Source file src/pkg/cmd/compile/internal/arm/ggen.go

     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 arm
     6	
     7	import (
     8		"cmd/compile/internal/gc"
     9		"cmd/internal/obj"
    10		"cmd/internal/obj/arm"
    11	)
    12	
    13	func zerorange(pp *gc.Progs, p *obj.Prog, off, cnt int64, r0 *uint32) *obj.Prog {
    14		if cnt == 0 {
    15			return p
    16		}
    17		if *r0 == 0 {
    18			p = pp.Appendpp(p, arm.AMOVW, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, arm.REG_R0, 0)
    19			*r0 = 1
    20		}
    21	
    22		if cnt < int64(4*gc.Widthptr) {
    23			for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
    24				p = pp.Appendpp(p, arm.AMOVW, obj.TYPE_REG, arm.REG_R0, 0, obj.TYPE_MEM, arm.REGSP, 4+off+i)
    25			}
    26		} else if !gc.Nacl && (cnt <= int64(128*gc.Widthptr)) {
    27			p = pp.Appendpp(p, arm.AADD, obj.TYPE_CONST, 0, 4+off, obj.TYPE_REG, arm.REG_R1, 0)
    28			p.Reg = arm.REGSP
    29			p = pp.Appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
    30			p.To.Name = obj.NAME_EXTERN
    31			p.To.Sym = gc.Duffzero
    32			p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
    33		} else {
    34			p = pp.Appendpp(p, arm.AADD, obj.TYPE_CONST, 0, 4+off, obj.TYPE_REG, arm.REG_R1, 0)
    35			p.Reg = arm.REGSP
    36			p = pp.Appendpp(p, arm.AADD, obj.TYPE_CONST, 0, cnt, obj.TYPE_REG, arm.REG_R2, 0)
    37			p.Reg = arm.REG_R1
    38			p = pp.Appendpp(p, arm.AMOVW, obj.TYPE_REG, arm.REG_R0, 0, obj.TYPE_MEM, arm.REG_R1, 4)
    39			p1 := p
    40			p.Scond |= arm.C_PBIT
    41			p = pp.Appendpp(p, arm.ACMP, obj.TYPE_REG, arm.REG_R1, 0, obj.TYPE_NONE, 0, 0)
    42			p.Reg = arm.REG_R2
    43			p = pp.Appendpp(p, arm.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
    44			gc.Patch(p, p1)
    45		}
    46	
    47		return p
    48	}
    49	
    50	func zeroAuto(pp *gc.Progs, n *gc.Node) {
    51		// Note: this code must not clobber any registers.
    52		sym := n.Sym.Linksym()
    53		size := n.Type.Size()
    54		p := pp.Prog(arm.AMOVW)
    55		p.From.Type = obj.TYPE_CONST
    56		p.From.Offset = 0
    57		p.To.Type = obj.TYPE_REG
    58		p.To.Reg = arm.REGTMP
    59		for i := int64(0); i < size; i += 4 {
    60			p := pp.Prog(arm.AMOVW)
    61			p.From.Type = obj.TYPE_REG
    62			p.From.Reg = arm.REGTMP
    63			p.To.Type = obj.TYPE_MEM
    64			p.To.Name = obj.NAME_AUTO
    65			p.To.Reg = arm.REGSP
    66			p.To.Offset = n.Xoffset + i
    67			p.To.Sym = sym
    68		}
    69	}
    70	
    71	func ginsnop(pp *gc.Progs) *obj.Prog {
    72		p := pp.Prog(arm.AAND)
    73		p.From.Type = obj.TYPE_REG
    74		p.From.Reg = arm.REG_R0
    75		p.To.Type = obj.TYPE_REG
    76		p.To.Reg = arm.REG_R0
    77		p.Scond = arm.C_SCOND_EQ
    78		return p
    79	}
    80	

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