sys/src/cmd/cc/pswt.c

   1 #include "gc.h"
   2
   3 int
   4 swcmp(const void *a1, const void *a2)
   5 {
   6         C1 *p1, *p2;
   7
   8         p1 = (C1*)a1;
   9         p2 = (C1*)a2;
  10         if(p1->val < p2->val)
  11                 return -1;
  12         return p1->val > p2->val;
  13 }
  14
  15 void
  16 doswit(Node *n)
  17 {
  18         Case *c;
  19         C1 *q, *iq, *iqh, *iql;
  20         long def, nc, i, j, isv, nh;
  21         Prog *hsb;
  22         Node *vr[2];
  23         int dup;
  24
  25         def = 0;
  26         nc = 0;
  27         isv = 0;
  28         for(c = cases; c->link != C; c = c->link) {
  29                 if(c->def) {
  30                         if(def)
  31                                 diag(n, "more than one default in switch");
  32                         def = c->label;
  33                         continue;
  34                 }
  35                 isv |= c->isv;
  36                 nc++;
  37         }
  38         if(typev[n->type->etype])
  39                 isv = 1;
  40         else if(isv){
  41                 warn(n, "32-bit switch expression with 64-bit case constant");
  42                 isv = 0;
  43         }
  44
  45         iq = alloc(nc*sizeof(C1));
  46         q = iq;
  47         for(c = cases; c->link != C; c = c->link) {
  48                 if(c->def)
  49                         continue;
  50                 if(c->isv && !isv)
  51                         continue;       /* can never match */
  52                 q->label = c->label;
  53                 if(isv)
  54                         q->val = c->val;
  55                 else
  56                         q->val = (long)c->val;  /* cast ensures correct value for 32-bit switch on 64-bit architecture */
  57                 q++;
  58         }
  59         qsort(iq, nc, sizeof(C1), swcmp);
  60         if(debug['W'])
  61         for(i=0; i<nc; i++)
  62                 print("case %2ld: = %.8llux\n", i, (vlong)iq[i].val);
  63         dup = 0;
  64         for(i=0; i<nc-1; i++)
  65                 if(iq[i].val == iq[i+1].val) {
  66                         diag(n, "duplicate cases in switch %lld", (vlong)iq[i].val);
  67                         dup = 1;
  68                 }
  69         if(dup)
  70                 return;
  71         if(def == 0) {
  72                 def = breakpc;
  73                 nbreak++;
  74         }
  75         if(!isv || ewidth[TIND] > ewidth[TLONG] || n->op == OREGISTER) {
  76                 swit1(iq, nc, def, n);
  77                 return;
  78         }
  79
  80         /*
  81          * 64-bit case on 32-bit machine:
  82          * switch on high-order words, and
  83          * in each of those, switch on low-order words
  84          */
  85         if(n->op != OREGPAIR)
  86                 fatal(n, "internal: expected register pair");
  87         if(thechar == '8'){     /* TO DO: need an enquiry function */
  88                 vr[0] = n->left;        /* low */
  89                 vr[1] = n->right;       /* high */
  90         }else{
  91                 vr[0] = n->right;
  92                 vr[1] = n->left;
  93         }
  94         vr[0]->type = types[TLONG];
  95         vr[1]->type = types[TLONG];
  96         gbranch(OGOTO);
  97         hsb = p;
  98         iqh = alloc(nc*sizeof(C1));
  99         iql = alloc(nc*sizeof(C1));
 100         nh = 0;
 101         for(i=0; i<nc;){
 102                 iqh[nh].val = iq[i].val >> 32;
 103                 q = iql;
 104                 /* iq is sorted, so equal top halves are adjacent */
 105                 for(j = i; j < nc; j++){
 106                         if((iq[j].val>>32) != iqh[nh].val)
 107                                 break;
 108                         q->val = (long)iq[j].val;
 109                         q->label = iq[j].label;
 110                         q++;
 111                 }
 112                 qsort(iql,  q-iql, sizeof(C1), swcmp);
 113 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);}
 114                 iqh[nh].label = pc;
 115                 nh++;
 116                 swit1(iql, q-iql, def, vr[0]);
 117                 i = j;
 118         }
 119         patch(hsb, pc);
 120 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);}
 121         swit1(iqh, nh, def, vr[1]);
 122 }
 123
 124 void
 125 casf(void)
 126 {
 127         Case *c;
 128
 129         c = alloc(sizeof(*c));
 130         c->link = cases;
 131         cases = c;
 132 }
 133
 134 long
 135 outlstring(Rune *s, long n)
 136 {
 137         char buf[sizeof(Rune)];
 138         int c, i;
 139         long r;
 140
 141         if(suppress)
 142                 return nstring;
 143         while(nstring % sizeof buf)
 144                 outstring("", 1);
 145         r = nstring;
 146         while(n > 0) {
 147                 c = *s++;
 148                 if(align(0, types[TCHAR], Aarg1)) {
 149                         for(i = sizeof buf; i > 0; c >>= 8)
 150                                 buf[--i] = c;
 151                 } else {
 152                         for(i = 0; i < sizeof buf; c >>= 8)
 153                                 buf[i++] = c;
 154                 }
 155                 outstring(buf, sizeof buf);
 156                 n -= sizeof buf;
 157         }
 158         return r;
 159 }
 160
 161 void
 162 nullwarn(Node *l, Node *r)
 163 {
 164         warn(Z, "result of operation not used");
 165         if(l != Z)
 166                 cgen(l, Z);
 167         if(r != Z)
 168                 cgen(r, Z);
 169 }
 170
 171 void
 172 ieeedtod(Ieee *ieee, double native)
 173 {
 174         double fr, ho, f;
 175         int exp;
 176
 177         if(native < 0) {
 178                 ieeedtod(ieee, -native);
 179                 ieee->h |= 0x80000000L;
 180                 return;
 181         }
 182         if(native == 0) {
 183                 ieee->l = 0;
 184                 ieee->h = 0;
 185                 return;
 186         }
 187         fr = frexp(native, &exp);
 188         f = 2097152L;           /* shouldnt use fp constants here */
 189         fr = modf(fr*f, &ho);
 190         ieee->h = ho;
 191         ieee->h &= 0xfffffL;
 192         ieee->h |= (exp+1022L) << 20;
 193         f = 65536L;
 194         fr = modf(fr*f, &ho);
 195         ieee->l = ho;
 196         ieee->l <<= 16;
 197         ieee->l |= (long)(fr*f);
 198 }