ref: 1e8eb61a3715b12d8bc1cfd866f5bb180f2941f2
dir: /sys/src/cmd/cc/pswt.c/
#include "gc.h" int swcmp(const void *a1, const void *a2) { C1 *p1, *p2; p1 = (C1*)a1; p2 = (C1*)a2; if(p1->val < p2->val) return -1; return p1->val > p2->val; } void doswit(Node *n) { Case *c; C1 *q, *iq, *iqh, *iql; long def, nc, i, j, isv, nh; Prog *hsb; Node *vr[2]; int dup; def = 0; nc = 0; isv = 0; for(c = cases; c->link != C; c = c->link) { if(c->def) { if(def) diag(n, "more than one default in switch"); def = c->label; continue; } isv |= c->isv; nc++; } if(typev[n->type->etype]) isv = 1; else if(isv){ warn(n, "32-bit switch expression with 64-bit case constant"); isv = 0; } iq = alloc(nc*sizeof(C1)); q = iq; for(c = cases; c->link != C; c = c->link) { if(c->def) continue; if(c->isv && !isv) continue; /* can never match */ q->label = c->label; if(isv) q->val = c->val; else q->val = (long)c->val; /* cast ensures correct value for 32-bit switch on 64-bit architecture */ q++; } qsort(iq, nc, sizeof(C1), swcmp); if(debug['W']) for(i=0; i<nc; i++) print("case %2ld: = %.8llux\n", i, (vlong)iq[i].val); dup = 0; for(i=0; i<nc-1; i++) if(iq[i].val == iq[i+1].val) { diag(n, "duplicate cases in switch %lld", (vlong)iq[i].val); dup = 1; } if(dup) return; if(def == 0) { def = breakpc; nbreak++; } if(!isv || ewidth[TIND] > ewidth[TLONG] || n->op == OREGISTER) { swit1(iq, nc, def, n); return; } /* * 64-bit case on 32-bit machine: * switch on high-order words, and * in each of those, switch on low-order words */ if(n->op != OREGPAIR) fatal(n, "internal: expected register pair"); if(thechar == '8'){ /* TO DO: need an enquiry function */ vr[0] = n->left; /* low */ vr[1] = n->right; /* high */ }else{ vr[0] = n->right; vr[1] = n->left; } vr[0]->type = types[TLONG]; vr[1]->type = types[TLONG]; gbranch(OGOTO); hsb = p; iqh = alloc(nc*sizeof(C1)); iql = alloc(nc*sizeof(C1)); nh = 0; for(i=0; i<nc;){ iqh[nh].val = iq[i].val >> 32; q = iql; /* iq is sorted, so equal top halves are adjacent */ for(j = i; j < nc; j++){ if((iq[j].val>>32) != iqh[nh].val) break; q->val = (long)iq[j].val; q->label = iq[j].label; q++; } qsort(iql, q-iql, sizeof(C1), swcmp); if(0){for(int k=0; k<(q-iql); k++)print("nh=%ld k=%d h=%#llux l=%#llux lab=%ld\n", nh, k, (vlong)iqh[nh].val, (vlong)iql[k].val, iql[k].label);} iqh[nh].label = pc; nh++; swit1(iql, q-iql, def, vr[0]); i = j; } patch(hsb, pc); if(0){for(int k=0; k<nh; k++)print("k*=%d h=%#llux lab=%ld\n", k, (vlong)iqh[k].val, iqh[k].label);} swit1(iqh, nh, def, vr[1]); } void casf(void) { Case *c; c = alloc(sizeof(*c)); c->link = cases; cases = c; } long outlstring(Rune *s, long n) { char buf[sizeof(Rune)]; int c, i; long r; if(suppress) return nstring; while(nstring % sizeof buf) outstring("", 1); r = nstring; while(n > 0) { c = *s++; if(align(0, types[TCHAR], Aarg1)) { for(i = sizeof buf; i > 0; c >>= 8) buf[--i] = c; } else { for(i = 0; i < sizeof buf; c >>= 8) buf[i++] = c; } outstring(buf, sizeof buf); n -= sizeof buf; } return r; } void nullwarn(Node *l, Node *r) { warn(Z, "result of operation not used"); if(l != Z) cgen(l, Z); if(r != Z) cgen(r, Z); } void ieeedtod(Ieee *ieee, double native) { double fr, ho, f; int exp; if(native < 0) { ieeedtod(ieee, -native); ieee->h |= 0x80000000L; return; } if(native == 0) { ieee->l = 0; ieee->h = 0; return; } fr = frexp(native, &exp); f = 2097152L; /* shouldnt use fp constants here */ fr = modf(fr*f, &ho); ieee->h = ho; ieee->h &= 0xfffffL; ieee->h |= (exp+1022L) << 20; f = 65536L; fr = modf(fr*f, &ho); ieee->l = ho; ieee->l <<= 16; ieee->l |= (long)(fr*f); }