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Source file src/cmd/compile/internal/arm64/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/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 FP&LR)
    18  	// be 16 bytes aligned. If not, pad it.
    19  	if frame%16 != 0 {
    20  		frame += 16 - (frame % 16)
    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  		if cnt%(2*int64(gc.Widthptr)) != 0 {
    35  			p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGSP, 8+off)
    36  			off += int64(gc.Widthptr)
    37  			cnt -= int64(gc.Widthptr)
    38  		}
    39  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REG_R20, 0)
    40  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_CONST, 0, 8+off, obj.TYPE_REG, arm64.REG_R20, 0)
    41  		p.Reg = arm64.REG_R20
    42  		p = pp.Appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
    43  		p.To.Name = obj.NAME_EXTERN
    44  		p.To.Sym = gc.Duffzero
    45  		p.To.Offset = 4 * (64 - cnt/(2*int64(gc.Widthptr)))
    46  	} else {
    47  		// Not using REGTMP, so this is async preemptible (async preemption clobbers REGTMP).
    48  		// We are at the function entry, where no register is live, so it is okay to clobber
    49  		// other registers
    50  		const rtmp = arm64.REG_R20
    51  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_CONST, 0, 8+off-8, obj.TYPE_REG, rtmp, 0)
    52  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGSP, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    53  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_REG, rtmp, 0, obj.TYPE_REG, arm64.REGRT1, 0)
    54  		p.Reg = arm64.REGRT1
    55  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, rtmp, 0)
    56  		p = pp.Appendpp(p, arm64.AADD, obj.TYPE_REG, rtmp, 0, obj.TYPE_REG, arm64.REGRT2, 0)
    57  		p.Reg = arm64.REGRT1
    58  		p = pp.Appendpp(p, arm64.AMOVD, obj.TYPE_REG, arm64.REGZERO, 0, obj.TYPE_MEM, arm64.REGRT1, int64(gc.Widthptr))
    59  		p.Scond = arm64.C_XPRE
    60  		p1 := p
    61  		p = pp.Appendpp(p, arm64.ACMP, obj.TYPE_REG, arm64.REGRT1, 0, obj.TYPE_NONE, 0, 0)
    62  		p.Reg = arm64.REGRT2
    63  		p = pp.Appendpp(p, arm64.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
    64  		gc.Patch(p, p1)
    65  	}
    66  
    67  	return p
    68  }
    69  
    70  func ginsnop(pp *gc.Progs) *obj.Prog {
    71  	p := pp.Prog(arm64.AHINT)
    72  	p.From.Type = obj.TYPE_CONST
    73  	return p
    74  }
    75  

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