output/outas86.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 1996-2013 The NASM Authors - All Rights Reserved
   4  *   See the file AUTHORS included with the NASM distribution for
   5  *   the specific copyright holders.
   6  *
   7  *   Redistribution and use in source and binary forms, with or without
   8  *   modification, are permitted provided that the following
   9  *   conditions are met:
  10  *
  11  *   * Redistributions of source code must retain the above copyright
  12  *     notice, this list of conditions and the following disclaimer.
  13  *   * Redistributions in binary form must reproduce the above
  14  *     copyright notice, this list of conditions and the following
  15  *     disclaimer in the documentation and/or other materials provided
  16  *     with the distribution.
  17  *
  18  *     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  19  *     CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  20  *     INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  21  *     MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  22  *     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  23  *     CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  24  *     SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  25  *     NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  26  *     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  *     HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  *     CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  29  *     OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  30  *     EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  * ----------------------------------------------------------------------- */
  33
  34 /*
  35  * outas86.c    output routines for the Netwide Assembler to produce
  36  *              Linux as86 (bin86-0.3) object files
  37  */
  38
  39 #include "compiler.h"
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <ctype.h>
  45 #include <inttypes.h>
  46
  47 #include "nasm.h"
  48 #include "nasmlib.h"
  49 #include "saa.h"
  50 #include "raa.h"
  51 #include "output/outform.h"
  52 #include "output/outlib.h"
  53
  54 #ifdef OF_AS86
  55
  56 struct Piece {
  57     struct Piece *next;
  58     int type;                   /* 0 = absolute, 1 = seg, 2 = sym */
  59     int32_t offset;             /* relative offset */
  60     int number;                 /* symbol/segment number (4=bss) */
  61     int32_t bytes;              /* size of reloc or of absolute data */
  62     bool relative;              /* relative address? */
  63 };
  64
  65 struct Symbol {
  66     int32_t strpos;             /* string table position of name */
  67     int flags;                  /* symbol flags */
  68     int segment;                /* 4=bss at this point */
  69     int32_t value;              /* address, or COMMON variable size */
  70 };
  71
  72 /*
  73  * Section IDs - used in Piece.number and Symbol.segment.
  74  */
  75 #define SECT_TEXT 0             /* text section */
  76 #define SECT_DATA 3             /* data section */
  77 #define SECT_BSS 4              /* bss section */
  78
  79 /*
  80  * Flags used in Symbol.flags.
  81  */
  82 #define SYM_ENTRY (1<<8)
  83 #define SYM_EXPORT (1<<7)
  84 #define SYM_IMPORT (1<<6)
  85 #define SYM_ABSOLUTE (1<<4)
  86
  87 struct Section {
  88     struct SAA *data;
  89     uint32_t datalen, size, len;
  90     int32_t index;
  91     struct Piece *head, *last, **tail;
  92 };
  93
  94 static char as86_module[FILENAME_MAX];
  95
  96 static struct Section stext, sdata;
  97 static uint32_t bsslen;
  98 static int32_t bssindex;
  99
 100 static struct SAA *syms;
 101 static uint32_t nsyms;
 102
 103 static struct RAA *bsym;
 104
 105 static struct SAA *strs;
 106 static uint32_t strslen;
 107
 108 static int as86_reloc_size;
 109
 110 static void as86_write(void);
 111 static void as86_write_section(struct Section *, int);
 112 static int as86_add_string(char *name);
 113 static void as86_sect_write(struct Section *, const uint8_t *,
 114                             uint32_t);
 115
 116 static void as86_init(void)
 117 {
 118     stext.data = saa_init(1L);
 119     stext.datalen = 0L;
 120     stext.head = stext.last = NULL;
 121     stext.tail = &stext.head;
 122     sdata.data = saa_init(1L);
 123     sdata.datalen = 0L;
 124     sdata.head = sdata.last = NULL;
 125     sdata.tail = &sdata.head;
 126     bsslen =
 127         stext.len = stext.datalen = stext.size =
 128         sdata.len = sdata.datalen = sdata.size = 0;
 129     stext.index = seg_alloc();
 130     sdata.index = seg_alloc();
 131     bssindex = seg_alloc();
 132     syms = saa_init((int32_t)sizeof(struct Symbol));
 133     nsyms = 0;
 134     bsym = raa_init();
 135     strs = saa_init(1L);
 136     strslen = 0;
 137
 138     as86_add_string(as86_module);
 139 }
 140
 141 static void as86_cleanup(void)
 142 {
 143     struct Piece *p;
 144
 145     as86_write();
 146     saa_free(stext.data);
 147     while (stext.head) {
 148         p = stext.head;
 149         stext.head = stext.head->next;
 150         nasm_free(p);
 151     }
 152     saa_free(sdata.data);
 153     while (sdata.head) {
 154         p = sdata.head;
 155         sdata.head = sdata.head->next;
 156         nasm_free(p);
 157     }
 158     saa_free(syms);
 159     raa_free(bsym);
 160     saa_free(strs);
 161 }
 162
 163 static int32_t as86_section_names(char *name, int pass, int *bits)
 164 {
 165
 166     (void)pass;
 167
 168     /*
 169      * Default is 16 bits.
 170      */
 171     if (!name)
 172         *bits = 16;
 173
 174     if (!name)
 175         return stext.index;
 176
 177     if (!strcmp(name, ".text"))
 178         return stext.index;
 179     else if (!strcmp(name, ".data"))
 180         return sdata.index;
 181     else if (!strcmp(name, ".bss"))
 182         return bssindex;
 183     else
 184         return NO_SEG;
 185 }
 186
 187 static int as86_add_string(char *name)
 188 {
 189     int pos = strslen;
 190     int length = strlen(name);
 191
 192     saa_wbytes(strs, name, (int32_t)(length + 1));
 193     strslen += 1 + length;
 194
 195     return pos;
 196 }
 197
 198 static void as86_deflabel(char *name, int32_t segment, int64_t offset,
 199                           int is_global, char *special)
 200 {
 201     bool is_start = false;
 202     struct Symbol *sym;
 203
 204     if (special)
 205         nasm_error(ERR_NONFATAL, "as86 format does not support any"
 206               " special symbol types");
 207
 208
 209     if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
 210         if (strcmp(name, "..start")) {
 211             nasm_error(ERR_NONFATAL, "unrecognised special symbol `%s'", name);
 212             return;
 213         } else {
 214             is_start = true;
 215         }
 216     }
 217
 218     sym = saa_wstruct(syms);
 219
 220     sym->strpos = as86_add_string(name);
 221     sym->flags = 0;
 222
 223     if (is_start)
 224       sym->flags = SYM_ENTRY;
 225
 226     if (segment == NO_SEG)
 227         sym->flags |= SYM_ABSOLUTE, sym->segment = 0;
 228     else if (segment == stext.index)
 229         sym->segment = SECT_TEXT;
 230     else if (segment == sdata.index)
 231         sym->segment = SECT_DATA;
 232     else if (segment == bssindex)
 233         sym->segment = SECT_BSS;
 234     else {
 235         sym->flags |= SYM_IMPORT;
 236         sym->segment = 15;
 237     }
 238
 239     if (is_global == 2)
 240         sym->segment = 3;       /* already have IMPORT */
 241
 242     if (is_global && !(sym->flags & SYM_IMPORT))
 243         sym->flags |= SYM_EXPORT;
 244
 245     sym->value = offset;
 246
 247     /*
 248      * define the references from external-symbol segment numbers
 249      * to these symbol records.
 250      */
 251     if (segment != NO_SEG && segment != stext.index &&
 252         segment != sdata.index && segment != bssindex)
 253         bsym = raa_write(bsym, segment, nsyms);
 254
 255     nsyms++;
 256 }
 257
 258 static void as86_add_piece(struct Section *sect, int type, int32_t offset,
 259                            int32_t segment, int32_t bytes, int relative)
 260 {
 261     struct Piece *p;
 262
 263     sect->len += bytes;
 264
 265     if (type == 0 && sect->last && sect->last->type == 0) {
 266         sect->last->bytes += bytes;
 267         return;
 268     }
 269
 270     p = sect->last = *sect->tail = nasm_malloc(sizeof(struct Piece));
 271     sect->tail = &p->next;
 272     p->next = NULL;
 273
 274     p->type = type;
 275     p->offset = offset;
 276     p->bytes = bytes;
 277     p->relative = relative;
 278
 279     if (type == 1 && segment == stext.index)
 280         p->number = SECT_TEXT;
 281     else if (type == 1 && segment == sdata.index)
 282         p->number = SECT_DATA;
 283     else if (type == 1 && segment == bssindex)
 284         p->number = SECT_BSS;
 285     else if (type == 1)
 286         p->number = raa_read(bsym, segment), p->type = 2;
 287 }
 288
 289 static void as86_out(int32_t segto, const void *data,
 290                      enum out_type type, uint64_t size,
 291                      int32_t segment, int32_t wrt)
 292 {
 293     struct Section *s;
 294     int32_t offset;
 295     uint8_t mydata[4], *p;
 296
 297     if (wrt != NO_SEG) {
 298         wrt = NO_SEG;           /* continue to do _something_ */
 299         nasm_error(ERR_NONFATAL, "WRT not supported by as86 output format");
 300     }
 301
 302     /*
 303      * handle absolute-assembly (structure definitions)
 304      */
 305     if (segto == NO_SEG) {
 306         if (type != OUT_RESERVE)
 307             nasm_error(ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
 308                   " space");
 309         return;
 310     }
 311
 312     if (segto == stext.index)
 313         s = &stext;
 314     else if (segto == sdata.index)
 315         s = &sdata;
 316     else if (segto == bssindex)
 317         s = NULL;
 318     else {
 319         nasm_error(ERR_WARNING, "attempt to assemble code in"
 320               " segment %d: defaulting to `.text'", segto);
 321         s = &stext;
 322     }
 323
 324     if (!s && type != OUT_RESERVE) {
 325         nasm_error(ERR_WARNING, "attempt to initialize memory in the"
 326               " BSS section: ignored");
 327         bsslen += realsize(type, size);
 328         return;
 329     }
 330
 331     memset(mydata, 0, sizeof(mydata));
 332
 333     if (type == OUT_RESERVE) {
 334         if (s) {
 335             nasm_error(ERR_WARNING, "uninitialized space declared in"
 336                   " %s section: zeroing",
 337                   (segto == stext.index ? "code" : "data"));
 338             as86_sect_write(s, NULL, size);
 339             as86_add_piece(s, 0, 0L, 0L, size, 0);
 340         } else
 341             bsslen += size;
 342     } else if (type == OUT_RAWDATA) {
 343         if (segment != NO_SEG)
 344             nasm_panic(0, "OUT_RAWDATA with other than NO_SEG");
 345         as86_sect_write(s, data, size);
 346         as86_add_piece(s, 0, 0L, 0L, size, 0);
 347     } else if (type == OUT_ADDRESS) {
 348         int asize = abs((int)size);
 349         if (segment != NO_SEG) {
 350             if (segment % 2) {
 351                 nasm_error(ERR_NONFATAL, "as86 format does not support"
 352                       " segment base references");
 353             } else {
 354                 offset = *(int64_t *)data;
 355                 as86_add_piece(s, 1, offset, segment, asize, 0);
 356             }
 357         } else {
 358             p = mydata;
 359             WRITELONG(p, *(int64_t *)data);
 360             as86_sect_write(s, data, asize);
 361             as86_add_piece(s, 0, 0L, 0L, asize, 0);
 362         }
 363     } else if (type == OUT_REL2ADR) {
 364         if (segment == segto)
 365             nasm_panic(0, "intra-segment OUT_REL2ADR");
 366         if (segment != NO_SEG) {
 367             if (segment % 2) {
 368                 nasm_error(ERR_NONFATAL, "as86 format does not support"
 369                       " segment base references");
 370             } else {
 371                 offset = *(int64_t *)data;
 372                 as86_add_piece(s, 1, offset - size + 2, segment, 2L,
 373                                1);
 374             }
 375         }
 376     } else if (type == OUT_REL4ADR) {
 377         if (segment == segto)
 378             nasm_panic(0, "intra-segment OUT_REL4ADR");
 379         if (segment != NO_SEG) {
 380             if (segment % 2) {
 381                 nasm_error(ERR_NONFATAL, "as86 format does not support"
 382                       " segment base references");
 383             } else {
 384                 offset = *(int64_t *)data;
 385                 as86_add_piece(s, 1, offset - size + 4, segment, 4L,
 386                                1);
 387             }
 388         }
 389     }
 390 }
 391
 392 static void as86_write(void)
 393 {
 394     uint32_t i;
 395     int32_t symlen, seglen, segsize;
 396
 397     /*
 398      * First, go through the symbol records working out how big
 399      * each will be. Also fix up BSS references at this time, and
 400      * set the flags words up completely.
 401      */
 402     symlen = 0;
 403     saa_rewind(syms);
 404     for (i = 0; i < nsyms; i++) {
 405         struct Symbol *sym = saa_rstruct(syms);
 406         if (sym->segment == SECT_BSS)
 407             sym->segment = SECT_DATA, sym->value += sdata.len;
 408         sym->flags |= sym->segment;
 409         if (sym->value == 0)
 410             sym->flags |= 0 << 14, symlen += 4;
 411         else if (sym->value >= 0 && sym->value <= 255)
 412             sym->flags |= 1 << 14, symlen += 5;
 413         else if (sym->value >= 0 && sym->value <= 65535L)
 414             sym->flags |= 2 << 14, symlen += 6;
 415         else
 416             sym->flags |= 3 << 14, symlen += 8;
 417     }
 418
 419     /*
 420      * Now do the same for the segments, and get the segment size
 421      * descriptor word at the same time.
 422      */
 423     seglen = segsize = 0;
 424     if ((uint32_t)stext.len > 65535L)
 425         segsize |= 0x03000000L, seglen += 4;
 426     else
 427         segsize |= 0x02000000L, seglen += 2;
 428     if ((uint32_t)sdata.len > 65535L)
 429         segsize |= 0xC0000000L, seglen += 4;
 430     else
 431         segsize |= 0x80000000L, seglen += 2;
 432
 433     /*
 434      * Emit the as86 header.
 435      */
 436     fwriteint32_t(0x000186A3L, ofile);
 437     fputc(0x2A, ofile);
 438     fwriteint32_t(27 + symlen + seglen + strslen, ofile); /* header length */
 439     fwriteint32_t(stext.len + sdata.len + bsslen, ofile);
 440     fwriteint16_t(strslen, ofile);
 441     fwriteint16_t(0, ofile);     /* class = revision = 0 */
 442     fwriteint32_t(0x55555555L, ofile);    /* segment max sizes: always this */
 443     fwriteint32_t(segsize, ofile);        /* segment size descriptors */
 444     if (segsize & 0x01000000L)
 445         fwriteint32_t(stext.len, ofile);
 446     else
 447         fwriteint16_t(stext.len, ofile);
 448     if (segsize & 0x40000000L)
 449         fwriteint32_t(sdata.len + bsslen, ofile);
 450     else
 451         fwriteint16_t(sdata.len + bsslen, ofile);
 452     fwriteint16_t(nsyms, ofile);
 453
 454     /*
 455      * Write the symbol table.
 456      */
 457     saa_rewind(syms);
 458     for (i = 0; i < nsyms; i++) {
 459         struct Symbol *sym = saa_rstruct(syms);
 460         fwriteint16_t(sym->strpos, ofile);
 461         fwriteint16_t(sym->flags, ofile);
 462         switch (sym->flags & (3 << 14)) {
 463         case 0 << 14:
 464             break;
 465         case 1 << 14:
 466             fputc(sym->value, ofile);
 467             break;
 468         case 2 << 14:
 469             fwriteint16_t(sym->value, ofile);
 470             break;
 471         case 3 << 14:
 472             fwriteint32_t(sym->value, ofile);
 473             break;
 474         }
 475     }
 476
 477     /*
 478      * Write out the string table.
 479      */
 480     saa_fpwrite(strs, ofile);
 481
 482     /*
 483      * Write the program text.
 484      */
 485     as86_reloc_size = -1;
 486     as86_write_section(&stext, SECT_TEXT);
 487     as86_write_section(&sdata, SECT_DATA);
 488     /*
 489      * Append the BSS section to the .data section
 490      */
 491     if (bsslen > 65535L) {
 492         fputc(0x13, ofile);
 493         fwriteint32_t(bsslen, ofile);
 494     } else if (bsslen > 255) {
 495         fputc(0x12, ofile);
 496         fwriteint16_t(bsslen, ofile);
 497     } else if (bsslen) {
 498         fputc(0x11, ofile);
 499         fputc(bsslen, ofile);
 500     }
 501
 502     fputc(0, ofile);           /* termination */
 503 }
 504
 505 static void as86_set_rsize(int size)
 506 {
 507     if (as86_reloc_size != size) {
 508         switch (as86_reloc_size = size) {
 509         case 1:
 510             fputc(0x01, ofile);
 511             break;
 512         case 2:
 513             fputc(0x02, ofile);
 514             break;
 515         case 4:
 516             fputc(0x03, ofile);
 517             break;
 518         default:
 519             nasm_panic(0, "bizarre relocation size %d", size);
 520             break;
 521         }
 522     }
 523 }
 524
 525 static void as86_write_section(struct Section *sect, int index)
 526 {
 527     struct Piece *p;
 528     uint32_t s;
 529     int32_t length;
 530
 531     fputc(0x20 + index, ofile);        /* select the right section */
 532
 533     saa_rewind(sect->data);
 534
 535     for (p = sect->head; p; p = p->next)
 536         switch (p->type) {
 537         case 0:
 538             /*
 539              * Absolute data. Emit it in chunks of at most 64
 540              * bytes.
 541              */
 542             length = p->bytes;
 543             do {
 544                 char buf[64];
 545                 int32_t tmplen = (length > 64 ? 64 : length);
 546                 fputc(0x40 | (tmplen & 0x3F), ofile);
 547                 saa_rnbytes(sect->data, buf, tmplen);
 548                 nasm_write(buf, tmplen, ofile);
 549                 length -= tmplen;
 550             } while (length > 0);
 551             break;
 552         case 1:
 553             /*
 554              * A segment-type relocation. First fix up the BSS.
 555              */
 556             if (p->number == SECT_BSS)
 557                 p->number = SECT_DATA, p->offset += sdata.len;
 558             as86_set_rsize(p->bytes);
 559             fputc(0x80 | (p->relative ? 0x20 : 0) | p->number, ofile);
 560             if (as86_reloc_size == 2)
 561                 fwriteint16_t(p->offset, ofile);
 562             else
 563                 fwriteint32_t(p->offset, ofile);
 564             break;
 565         case 2:
 566             /*
 567              * A symbol-type relocation.
 568              */
 569             as86_set_rsize(p->bytes);
 570             s = p->offset;
 571             if (s > 65535L)
 572                 s = 3;
 573             else if (s > 255)
 574                 s = 2;
 575             else if (s > 0)
 576                 s = 1;
 577             else
 578                 s = 0;
 579             fputc(0xC0 |
 580                   (p->relative ? 0x20 : 0) |
 581                   (p->number > 255 ? 0x04 : 0) | s, ofile);
 582             if (p->number > 255)
 583                 fwriteint16_t(p->number, ofile);
 584             else
 585                 fputc(p->number, ofile);
 586             switch ((int)s) {
 587             case 0:
 588                 break;
 589             case 1:
 590                 fputc(p->offset, ofile);
 591                 break;
 592             case 2:
 593                 fwriteint16_t(p->offset, ofile);
 594                 break;
 595             case 3:
 596                 fwriteint32_t(p->offset, ofile);
 597                 break;
 598             }
 599             break;
 600         }
 601 }
 602
 603 static void as86_sect_write(struct Section *sect,
 604                             const uint8_t *data, uint32_t len)
 605 {
 606     saa_wbytes(sect->data, data, len);
 607     sect->datalen += len;
 608 }
 609
 610 static int32_t as86_segbase(int32_t segment)
 611 {
 612     return segment;
 613 }
 614
 615 static void as86_filename(char *inname, char *outname)
 616 {
 617     char *p;
 618
 619     if ((p = strrchr(inname, '.')) != NULL) {
 620         strncpy(as86_module, inname, p - inname);
 621         as86_module[p - inname] = '\0';
 622     } else
 623         strcpy(as86_module, inname);
 624
 625     standard_extension(inname, outname, ".o");
 626 }
 627
 628 extern macros_t as86_stdmac[];
 629
 630 struct ofmt of_as86 = {
 631     "Linux as86 (bin86 version 0.3) object files",
 632     "as86",
 633     0,
 634     32,
 635     null_debug_arr,
 636     &null_debug_form,
 637     as86_stdmac,
 638     as86_init,
 639     null_setinfo,
 640     as86_out,
 641     as86_deflabel,
 642     as86_section_names,
 643     null_sectalign,
 644     as86_segbase,
 645     null_directive,
 646     as86_filename,
 647     as86_cleanup
 648 };
 649
 650 #endif                          /* OF_AS86 */