ggen.go

Documentation: cmd/compile/internal/arm64

     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/ir"
     9  	"cmd/compile/internal/objw"
    10  	"cmd/compile/internal/types"
    11  	"cmd/internal/obj"
    12  	"cmd/internal/obj/arm64"
    13  	"internal/buildcfg"
    14  )
    15  
    16  var darwin = buildcfg.GOOS == "darwin" || buildcfg.GOOS == "ios"
    17  
    18  func padframe(frame int64) int64 {
    19  	// arm64 requires that the frame size (not counting saved FP&LR)
    20  	// be 16 bytes aligned. If not, pad it.
    21  	if frame%16 != 0 {
    22  		frame += 16 - (frame % 16)
    23  	}
    24  	return frame
    25  }
    26  
    27  func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, _ *uint32) *obj.Prog {
    28  	if cnt == 0 {
    29  		return p
    30  	}
    31  	if cnt < int64(4*types.PtrSize) {
    32  		for i := int64(0); i < cnt; i += int64(types.PtrSize) {
    33  			p = pp.Append(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGSP, 8+off+i)
    34  		}
    35  	} else if cnt <= int64(128*types.PtrSize) && !darwin { // darwin ld64 cannot handle BR26 reloc with non-zero addend
    36  		if cnt%(2*int64(types.PtrSize)) != 0 {
    37  			p = pp.Append(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGSP, 8+off)
    38  			off += int64(types.PtrSize)
    39  			cnt -= int64(types.PtrSize)
    40  		}
    41  		p = pp.Append(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REG_R20, 0)
    42  		p = pp.Append(p, arm64.AADD, obj.TYPE_CONST, 0, 8+off, obj.TYPE_REG, arm64.REG_R20, 0)
    43  		p.Reg = arm64.REG_R20
    44  		p = pp.Append(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
    45  		p.To.Name = obj.NAME_EXTERN
    46  		p.To.Sym = ir.Syms.Duffzero
    47  		p.To.Offset = 4 * (64 - cnt/(2*int64(types.PtrSize)))
    48  	} else {
    49  		// Not using REGTMP, so this is async preemptible (async preemption clobbers REGTMP).
    50  		// We are at the function entry, where no register is live, so it is okay to clobber
    51  		// other registers
    52  		const rtmp = arm64.REG_R20
    53  		p = pp.Append(p, arm64.AMOVD, obj.TYPE_CONST, 0, 8+off-8, obj.TYPE_REG, rtmp, 0)
    54  		p = pp.Append(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    55  		p = pp.Append(p, arm64.AADD, obj.TYPE_REG, rtmp, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    56  		p.Reg = arm64.REGRT1
    57  		p = pp.Append(p, arm64.AMOVD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, rtmp, 0)
    58  		p = pp.Append(p, arm64.AADD, obj.TYPE_REG, rtmp, 0, obj.TYPE_REG, arm64.REGRT2, 0)
    59  		p.Reg = arm64.REGRT1
    60  		p = pp.Append(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGRT1, int64(types.PtrSize))
    61  		p.Scond = arm64.C_XPRE
    62  		p1 := p
    63  		p = pp.Append(p, arm64.ACMP, obj.TYPE_REG, arm64.REGRT1, 0, obj.TYPE_NONE, 0, 0)
    64  		p.Reg = arm64.REGRT2
    65  		p = pp.Append(p, arm64.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
    66  		p.To.SetTarget(p1)
    67  	}
    68  
    69  	return p
    70  }
    71  
    72  func ginsnop(pp *objw.Progs) *obj.Prog {
    73  	p := pp.Prog(arm64.AHINT)
    74  	p.From.Type = obj.TYPE_CONST
    75  	return p
    76  }
    77
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