github.com/goproxy0/go@v0.0.0-20171111080102-49cc0c489d2c/src/cmd/compile/internal/ppc64/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 ppc64
     6  
     7  import (
     8  	"cmd/compile/internal/gc"
     9  	"cmd/internal/obj"
    10  	"cmd/internal/obj/ppc64"
    11  )
    12  
    13  func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
    14  	if cnt == 0 {
    15  		return p
    16  	}
    17  	if cnt < int64(4*gc.Widthptr) {
    18  		for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
    19  			p = pp.Appendpp(p, ppc64.AMOVD, obj.TYPE_REG, ppc64.REGZERO, 0, obj.TYPE_MEM, ppc64.REGSP, gc.Ctxt.FixedFrameSize()+off+i)
    20  		}
    21  	} else if cnt <= int64(128*gc.Widthptr) {
    22  		p = pp.Appendpp(p, ppc64.AADD, obj.TYPE_CONST, 0, gc.Ctxt.FixedFrameSize()+off-8, obj.TYPE_REG, ppc64.REGRT1, 0)
    23  		p.Reg = ppc64.REGSP
    24  		p = pp.Appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
    25  		p.To.Name = obj.NAME_EXTERN
    26  		p.To.Sym = gc.Duffzero
    27  		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
    28  	} else {
    29  		p = pp.Appendpp(p, ppc64.AMOVD, obj.TYPE_CONST, 0, gc.Ctxt.FixedFrameSize()+off-8, obj.TYPE_REG, ppc64.REGTMP, 0)
    30  		p = pp.Appendpp(p, ppc64.AADD, obj.TYPE_REG, ppc64.REGTMP, 0, obj.TYPE_REG, ppc64.REGRT1, 0)
    31  		p.Reg = ppc64.REGSP
    32  		p = pp.Appendpp(p, ppc64.AMOVD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, ppc64.REGTMP, 0)
    33  		p = pp.Appendpp(p, ppc64.AADD, obj.TYPE_REG, ppc64.REGTMP, 0, obj.TYPE_REG, ppc64.REGRT2, 0)
    34  		p.Reg = ppc64.REGRT1
    35  		p = pp.Appendpp(p, ppc64.AMOVDU, obj.TYPE_REG, ppc64.REGZERO, 0, obj.TYPE_MEM, ppc64.REGRT1, int64(gc.Widthptr))
    36  		p1 := p
    37  		p = pp.Appendpp(p, ppc64.ACMP, obj.TYPE_REG, ppc64.REGRT1, 0, obj.TYPE_REG, ppc64.REGRT2, 0)
    38  		p = pp.Appendpp(p, ppc64.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
    39  		gc.Patch(p, p1)
    40  	}
    41  
    42  	return p
    43  }
    44  
    45  func zeroAuto(pp *gc.Progs, n *gc.Node) {
    46  	// Note: this code must not clobber any registers.
    47  	sym := n.Sym.Linksym()
    48  	size := n.Type.Size()
    49  	for i := int64(0); i < size; i += 8 {
    50  		p := pp.Prog(ppc64.AMOVD)
    51  		p.From.Type = obj.TYPE_REG
    52  		p.From.Reg = ppc64.REGZERO
    53  		p.To.Type = obj.TYPE_MEM
    54  		p.To.Name = obj.NAME_AUTO
    55  		p.To.Reg = ppc64.REGSP
    56  		p.To.Offset = n.Xoffset + i
    57  		p.To.Sym = sym
    58  	}
    59  }
    60  
    61  func ginsnop(pp *gc.Progs) {
    62  	p := pp.Prog(ppc64.AOR)
    63  	p.From.Type = obj.TYPE_REG
    64  	p.From.Reg = ppc64.REG_R0
    65  	p.To.Type = obj.TYPE_REG
    66  	p.To.Reg = ppc64.REG_R0
    67  }
    68  
    69  func ginsnop2(pp *gc.Progs) {
    70  	// PPC64 is unusual because TWO nops are required
    71  	// (see gc/cgen.go, gc/plive.go -- copy of comment below)
    72  	//
    73  	// On ppc64, when compiling Go into position
    74  	// independent code on ppc64le we insert an
    75  	// instruction to reload the TOC pointer from the
    76  	// stack as well. See the long comment near
    77  	// jmpdefer in runtime/asm_ppc64.s for why.
    78  	// If the MOVD is not needed, insert a hardware NOP
    79  	// so that the same number of instructions are used
    80  	// on ppc64 in both shared and non-shared modes.
    81  
    82  	ginsnop(pp)
    83  	if gc.Ctxt.Flag_shared {
    84  		p := pp.Prog(ppc64.AMOVD)
    85  		p.From.Type = obj.TYPE_MEM
    86  		p.From.Offset = 24
    87  		p.From.Reg = ppc64.REGSP
    88  		p.To.Type = obj.TYPE_REG
    89  		p.To.Reg = ppc64.REG_R2
    90  	} else {
    91  		ginsnop(pp)
    92  	}
    93  }