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#include "all.h"
static void
blit(Ref sd[2], int sz, Fn *fn)
{
struct { int st, ld, cls, size; } *p, tbl[] = {
{ Ostorel, Oload, Kl, 8 },
{ Ostorew, Oload, Kw, 4 },
{ Ostoreh, Oloaduh, Kw, 2 },
{ Ostoreb, Oloadub, Kw, 1 }
};
Ref r, r1, ro;
int off, fwd, n;
fwd = sz >= 0;
sz = abs(sz);
off = fwd ? sz : 0;
for (p=tbl; sz; p++)
for (n=p->size; sz>=n; sz-=n) {
off -= fwd ? n : 0;
r = newtmp("blt", Kl, fn);
r1 = newtmp("blt", Kl, fn);
ro = getcon(off, fn);
emit(p->st, 0, R, r, r1);
emit(Oadd, Kl, r1, sd[1], ro);
r1 = newtmp("blt", Kl, fn);
emit(p->ld, p->cls, r, r1, R);
emit(Oadd, Kl, r1, sd[0], ro);
off += fwd ? 0 : n;
}
}
static void
ins(Ins **pi, int *new, Blk *b, Fn *fn)
{
ulong ni;
Ins *i;
i = *pi;
/* simplify more instructions here;
* copy 0 into xor, mul 2^n into shift,
* bit rotations, ... */
switch (i->op) {
case Oblit1:
assert(i > b->ins);
assert((i-1)->op == Oblit0);
if (!*new) {
curi = &insb[NIns];
ni = &b->ins[b->nins] - (i+1);
curi -= ni;
icpy(curi, i+1, ni);
*new = 1;
}
blit((i-1)->arg, rsval(i->arg[0]), fn);
*pi = i-1;
break;
default:
if (*new)
emiti(*i);
break;
}
}
void
simpl(Fn *fn)
{
Blk *b;
Ins *i;
int new;
for (b=fn->start; b; b=b->link) {
new = 0;
for (i=&b->ins[b->nins]; i!=b->ins;) {
--i;
ins(&i, &new, b, fn);
}
if (new) {
b->nins = &insb[NIns] - curi;
idup(&b->ins, curi, b->nins);
}
}
}
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