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fix fp subtractions on amd64

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The stashing of constants in gas.c was also
changed to support 16-bytes constants.
This commit is contained in:
Quentin Carbonneaux 2017-06-06 18:06:34 -04:00
parent 9908ae067a
commit 64c79edda0
5 changed files with 60 additions and 46 deletions
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22
amd64/emit.c
View file

@ -350,6 +350,11 @@ Next:
goto Next;
}
static void *negmask[4] = {
[Ks] = (uint32_t[4]){ 0x80000000 },
[Kd] = (uint64_t[2]){ 0x8000000000000000 },
};
static void
emitins(Ins i, Fn *fn, FILE *f)
{
@ -398,16 +403,25 @@ emitins(Ins i, Fn *fn, FILE *f)
goto Table;
case Osub:
/* we have to use the negation trick to handle
* some 3-address substractions */
* some 3-address subtractions */
if (req(i.to, i.arg[1])) {
emitf("neg%k %=", &i, fn, f);
if (KBASE(i.cls) == 0)
emitf("neg%k %=", &i, fn, f);
else
fprintf(f,
"\txorp%c %sfp%d(%%rip), %%%s\n",
"xxsd"[i.cls],
gasloc,
gasstash(negmask[i.cls], 16),
regtoa(i.to.val, SLong)
);
emitf("add%k %0, %=", &i, fn, f);
break;
}
goto Table;
case Odiv:
/* adjust the instruction when the conversion to
* a 2-address division is impossible */
/* use xmm15 to adjust the instruction when the
* conversion to 2-address in emitf() would fail */
if (req(i.to, i.arg[1])) {
i.arg[1] = TMP(XMM0+15);
emitf("mov%k %=, %1", &i, fn, f);

2
amd64/isel.c
View file

@ -80,7 +80,7 @@ fixarg(Ref *r, int k, int op, Fn *fn)
memset(&a, 0, sizeof a);
a.offset.type = CAddr;
a.offset.local = 1;
n = gasstashfp(fn->con[r0.val].bits.i, KWIDE(k));
n = gasstash(&fn->con[r0.val].bits, KWIDE(k) ? 8 : 4);
sprintf(buf, "fp%d", n);
a.offset.label = intern(buf);
fn->mem[fn->nmem-1] = a;