Golang Addr.Index方法代碼示例

func nacladdr(ctxt *obj.Link, p *obj.Prog, a *obj.Addr) {
	if p.As == ALEAL || p.As == ALEAQ {
		return
	}

	if a.Reg == REG_BP {
		ctxt.Diag("invalid address: %v", p)
		return
	}

	if a.Reg == REG_TLS {
		a.Reg = REG_BP
	}
	if a.Type == obj.TYPE_MEM && a.Name == obj.NAME_NONE {
		switch a.Reg {
		// all ok
		case REG_BP, REG_SP, REG_R15:
			break

		default:
			if a.Index != REG_NONE {
				ctxt.Diag("invalid address %v", p)
			}
			a.Index = a.Reg
			if a.Index != REG_NONE {
				a.Scale = 1
			}
			a.Reg = REG_R15
		}
	}
}

/*
 * substitute s for v in a
 * return failure to substitute
 */
func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int {
	if copyas(a, v) {
		reg := int(int(s.Reg))
		if reg >= x86.REG_AX && reg <= x86.REG_R15 || reg >= x86.REG_X0 && reg <= x86.REG_X0+15 {
			if f != 0 {
				a.Reg = int16(reg)
			}
		}

		return 0
	}

	if regtyp(v) {
		reg := int(int(v.Reg))
		if a.Type == obj.TYPE_MEM && int(a.Reg) == reg {
			if (s.Reg == x86.REG_BP || s.Reg == x86.REG_R13) && a.Index != x86.REG_NONE {
				return 1 /* can't use BP-base with index */
			}
			if f != 0 {
				a.Reg = s.Reg
			}
		}

		//			return 0;
		if int(a.Index) == reg {
			if f != 0 {
				a.Index = s.Reg
			}
			return 0
		}

		return 0
	}

	return 0
}

// registerIndirect parses the general form of a register indirection.
// It is can be (R1), (R2*scale), or (R1)(R2*scale) where R1 may be a simple
// register or register pair R:R or (R, R) or (R+R).
// Or it might be a pseudo-indirection like (FP).
// We are sitting on the opening parenthesis.
func (p *Parser) registerIndirect(a *obj.Addr, prefix rune) {
	p.get('(')
	tok := p.next()
	name := tok.String()
	r1, r2, scale, ok := p.register(name, 0)
	if !ok {
		p.errorf("indirect through non-register %s", tok)
	}
	p.get(')')
	a.Type = obj.TYPE_MEM
	if r1 < 0 {
		// Pseudo-register reference.
		if r2 != 0 {
			p.errorf("cannot use pseudo-register in pair")
			return
		}
		// For SB, SP, and FP, there must be a name here. 0(FP) is not legal.
		if name != "PC" && a.Name == obj.NAME_NONE {
			p.errorf("cannot reference %s without a symbol", name)
		}
		p.setPseudoRegister(a, name, false, prefix)
		return
	}
	a.Reg = r1
	if r2 != 0 {
		// TODO: Consistency in the encoding would be nice here.
		if p.arch.Thechar == '5' || p.arch.Thechar == '7' {
			// Special form
			// ARM: destination register pair (R1, R2).
			// ARM64: register pair (R1, R2) for LDP/STP.
			if prefix != 0 || scale != 0 {
				p.errorf("illegal address mode for register pair")
				return
			}
			a.Type = obj.TYPE_REGREG
			a.Offset = int64(r2)
			// Nothing may follow
			return
		}
		if p.arch.Thechar == '9' {
			// Special form for PPC64: (R1+R2); alias for (R1)(R2*1).
			if prefix != 0 || scale != 0 {
				p.errorf("illegal address mode for register+register")
				return
			}
			a.Type = obj.TYPE_MEM
			a.Scale = 1
			a.Index = r2
			// Nothing may follow.
			return
		}
	}
	if r2 != 0 {
		p.errorf("indirect through register pair")
	}
	if prefix == '$' {
		a.Type = obj.TYPE_ADDR
	}
	if r1 == arch.RPC && prefix != 0 {
		p.errorf("illegal addressing mode for PC")
	}
	if scale == 0 && p.peek() == '(' {
		// General form (R)(R*scale).
		p.next()
		tok := p.next()
		r1, r2, scale, ok = p.register(tok.String(), 0)
		if !ok {
			p.errorf("indirect through non-register %s", tok)
		}
		if r2 != 0 {
			p.errorf("unimplemented two-register form")
		}
		a.Index = r1
		a.Scale = int16(scale)
		p.get(')')
	} else if scale != 0 {
		// First (R) was missing, all we have is (R*scale).
		a.Reg = 0
		a.Index = r1
		a.Scale = int16(scale)
	}
}

//.........這裏部分代碼省略.........
			x86.AADDW,
			x86.AADDL,
			x86.AADDQ,
			x86.ASUBB,
			x86.ASUBW,
			x86.ASUBL,
			x86.ASUBQ,
			x86.AANDB,
			x86.AANDW,
			x86.AANDL,
			x86.AANDQ,
			x86.AORB,
			x86.AORW,
			x86.AORL,
			x86.AORQ,
			x86.AXORB,
			x86.AXORW,
			x86.AXORL,
			x86.AXORQ,
			x86.AINCB,
			x86.AINCW,
			x86.AINCL,
			x86.AINCQ,
			x86.ADECB,
			x86.ADECW,
			x86.ADECL,
			x86.ADECQ,
			x86.AMOVB,
			x86.AMOVW,
			x86.AMOVL,
			x86.AMOVQ:
			break
		}

		cleani += 2
		reg := &clean[cleani-1]
		reg1 := &clean[cleani-2]
		reg.Op = gc.OEMPTY
		reg1.Op = gc.OEMPTY
		gc.Naddr(a, n)
		return true

	case gc.ODOT,
		gc.ODOTPTR:
		cleani += 2
		reg := &clean[cleani-1]
		reg1 := &clean[cleani-2]
		reg.Op = gc.OEMPTY
		reg1.Op = gc.OEMPTY
		var nn *gc.Node
		var oary [10]int64
		o := gc.Dotoffset(n, oary[:], &nn)
		if nn == nil {
			sudoclean()
			return false
		}

		if nn.Addable && o == 1 && oary[0] >= 0 {
			// directly addressable set of DOTs
			n1 := *nn

			n1.Type = n.Type
			n1.Xoffset += oary[0]
			gc.Naddr(a, &n1)
			return true
		}

		gc.Regalloc(reg, gc.Types[gc.Tptr], nil)
		n1 := *reg
		n1.Op = gc.OINDREG
		if oary[0] >= 0 {
			gc.Agen(nn, reg)
			n1.Xoffset = oary[0]
		} else {
			gc.Cgen(nn, reg)
			gc.Cgen_checknil(reg)
			n1.Xoffset = -(oary[0] + 1)
		}

		for i := 1; i < o; i++ {
			if oary[i] >= 0 {
				gc.Fatalf("can't happen")
			}
			gins(movptr, &n1, reg)
			gc.Cgen_checknil(reg)
			n1.Xoffset = -(oary[i] + 1)
		}

		a.Type = obj.TYPE_NONE
		a.Index = obj.TYPE_NONE
		gc.Fixlargeoffset(&n1)
		gc.Naddr(a, &n1)
		return true

	case gc.OINDEX:
		return false
	}

	return false
}