func oplook(ctxt *obj.Link, p *obj.Prog) *Optab {
if oprange[AOR&obj.AMask].start == nil {
buildop(ctxt)
}
a1 := int(p.Optab)
if a1 != 0 {
return &optab[a1-1:][0]
}
a1 = int(p.From.Class)
if a1 == 0 {
a1 = aclass(ctxt, &p.From) + 1
p.From.Class = int8(a1)
}
a1--
a3 := int(p.To.Class)
if a3 == 0 {
a3 = aclass(ctxt, &p.To) + 1
p.To.Class = int8(a3)
}
a3--
a2 := C_NONE
if p.Reg != 0 {
a2 = C_REG
}
//print("oplook %P %d %d %d\n", p, a1, a2, a3);
r0 := p.As & obj.AMask
o := oprange[r0].start
if o == nil {
o = oprange[r0].stop /* just generate an error */
}
e := oprange[r0].stop
c1 := xcmp[a1][:]
c3 := xcmp[a3][:]
for ; -cap(o) < -cap(e); o = o[1:] {
if int(o[0].a2) == a2 {
if c1[o[0].a1] != 0 {
if c3[o[0].a3] != 0 {
p.Optab = uint16((-cap(o) + cap(optab)) + 1)
return &o[0]
}
}
}
}
ctxt.Diag("illegal combination %v %v %v %v", obj.Aconv(int(p.As)), DRconv(a1), DRconv(a2), DRconv(a3))
prasm(p)
if o == nil {
o = optab
}
return &o[0]
}
func nocache(p *obj.Prog) {
p.Optab = 0
p.From.Class = 0
p.To.Class = 0
}