/* else binary */
void
swit1(C1 *q, int nc, long def, int g, Node *n)
{
C1 *r, *s;
int i, l, m, y;
long v, range;
Prog *sp1, *sp2;
/* note that g and g+1 are not allocated */
if(nc <= N1)
goto linear;
y = 23*nc/100 + 5; /* number of cases needed to make */
if(y < N2) /* direct switch worthwile */
y = N2; /* try to do better than n**2 here */
for(m=nc; m>=y; m--) { /* m is number of cases */
s = q+nc;
r = s-m;
for(l=nc-m; l>=0; l--) { /* l is base of contig cases */
s--;
range = s->val - r->val;
if(range > 0 && range <= N3*m)
goto direct;
r--;
}
}
/*
* divide and conquer
*/
i = nc / 2;
r = q+i;
v = r->val;
/* compare median */
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OLT);
sp1 = p;
gbranch(OGT);
sp2 = p;
gbranch(OGOTO);
patch(p, r->label);
patch(sp1, pc);
swit1(q, i, def, g, n);
patch(sp2, pc);
swit1(r+1, nc-i-1, def, g, n);
return;
direct:
/* compare low bound */
v = r->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OLT);
sp1 = p;
/* compare high bound */
v = s->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g, n, g+1, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OGT);
sp2 = p;
/* switch */
v = r->val;
gpseudo(AMOVW, symstatic, D_R0, 0L);
p->from.offset = nstatic - v*2;
p->from.index = g|I_INDEX1;
p->from.scale = 5;
nextpc();
p->as = ACASEW;
/* table */
for(i=0; i<=range; i++) {
gbranch(OCASE);
if(v == r->val) {
patch(p, r->label);
r++;
} else
patch(p, def);
p->from.type = D_STATIC;
p->from.sym = symstatic;
p->from.offset = nstatic;
nstatic += types[TSHORT]->width;
v++;
}
gbranch(OGOTO);
patch(p, def);
if(r != s+1)
print("smelly direct switch\n");
if(l > 0) {
patch(sp1, pc);
swit1(q, l, def, g, n);
} else
patch(sp1, def);
m += l;
if(m < nc) {
patch(sp2, pc);
swit1(q+m, nc-m, def, g, n);
} else
patch(sp2, def);
return;
linear:
for(i=0; i<nc; i++) {
v = q->val;
if(v >= -128 && v < 128) {
gopcode(OAS, n->type, D_CONST, nodconst(v), g+1, n);
gopcode(OEQ, n->type, g+1, n, g, n);
} else
gopcode(OEQ, n->type, g, n, D_CONST, nodconst(v));
gbranch(OEQ);
patch(p, q->label);
q++;
}
gbranch(OGOTO);
patch(p, def);
}
void
swit2(C1 *q, int nc, int32 def, Node *n)
{
C1 *r;
int i;
int32 v;
Prog *sp;
if(nc >= 3) {
i = (q+nc-1)->val - (q+0)->val;
if(i > 0 && i < nc*2)
goto direct;
}
if(nc < 5) {
for(i=0; i<nc; i++) {
if(debug['W'])
print("case = %.8ux\n", q->val);
gopcode(OEQ, nodconst(q->val), n, Z);
patch(p, q->label);
q++;
}
gbranch(OGOTO);
patch(p, def);
return;
}
i = nc / 2;
r = q+i;
if(debug['W'])
print("case > %.8ux\n", r->val);
gopcode(OGT, nodconst(r->val), n, Z);
sp = p;
gopcode(OEQ, nodconst(r->val), n, Z); /* just gen the B.EQ */
patch(p, r->label);
swit2(q, i, def, n);
if(debug['W'])
print("case < %.8ux\n", r->val);
patch(sp, pc);
swit2(r+1, nc-i-1, def, n);
return;
direct:
v = q->val;
if(v != 0)
gopcode(OSUB, nodconst(v), Z, n);
gopcode(OCASE, nodconst((q+nc-1)->val - v), n, Z);
patch(p, def);
for(i=0; i<nc; i++) {
if(debug['W'])
print("case = %.8ux\n", q->val);
while(q->val != v) {
nextpc();
p->as = ABCASE;
patch(p, def);
v++;
}
nextpc();
p->as = ABCASE;
patch(p, q->label);
q++;
v++;
}
gbranch(OGOTO); /* so that regopt() won't be confused */
patch(p, def);
}
