/*
* generate high multiply:
* res = (nl*nr) >> width
*/
func cgen_hmul(nl *gc.Node, nr *gc.Node, res *gc.Node) {
t := nl.Type
a := optoas(gc.OHMUL, t)
if nl.Ullman < nr.Ullman {
tmp := nl
nl = nr
nr = tmp
}
var n1 gc.Node
gc.Cgenr(nl, &n1, res)
var n2 gc.Node
gc.Cgenr(nr, &n2, nil)
var ax gc.Node
gc.Nodreg(&ax, t, x86.REG_AX)
gmove(&n1, &ax)
gins(a, &n2, nil)
gc.Regfree(&n2)
gc.Regfree(&n1)
var dx gc.Node
if t.Width == 1 {
// byte multiply behaves differently.
gc.Nodreg(&ax, t, x86.REG_AH)
gc.Nodreg(&dx, t, x86.REG_DX)
gmove(&ax, &dx)
}
gc.Nodreg(&dx, t, x86.REG_DX)
gmove(&dx, res)
}
/*
* generate high multiply:
* res = (nl*nr) >> width
*/
func cgen_hmul(nl *gc.Node, nr *gc.Node, res *gc.Node) {
// largest ullman on left.
if nl.Ullman < nr.Ullman {
tmp := (*gc.Node)(nl)
nl = nr
nr = tmp
}
t := (*gc.Type)(nl.Type)
w := int(int(t.Width * 8))
var n1 gc.Node
gc.Cgenr(nl, &n1, res)
var n2 gc.Node
gc.Cgenr(nr, &n2, nil)
switch gc.Simtype[t.Etype] {
case gc.TINT8,
gc.TINT16,
gc.TINT32:
gins(optoas(gc.OMUL, t), &n2, &n1)
p := (*obj.Prog)(gins(ppc64.ASRAD, nil, &n1))
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(w)
case gc.TUINT8,
gc.TUINT16,
gc.TUINT32:
gins(optoas(gc.OMUL, t), &n2, &n1)
p := (*obj.Prog)(gins(ppc64.ASRD, nil, &n1))
p.From.Type = obj.TYPE_CONST
p.From.Offset = int64(w)
case gc.TINT64,
gc.TUINT64:
if gc.Issigned[t.Etype] {
gins(ppc64.AMULHD, &n2, &n1)
} else {
gins(ppc64.AMULHDU, &n2, &n1)
}
default:
gc.Fatal("cgen_hmul %v", gc.Tconv(t, 0))
}
gc.Cgen(&n1, res)
gc.Regfree(&n1)
gc.Regfree(&n2)
}
