gas.c

   1 #include "all.h"
   2
   3
   4 char *gasloc, *gassym;
   5
   6 void
   7 gasemitdat(Dat *d, FILE *f)
   8 {
   9         static int align;
  10         static char *dtoa[] = {
  11                 [DAlign] = ".balign",
  12                 [DB] = "\t.byte",
  13                 [DH] = "\t.short",
  14                 [DW] = "\t.int",
  15                 [DL] = "\t.quad"
  16         };
  17         char *p;
  18
  19         switch (d->type) {
  20         case DStart:
  21                 align = 0;
  22                 fprintf(f, ".data\n");
  23                 break;
  24         case DEnd:
  25                 break;
  26         case DName:
  27                 if (!align)
  28                         fprintf(f, ".balign 8\n");
  29                 p = d->u.str[0] == '"' ? "" : gassym;
  30                 if (d->export)
  31                         fprintf(f, ".globl %s%s\n", p, d->u.str);
  32                 fprintf(f, "%s%s:\n", p, d->u.str);
  33                 break;
  34         case DZ:
  35                 fprintf(f, "\t.fill %"PRId64",1,0\n", d->u.num);
  36                 break;
  37         default:
  38                 if (d->type == DAlign)
  39                         align = 1;
  40
  41                 if (d->isstr) {
  42                         if (d->type != DB)
  43                                 err("strings only supported for 'b' currently");
  44                         fprintf(f, "\t.ascii %s\n", d->u.str);
  45                 }
  46                 else if (d->isref) {
  47                         p = d->u.ref.nam[0] == '"' ? "" : gassym;
  48                         fprintf(f, "%s %s%s%+"PRId64"\n",
  49                                 dtoa[d->type], p, d->u.ref.nam,
  50                                 d->u.ref.off);
  51                 }
  52                 else {
  53                         fprintf(f, "%s %"PRId64"\n",
  54                                 dtoa[d->type], d->u.num);
  55                 }
  56                 break;
  57         }
  58 }
  59
  60 typedef struct Asmbits Asmbits;
  61
  62 struct Asmbits {
  63         char bits[16];
  64         int size;
  65         Asmbits *link;
  66 };
  67
  68 static Asmbits *stash;
  69
  70 int
  71 gasstash(void *bits, int size)
  72 {
  73         Asmbits **pb, *b;
  74         int i;
  75
  76         assert(size == 4 || size == 8 || size == 16);
  77         for (pb=&stash, i=0; (b=*pb); pb=&b->link, i++)
  78                 if (size <= b->size)
  79                 if (memcmp(bits, b->bits, size) == 0)
  80                         return i;
  81         b = emalloc(sizeof *b);
  82         memcpy(b->bits, bits, size);
  83         b->size = size;
  84         b->link = 0;
  85         *pb = b;
  86         return i;
  87 }
  88
  89 void
  90 gasemitfin(FILE *f)
  91 {
  92         Asmbits *b;
  93         char *p;
  94         int sz, i;
  95         double d;
  96
  97         if (!stash)
  98                 return;
  99         fprintf(f, "/* floating point constants */\n.data\n");
 100         for (sz=16; sz>=4; sz/=2)
 101                 for (b=stash, i=0; b; b=b->link, i++) {
 102                         if (b->size == sz) {
 103                                 fprintf(f,
 104                                         ".balign %d\n"
 105                                         "%sfp%d:",
 106                                         sz, gasloc, i
 107                                 );
 108                                 for (p=b->bits; p<&b->bits[sz]; p+=4)
 109                                         fprintf(f, "\n\t.int %"PRId32,
 110                                                 *(int32_t *)p);
 111                                 if (sz <= 8) {
 112                                         if (sz == 4)
 113                                                 d = *(float *)b->bits;
 114                                         else
 115                                                 d = *(double *)b->bits;
 116                                         fprintf(f, " /* %f */\n", d);
 117                                 } else
 118                                         fprintf(f, "\n");
 119                         }
 120                 }
 121         while ((b=stash)) {
 122                 stash = b->link;
 123                 free(b);
 124         }
 125 }