gfFour(prg.gfMaxN)
			for ii := int32(0); ii <= 255; ii++ {
				k = ii
				_ = k
				if prg.charExists[k] {
					x = prg.gfDx[k] / 0200000
					if prg.gfDy[k] == 0 && x >= 0 && x < 256 && prg.gfDx[k] == x*0200000 {
						{
							prg.gfBuf[prg.gfPtr] = byte(charLoc + 1)
							prg.gfPtr = byte(int32(prg.gfPtr) + 1)
							if int32(prg.gfPtr) == int32(prg.gfLimit) {
								prg.gfSwap()
							}
						}
						{
							prg.gfBuf[prg.gfPtr] = byte(k)
							prg.gfPtr = byte(int32(prg.gfPtr) + 1)
							if int32(prg.gfPtr) == int32(prg.gfLimit) {
								prg.gfSwap()
							}
						}
						{
							prg.gfBuf[prg.gfPtr] = byte(x)
							prg.gfPtr = byte(int32(prg.gfPtr) + 1)
							if int32(prg.gfPtr) == int32(prg.gfLimit) {
								prg.gfSwap()
							}
						}
					} else {
						{
							prg.gfBuf[prg.gfPtr] = byte(charLoc)
							prg.gfPtr = byte(int32(prg.gfPtr) + 1)
							if int32(prg.gfPtr) == int32(prg.gfLimit) {
								prg.gfSwap()
							}
						}
						{
							prg.gfBuf[prg.gfPtr] = byte(k)
							prg.gfPtr = byte(int32(prg.gfPtr) + 1)
							if int32(prg.gfPtr) == int32(prg.gfLimit) {
								prg.gfSwap()
							}
						}
						prg.gfFour(prg.gfDx[k])
						prg.gfFour(prg.gfDy[k])
					}
					x = *prg.mem[prg.tfmWidth[k]+1].int()
					if abs(x) > prg.maxTfmDimen {
						if x > 0 {
							x = 0100000000 - 1
						} else {
							x = 1 - 0100000000
						}
					} else {
						x = prg.makeScaled(x*16, prg.internal[designSize-1])
					}
					prg.gfFour(x)
					prg.gfFour(prg.charPtr[k])
				}
			}
			{
				prg.gfBuf[prg.gfPtr] = byte(postPost)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}
			prg.gfFour(prg.gfPrevPtr)
			{
				prg.gfBuf[prg.gfPtr] = byte(gfIdByte)
				prg.gfPtr = byte(int32(prg.gfPtr) + 1)
				if int32(prg.gfPtr) == int32(prg.gfLimit) {
					prg.gfSwap()
				}
			}

			k = 4 + (gfBufSize-int32(prg.gfPtr))%4 // the number of 223's
			for k > 0 {
				{
					prg.gfBuf[prg.gfPtr] = 223
					prg.gfPtr = byte(int32(prg.gfPtr) + 1)
					if int32(prg.gfPtr) == int32(prg.gfLimit) {
						prg.gfSwap()
					}
				}
				k = k - 1
			}

			// Empty the last bytes out of |gf_buf|
			if int32(prg.gfLimit) == int32(prg.halfBuf) {
				prg.writeGf(prg.halfBuf, gfIndex(gfBufSize-1))
			}
			if int32(prg.gfPtr) > 0 {
				prg.writeGf(gfIndex(0), gfIndex(int32(prg.gfPtr)-1))
			}
			prg.printNl(strNumber( /* "Output written on " */ 1063))
			prg.slowPrint(int32(prg.outputFileName))
			// \xref[Output written...]
			prg.print( /* " (" */ 558)
			prg.printInt(prg.totalChars)
			prg.print( /* " character" */ 1064)
			if prg.totalChars != 1 {
				prg.printChar(asciiCode('s'))
			}
			prg.print( /* ", " */ 1065)
			prg.printInt(prg.gfOffset + int32(prg.gfPtr))
			prg.print( /* " bytes)." */ 1066)
			prg.bClose(prg.gfFile)
		}
	}
	if prg.logOpened {
		prg.logFile.Writeln()
		prg.aClose(prg.logFile)
		prg.selector = byte(int32(prg.selector) - 2)
		if int32(prg.selector) == termOnly {
			prg.printNl(strNumber( /* "Transcript written on " */ 1074))
			// \xref[Transcript written...]
			prg.slowPrint(int32(prg.logName))
			prg.printChar(asciiCode('.'))
		}
	}
	prg.termOut.Writeln()
}

func (prg *prg) finalCleanup() {
	var (
		c smallNumber // 0 for \&[end], 1 for \&[dump]
	)
	c = byte(prg.curMod)
	if int32(prg.jobName) == 0 {
		prg.openLogFile()
	}
	for int32(prg.inputPtr) > 0 {
		if int32(prg.curInput.indexField) > maxInOpen {
			prg.endTokenList()
		} else {
			prg.endFileReading()
		}
	}
	for int32(prg.loopPtr) != memMin {
		prg.stopIteration()
	}
	for int32(prg.openParens) > 0 {
		prg.print( /* " )" */ 1075)
		prg.openParens = byte(int32(prg.openParens) - 1)
	}
	for int32(prg.condPtr) != memMin {
		prg.printNl(strNumber( /* "(end occurred when " */ 1076))

		// \xref[end occurred...]
		prg.printCmdMod(fiOrElse, int32(prg.curIf))
		// `\.[if]' or `\.[elseif]' or `\.[else]'
		if prg.ifLine != 0 {
			prg.print( /* " on line " */ 1077)
			prg.printInt(prg.ifLine)
		}
		prg.print( /* " was incomplete)" */ 1078)
		prg.ifLine = *prg.mem[int32(prg.condPtr)+1].int()
		prg.curIf = *(*prg.mem[prg.condPtr].hh()).b1()
		prg.loopPtr = prg.condPtr
		prg.condPtr = *(*prg.mem[prg.condPtr].hh()).rh()
		prg.freeNode(prg.loopPtr, halfword(ifNodeSize))
	}
	if int32(prg.history) != spotless {
		if int32(prg.history) == warningIssued || int32(prg.interaction) < errorStopMode {
			if int32(prg.selector) == termAndLog {
				prg.selector = byte(termOnly)
				prg.printNl(strNumber( /* "(see the transcript file for additional information)" */ 1079))
				// \xref[see the transcript file...]
				prg.selector = byte(termAndLog)
			}
		}
	}
	if int32(c) == 1 {
		prg.storeBaseFile()
		goto exit

		prg.printNl(strNumber( /* "(dump is performed only by INIMF)" */ 1080))
		goto exit
		// \xref[dump...only by INIMF]
	}

exit:
}

func (prg *prg) initPrim() {
	prg.primitive(strNumber( /* "tracingtitles" */ 410), halfword(internalQuantity), halfword(tracingTitles))

	// \xref[tracingtitles_][\&[tracingtitles] primitive]
	prg.primitive(strNumber( /* "tracingequations" */ 411), halfword(internalQuantity), halfword(tracingEquations))

	// \xref[tracing_equations_][\&[tracingequations] primitive]
	prg.primitive(strNumber( /* "tracingcapsules" */ 412), halfword(internalQuantity), halfword(tracingCapsules))

	// \xref[tracing_capsules_][\&[tracingcapsules] primitive]
	prg.primitive(strNumber( /* "tracingchoices" */ 413), halfword(internalQuantity), halfword(tracingChoices))

	// \xref[tracing_choices_][\&[tracingchoices] primitive]
	prg.primitive(strNumber( /* "tracingspecs" */ 414), halfword(internalQuantity), halfword(tracingSpecs))

	// \xref[tracing_specs_][\&[tracingspecs] primitive]
	prg.primitive(strNumber( /* "tracingpens" */ 415), halfword(internalQuantity), halfword(tracingPens))

	// \xref[tracing_pens_][\&[tracingpens] primitive]
	prg.primitive(strNumber( /* "tracingcommands" */ 416), halfword(internalQuantity), halfword(tracingCommands))

	// \xref[tracing_commands_][\&[tracingcommands] primitive]
	prg.primitive(strNumber( /* "tracingrestores" */ 417), halfword(internalQuantity), halfword(tracingRestores))

	// \xref[tracing_restores_][\&[tracingrestores] primitive]
	prg.primitive(strNumber( /* "tracingmacros" */ 418), halfword(internalQuantity), halfword(tracingMacros))

	// \xref[tracing_macros_][\&[tracingmacros] primitive]
	prg.primitive(strNumber( /* "tracingedges" */ 419), halfword(internalQuantity), halfword(tracingEdges))

	// \xref[tracing_edges_][\&[tracingedges] primitive]
	prg.primitive(strNumber( /* "tracingoutput" */ 420), halfword(internalQuantity), halfword(tracingOutput))

	// \xref[tracing_output_][\&[tracingoutput] primitive]
	prg.primitive(strNumber( /* "tracingstats" */ 421), halfword(internalQuantity), halfword(tracingStats))

	// \xref[tracing_stats_][\&[tracingstats] primitive]
	prg.primitive(strNumber( /* "tracingonline" */ 422), halfword(internalQuantity), halfword(tracingOnline))

	// \xref[tracing_online_][\&[tracingonline] primitive]
	prg.primitive(strNumber( /* "year" */ 423), halfword(internalQuantity), halfword(year))

	// \xref[year_][\&[year] primitive]
	prg.primitive(strNumber( /* "month" */ 424), halfword(internalQuantity), halfword(month))

	// \xref[month_][\&[month] primitive]
	prg.primitive(strNumber( /* "day" */ 425), halfword(internalQuantity), halfword(day))

	// \xref[day_][\&[day] primitive]
	prg.primitive(strNumber( /* "time" */ 426), halfword(internalQuantity), halfword(time))

	// \xref[time_][\&[time] primitive]
	prg.primitive(strNumber( /* "charcode" */ 427), halfword(internalQuantity), halfword(charCode))

	// \xref[char_code_][\&[charcode] primitive]
	prg.primitive(strNumber( /* "charext" */ 428), halfword(internalQuantity), halfword(charExt))

	// \xref[char_ext_][\&[charext] primitive]
	prg.primitive(strNumber( /* "charwd" */ 429), halfword(internalQuantity), halfword(charWd))

	// \xref[char_wd_][\&[charwd] primitive]
	prg.primitive(strNumber( /* "charht" */ 430), halfword(internalQuantity), halfword(charHt))

	// \xref[char_ht_][\&[charht] primitive]
	prg.primitive(strNumber( /* "chardp" */ 431), halfword(internalQuantity), halfword(charDp))

	// \xref[char_dp_][\&[chardp] primitive]
	prg.primitive(strNumber( /* "charic" */ 432), halfword(internalQuantity), halfword(charIc))

	// \xref[char_ic_][\&[charic] primitive]
	prg.primitive(strNumber( /* "chardx" */ 433), halfword(internalQuantity), halfword(charDx))

	// \xref[char_dx_][\&[chardx] primitive]
	prg.primitive(strNumber( /* "chardy" */ 434), halfword(internalQuantity), halfword(charDy))

	// \xref[char_dy_][\&[chardy] primitive]
	prg.primitive(strNumber( /* "designsize" */ 435), halfword(internalQuantity), halfword(designSize))

	// \xref[design_size_][\&[designsize] primitive]
	prg.primitive(strNumber( /* "hppp" */ 436), halfword(internalQuantity), halfword(hppp))

	// \xref[hppp_][\&[hppp] primitive]
	prg.primitive(strNumber( /* "vppp" */ 437), halfword(internalQuantity), halfword(vppp))

	// \xref[vppp_][\&[vppp] primitive]
	prg.primitive(strNumber( /* "xoffset" */ 438), halfword(internalQuantity), halfword(xOffset))

	// \xref[x_offset_][\&[xoffset] primitive]
	prg.primitive(strNumber( /* "yoffset" */ 439), halfword(internalQuantity), halfword(yOffset))

	// \xref[y_offset_][\&[yoffset] primitive]
	prg.primitive(strNumber( /* "pausing" */ 440), halfword(internalQuantity), halfword(pausing))

	// \xref[pausing_][\&[pausing] primitive]
	prg.primitive(strNumber( /* "showstopping" */ 441), halfword(internalQuantity), halfword(showstopping))

	// \xref[showstopping_][\&[showstopping] primitive]
	prg.primitive(strNumber( /* "fontmaking" */ 442), halfword(internalQuantity), halfword(fontmaking))

	// \xref[fontmaking_][\&[fontmaking] primitive]
	prg.primitive(strNumber( /* "proofing" */ 443), halfword(internalQuantity), halfword(proofing))

	// \xref[proofing_][\&[proofing] primitive]
	prg.primitive(strNumber( /* "smoothing" */ 444), halfword(internalQuantity), halfword(smoothing))

	// \xref[smoothing_][\&[smoothing] primitive]
	prg.primitive(strNumber( /* "autorounding" */ 445), halfword(internalQuantity), halfword(autorounding))

	// \xref[autorounding_][\&[autorounding] primitive]
	prg.primitive(strNumber( /* "granularity" */ 446), halfword(internalQuantity), halfword(granularity))

	// \xref[granularity_][\&[granularity] primitive]
	prg.primitive(strNumber( /* "fillin" */ 447), halfword(internalQuantity), halfword(fillin))

	// \xref[fillin_][\&[fillin] primitive]
	prg.primitive(strNumber( /* "turningcheck" */ 448), halfword(internalQuantity), halfword(turningCheck))

	// \xref[turning_check_][\&[turningcheck] primitive]
	prg.primitive(strNumber( /* "warningcheck" */ 449), halfword(internalQuantity), halfword(warningCheck))

	// \xref[warning_check_][\&[warningcheck] primitive]
	prg.primitive(strNumber( /* "boundarychar" */ 450), halfword(internalQuantity), halfword(boundaryChar))

	// \xref[boundary_char_][\&[boundarychar] primitive]

	prg.primitive(strNumber( /* ".." */ 409), halfword(pathJoin), halfword(0))

	// \xref[.._][\.[..] primitive]
	prg.primitive(strNumber('['), halfword(leftBracket), halfword(0))
	prg.eqtb[hashBase+hashSize+3-1] = prg.eqtb[prg.curSym-1]

	// \xref[[ ][\.[[] primitive]
	prg.primitive(strNumber(']'), halfword(rightBracket), halfword(0))

	// \xref[] ][\.[]] primitive]
	prg.primitive(strNumber('}'), halfword(rightBrace), halfword(0))

	// \xref[]]][\.[\char`\]] primitive]
	prg.primitive(strNumber('{'), halfword(leftBrace), halfword(0))

	// \xref[][][\.[\char`\[] primitive]
	prg.primitive(strNumber(':'), halfword(colon), halfword(0))
	prg.eqtb[hashBase+hashSize+5-1] = prg.eqtb[prg.curSym-1]

	// \xref[: ][\.[:] primitive]
	prg.primitive(strNumber( /* "::" */ 459), halfword(doubleColon), halfword(0))

	// \xref[:: ][\.[::] primitive]
	prg.primitive(strNumber( /* "||:" */ 460), halfword(bcharLabel), halfword(0))

	// \xref[::: ][\.[\char'174\char'174:] primitive]
	prg.primitive(strNumber( /* ":=" */ 461), halfword(assignment), halfword(0))

	// \xref[:=_][\.[:=] primitive]
	prg.primitive(strNumber(','), halfword(comma), halfword(0))

	// \xref[, ][\., primitive]
	prg.primitive(strNumber(';'), halfword(semicolon), halfword(0))
	prg.eqtb[hashBase+hashSize+6-1] = prg.eqtb[prg.curSym-1]

	// \xref[; ][\.; primitive]
	prg.primitive(strNumber('\\'), halfword(relax), halfword(0))

	// \xref[]]\\][\.[\char`\\] primitive]

	prg.primitive(strNumber( /* "addto" */ 462), halfword(addToCommand), halfword(0))

	// \xref[add_to_][\&[addto] primitive]
	prg.primitive(strNumber( /* "at" */ 463), halfword(atToken), halfword(0))

	// \xref[at_][\&[at] primitive]
	prg.primitive(strNumber( /* "atleast" */ 464), halfword(atLeast), halfword(0))

	// \xref[at_least_][\&[atleast] primitive]
	prg.primitive(strNumber( /* "begingroup" */ 465), halfword(beginGroup), halfword(0))
	prg.bgLoc = prg.curSym

	// \xref[begin_group_][\&[begingroup] primitive]
	prg.primitive(strNumber( /* "controls" */ 466), halfword(controls), halfword(0))

	// \xref[controls_][\&[controls] primitive]
	prg.primitive(strNumber( /* "cull" */ 467), halfword(cullCommand), halfword(0))

	// \xref[cull_][\&[cull] primitive]
	prg.primitive(strNumber( /* "curl" */ 468), halfword(curlCommand), halfword(0))

	// \xref[curl_][\&[curl] primitive]
	prg.primitive(strNumber( /* "delimiters" */ 469), halfword(delimiters), halfword(0))

	// \xref[delimiters_][\&[delimiters] primitive]
	prg.primitive(strNumber( /* "display" */ 470), halfword(displayCommand), halfword(0))

	// \xref[display_][\&[display] primitive]
	prg.primitive(strNumber( /* "endgroup" */ 453), halfword(endGroup), halfword(0))
	prg.eqtb[hashBase+hashSize+10-1] = prg.eqtb[prg.curSym-1]
	prg.egLoc = prg.curSym

	// \xref[endgroup_][\&[endgroup] primitive]
	prg.primitive(strNumber( /* "everyjob" */ 471), halfword(everyJobCommand), halfword(0))

	// \xref[every_job_][\&[everyjob] primitive]
	prg.primitive(strNumber( /* "exitif" */ 472), halfword(exitTest), halfword(0))

	// \xref[exit_if_][\&[exitif] primitive]
	prg.primitive(strNumber( /* "expandafter" */ 473), halfword(expandAfter), halfword(0))

	// \xref[expand_after_][\&[expandafter] primitive]
	prg.primitive(strNumber( /* "from" */ 474), halfword(fromToken), halfword(0))

	// \xref[from_][\&[from] primitive]
	prg.primitive(strNumber( /* "inwindow" */ 475), halfword(inWindow), halfword(0))

	// \xref[in_window_][\&[inwindow] primitive]
	prg.primitive(strNumber( /* "interim" */ 476), halfword(interimCommand), halfword(0))

	// \xref[interim_][\&[interim] primitive]
	prg.primitive(strNumber( /* "let" */ 477), halfword(letCommand), halfword(0))

	// \xref[let_][\&[let] primitive]
	prg.primitive(strNumber( /* "newinternal" */ 478), halfword(newInternal), halfword(0))

	// \xref[new_internal_][\&[newinternal] primitive]
	prg.primitive(strNumber( /* "of" */ 479), halfword(ofToken), halfword(0))

	// \xref[of_][\&[of] primitive]
	prg.primitive(strNumber( /* "openwindow" */ 480), halfword(openWindow), halfword(0))

	// \xref[open_window_][\&[openwindow] primitive]
	prg.primitive(strNumber( /* "randomseed" */ 481), halfword(randomSeed), halfword(0))

	// \xref[random_seed_][\&[randomseed] primitive]
	prg.primitive(strNumber( /* "save" */ 482), halfword(saveCommand), halfword(0))

	// \xref[save_][\&[save] primitive]
	prg.primitive(strNumber( /* "scantokens" */ 483), halfword(scanTokens), halfword(0))

	// \xref[scan_tokens_][\&[scantokens] primitive]
	prg.primitive(strNumber( /* "shipout" */ 484), halfword(shipOutCommand), halfword(0))

	// \xref[ship_out_][\&[shipout] primitive]
	prg.primitive(strNumber( /* "skipto" */ 485), halfword(skipTo), halfword(0))

	// \xref[skip_to_][\&[skipto] primitive]
	prg.primitive(strNumber( /* "step" */ 486), halfword(stepToken), halfword(0))

	// \xref[step_][\&[step] primitive]
	prg.primitive(strNumber( /* "str" */ 487), halfword(strOp), halfword(0))

	// \xref[str_][\&[str] primitive]
	prg.primitive(strNumber( /* "tension" */ 488), halfword(tension), halfword(0))

	// \xref[tension_][\&[tension] primitive]
	prg.primitive(strNumber( /* "to" */ 489), halfword(toToken), halfword(0))

	// \xref[to_][\&[to] primitive]
	prg.primitive(strNumber( /* "until" */ 490), halfword(untilToken), halfword(0))

	// \xref[until_][\&[until] primitive]

	prg.primitive(strNumber( /* "def" */ 654), halfword(macroDef), halfword(startDef))

	// \xref[def_][\&[def] primitive]
	prg.primitive(strNumber( /* "vardef" */ 655), halfword(macroDef), halfword(varDef))

	// \xref[var_def_][\&[vardef] primitive]
	prg.primitive(strNumber( /* "primarydef" */ 656), halfword(macroDef), halfword(secondaryPrimaryMacro))

	// \xref[primary_def_][\&[primarydef] primitive]
	prg.primitive(strNumber( /* "secondarydef" */ 657), halfword(macroDef), halfword(tertiarySecondaryMacro))

	// \xref[secondary_def_][\&[secondarydef] primitive]
	prg.primitive(strNumber( /* "tertiarydef" */ 658), halfword(macroDef), halfword(expressionTertiaryMacro))

	// \xref[tertiary_def_][\&[tertiarydef] primitive]
	prg.primitive(strNumber( /* "enddef" */ 454), halfword(macroDef), halfword(endDef))
	prg.eqtb[hashBase+hashSize+8-1] = prg.eqtb[prg.curSym-1]

	// \xref[end_def_][\&[enddef] primitive]

	prg.primitive(strNumber( /* "for" */ 659), halfword(iteration), halfword(hashBase+hashSize+12+1))

	// \xref[for_][\&[for] primitive]
	prg.primitive(strNumber( /* "forsuffixes" */ 660), halfword(iteration), halfword(hashBase+hashSize+12+1+paramSize))

	// \xref[for_suffixes_][\&[forsuffixes] primitive]
	prg.primitive(strNumber( /* "forever" */ 661), halfword(iteration), halfword(startForever))

	// \xref[forever_][\&[forever] primitive]
	prg.primitive(strNumber( /* "endfor" */ 455), halfword(iteration), halfword(endFor))
	prg.eqtb[hashBase+hashSize+7-1] = prg.eqtb[prg.curSym-1]

	// \xref[end_for_][\&[endfor] primitive]

	prg.primitive(strNumber( /* "quote" */ 662), halfword(macroSpecial), halfword(quote))

	// \xref[quote_][\&[quote] primitive]
	prg.primitive(strNumber( /* "#@" */ 663), halfword(macroSpecial), halfword(macroPrefix))

	// \xref[]]]\#\AT!_][\.[\#\AT!] primitive]
	prg.primitive(strNumber('@'), halfword(macroSpecial), halfword(macroAt))

	// \xref[]]]\AT!_][\.[\AT!] primitive]
	prg.primitive(strNumber( /* "@#" */ 664), halfword(macroSpecial), halfword(macroSuffix))

	// \xref[]]]\AT!\#_][\.[\AT!\#] primitive]

	prg.primitive(strNumber( /* "expr" */ 675), halfword(paramType), halfword(hashBase+hashSize+12+1))

	// \xref[expr_][\&[expr] primitive]
	prg.primitive(strNumber( /* "suffix" */ 676), halfword(paramType), halfword(hashBase+hashSize+12+1+paramSize))

	// \xref[suffix_][\&[suffix] primitive]
	prg.primitive(strNumber( /* "text" */ 677), halfword(paramType), halfword(hashBase+hashSize+12+1+paramSize+paramSize))

	// \xref[text_][\&[text] primitive]
	prg.primitive(strNumber( /* "primary" */ 678), halfword(paramType), halfword(primaryMacro))

	// \xref[primary_][\&[primary] primitive]
	prg.primitive(strNumber( /* "secondary" */ 679), halfword(paramType), halfword(secondaryMacro))

	// \xref[secondary_][\&[secondary] primitive]
	prg.primitive(strNumber( /* "tertiary" */ 680), halfword(paramType), halfword(tertiaryMacro))

	// \xref[tertiary_][\&[tertiary] primitive]

	prg.primitive(strNumber( /* "input" */ 690), halfword(input), halfword(0))

	// \xref[input_][\&[input] primitive]
	prg.primitive(strNumber( /* "endinput" */ 616), halfword(input), halfword(1))

	// \xref[end_input_][\&[endinput] primitive]

	prg.primitive(strNumber( /* "if" */ 717), halfword(ifTest), halfword(ifCode))

	// \xref[if_][\&[if] primitive]
	prg.primitive(strNumber( /* "fi" */ 452), halfword(fiOrElse), halfword(fiCode))
	prg.eqtb[hashBase+hashSize+9-1] = prg.eqtb[prg.curSym-1]

	// \xref[fi_][\&[fi] primitive]
	prg.primitive(strNumber( /* "else" */ 718), halfword(fiOrElse), halfword(elseCode))

	// \xref[else_][\&[else] primitive]
	prg.primitive(strNumber( /* "elseif" */ 719), halfword(fiOrElse), halfword(elseIfCode))

	// \xref[else_if_][\&[elseif] primitive]

	prg.primitive(strNumber( /* "true" */ 348), halfword(nullary), halfword(trueCode))

	// \xref[true_][\&[true] primitive]
	prg.primitive(strNumber( /* "false" */ 349), halfword(nullary), halfword(falseCode))

	// \xref[false_][\&[false] primitive]
	prg.primitive(strNumber( /* "nullpicture" */ 350), halfword(nullary), halfword(nullPictureCode))

	// \xref[null_picture_][\&[nullpicture] primitive]
	prg.primitive(strNumber( /* "nullpen" */ 351), halfword(nullary), halfword(nullPenCode))

	// \xref[null_pen_][\&[nullpen] primitive]
	prg.primitive(strNumber( /* "jobname" */ 352), halfword(nullary), halfword(jobNameOp))

	// \xref[job_name_][\&[jobname] primitive]
	prg.primitive(strNumber( /* "readstring" */ 353), halfword(nullary), halfword(readStringOp))

	// \xref[read_string_][\&[readstring] primitive]
	prg.primitive(strNumber( /* "pencircle" */ 354), halfword(nullary), halfword(penCircle))

	// \xref[pen_circle_][\&[pencircle] primitive]
	prg.primitive(strNumber( /* "normaldeviate" */ 355), halfword(nullary), halfword(normalDeviate))

	// \xref[normal_deviate_][\&[normaldeviate] primitive]
	prg.primitive(strNumber( /* "odd" */ 356), halfword(unary), halfword(oddOp))

	// \xref[odd_][\&[odd] primitive]
	prg.primitive(strNumber( /* "known" */ 357), halfword(unary), halfword(knownOp))

	// \xref[known_][\&[known] primitive]
	prg.primitive(strNumber( /* "unknown" */ 358), halfword(unary), halfword(unknownOp))

	// \xref[unknown_][\&[unknown] primitive]
	prg.primitive(strNumber( /* "not" */ 359), halfword(unary), halfword(notOp))

	// \xref[not_][\&[not] primitive]
	prg.primitive(strNumber( /* "decimal" */ 360), halfword(unary), halfword(decimal))

	// \xref[decimal_][\&[decimal] primitive]
	prg.primitive(strNumber( /* "reverse" */ 361), halfword(unary), halfword(reverse))

	// \xref[reverse_][\&[reverse] primitive]
	prg.primitive(strNumber( /* "makepath" */ 362), halfword(unary), halfword(makePathOp))

	// \xref[make_path_][\&[makepath] primitive]
	prg.primitive(strNumber( /* "makepen" */ 363), halfword(unary), halfword(makePenOp))

	// \xref[make_pen_][\&[makepen] primitive]
	prg.primitive(strNumber( /* "totalweight" */ 364), halfword(unary), halfword(totalWeightOp))

	// \xref[total_weight_][\&[totalweight] primitive]
	prg.primitive(strNumber( /* "oct" */ 365), halfword(unary), halfword(octOp))

	// \xref[oct_][\&[oct] primitive]
	prg.primitive(strNumber( /* "hex" */ 366), halfword(unary), halfword(hexOp))

	// \xref[hex_][\&[hex] primitive]
	prg.primitive(strNumber( /* "ASCII" */ 367), halfword(unary), halfword(asciiOp))

	// \xref[ASCII_][\&[ASCII] primitive]
	prg.primitive(strNumber( /* "char" */ 368), halfword(unary), halfword(charOp))

	// \xref[char_][\&[char] primitive]
	prg.primitive(strNumber( /* "length" */ 369), halfword(unary), halfword(lengthOp))

	// \xref[length_][\&[length] primitive]
	prg.primitive(strNumber( /* "turningnumber" */ 370), halfword(unary), halfword(turningOp))

	// \xref[turning_number_][\&[turningnumber] primitive]
	prg.primitive(strNumber( /* "xpart" */ 371), halfword(unary), halfword(xPart))

	// \xref[x_part_][\&[xpart] primitive]
	prg.primitive(strNumber( /* "ypart" */ 372), halfword(unary), halfword(yPart))

	// \xref[y_part_][\&[ypart] primitive]
	prg.primitive(strNumber( /* "xxpart" */ 373), halfword(unary), halfword(xxPart))

	// \xref[xx_part_][\&[xxpart] primitive]
	prg.primitive(strNumber( /* "xypart" */ 374), halfword(unary), halfword(xyPart))

	// \xref[xy_part_][\&[xypart] primitive]
	prg.primitive(strNumber( /* "yxpart" */ 375), halfword(unary), halfword(yxPart))

	// \xref[yx_part_][\&[yxpart] primitive]
	prg.primitive(strNumber( /* "yypart" */ 376), halfword(unary), halfword(yyPart))

	// \xref[yy_part_][\&[yypart] primitive]
	prg.primitive(strNumber( /* "sqrt" */ 377), halfword(unary), halfword(sqrtOp))

	// \xref[sqrt_][\&[sqrt] primitive]
	prg.primitive(strNumber( /* "mexp" */ 378), halfword(unary), halfword(mExpOp))

	// \xref[m_exp_][\&[mexp] primitive]
	prg.primitive(strNumber( /* "mlog" */ 379), halfword(unary), halfword(mLogOp))

	// \xref[m_log_][\&[mlog] primitive]
	prg.primitive(strNumber( /* "sind" */ 380), halfword(unary), halfword(sinDOp))

	// \xref[sin_d_][\&[sind] primitive]
	prg.primitive(strNumber( /* "cosd" */ 381), halfword(unary), halfword(cosDOp))

	// \xref[cos_d_][\&[cosd] primitive]
	prg.primitive(strNumber( /* "floor" */ 382), halfword(unary), halfword(floorOp))

	// \xref[floor_][\&[floor] primitive]
	prg.primitive(strNumber( /* "uniformdeviate" */ 383), halfword(unary), halfword(uniformDeviate))

	// \xref[uniform_deviate_][\&[uniformdeviate] primitive]
	prg.primitive(strNumber( /* "charexists" */ 384), halfword(unary), halfword(charExistsOp))

	// \xref[char_exists_][\&[charexists] primitive]
	prg.primitive(strNumber( /* "angle" */ 385), halfword(unary), halfword(angleOp))

	// \xref[angle_][\&[angle] primitive]
	prg.primitive(strNumber( /* "cycle" */ 386), halfword(cycle), halfword(cycleOp))

	// \xref[cycle_][\&[cycle] primitive]
	prg.primitive(strNumber('+'), halfword(plusOrMinus), halfword(plus))

	// \xref[+ ][\.[+] primitive]
	prg.primitive(strNumber('-'), halfword(plusOrMinus), halfword(minus))

	// \xref[- ][\.[-] primitive]
	prg.primitive(strNumber('*'), halfword(secondaryBinary), halfword(times))

	// \xref[* ][\.[*] primitive]
	prg.primitive(strNumber('/'), halfword(slash), halfword(over))
	prg.eqtb[hashBase+hashSize+4-1] = prg.eqtb[prg.curSym-1]

	// \xref[/ ][\.[/] primitive]
	prg.primitive(strNumber( /* "++" */ 387), halfword(tertiaryBinary), halfword(pythagAdd))

	// \xref[++_][\.[++] primitive]
	prg.primitive(strNumber( /* "+-+" */ 311), halfword(tertiaryBinary), halfword(pythagSub))

	// \xref[+-+_][\.[+-+] primitive]
	prg.primitive(strNumber( /* "and" */ 389), halfword(andCommand), halfword(andOp))

	// \xref[and_][\&[and] primitive]
	prg.primitive(strNumber( /* "or" */ 388), halfword(tertiaryBinary), halfword(orOp))

	// \xref[or_][\&[or] primitive]
	prg.primitive(strNumber('<'), halfword(expressionBinary), halfword(lessThan))

	// \xref[< ][\.[<] primitive]
	prg.primitive(strNumber( /* "<=" */ 390), halfword(expressionBinary), halfword(lessOrEqual))

	// \xref[<=_][\.[<=] primitive]
	prg.primitive(strNumber('>'), halfword(expressionBinary), halfword(greaterThan))

	// \xref[> ][\.[>] primitive]
	prg.primitive(strNumber( /* ">=" */ 391), halfword(expressionBinary), halfword(greaterOrEqual))

	// \xref[>=_][\.[>=] primitive]
	prg.primitive(strNumber('='), halfword(equals), halfword(equalTo))

	// \xref[= ][\.[=] primitive]
	prg.primitive(strNumber( /* "<>" */ 392), halfword(expressionBinary), halfword(unequalTo))

	// \xref[<>_][\.[<>] primitive]
	prg.primitive(strNumber( /* "substring" */ 402), halfword(primaryBinary), halfword(substringOf))

	// \xref[substring_][\&[substring] primitive]
	prg.primitive(strNumber( /* "subpath" */ 403), halfword(primaryBinary), halfword(subpathOf))

	// \xref[subpath_][\&[subpath] primitive]
	prg.primitive(strNumber( /* "directiontime" */ 404), halfword(primaryBinary), halfword(directionTimeOf))

	// \xref[direction_time_][\&[directiontime] primitive]
	prg.primitive(strNumber( /* "point" */ 405), halfword(primaryBinary), halfword(pointOf))

	// \xref[point_][\&[point] primitive]
	prg.primitive(strNumber( /* "precontrol" */ 406), halfword(primaryBinary), halfword(precontrolOf))

	// \xref[precontrol_][\&[precontrol] primitive]
	prg.primitive(strNumber( /* "postcontrol" */ 407), halfword(primaryBinary), halfword(postcontrolOf))

	// \xref[postcontrol_][\&[postcontrol] primitive]
	prg.primitive(strNumber( /* "penoffset" */ 408), halfword(primaryBinary), halfword(penOffsetOf))

	// \xref[pen_offset_][\&[penoffset] primitive]
	prg.primitive(strNumber('&'), halfword(ampersand), halfword(concatenate))

	// \xref[!!!][\.[\&] primitive]
	prg.primitive(strNumber( /* "rotated" */ 393), halfword(secondaryBinary), halfword(rotatedBy))

	// \xref[rotated_][\&[rotated] primitive]
	prg.primitive(strNumber( /* "slanted" */ 394), halfword(secondaryBinary), halfword(slantedBy))

	// \xref[slanted_][\&[slanted] primitive]
	prg.primitive(strNumber( /* "scaled" */ 395), halfword(secondaryBinary), halfword(scaledBy))

	// \xref[scaled_][\&[scaled] primitive]
	prg.primitive(strNumber( /* "shifted" */ 396), halfword(secondaryBinary), halfword(shiftedBy))

	// \xref[shifted_][\&[shifted] primitive]
	prg.primitive(strNumber( /* "transformed" */ 397), halfword(secondaryBinary), halfword(transformedBy))

	// \xref[transformed_][\&[transformed] primitive]
	prg.primitive(strNumber( /* "xscaled" */ 398), halfword(secondaryBinary), halfword(xScaled))

	// \xref[x_scaled_][\&[xscaled] primitive]
	prg.primitive(strNumber( /* "yscaled" */ 399), halfword(secondaryBinary), halfword(yScaled))

	// \xref[y_scaled_][\&[yscaled] primitive]
	prg.primitive(strNumber( /* "zscaled" */ 400), halfword(secondaryBinary), halfword(zScaled))

	// \xref[z_scaled_][\&[zscaled] primitive]
	prg.primitive(strNumber( /* "intersectiontimes" */ 401), halfword(tertiaryBinary), halfword(intersect))

	// \xref[intersection_times_][\&[intersectiontimes] primitive]

	prg.primitive(strNumber( /* "numeric" */ 341), halfword(typeName), halfword(numericType))

	// \xref[numeric_][\&[numeric] primitive]
	prg.primitive(strNumber( /* "string" */ 327), halfword(typeName), halfword(stringType))

	// \xref[string_][\&[string] primitive]
	prg.primitive(strNumber( /* "boolean" */ 325), halfword(typeName), halfword(booleanType))

	// \xref[boolean_][\&[boolean] primitive]
	prg.primitive(strNumber( /* "path" */ 332), halfword(typeName), halfword(pathType))

	// \xref[path_][\&[path] primitive]
	prg.primitive(strNumber( /* "pen" */ 329), halfword(typeName), halfword(penType))

	// \xref[pen_][\&[pen] primitive]
	prg.primitive(strNumber( /* "picture" */ 334), halfword(typeName), halfword(pictureType))

	// \xref[picture_][\&[picture] primitive]
	prg.primitive(strNumber( /* "transform" */ 336), halfword(typeName), halfword(transformType))

	// \xref[transform_][\&[transform] primitive]
	prg.primitive(strNumber( /* "pair" */ 337), halfword(typeName), halfword(pairType))

	// \xref[pair_][\&[pair] primitive]

	prg.primitive(strNumber( /* "end" */ 912), halfword(stop), halfword(0))

	// \xref[end_][\&[end] primitive]
	prg.primitive(strNumber( /* "dump" */ 913), halfword(stop), halfword(1))

	// \xref[dump_][\&[dump] primitive]

	prg.primitive(strNumber( /* "batchmode" */ 273), halfword(modeCommand), halfword(batchMode))
	// \xref[batch_mode_][\&[batchmode] primitive]
	prg.primitive(strNumber( /* "nonstopmode" */ 274), halfword(modeCommand), halfword(nonstopMode))
	// \xref[nonstop_mode_][\&[nonstopmode] primitive]
	prg.primitive(strNumber( /* "scrollmode" */ 275), halfword(modeCommand), halfword(scrollMode))
	// \xref[scroll_mode_][\&[scrollmode] primitive]
	prg.primitive(strNumber( /* "errorstopmode" */ 919), halfword(modeCommand), halfword(errorStopMode))
	// \xref[error_stop_mode_][\&[errorstopmode] primitive]

	prg.primitive(strNumber( /* "inner" */ 920), halfword(protectionCommand), halfword(0))

	// \xref[inner_][\&[inner] primitive]
	prg.primitive(strNumber( /* "outer" */ 921), halfword(protectionCommand), halfword(1))

	// \xref[outer_][\&[outer] primitive]

	prg.primitive(strNumber( /* "showtoken" */ 935), halfword(showCommand), halfword(showTokenCode))

	// \xref[show_token_][\&[showtoken] primitive]
	prg.primitive(strNumber( /* "showstats" */ 936), halfword(showCommand), halfword(showStatsCode))

	// \xref[show_stats_][\&[showstats] primitive]
	prg.primitive(strNumber( /* "show" */ 937), halfword(showCommand), halfword(showCode))

	// \xref[show_][\&[show] primitive]
	prg.primitive(strNumber( /* "showvariable" */ 938), halfword(showCommand), halfword(showVarCode))

	// \xref[show_var_][\&[showvariable] primitive]
	prg.primitive(strNumber( /* "showdependencies" */ 939), halfword(showCommand), halfword(showDependenciesCode))

	// \xref[show_dependencies_][\&[showdependencies] primitive]

	prg.primitive(strNumber( /* "contour" */ 956), halfword(thingToAdd), halfword(contourCode))

	// \xref[contour_][\&[contour] primitive]
	prg.primitive(strNumber( /* "doublepath" */ 957), halfword(thingToAdd), halfword(doublePathCode))

	// \xref[double_path_][\&[doublepath] primitive]
	prg.primitive(strNumber( /* "also" */ 958), halfword(thingToAdd), halfword(alsoCode))

	// \xref[also_][\&[also] primitive]
	prg.primitive(strNumber( /* "withpen" */ 959), halfword(withOption), halfword(penType))

	// \xref[with_pen_][\&[withpen] primitive]
	prg.primitive(strNumber( /* "withweight" */ 960), halfword(withOption), halfword(known))

	// \xref[with_weight_][\&[withweight] primitive]
	prg.primitive(strNumber( /* "dropping" */ 961), halfword(cullOp), halfword(dropCode))

	// \xref[dropping_][\&[dropping] primitive]
	prg.primitive(strNumber( /* "keeping" */ 962), halfword(cullOp), halfword(keepCode))

	// \xref[keeping_][\&[keeping] primitive]

	prg.primitive(strNumber( /* "message" */ 992), halfword(messageCommand), halfword(messageCode))

	// \xref[message_][\&[message] primitive]
	prg.primitive(strNumber( /* "errmessage" */ 993), halfword(messageCommand), halfword(errMessageCode))

	// \xref[err_message_][\&[errmessage] primitive]
	prg.primitive(strNumber( /* "errhelp" */ 994), halfword(messageCommand), halfword(errHelpCode))

	// \xref[err_help_][\&[errhelp] primitive]

	prg.primitive(strNumber( /* "charlist" */ 1004), halfword(tfmCommand), halfword(charListCode))

	// \xref[char_list_][\&[charlist] primitive]
	prg.primitive(strNumber( /* "ligtable" */ 1005), halfword(tfmCommand), halfword(ligTableCode))

	// \xref[lig_table_][\&[ligtable] primitive]
	prg.primitive(strNumber( /* "extensible" */ 1006), halfword(tfmCommand), halfword(extensibleCode))

	// \xref[extensible_][\&[extensible] primitive]
	prg.primitive(strNumber( /* "headerbyte" */ 1007), halfword(tfmCommand), halfword(headerByteCode))

	// \xref[header_byte_][\&[headerbyte] primitive]
	prg.primitive(strNumber( /* "fontdimen" */ 1008), halfword(tfmCommand), halfword(fontDimenCode))

	// \xref[font_dimen_][\&[fontdimen] primitive]

	prg.primitive(strNumber( /* "=:" */ 1026), halfword(ligKernToken), halfword(0))
	// \xref[=:_][\.[=:] primitive]
	prg.primitive(strNumber( /* "=:|" */ 1027), halfword(ligKernToken), halfword(1))
	// \xref[=:/_][\.[=:\char'174] primitive]
	prg.primitive(strNumber( /* "=:|>" */ 1028), halfword(ligKernToken), halfword(5))
	// \xref[=:/>_][\.[=:\char'174>] primitive]
	prg.primitive(strNumber( /* "|=:" */ 1029), halfword(ligKernToken), halfword(2))
	// \xref[=:/_][\.[\char'174=:] primitive]
	prg.primitive(strNumber( /* "|=:>" */ 1030), halfword(ligKernToken), halfword(6))
	// \xref[=:/>_][\.[\char'174=:>] primitive]
	prg.primitive(strNumber( /* "|=:|" */ 1031), halfword(ligKernToken), halfword(3))
	// \xref[=:/_][\.[\char'174=:\char'174] primitive]
	prg.primitive(strNumber( /* "|=:|>" */ 1032), halfword(ligKernToken), halfword(7))
	// \xref[=:/>_][\.[\char'174=:\char'174>] primitive]
	prg.primitive(strNumber( /* "|=:|>>" */ 1033), halfword(ligKernToken), halfword(11))
	// \xref[=:/>_][\.[\char'174=:\char'174>>] primitive]
	prg.primitive(strNumber( /* "kern" */ 1034), halfword(ligKernToken), halfword(128))
	// \xref[kern_][\&[kern] primitive]

	prg.primitive(strNumber( /* "special" */ 1058), halfword(specialCommand), halfword(stringType))

	// \xref[special_][\&[special] primitive]
	prg.primitive(strNumber( /* "numspecial" */ 1059), halfword(specialCommand), halfword(known))

	// \xref[num_special_][\&[numspecial] primitive]

}

func (prg *prg) initTab() { // initialize other tables
	var (
		k int32 // all-purpose index
	)
	prg.rover = uint16(memMin + 3 + 10 + 2 + 2 + 2 + 2 + 1 + 1) // initialize the dynamic memory
	*(*prg.mem[prg.rover].hh()).rh() = 65535
	*(*prg.mem[prg.rover].hh()).lh() = 1000 // which is a 1000-word available node
	*(*prg.mem[int32(prg.rover)+1].hh()).lh() = prg.rover
	*(*prg.mem[int32(prg.rover)+1].hh()).rh() = prg.rover

	prg.loMemMax = uint16(int32(prg.rover) + 1000)
	*(*prg.mem[prg.loMemMax].hh()).rh() = uint16(memMin)
	*(*prg.mem[prg.loMemMax].hh()).lh() = uint16(memMin)

	for ii := int32(3000 - 2); ii <= 3000; ii++ {
		k = ii
		_ = k
		prg.mem[k] = prg.mem[prg.loMemMax]
	} // clear list heads
	prg.avail = uint16(memMin)
	prg.memEnd = 3000
	prg.hiMemMin = uint16(3000 - 2) // initialize the one-word memory
	prg.varUsed = memMin + 3 + 10 + 2 + 2 + 2 + 2 + 1 + 1 - memMin
	prg.dynUsed = 3000 + 1 - int32(prg.hiMemMin)
	// initialize statistics

	prg.intName[tracingTitles-1] = /* "tracingtitles" */ 410
	prg.intName[tracingEquations-1] = /* "tracingequations" */ 411
	prg.intName[tracingCapsules-1] = /* "tracingcapsules" */ 412
	prg.intName[tracingChoices-1] = /* "tracingchoices" */ 413
	prg.intName[tracingSpecs-1] = /* "tracingspecs" */ 414
	prg.intName[tracingPens-1] = /* "tracingpens" */ 415
	prg.intName[tracingCommands-1] = /* "tracingcommands" */ 416
	prg.intName[tracingRestores-1] = /* "tracingrestores" */ 417
	prg.intName[tracingMacros-1] = /* "tracingmacros" */ 418
	prg.intName[tracingEdges-1] = /* "tracingedges" */ 419
	prg.intName[tracingOutput-1] = /* "tracingoutput" */ 420
	prg.intName[tracingStats-1] = /* "tracingstats" */ 421
	prg.intName[tracingOnline-1] = /* "tracingonline" */ 422
	prg.intName[year-1] = /* "year" */ 423
	prg.intName[month-1] = /* "month" */ 424
	prg.intName[day-1] = /* "day" */ 425
	prg.intName[time-1] = /* "time" */ 426
	prg.intName[charCode-1] = /* "charcode" */ 427
	prg.intName[charExt-1] = /* "charext" */ 428
	prg.intName[charWd-1] = /* "charwd" */ 429
	prg.intName[charHt-1] = /* "charht" */ 430
	prg.intName[charDp-1] = /* "chardp" */ 431
	prg.intName[charIc-1] = /* "charic" */ 432
	prg.intName[charDx-1] = /* "chardx" */ 433
	prg.intName[charDy-1] = /* "chardy" */ 434
	prg.intName[designSize-1] = /* "designsize" */ 435
	prg.intName[hppp-1] = /* "hppp" */ 436
	prg.intName[vppp-1] = /* "vppp" */ 437
	prg.intName[xOffset-1] = /* "xoffset" */ 438
	prg.intName[yOffset-1] = /* "yoffset" */ 439
	prg.intName[pausing-1] = /* "pausing" */ 440
	prg.intName[showstopping-1] = /* "showstopping" */ 441
	prg.intName[fontmaking-1] = /* "fontmaking" */ 442
	prg.intName[proofing-1] = /* "proofing" */ 443
	prg.intName[smoothing-1] = /* "smoothing" */ 444
	prg.intName[autorounding-1] = /* "autorounding" */ 445
	prg.intName[granularity-1] = /* "granularity" */ 446
	prg.intName[fillin-1] = /* "fillin" */ 447
	prg.intName[turningCheck-1] = /* "turningcheck" */ 448
	prg.intName[warningCheck-1] = /* "warningcheck" */ 449
	prg.intName[boundaryChar-1] = /* "boundarychar" */ 450

	prg.hashUsed = uint16(hashBase + hashSize) // nothing is used
	prg.stCount = 0

	*prg.hash[hashBase+hashSize+11-1].rh() = 451
	*prg.hash[hashBase+hashSize+9-1].rh() = 452
	*prg.hash[hashBase+hashSize+10-1].rh() = 453
	*prg.hash[hashBase+hashSize+8-1].rh() = 454
	*prg.hash[hashBase+hashSize+7-1].rh() = 455

	*prg.hash[hashBase+hashSize+6-1].rh() = ';'
	*prg.hash[hashBase+hashSize+5-1].rh() = ':'
	*prg.hash[hashBase+hashSize+4-1].rh() = '/'
	*prg.hash[hashBase+hashSize+3-1].rh() = '['
	*prg.hash[hashBase+hashSize+2-1].rh() = ')'

	*prg.hash[hashBase+hashSize-1].rh() = 456

	*prg.eqtb[hashBase+hashSize+2-1].lh() = uint16(rightDelimiter)

	*(*prg.mem[memMin+3+10+2+2+2].hh()).lh() = uint16(hashBase + hashSize + 12 + 1)
	*(*prg.mem[memMin+3+10+2+2+2].hh()).rh() = uint16(memMin)

	*(*prg.mem[3000].hh()).lh() = 65535 // |link(sentinel)=null|

	*(*prg.mem[memMin+3].hh()).lh() = uint16(memMin)
	*(*prg.mem[memMin+3].hh()).rh() = uint16(memMin)

	*(*prg.mem[memMin+3+1].hh()).lh() = 1
	*(*prg.mem[memMin+3+1].hh()).rh() = uint16(memMin)
	for ii := int32(memMin + 3 + 2); ii <= memMin+3+8; ii++ {
		k = ii
		_ = k
		prg.mem[k] = prg.mem[memMin+3+1]
	}
	*prg.mem[memMin+3+9].int() = 0

	*(*prg.mem[memMin].hh()).rh() = uint16(memMin)
	*(*prg.mem[memMin].hh()).lh() = uint16(memMin)

	*prg.mem[memMin+1].int() = 0
	*prg.mem[memMin+2].int() = 0

	prg.serialNo = 0
	*(*prg.mem[memMin+3+10].hh()).rh() = uint16(memMin + 3 + 10)
	*(*prg.mem[memMin+3+10+1].hh()).lh() = uint16(memMin + 3 + 10)
	*(*prg.mem[memMin+3+10].hh()).lh() = uint16(memMin)
	*(*prg.mem[memMin+3+10+1].hh()).rh() = uint16(memMin)

	*(*prg.mem[memMin+3+10+2+2+2+2].hh()).b1() = byte(root)
	*(*prg.mem[memMin+3+10+2+2+2+2].hh()).rh() = uint16(hashBase + hashSize + 11)
	*prg.eqtb[hashBase+hashSize+11-1].rh() = uint16(memMin + 3 + 10 + 2 + 2 + 2 + 2)
	*prg.eqtb[hashBase+hashSize+11-1].lh() = uint16(tagToken)

	*prg.eqtb[hashBase+hashSize+1-1].lh() = uint16(repeatLoop + outerTag)
	*prg.hash[hashBase+hashSize+1-1].rh() = 734

	*(*prg.mem[memMin+3+10+2+2].hh()).b1() = byte(capsule)

	*prg.mem[memMin+3+10+2+2+2+1].int() = 010000000000

	*prg.mem[memMin+3+10+2+1].int() = 0
	*(*prg.mem[memMin+3+10+2].hh()).lh() = 0

	prg.baseIdent = /* " (INIMF)" */ 1067

}

//  procedure debug_help; [routine to display various things]
// label breakpoint,exit;
// var  k, l, m, n:integer;
// begin  ;
//    while true do  begin    ;
//   print_nl(["debug # (-1 to exit):"=]1081);  ;
// [ \xref[debug \#] ]
//   read(term_in,m);
//   if m<0 then  goto exit
//   else if m=0 then
//     begin goto breakpoint;
//  [go to every declared label at least once]
//     breakpoint: m:=0; ['BREAKPOINT']
//
//     end
//   else  begin read(term_in,n);
//     case m of
//     [ \4 ]
// [ Numbered cases for |debug_help| ]
// 1: print_word(mem[n]); [display |mem[n]| in all forms]
// 2: print_int( mem[ n].hh.lh );
// 3: print_int( mem[ n].hh.rh );
// 4: begin print_int( eqtb[ n].lh ); print_char([":"=]58); print_int( eqtb[ n].rh );
//   end;
// 5: print_variable_name(n);
// 6: print_int(internal[n]);
// 7: do_show_dependencies;
// 9: show_token_list(n,mem_min ,100000,0);
// 10: slow_print(n);
// 11: check_mem(n>0); [check wellformedness; print new busy locations if |n>0|]
// 12: search_mem(n); [look for pointers to |n|]
// 13: begin read(term_in,l); print_cmd_mod(n,l);
//   end;
// 14: for k:=0 to n do print(buffer[k]);
// 15: panicking:=not panicking;
//
//
//      else  print(["?"=]63)
//      end ;
//     end;
//   end;
// exit:end;
// [  ]

// 1204.

// tangle:pos ../../mf.web:22852:3:

// Now this is really it: \MF\ starts and ends here.
//
// The initial test involving |ready_already| should be deleted if the
// \PASCAL\ runtime system is smart enough to detect such a ``mistake.''
// \xref[system dependencies]
func (prg *prg) main() {
	defer func() {
		if prg.baseFile != nil {
			prg.baseFile.Close()
		}
		if prg.gfFile != nil {
			prg.gfFile.Close()
		}
		if prg.logFile != nil {
			prg.logFile.Close()
		}
		if prg.poolFile != nil {
			prg.poolFile.Close()
		}
		if prg.stderr != nil {
			prg.stderr.Close()
		}
		if prg.stdin != nil {
			prg.stdin.Close()
		}
		if prg.stdout != nil {
			prg.stdout.Close()
		}
		if prg.termIn != nil {
			prg.termIn.Close()
		}
		if prg.termOut != nil {
			prg.termOut.Close()
		}
		if prg.tfmFile != nil {
			prg.tfmFile.Close()
		}
	}()

	prg.history = byte(fatalErrorStop) // in case we quit during initialization
	prg.termOut.Rewrite("TTY:", "/O")  // open the terminal for output
	if prg.readyAlready == 314159 {
		goto startOfMf
	}

	// Check the “constant” values...
	prg.bad = 0
	if halfErrorLine < 30 || halfErrorLine > errorLine-15 {
		prg.bad = 1
	}
	if maxPrintLine < 60 {
		prg.bad = 2
	}
	if gfBufSize%8 != 0 {
		prg.bad = 3
	}
	if memMin+1100 > 3000 {
		prg.bad = 4
	}
	if hashPrime > hashSize {
		prg.bad = 5
	}
	if headerSize%4 != 0 {
		prg.bad = 6
	}
	if ligTableSize < 255 || ligTableSize > 32510 {
		prg.bad = 7
	}

	if memMax != 3000 {
		prg.bad = 10
	}

	if memMax < 3000 {
		prg.bad = 10
	}
	if minQuarterword > 0 || maxQuarterword < 127 {
		prg.bad = 11
	}
	if 0 > 0 || 65535 < 32767 {
		prg.bad = 12
	}
	if minQuarterword < 0 || maxQuarterword > 65535 {
		prg.bad = 13
	}
	if memMin < 0 || memMax >= 65535 {
		prg.bad = 14
	}
	if maxStrings > 65535 {
		prg.bad = 15
	}
	if bufSize > 65535 {
		prg.bad = 16
	}
	if maxQuarterword-minQuarterword < 255 || 65535-0 < 65535 {
		prg.bad = 17
	}

	if hashBase+hashSize+12+maxInternal > 65535 {
		prg.bad = 21
	}

	if hashBase+hashSize+12+1+paramSize+paramSize+paramSize > 65535 {
		prg.bad = 22
	}

	if 15*moveIncrement > bistackSize {
		prg.bad = 31
	}

	if intPackets+17*intIncrement > bistackSize {
		prg.bad = 32
	}

	if baseDefaultLength > fileNameSize {
		prg.bad = 41
	}

	if prg.bad > 0 {
		prg.termOut.Writeln("Ouch---my internal constants have been clobbered!",
			"---case ", prg.bad, knuth.WriteWidth(1))
		// \xref[Ouch...clobbered]

		// \xref[Ouch...clobbered]
		goto finalEnd
	}
	prg.initialize() // set global variables to their starting values
	if !prg.getStringsStarted() {
		goto finalEnd
	}
	prg.initTab()  // initialize the tables
	prg.initPrim() // call |primitive| for each primitive
	prg.initStrPtr = prg.strPtr
	prg.initPoolPtr = prg.poolPtr

	prg.maxStrPtr = prg.strPtr
	prg.maxPoolPtr = prg.poolPtr
	prg.fixDateAndTime()

	prg.readyAlready = 314159

startOfMf:
	prg.selector = byte(termOnly)
	prg.tally = 0
	prg.termOffset = 0
	prg.fileOffset = 0

	prg.termOut.Write("This is METAFONT, Version 2.71828182 (TRAP)")
	if int32(prg.baseIdent) == 0 {
		prg.termOut.Writeln(" (no base preloaded)")
	} else {
		prg.slowPrint(int32(prg.baseIdent))
		prg.printLn()
	}

	prg.jobName = 0
	prg.logOpened = false

	prg.outputFileName = 0

	// Get the first line of input and prepare to start
	{
		{
			prg.inputPtr = 0
			prg.maxInStack = 0
			prg.inOpen = 0
			prg.openParens = 0
			prg.maxBufStack = 0
			prg.paramPtr = 0
			prg.maxParamStack = 0
			prg.first = 1
			prg.curInput.startField = 1
			prg.curInput.indexField = 0
			prg.line = 0
			prg.curInput.nameField = 0
			prg.forceEof = false
			if !prg.initTerminal() {
				goto finalEnd
			}
			prg.curInput.limitField = prg.last
			prg.first = uint16(int32(prg.last) + 1) // |init_terminal| has set |loc| and |last|
		}

		prg.scannerStatus = byte(normal)

		if int32(prg.baseIdent) == 0 || int32(prg.buffer[prg.curInput.locField]) == '&' {
			if int32(prg.baseIdent) != 0 {
				prg.initialize()
			} // erase preloaded base
			if !prg.openBaseFile() {
				goto finalEnd
			}
			if !prg.loadBaseFile() {
				prg.wClose(prg.baseFile)
				goto finalEnd
			}
			prg.wClose(prg.baseFile)
			for int32(prg.curInput.locField) < int32(prg.curInput.limitField) && int32(prg.buffer[prg.curInput.locField]) == ' ' {
				prg.curInput.locField = uint16(int32(prg.curInput.locField) + 1)
			}
		}
		prg.buffer[prg.curInput.limitField] = '%'

		prg.fixDateAndTime()
		prg.initRandoms(prg.sysTime + prg.sysDay*0200000)

		// Initialize the print |selector|...
		if int32(prg.interaction) == batchMode {
			prg.selector = byte(noPrint)
		} else {
			prg.selector = byte(termOnly)
		}
		if int32(prg.curInput.locField) < int32(prg.curInput.limitField) {
			if int32(prg.buffer[prg.curInput.locField]) != '\\' {
				prg.startInput()
			}
		} // \&[input] assumed
	}
	prg.history = byte(spotless) // ready to go!
	if int32(prg.startSym) > 0 {
		prg.curSym = prg.startSym
		prg.backInput()
	}
	prg.mainControl()  // come to life
	prg.finalCleanup() // prepare for death
	prg.closeFilesAndTerminate()

finalEnd:
	prg.readyAlready = 0
}

// 1214. \[51] System-dependent changes

// tangle:pos ../../mf.web:23125:35:

// This section should be replaced, if necessary, by any special
// modifications of the program
// that are necessary to make \MF\ work at a particular installation.
// It is usually best to design your change file so that all changes to
// previous sections preserve the section numbering; then everybody's version
// will be consistent with the published program. More extensive changes,
// which introduce new sections, can be inserted here; then only the index
// itself will get a new section number.
// \xref[system dependencies]

// 1215. \[52] Index

// tangle:pos ../../mf.web:23136:16:

// Here is where you can find all uses of each identifier in the program,
// with underlined entries pointing to where the identifier was defined.
// If the identifier is only one letter long, however, you get to see only
// the underlined entries. [\sl All references are to section numbers instead of
// page numbers.]
//
// This index also lists error messages and other aspects of the program
// that you might want to look up some day. For example, the entry
// for ``system dependencies'' lists all sections that should receive
// special attention from people who are installing \MF\ in a new
// operating environment. A list of various things that can't happen appears
// under ``this can't happen''.
// Approximately 25 sections are listed under ``inner loop''; these account
// for more than 60\pct! of \MF's running time, exclusive of input and output.