sys/src/cmd/5c/sgen.c

   1 #include "gc.h"
   2
   3 void
   4 noretval(int n)
   5 {
   6
   7         if(n & 1) {
   8                 gins(ANOP, Z, Z);
   9                 p->to.type = D_REG;
  10                 p->to.reg = REGRET;
  11         }
  12         if(n & 2) {
  13                 gins(ANOP, Z, Z);
  14                 p->to.type = D_FREG;
  15                 p->to.reg = FREGRET;
  16         }
  17 }
  18
  19 /*
  20  *      calculate addressability as follows
  21  *              CONST ==> 20            $value
  22  *              NAME ==> 10             name
  23  *              REGISTER ==> 11         register
  24  *              INDREG ==> 12           *[(reg)+offset]
  25  *              &10 ==> 2               $name
  26  *              ADD(2, 20) ==> 2        $name+offset
  27  *              ADD(3, 20) ==> 3        $(reg)+offset
  28  *              &12 ==> 3               $(reg)+offset
  29  *              *11 ==> 11              ??
  30  *              *2 ==> 10               name
  31  *              *3 ==> 12               *(reg)+offset
  32  *      calculate complexity (number of registers)
  33  */
  34 void
  35 xcom(Node *n)
  36 {
  37         Node *l, *r;
  38         int t;
  39
  40         if(n == Z)
  41                 return;
  42         l = n->left;
  43         r = n->right;
  44         n->addable = 0;
  45         n->complex = 0;
  46         switch(n->op) {
  47         case OCONST:
  48                 n->addable = 20;
  49                 return;
  50
  51         case OREGISTER:
  52                 n->addable = 11;
  53                 return;
  54
  55         case OINDREG:
  56                 n->addable = 12;
  57                 return;
  58
  59         case ONAME:
  60                 n->addable = 10;
  61                 return;
  62
  63         case OADDR:
  64                 xcom(l);
  65                 if(l->addable == 10)
  66                         n->addable = 2;
  67                 if(l->addable == 12)
  68                         n->addable = 3;
  69                 break;
  70
  71         case OIND:
  72                 xcom(l);
  73                 if(l->addable == 11)
  74                         n->addable = 12;
  75                 if(l->addable == 3)
  76                         n->addable = 12;
  77                 if(l->addable == 2)
  78                         n->addable = 10;
  79                 break;
  80
  81         case OADD:
  82                 xcom(l);
  83                 xcom(r);
  84                 if(l->addable == 20) {
  85                         if(r->addable == 2)
  86                                 n->addable = 2;
  87                         if(r->addable == 3)
  88                                 n->addable = 3;
  89                 }
  90                 if(r->addable == 20) {
  91                         if(l->addable == 2)
  92                                 n->addable = 2;
  93                         if(l->addable == 3)
  94                                 n->addable = 3;
  95                 }
  96                 break;
  97
  98         case OASLMUL:
  99         case OASMUL:
 100                 xcom(l);
 101                 xcom(r);
 102                 t = vlog(r);
 103                 if(t >= 0) {
 104                         n->op = OASASHL;
 105                         r->vconst = t;
 106                         r->type = types[TINT];
 107                 }
 108                 break;
 109
 110         case OMUL:
 111         case OLMUL:
 112                 xcom(l);
 113                 xcom(r);
 114                 t = vlog(r);
 115                 if(t >= 0) {
 116                         n->op = OASHL;
 117                         r->vconst = t;
 118                         r->type = types[TINT];
 119                 }
 120                 t = vlog(l);
 121                 if(t >= 0) {
 122                         n->op = OASHL;
 123                         n->left = r;
 124                         n->right = l;
 125                         r = l;
 126                         l = n->left;
 127                         r->vconst = t;
 128                         r->type = types[TINT];
 129                 }
 130                 break;
 131
 132         case OASLDIV:
 133                 xcom(l);
 134                 xcom(r);
 135                 t = vlog(r);
 136                 if(t >= 0) {
 137                         n->op = OASLSHR;
 138                         r->vconst = t;
 139                         r->type = types[TINT];
 140                 }
 141                 break;
 142
 143         case OLDIV:
 144                 xcom(l);
 145                 xcom(r);
 146                 t = vlog(r);
 147                 if(t >= 0) {
 148                         n->op = OLSHR;
 149                         r->vconst = t;
 150                         r->type = types[TINT];
 151                 }
 152                 break;
 153
 154         case OASLMOD:
 155                 xcom(l);
 156                 xcom(r);
 157                 t = vlog(r);
 158                 if(t >= 0) {
 159                         n->op = OASAND;
 160                         r->vconst--;
 161                 }
 162                 break;
 163
 164         case OLMOD:
 165                 xcom(l);
 166                 xcom(r);
 167                 t = vlog(r);
 168                 if(t >= 0) {
 169                         n->op = OAND;
 170                         r->vconst--;
 171                 }
 172                 break;
 173
 174         default:
 175                 if(l != Z)
 176                         xcom(l);
 177                 if(r != Z)
 178                         xcom(r);
 179                 break;
 180         }
 181         if(n->addable >= 10)
 182                 return;
 183
 184         if(l != Z)
 185                 n->complex = l->complex;
 186         if(r != Z) {
 187                 if(r->complex == n->complex)
 188                         n->complex = r->complex+1;
 189                 else
 190                 if(r->complex > n->complex)
 191                         n->complex = r->complex;
 192         }
 193         if(n->complex == 0)
 194                 n->complex++;
 195
 196         if(com64(n))
 197                 return;
 198
 199         switch(n->op) {
 200         case OFUNC:
 201                 n->complex = FNX;
 202                 break;
 203
 204         case OADD:
 205         case OXOR:
 206         case OAND:
 207         case OOR:
 208         case OEQ:
 209         case ONE:
 210                 /*
 211                  * immediate operators, make const on right
 212                  */
 213                 if(l->op == OCONST) {
 214                         n->left = r;
 215                         n->right = l;
 216                 }
 217                 break;
 218         }
 219 }