github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpn/x86/pentium/hamdist.asm (about)

     1  dnl  Intel P5 mpn_hamdist -- mpn hamming distance.
     2  
     3  dnl  Copyright 2001, 2002, 2014, 2015 Free Software Foundation, Inc.
     4  
     5  dnl  This file is part of the GNU MP Library.
     6  dnl
     7  dnl  The GNU MP Library is free software; you can redistribute it and/or modify
     8  dnl  it under the terms of either:
     9  dnl
    10  dnl    * the GNU Lesser General Public License as published by the Free
    11  dnl      Software Foundation; either version 3 of the License, or (at your
    12  dnl      option) any later version.
    13  dnl
    14  dnl  or
    15  dnl
    16  dnl    * the GNU General Public License as published by the Free Software
    17  dnl      Foundation; either version 2 of the License, or (at your option) any
    18  dnl      later version.
    19  dnl
    20  dnl  or both in parallel, as here.
    21  dnl
    22  dnl  The GNU MP Library is distributed in the hope that it will be useful, but
    23  dnl  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    24  dnl  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    25  dnl  for more details.
    26  dnl
    27  dnl  You should have received copies of the GNU General Public License and the
    28  dnl  GNU Lesser General Public License along with the GNU MP Library.  If not,
    29  dnl  see https://www.gnu.org/licenses/.
    30  
    31  include(`../config.m4')
    32  
    33  
    34  C P5: 14.0 cycles/limb
    35  
    36  
    37  C unsigned long mpn_hamdist (mp_srcptr src1, mp_srcptr src2, mp_size_t size);
    38  C
    39  C It might be possible to shave 1 cycle from the loop, and hence 2
    40  C cycles/limb.  The xorb is taking 2 cycles, but a separate load and xor
    41  C would be 1, if the right schedule could be found (not found so far).
    42  C Wanting to avoid potential cache bank clashes makes it tricky.
    43  
    44  C The slightly strange quoting here helps the renaming done by tune/many.pl.
    45  deflit(TABLE_NAME,
    46  m4_assert_defined(`GSYM_PREFIX')
    47  GSYM_PREFIX`'mpn_popcount``'_table')
    48  
    49  C FIXME: referencing popcount.asm's table is incorrect as it hurt incremental
    50  C linking.
    51  
    52  defframe(PARAM_SIZE,12)
    53  defframe(PARAM_SRC2, 8)
    54  defframe(PARAM_SRC1, 4)
    55  
    56  	TEXT
    57  	ALIGN(8)
    58  
    59  PROLOGUE(mpn_hamdist)
    60  deflit(`FRAME',0)
    61  
    62  	movl	PARAM_SIZE, %ecx
    63  	pushl	%esi	FRAME_pushl()
    64  
    65  	shll	%ecx		C size in byte pairs
    66  	pushl	%edi	FRAME_pushl()
    67  
    68  ifdef(`PIC',`
    69  	pushl	%ebx	FRAME_pushl()
    70  	pushl	%ebp	FRAME_pushl()
    71  ifdef(`DARWIN',`
    72  	movl	PARAM_SRC1, %esi
    73  	movl	PARAM_SRC2, %edi
    74  	LEA(	TABLE_NAME, %ebp)
    75  	xorl	%ebx, %ebx	C byte
    76  	xorl	%edx, %edx	C byte
    77  	xorl	%eax, %eax	C total
    78  ',`
    79  	call	L(here)	FRAME_pushl()
    80  L(here):
    81  	movl	PARAM_SRC1, %esi
    82  	popl	%ebp	FRAME_popl()
    83  
    84  	movl	PARAM_SRC2, %edi
    85  	addl	$_GLOBAL_OFFSET_TABLE_+[.-L(here)], %ebp
    86  
    87  	xorl	%ebx, %ebx	C byte
    88  	xorl	%edx, %edx	C byte
    89  
    90  	movl	TABLE_NAME@GOT(%ebp), %ebp
    91  	xorl	%eax, %eax	C total
    92  ')
    93  define(TABLE,`(%ebp,$1)')
    94  ',`
    95  dnl non-PIC
    96  	movl	PARAM_SRC1, %esi
    97  	movl	PARAM_SRC2, %edi
    98  
    99  	xorl	%eax, %eax	C total
   100  	pushl	%ebx	FRAME_pushl()
   101  
   102  	xorl	%edx, %edx	C byte
   103  	xorl	%ebx, %ebx	C byte
   104  
   105  define(TABLE,`TABLE_NAME($1)')
   106  ')
   107  
   108  
   109  	C The nop after the xorb seems necessary.  Although a movb might be
   110  	C expected to go down the V pipe in the second cycle of the xorb, it
   111  	C doesn't and costs an extra 2 cycles.
   112  L(top):
   113  	C eax	total
   114  	C ebx	byte
   115  	C ecx	counter, 2*size to 2
   116  	C edx	byte
   117  	C esi	src1
   118  	C edi	src2
   119  	C ebp	[PIC] table
   120  
   121  	addl	%ebx, %eax
   122  	movb	-1(%esi,%ecx,2), %bl
   123  
   124  	addl	%edx, %eax
   125  	movb	-1(%edi,%ecx,2), %dl
   126  
   127  	xorb	%dl, %bl
   128  	movb	-2(%esi,%ecx,2), %dl
   129  
   130  	xorb	-2(%edi,%ecx,2), %dl
   131  	nop
   132  
   133  	movb	TABLE(%ebx), %bl
   134  	decl	%ecx
   135  
   136  	movb	TABLE(%edx), %dl
   137  	jnz	L(top)
   138  
   139  
   140  ifdef(`PIC',`
   141  	popl	%ebp
   142  ')
   143  	addl	%ebx, %eax
   144  	popl	%ebx
   145  
   146  	addl	%edx, %eax
   147  	popl	%edi
   148  
   149  	popl	%esi
   150  
   151  	ret
   152  
   153  EPILOGUE()
   154  ASM_END()