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