github.com/slayercat/go@v0.0.0-20170428012452-c51559813f61/src/cmd/compile/internal/arm64/ggen.go (about)

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package arm64
     6  
     7  import (
     8  	"cmd/compile/internal/gc"
     9  	"cmd/internal/obj"
    10  	"cmd/internal/obj/arm64"
    11  	"cmd/internal/objabi"
    12  )
    13  
    14  var darwin = objabi.GOOS == "darwin"
    15  
    16  func padframe(frame int64) int64 {
    17  	// arm64 requires that the frame size (not counting saved LR)
    18  	// be empty or be 8 mod 16. If not, pad it.
    19  	if frame != 0 && frame%16 != 8 {
    20  		frame += 8
    21  	}
    22  	return frame
    23  }
    24  
    25  func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
    26  	if cnt == 0 {
    27  		return p
    28  	}
    29  	if cnt < int64(4*gc.Widthptr) {
    30  		for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
    31  			p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGSP, 8+off+i)
    32  		}
    33  	} else if cnt <= int64(128*gc.Widthptr) && !darwin { // darwin ld64 cannot handle BR26 reloc with non-zero addend
    34  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    35  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_CONST, 0, 8+off-8, obj.TYPE_REG, arm64.REGRT1, 0)
    36  		p.Reg = arm64.REGRT1
    37  		p = pp.Appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
    38  		p.To.Name = obj.NAME_EXTERN
    39  		p.To.Sym = gc.Duffzero
    40  		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
    41  	} else {
    42  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_CONST, 0, 8+off-8, obj.TYPE_REG, arm64.REGTMP, 0)
    43  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    44  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_REG, arm64.REGTMP, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    45  		p.Reg = arm64.REGRT1
    46  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, arm64.REGTMP, 0)
    47  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_REG, arm64.REGTMP, 0, obj.TYPE_REG, arm64.REGRT2, 0)
    48  		p.Reg = arm64.REGRT1
    49  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGRT1, int64(gc.Widthptr))
    50  		p.Scond = arm64.C_XPRE
    51  		p1 := p
    52  		p = pp.Appendpp(p, arm64.ACMP, obj.TYPE_REG, arm64.REGRT1, 0, obj.TYPE_NONE, 0, 0)
    53  		p.Reg = arm64.REGRT2
    54  		p = pp.Appendpp(p, arm64.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
    55  		gc.Patch(p, p1)
    56  	}
    57  
    58  	return p
    59  }
    60  
    61  func zeroAuto(pp *gc.Progs, n *gc.Node) {
    62  	// Note: this code must not clobber any registers.
    63  	sym := n.Sym.Linksym()
    64  	size := n.Type.Size()
    65  	for i := int64(0); i < size; i += 8 {
    66  		p := pp.Prog(arm64.AMOVD)
    67  		p.From.Type = obj.TYPE_REG
    68  		p.From.Reg = arm64.REGZERO
    69  		p.To.Type = obj.TYPE_MEM
    70  		p.To.Name = obj.NAME_AUTO
    71  		p.To.Reg = arm64.REGSP
    72  		p.To.Offset = n.Xoffset + i
    73  		p.To.Sym = sym
    74  	}
    75  }
    76  
    77  func ginsnop(pp *gc.Progs) {
    78  	p := pp.Prog(arm64.AHINT)
    79  	p.From.Type = obj.TYPE_CONST
    80  }