Golang Prog.Scond方法代碼示例

// Called after regopt and peep have run.
// Expand CHECKNIL pseudo-op into actual nil pointer check.
func expandchecks(firstp *obj.Prog) {
	var reg int
	var p1 *obj.Prog

	for p := firstp; p != nil; p = p.Link {
		if p.As != obj.ACHECKNIL {
			continue
		}
		if gc.Debug_checknil != 0 && p.Lineno > 1 { // p->lineno==1 in generated wrappers
			gc.Warnl(p.Lineno, "generated nil check")
		}
		if p.From.Type != obj.TYPE_REG {
			gc.Fatalf("invalid nil check %v", p)
		}
		reg = int(p.From.Reg)

		// check is
		//	CMP arg, $0
		//	MOV.EQ arg, 0(arg)
		p1 = gc.Ctxt.NewProg()

		gc.Clearp(p1)
		p1.Link = p.Link
		p.Link = p1
		p1.Lineno = p.Lineno
		p1.Pc = 9999
		p1.As = arm.AMOVW
		p1.From.Type = obj.TYPE_REG
		p1.From.Reg = int16(reg)
		p1.To.Type = obj.TYPE_MEM
		p1.To.Reg = int16(reg)
		p1.To.Offset = 0
		p1.Scond = arm.C_SCOND_EQ
		p.As = arm.ACMP
		p.From.Type = obj.TYPE_CONST
		p.From.Reg = 0
		p.From.Offset = 0
		p.Reg = int16(reg)
	}
}

func zerorange(p *obj.Prog, frame int64, lo int64, hi int64, r0 *uint32) *obj.Prog {
	cnt := hi - lo
	if cnt == 0 {
		return p
	}
	if *r0 == 0 {
		p = appendpp(p, arm.AMOVW, obj.TYPE_CONST, 0, 0, obj.TYPE_REG, arm.REG_R0, 0)
		*r0 = 1
	}

	if cnt < int64(4*gc.Widthptr) {
		for i := int64(0); i < cnt; i += int64(gc.Widthptr) {
			p = appendpp(p, arm.AMOVW, obj.TYPE_REG, arm.REG_R0, 0, obj.TYPE_MEM, arm.REGSP, int32(4+frame+lo+i))
		}
	} else if !gc.Nacl && (cnt <= int64(128*gc.Widthptr)) {
		p = appendpp(p, arm.AADD, obj.TYPE_CONST, 0, int32(4+frame+lo), obj.TYPE_REG, arm.REG_R1, 0)
		p.Reg = arm.REGSP
		p = appendpp(p, obj.ADUFFZERO, obj.TYPE_NONE, 0, 0, obj.TYPE_MEM, 0, 0)
		f := gc.Sysfunc("duffzero")
		gc.Naddr(&p.To, f)
		gc.Afunclit(&p.To, f)
		p.To.Offset = 4 * (128 - cnt/int64(gc.Widthptr))
	} else {
		p = appendpp(p, arm.AADD, obj.TYPE_CONST, 0, int32(4+frame+lo), obj.TYPE_REG, arm.REG_R1, 0)
		p.Reg = arm.REGSP
		p = appendpp(p, arm.AADD, obj.TYPE_CONST, 0, int32(cnt), obj.TYPE_REG, arm.REG_R2, 0)
		p.Reg = arm.REG_R1
		p = appendpp(p, arm.AMOVW, obj.TYPE_REG, arm.REG_R0, 0, obj.TYPE_MEM, arm.REG_R1, 4)
		p1 := p
		p.Scond |= arm.C_PBIT
		p = appendpp(p, arm.ACMP, obj.TYPE_REG, arm.REG_R1, 0, obj.TYPE_NONE, 0, 0)
		p.Reg = arm.REG_R2
		p = appendpp(p, arm.ABNE, obj.TYPE_NONE, 0, 0, obj.TYPE_BRANCH, 0, 0)
		gc.Patch(p, p1)
	}

	return p
}

func stacksplit(ctxt *obj.Link, p *obj.Prog, framesize int32) *obj.Prog {
	// MOVW			g_stackguard(g), R1
	p = obj.Appendp(ctxt, p)

	p.As = AMOVW
	p.From.Type = obj.TYPE_MEM
	p.From.Reg = REGG
	p.From.Offset = 2 * int64(ctxt.Arch.PtrSize) // G.stackguard0
	if ctxt.Cursym.Cfunc {
		p.From.Offset = 3 * int64(ctxt.Arch.PtrSize) // G.stackguard1
	}
	p.To.Type = obj.TYPE_REG
	p.To.Reg = REG_R1

	if framesize <= obj.StackSmall {
		// small stack: SP < stackguard
		//	CMP	stackguard, SP
		p = obj.Appendp(ctxt, p)

		p.As = ACMP
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_R1
		p.Reg = REGSP
	} else if framesize <= obj.StackBig {
		// large stack: SP-framesize < stackguard-StackSmall
		//	MOVW $-framesize(SP), R2
		//	CMP stackguard, R2
		p = obj.Appendp(ctxt, p)

		p.As = AMOVW
		p.From.Type = obj.TYPE_ADDR
		p.From.Reg = REGSP
		p.From.Offset = int64(-framesize)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_R2

		p = obj.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_R1
		p.Reg = REG_R2
	} else {
		// Such a large stack we need to protect against wraparound
		// if SP is close to zero.
		//	SP-stackguard+StackGuard < framesize + (StackGuard-StackSmall)
		// The +StackGuard on both sides is required to keep the left side positive:
		// SP is allowed to be slightly below stackguard. See stack.h.
		//	CMP $StackPreempt, R1
		//	MOVW.NE $StackGuard(SP), R2
		//	SUB.NE R1, R2
		//	MOVW.NE $(framesize+(StackGuard-StackSmall)), R3
		//	CMP.NE R3, R2
		p = obj.Appendp(ctxt, p)

		p.As = ACMP
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = int64(uint32(obj.StackPreempt & (1<<32 - 1)))
		p.Reg = REG_R1

		p = obj.Appendp(ctxt, p)
		p.As = AMOVW
		p.From.Type = obj.TYPE_ADDR
		p.From.Reg = REGSP
		p.From.Offset = obj.StackGuard
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_R2
		p.Scond = C_SCOND_NE

		p = obj.Appendp(ctxt, p)
		p.As = ASUB
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_R1
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_R2
		p.Scond = C_SCOND_NE

		p = obj.Appendp(ctxt, p)
		p.As = AMOVW
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = int64(framesize) + (obj.StackGuard - obj.StackSmall)
		p.To.Type = obj.TYPE_REG
		p.To.Reg = REG_R3
		p.Scond = C_SCOND_NE

		p = obj.Appendp(ctxt, p)
		p.As = ACMP
		p.From.Type = obj.TYPE_REG
		p.From.Reg = REG_R3
		p.Reg = REG_R2
		p.Scond = C_SCOND_NE
	}

	// BLS call-to-morestack
	bls := obj.Appendp(ctxt, p)
	bls.As = ABLS
	bls.To.Type = obj.TYPE_BRANCH

	var last *obj.Prog
	for last = ctxt.Cursym.Text; last.Link != nil; last = last.Link {
	}
//.........這裏部分代碼省略.........

/*
 * attempt to generate 64-bit
 *	res = n
 * return 1 on success, 0 if op not handled.
 */
func cgen64(n *gc.Node, res *gc.Node) {
	if res.Op != gc.OINDREG && res.Op != gc.ONAME {
		gc.Dump("n", n)
		gc.Dump("res", res)
		gc.Fatalf("cgen64 %v of %v", n.Op, res.Op)
	}

	l := n.Left
	var t1 gc.Node
	if !l.Addable {
		gc.Tempname(&t1, l.Type)
		gc.Cgen(l, &t1)
		l = &t1
	}

	var hi1 gc.Node
	var lo1 gc.Node
	split64(l, &lo1, &hi1)
	switch n.Op {
	default:
		gc.Fatalf("cgen64 %v", n.Op)

	case gc.OMINUS:
		var lo2 gc.Node
		var hi2 gc.Node
		split64(res, &lo2, &hi2)

		gc.Regalloc(&t1, lo1.Type, nil)
		var al gc.Node
		gc.Regalloc(&al, lo1.Type, nil)
		var ah gc.Node
		gc.Regalloc(&ah, hi1.Type, nil)

		gins(arm.AMOVW, &lo1, &al)
		gins(arm.AMOVW, &hi1, &ah)

		gmove(ncon(0), &t1)
		p1 := gins(arm.ASUB, &al, &t1)
		p1.Scond |= arm.C_SBIT
		gins(arm.AMOVW, &t1, &lo2)

		gmove(ncon(0), &t1)
		gins(arm.ASBC, &ah, &t1)
		gins(arm.AMOVW, &t1, &hi2)

		gc.Regfree(&t1)
		gc.Regfree(&al)
		gc.Regfree(&ah)
		splitclean()
		splitclean()
		return

	case gc.OCOM:
		gc.Regalloc(&t1, lo1.Type, nil)
		gmove(ncon(^uint32(0)), &t1)

		var lo2 gc.Node
		var hi2 gc.Node
		split64(res, &lo2, &hi2)
		var n1 gc.Node
		gc.Regalloc(&n1, lo1.Type, nil)

		gins(arm.AMOVW, &lo1, &n1)
		gins(arm.AEOR, &t1, &n1)
		gins(arm.AMOVW, &n1, &lo2)

		gins(arm.AMOVW, &hi1, &n1)
		gins(arm.AEOR, &t1, &n1)
		gins(arm.AMOVW, &n1, &hi2)

		gc.Regfree(&t1)
		gc.Regfree(&n1)
		splitclean()
		splitclean()
		return

		// binary operators.
	// common setup below.
	case gc.OADD,
		gc.OSUB,
		gc.OMUL,
		gc.OLSH,
		gc.ORSH,
		gc.OAND,
		gc.OOR,
		gc.OXOR,
		gc.OLROT:
		break
	}

	// setup for binary operators
	r := n.Right

	if r != nil && !r.Addable {
		var t2 gc.Node
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........
				aoffset = 0xF0
			}
			if cursym.Text.Mark&LEAF != 0 {
				cursym.Leaf = true
				if ctxt.Autosize == 0 {
					break
				}
				aoffset = 0
			}

			q = p
			if ctxt.Autosize > aoffset {
				q = ctxt.NewProg()
				q.As = ASUB
				q.Lineno = p.Lineno
				q.From.Type = obj.TYPE_CONST
				q.From.Offset = int64(ctxt.Autosize) - int64(aoffset)
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REGSP
				q.Spadj = int32(q.From.Offset)
				q.Link = p.Link
				p.Link = q
				if cursym.Text.Mark&LEAF != 0 {
					break
				}
			}

			q1 = ctxt.NewProg()
			q1.As = AMOVD
			q1.Lineno = p.Lineno
			q1.From.Type = obj.TYPE_REG
			q1.From.Reg = REGLINK
			q1.To.Type = obj.TYPE_MEM
			q1.Scond = C_XPRE
			q1.To.Offset = int64(-aoffset)
			q1.To.Reg = REGSP
			q1.Link = q.Link
			q1.Spadj = aoffset
			q.Link = q1

			if cursym.Text.From3.Offset&obj.WRAPPER != 0 {
				// if(g->panic != nil && g->panic->argp == FP) g->panic->argp = bottom-of-frame
				//
				//	MOV g_panic(g), R1
				//	CMP ZR, R1
				//	BEQ end
				//	MOV panic_argp(R1), R2
				//	ADD $(autosize+8), RSP, R3
				//	CMP R2, R3
				//	BNE end
				//	ADD $8, RSP, R4
				//	MOVD R4, panic_argp(R1)
				// end:
				//	NOP
				//
				// The NOP is needed to give the jumps somewhere to land.
				// It is a liblink NOP, not a ARM64 NOP: it encodes to 0 instruction bytes.
				q = q1

				q = obj.Appendp(ctxt, q)
				q.As = AMOVD
				q.From.Type = obj.TYPE_MEM
				q.From.Reg = REGG
				q.From.Offset = 4 * int64(ctxt.Arch.PtrSize) // G.panic
				q.To.Type = obj.TYPE_REG
				q.To.Reg = REG_R1

func clearfat(nl *gc.Node) {
	/* clear a fat object */
	if gc.Debug['g'] != 0 {
		gc.Dump("\nclearfat", nl)
	}

	w := uint32(nl.Type.Width)

	// Avoid taking the address for simple enough types.
	if gc.Componentgen(nil, nl) {
		return
	}

	c := w % 4 // bytes
	q := w / 4 // quads

	if nl.Type.Align < 4 {
		q = 0
		c = w
	}

	var r0 gc.Node
	r0.Op = gc.OREGISTER

	r0.Reg = arm.REG_R0
	var r1 gc.Node
	r1.Op = gc.OREGISTER
	r1.Reg = arm.REG_R1
	var dst gc.Node
	gc.Regalloc(&dst, gc.Types[gc.Tptr], &r1)
	gc.Agen(nl, &dst)
	var nc gc.Node
	gc.Nodconst(&nc, gc.Types[gc.TUINT32], 0)
	var nz gc.Node
	gc.Regalloc(&nz, gc.Types[gc.TUINT32], &r0)
	gc.Cgen(&nc, &nz)

	if q > 128 {
		var end gc.Node
		gc.Regalloc(&end, gc.Types[gc.Tptr], nil)
		p := gins(arm.AMOVW, &dst, &end)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = int64(q) * 4

		p = gins(arm.AMOVW, &nz, &dst)
		p.To.Type = obj.TYPE_MEM
		p.To.Offset = 4
		p.Scond |= arm.C_PBIT
		pl := p

		p = gins(arm.ACMP, &dst, nil)
		raddr(&end, p)
		gc.Patch(gc.Gbranch(arm.ABNE, nil, 0), pl)

		gc.Regfree(&end)
	} else if q >= 4 && !gc.Nacl {
		f := gc.Sysfunc("duffzero")
		p := gins(obj.ADUFFZERO, nil, f)
		gc.Afunclit(&p.To, f)

		// 4 and 128 = magic constants: see ../../runtime/asm_arm.s
		p.To.Offset = 4 * (128 - int64(q))
	} else {
		var p *obj.Prog
		for q > 0 {
			p = gins(arm.AMOVW, &nz, &dst)
			p.To.Type = obj.TYPE_MEM
			p.To.Offset = 4
			p.Scond |= arm.C_PBIT

			//print("1. %v\n", p);
			q--
		}
	}

	if c > 4 {
		// Loop to zero unaligned memory.
		var end gc.Node
		gc.Regalloc(&end, gc.Types[gc.Tptr], nil)
		p := gins(arm.AMOVW, &dst, &end)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = int64(c)

		p = gins(arm.AMOVB, &nz, &dst)
		p.To.Type = obj.TYPE_MEM
		p.To.Offset = 1
		p.Scond |= arm.C_PBIT
		pl := p

		p = gins(arm.ACMP, &dst, nil)
		raddr(&end, p)
		gc.Patch(gc.Gbranch(arm.ABNE, nil, 0), pl)

		gc.Regfree(&end)
		c = 0
	}
	var p *obj.Prog
	for c > 0 {
		p = gins(arm.AMOVB, &nz, &dst)
		p.To.Type = obj.TYPE_MEM
//.........這裏部分代碼省略.........

/*
 * generate shift according to op, one of:
 *	res = nl << nr
 *	res = nl >> nr
 */
func cgen_shift(op gc.Op, bounded bool, nl *gc.Node, nr *gc.Node, res *gc.Node) {
	if nl.Type.Width > 4 {
		gc.Fatalf("cgen_shift %v", nl.Type)
	}

	w := int(nl.Type.Width * 8)

	if op == gc.OLROT {
		v := nr.Int64()
		var n1 gc.Node
		gc.Regalloc(&n1, nl.Type, res)
		if w == 32 {
			gc.Cgen(nl, &n1)
			gshift(arm.AMOVW, &n1, arm.SHIFT_RR, int32(w)-int32(v), &n1)
		} else {
			var n2 gc.Node
			gc.Regalloc(&n2, nl.Type, nil)
			gc.Cgen(nl, &n2)
			gshift(arm.AMOVW, &n2, arm.SHIFT_LL, int32(v), &n1)
			gshift(arm.AORR, &n2, arm.SHIFT_LR, int32(w)-int32(v), &n1)
			gc.Regfree(&n2)

			// Ensure sign/zero-extended result.
			gins(optoas(gc.OAS, nl.Type), &n1, &n1)
		}

		gmove(&n1, res)
		gc.Regfree(&n1)
		return
	}

	if nr.Op == gc.OLITERAL {
		var n1 gc.Node
		gc.Regalloc(&n1, nl.Type, res)
		gc.Cgen(nl, &n1)
		sc := uint64(nr.Int64())
		if sc == 0 {
		} else // nothing to do
		if sc >= uint64(nl.Type.Width*8) {
			if op == gc.ORSH && nl.Type.IsSigned() {
				gshift(arm.AMOVW, &n1, arm.SHIFT_AR, int32(w), &n1)
			} else {
				gins(arm.AEOR, &n1, &n1)
			}
		} else {
			if op == gc.ORSH && nl.Type.IsSigned() {
				gshift(arm.AMOVW, &n1, arm.SHIFT_AR, int32(sc), &n1)
			} else if op == gc.ORSH {
				gshift(arm.AMOVW, &n1, arm.SHIFT_LR, int32(sc), &n1) // OLSH
			} else {
				gshift(arm.AMOVW, &n1, arm.SHIFT_LL, int32(sc), &n1)
			}
		}

		if w < 32 && op == gc.OLSH {
			gins(optoas(gc.OAS, nl.Type), &n1, &n1)
		}
		gmove(&n1, res)
		gc.Regfree(&n1)
		return
	}

	tr := nr.Type
	var t gc.Node
	var n1 gc.Node
	var n2 gc.Node
	var n3 gc.Node
	if tr.Width > 4 {
		var nt gc.Node
		gc.Tempname(&nt, nr.Type)
		if nl.Ullman >= nr.Ullman {
			gc.Regalloc(&n2, nl.Type, res)
			gc.Cgen(nl, &n2)
			gc.Cgen(nr, &nt)
			n1 = nt
		} else {
			gc.Cgen(nr, &nt)
			gc.Regalloc(&n2, nl.Type, res)
			gc.Cgen(nl, &n2)
		}

		var hi gc.Node
		var lo gc.Node
		split64(&nt, &lo, &hi)
		gc.Regalloc(&n1, gc.Types[gc.TUINT32], nil)
		gc.Regalloc(&n3, gc.Types[gc.TUINT32], nil)
		gmove(&lo, &n1)
		gmove(&hi, &n3)
		splitclean()
		gins(arm.ATST, &n3, nil)
		gc.Nodconst(&t, gc.Types[gc.TUINT32], int64(w))
		p1 := gins(arm.AMOVW, &t, &n1)
		p1.Scond = arm.C_SCOND_NE
		tr = gc.Types[gc.TUINT32]
		gc.Regfree(&n3)
//.........這裏部分代碼省略.........

//.........這裏部分代碼省略.........

		var tmp gc.Node
		gc.Regalloc(&tmp, gc.Types[gc.Tptr], &r0)
		f := gc.Sysfunc("duffcopy")
		p := gins(obj.ADUFFCOPY, nil, f)
		gc.Afunclit(&p.To, f)

		// 8 and 128 = magic constants: see ../../runtime/asm_arm.s
		p.To.Offset = 8 * (128 - int64(c))

		gc.Regfree(&tmp)
		gc.Regfree(&src)
		gc.Regfree(&dst)
		return
	}

	var dst gc.Node
	var src gc.Node
	if n.Ullman >= res.Ullman {
		gc.Agenr(n, &dst, res) // temporarily use dst
		gc.Regalloc(&src, gc.Types[gc.Tptr], nil)
		gins(arm.AMOVW, &dst, &src)
		if res.Op == gc.ONAME {
			gc.Gvardef(res)
		}
		gc.Agen(res, &dst)
	} else {
		if res.Op == gc.ONAME {
			gc.Gvardef(res)
		}
		gc.Agenr(res, &dst, res)
		gc.Agenr(n, &src, nil)
	}

	var tmp gc.Node
	gc.Regalloc(&tmp, gc.Types[gc.TUINT32], nil)

	// set up end marker
	var nend gc.Node

	if c >= 4 {
		gc.Regalloc(&nend, gc.Types[gc.TUINT32], nil)

		p := gins(arm.AMOVW, &src, &nend)
		p.From.Type = obj.TYPE_ADDR
		if dir < 0 {
			p.From.Offset = int64(dir)
		} else {
			p.From.Offset = w
		}
	}

	// move src and dest to the end of block if necessary
	if dir < 0 {
		p := gins(arm.AMOVW, &src, &src)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = w + int64(dir)

		p = gins(arm.AMOVW, &dst, &dst)
		p.From.Type = obj.TYPE_ADDR
		p.From.Offset = w + int64(dir)
	}

	// move
	if c >= 4 {
		p := gins(op, &src, &tmp)
		p.From.Type = obj.TYPE_MEM
		p.From.Offset = int64(dir)
		p.Scond |= arm.C_PBIT
		ploop := p

		p = gins(op, &tmp, &dst)
		p.To.Type = obj.TYPE_MEM
		p.To.Offset = int64(dir)
		p.Scond |= arm.C_PBIT

		p = gins(arm.ACMP, &src, nil)
		raddr(&nend, p)

		gc.Patch(gc.Gbranch(arm.ABNE, nil, 0), ploop)
		gc.Regfree(&nend)
	} else {
		var p *obj.Prog
		for ; c > 0; c-- {
			p = gins(op, &src, &tmp)
			p.From.Type = obj.TYPE_MEM
			p.From.Offset = int64(dir)
			p.Scond |= arm.C_PBIT

			p = gins(op, &tmp, &dst)
			p.To.Type = obj.TYPE_MEM
			p.To.Offset = int64(dir)
			p.Scond |= arm.C_PBIT
		}
	}

	gc.Regfree(&dst)
	gc.Regfree(&src)
	gc.Regfree(&tmp)
}