github.com/sean-/go@v0.0.0-20151219100004-97f854cd7bb6/src/cmd/compile/internal/x86/reg.go (about)

     1  // Derived from Inferno utils/6c/reg.c
     2  // http://code.google.com/p/inferno-os/source/browse/utils/6c/reg.c
     3  //
     4  //	Copyright © 1994-1999 Lucent Technologies Inc.  All rights reserved.
     5  //	Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net)
     6  //	Portions Copyright © 1997-1999 Vita Nuova Limited
     7  //	Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com)
     8  //	Portions Copyright © 2004,2006 Bruce Ellis
     9  //	Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net)
    10  //	Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others
    11  //	Portions Copyright © 2009 The Go Authors.  All rights reserved.
    12  //
    13  // Permission is hereby granted, free of charge, to any person obtaining a copy
    14  // of this software and associated documentation files (the "Software"), to deal
    15  // in the Software without restriction, including without limitation the rights
    16  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    17  // copies of the Software, and to permit persons to whom the Software is
    18  // furnished to do so, subject to the following conditions:
    19  //
    20  // The above copyright notice and this permission notice shall be included in
    21  // all copies or substantial portions of the Software.
    22  //
    23  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    24  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    25  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
    26  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    27  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    28  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    29  // THE SOFTWARE.
    30  
    31  package x86
    32  
    33  import "cmd/internal/obj/x86"
    34  import "cmd/compile/internal/gc"
    35  
    36  const (
    37  	NREGVAR = 16 /* 8 integer + 8 floating */
    38  )
    39  
    40  var regname = []string{
    41  	".ax",
    42  	".cx",
    43  	".dx",
    44  	".bx",
    45  	".sp",
    46  	".bp",
    47  	".si",
    48  	".di",
    49  	".x0",
    50  	".x1",
    51  	".x2",
    52  	".x3",
    53  	".x4",
    54  	".x5",
    55  	".x6",
    56  	".x7",
    57  }
    58  
    59  func regnames(n *int) []string {
    60  	*n = NREGVAR
    61  	return regname
    62  }
    63  
    64  func excludedregs() uint64 {
    65  	if gc.Ctxt.Flag_shared != 0 {
    66  		return RtoB(x86.REG_SP) | RtoB(x86.REG_CX)
    67  	} else {
    68  		return RtoB(x86.REG_SP)
    69  	}
    70  }
    71  
    72  func doregbits(r int) uint64 {
    73  	b := uint64(0)
    74  	if r >= x86.REG_AX && r <= x86.REG_DI {
    75  		b |= RtoB(r)
    76  	} else if r >= x86.REG_AL && r <= x86.REG_BL {
    77  		b |= RtoB(r - x86.REG_AL + x86.REG_AX)
    78  	} else if r >= x86.REG_AH && r <= x86.REG_BH {
    79  		b |= RtoB(r - x86.REG_AH + x86.REG_AX)
    80  	} else if r >= x86.REG_X0 && r <= x86.REG_X0+7 {
    81  		b |= FtoB(r)
    82  	}
    83  	return b
    84  }
    85  
    86  func RtoB(r int) uint64 {
    87  	if r < x86.REG_AX || r > x86.REG_DI {
    88  		return 0
    89  	}
    90  	return 1 << uint(r-x86.REG_AX)
    91  }
    92  
    93  func BtoR(b uint64) int {
    94  	b &= 0xff
    95  	if b == 0 {
    96  		return 0
    97  	}
    98  	return gc.Bitno(b) + x86.REG_AX
    99  }
   100  
   101  func FtoB(f int) uint64 {
   102  	if f < x86.REG_X0 || f > x86.REG_X7 {
   103  		return 0
   104  	}
   105  	return 1 << uint(f-x86.REG_X0+8)
   106  }
   107  
   108  func BtoF(b uint64) int {
   109  	b &= 0xFF00
   110  	if b == 0 {
   111  		return 0
   112  	}
   113  	return gc.Bitno(b) - 8 + x86.REG_X0
   114  }