outbin.c

   1 /* outbin.c     output routines for the Netwide Assembler to produce
   2  *              flat-form binary files
   3  *
   4  * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
   5  * Julian Hall. All rights reserved. The software is
   6  * redistributable under the licence given in the file "Licence"
   7  * distributed in the NASM archive.
   8  */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include "nasm.h"
  14 #include "nasmlib.h"
  15 #include "outform.h"
  16
  17 #ifdef OF_BIN
  18
  19 static FILE *fp;
  20 static efunc error;
  21
  22 static struct Section {
  23     struct SAA *contents;
  24     long length;
  25     long index;
  26 } textsect, datasect;
  27 static long bsslen, bssindex;
  28
  29 static struct Reloc {
  30     struct Reloc *next;
  31     long posn;
  32     long bytes;
  33     long secref;
  34     long secrel;
  35     struct Section *target;
  36 } *relocs, **reloctail;
  37
  38 static int start_point;
  39
  40 static void add_reloc (struct Section *s, long bytes, long secref,
  41                        long secrel) {
  42     struct Reloc *r;
  43
  44     r = *reloctail = nasm_malloc(sizeof(struct Reloc));
  45     reloctail = &r->next;
  46     r->next = NULL;
  47     r->posn = s->length;
  48     r->bytes = bytes;
  49     r->secref = secref;
  50     r->secrel = secrel;
  51     r->target = s;
  52 }
  53
  54 static void bin_init (FILE *afp, efunc errfunc, ldfunc ldef) {
  55     fp = afp;
  56
  57     error = errfunc;
  58     (void) ldef;                       /* placate optimisers */
  59
  60     start_point = 0;                   /* default */
  61     textsect.contents = saa_init(1L);
  62     datasect.contents = saa_init(1L);
  63     textsect.length = datasect.length = 0;
  64     textsect.index = seg_alloc();
  65     datasect.index = seg_alloc();
  66     bsslen = 0;
  67     bssindex = seg_alloc();
  68     relocs = NULL;
  69     reloctail = &relocs;
  70 }
  71
  72 static void bin_cleanup (void) {
  73     struct Reloc *r;
  74     long datapos, dataalign, bsspos;
  75
  76     datapos = (start_point + textsect.length + 3) & ~3;/* align on 4 bytes */
  77     dataalign = datapos - (start_point + textsect.length);
  78
  79     saa_rewind (textsect.contents);
  80     saa_rewind (datasect.contents);
  81
  82     bsspos = (datapos + datasect.length + 3) & ~3;
  83
  84     for (r = relocs; r; r = r->next) {
  85         unsigned char *p, *q, mydata[4];
  86         long l;
  87
  88         saa_fread (r->target->contents, r->posn, mydata, r->bytes);
  89         p = q = mydata;
  90         l = *p++;
  91         l += ((long)*p++) << 8;
  92         if (r->bytes == 4) {
  93             l += ((long)*p++) << 16;
  94             l += ((long)*p++) << 24;
  95         }
  96
  97         if (r->secref == textsect.index)
  98             l += start_point;
  99         else if (r->secref == datasect.index)
 100             l += datapos;
 101         else if (r->secref == bssindex)
 102             l += bsspos;
 103
 104         if (r->secrel == textsect.index)
 105             l -= start_point;
 106         else if (r->secrel == datasect.index)
 107             l -= datapos;
 108         else if (r->secrel == bssindex)
 109             l -= bsspos;
 110
 111         if (r->bytes == 4)
 112             WRITELONG(q, l);
 113         else
 114             WRITESHORT(q, l);
 115         saa_fwrite (r->target->contents, r->posn, mydata, r->bytes);
 116     }
 117     saa_fpwrite (textsect.contents, fp);
 118     if (datasect.length > 0) {
 119         fwrite ("\0\0\0\0", dataalign, 1, fp);
 120         saa_fpwrite (datasect.contents, fp);
 121     }
 122     fclose (fp);
 123     saa_free (textsect.contents);
 124     saa_free (datasect.contents);
 125     while (relocs) {
 126         r = relocs->next;
 127         nasm_free (relocs);
 128         relocs = r;
 129     }
 130 }
 131
 132 static void bin_out (long segto, void *data, unsigned long type,
 133                      long segment, long wrt) {
 134     unsigned char *p, mydata[4];
 135     struct Section *s;
 136     long realbytes;
 137
 138     if (wrt != NO_SEG) {
 139         wrt = NO_SEG;                  /* continue to do _something_ */
 140         error (ERR_NONFATAL, "WRT not supported by binary output format");
 141     }
 142
 143     /*
 144      * handle absolute-assembly (structure definitions)
 145      */
 146     if (segto == NO_SEG) {
 147         if ((type & OUT_TYPMASK) != OUT_RESERVE)
 148             error (ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
 149                    " space");
 150         return;
 151     }
 152
 153     if (segto == bssindex) {           /* BSS */
 154         if ((type & OUT_TYPMASK) != OUT_RESERVE)
 155             error(ERR_WARNING, "attempt to initialise memory in the"
 156                   " BSS section: ignored");
 157         s = NULL;
 158     } else if (segto == textsect.index) {
 159         s = &textsect;
 160     } else if (segto == datasect.index) {
 161         s = &datasect;
 162     } else {
 163         error(ERR_WARNING, "attempt to assemble code in"
 164               " segment %d: defaulting to `.text'", segto);
 165         s = &textsect;
 166     }
 167
 168     if ((type & OUT_TYPMASK) == OUT_ADDRESS) {
 169         if (segment != NO_SEG &&
 170             segment != textsect.index &&
 171             segment != datasect.index &&
 172             segment != bssindex) {
 173             if (segment % 2)
 174                 error(ERR_NONFATAL, "binary output format does not support"
 175                       " segment base references");
 176             else
 177                 error(ERR_NONFATAL, "binary output format does not support"
 178                       " external references");
 179             segment = NO_SEG;
 180         }
 181         if (s) {
 182             if (segment != NO_SEG)
 183                 add_reloc (s, type & OUT_SIZMASK, segment, -1L);
 184             p = mydata;
 185             if ((type & OUT_SIZMASK) == 4)
 186                 WRITELONG (p, *(long *)data);
 187             else
 188                 WRITESHORT (p, *(long *)data);
 189             saa_wbytes (s->contents, mydata, type & OUT_SIZMASK);
 190             s->length += type & OUT_SIZMASK;
 191         } else
 192             bsslen += type & OUT_SIZMASK;
 193     } else if ((type & OUT_TYPMASK) == OUT_RAWDATA) {
 194         type &= OUT_SIZMASK;
 195         p = data;
 196         if (s) {
 197             saa_wbytes (s->contents, data, type);
 198             s->length += type;
 199         } else
 200             bsslen += type;
 201     } else if ((type & OUT_TYPMASK) == OUT_RESERVE) {
 202         if (s) {
 203             error(ERR_WARNING, "uninitialised space declared in"
 204                   " %s section: zeroing",
 205                   (segto == textsect.index ? "code" : "data"));
 206         }
 207         type &= OUT_SIZMASK;
 208         if (s) {
 209             saa_wbytes (s->contents, NULL, type);
 210             s->length += type;
 211         } else
 212             bsslen += type;
 213     } else if ((type & OUT_TYPMASK) == OUT_REL2ADR ||
 214                (type & OUT_TYPMASK) == OUT_REL4ADR) {
 215         realbytes = ((type & OUT_TYPMASK) == OUT_REL4ADR ? 4 : 2);
 216         if (segment != NO_SEG &&
 217             segment != textsect.index &&
 218             segment != datasect.index &&
 219             segment != bssindex) {
 220             if (segment % 2)
 221                 error(ERR_NONFATAL, "binary output format does not support"
 222                       " segment base references");
 223             else
 224                 error(ERR_NONFATAL, "binary output format does not support"
 225                       " external references");
 226             segment = NO_SEG;
 227         }
 228         if (s) {
 229             add_reloc (s, realbytes, segment, segto);
 230             p = mydata;
 231             if (realbytes == 4)
 232                 WRITELONG (p, *(long*)data - realbytes - s->length);
 233             else
 234                 WRITESHORT (p, *(long*)data - realbytes - s->length);
 235             saa_wbytes (s->contents, mydata, realbytes);
 236             s->length += realbytes;
 237         } else
 238             bsslen += realbytes;
 239     }
 240 }
 241
 242 static void bin_deflabel (char *name, long segment, long offset,
 243                           int is_global) {
 244     if (is_global == 2) {
 245         error (ERR_NONFATAL, "binary output format does not support common"
 246                " variables");
 247     }
 248 }
 249
 250 static long bin_secname (char *name, int pass, int *bits) {
 251     /*
 252      * Default is 16 bits.
 253      */
 254     if (!name)
 255         *bits = 16;
 256
 257     if (!name)
 258         return textsect.index;
 259
 260     if (!strcmp(name, ".text"))
 261         return textsect.index;
 262     else if (!strcmp(name, ".data"))
 263         return datasect.index;
 264     else if (!strcmp(name, ".bss"))
 265         return bssindex;
 266     else
 267         return NO_SEG;
 268 }
 269
 270 static long bin_segbase (long segment) {
 271     return segment;
 272 }
 273
 274 static int bin_directive (char *directive, char *value, int pass) {
 275     int rn_error;
 276
 277     if (!strcmp(directive, "org")) {
 278         start_point = readnum (value, &rn_error);
 279         if (rn_error)
 280             error (ERR_NONFATAL, "argument to ORG should be numeric");
 281         return 1;
 282     } else
 283         return 0;
 284 }
 285
 286 static void bin_filename (char *inname, char *outname, efunc error) {
 287     standard_extension (inname, outname, "", error);
 288 }
 289
 290 struct ofmt of_bin = {
 291     "flat-form binary files (e.g. DOS .COM, .SYS)",
 292     "bin",
 293     bin_init,
 294     bin_out,
 295     bin_deflabel,
 296     bin_secname,
 297     bin_segbase,
 298     bin_directive,
 299     bin_filename,
 300     bin_cleanup
 301 };
 302
 303 #endif /* OF_BIN */