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
}
}
}
// 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)
}
}