output/outas86.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 1996-2009 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 FILE *as86fp;
 111 static efunc error;
 112
 113 static void as86_write(void);
 114 static void as86_write_section(struct Section *, int);
 115 static int as86_add_string(char *name);
 116 static void as86_sect_write(struct Section *, const uint8_t *,
 117                             uint32_t);
 118
 119 static void as86_init(FILE * fp, efunc errfunc, ldfunc ldef, evalfunc eval)
 120 {
 121     as86fp = fp;
 122     error = errfunc;
 123     (void)ldef;                 /* placate optimisers */
 124     (void)eval;
 125     stext.data = saa_init(1L);
 126     stext.datalen = 0L;
 127     stext.head = stext.last = NULL;
 128     stext.tail = &stext.head;
 129     sdata.data = saa_init(1L);
 130     sdata.datalen = 0L;
 131     sdata.head = sdata.last = NULL;
 132     sdata.tail = &sdata.head;
 133     bsslen =
 134         stext.len = stext.datalen = stext.size =
 135         sdata.len = sdata.datalen = sdata.size = 0;
 136     stext.index = seg_alloc();
 137     sdata.index = seg_alloc();
 138     bssindex = seg_alloc();
 139     syms = saa_init((int32_t)sizeof(struct Symbol));
 140     nsyms = 0;
 141     bsym = raa_init();
 142     strs = saa_init(1L);
 143     strslen = 0;
 144
 145     as86_add_string(as86_module);
 146 }
 147
 148 static void as86_cleanup(int debuginfo)
 149 {
 150     struct Piece *p;
 151
 152     (void)debuginfo;
 153
 154     as86_write();
 155     saa_free(stext.data);
 156     while (stext.head) {
 157         p = stext.head;
 158         stext.head = stext.head->next;
 159         nasm_free(p);
 160     }
 161     saa_free(sdata.data);
 162     while (sdata.head) {
 163         p = sdata.head;
 164         sdata.head = sdata.head->next;
 165         nasm_free(p);
 166     }
 167     saa_free(syms);
 168     raa_free(bsym);
 169     saa_free(strs);
 170 }
 171
 172 static int32_t as86_section_names(char *name, int pass, int *bits)
 173 {
 174
 175     (void)pass;
 176
 177     /*
 178      * Default is 16 bits.
 179      */
 180     if (!name)
 181         *bits = 16;
 182
 183     if (!name)
 184         return stext.index;
 185
 186     if (!strcmp(name, ".text"))
 187         return stext.index;
 188     else if (!strcmp(name, ".data"))
 189         return sdata.index;
 190     else if (!strcmp(name, ".bss"))
 191         return bssindex;
 192     else
 193         return NO_SEG;
 194 }
 195
 196 static int as86_add_string(char *name)
 197 {
 198     int pos = strslen;
 199     int length = strlen(name);
 200
 201     saa_wbytes(strs, name, (int32_t)(length + 1));
 202     strslen += 1 + length;
 203
 204     return pos;
 205 }
 206
 207 static void as86_deflabel(char *name, int32_t segment, int64_t offset,
 208                           int is_global, char *special)
 209 {
 210     bool is_start = false;
 211     struct Symbol *sym;
 212
 213     if (special)
 214         error(ERR_NONFATAL, "as86 format does not support any"
 215               " special symbol types");
 216
 217
 218     if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
 219         if (strcmp(name, "..start")) {
 220             error(ERR_NONFATAL, "unrecognised special symbol `%s'", name);
 221             return;
 222         } else {
 223             is_start = true;
 224         }
 225     }
 226
 227     sym = saa_wstruct(syms);
 228
 229     sym->strpos = as86_add_string(name);
 230     sym->flags = 0;
 231
 232     if (is_start)
 233       sym->flags = SYM_ENTRY;
 234
 235     if (segment == NO_SEG)
 236         sym->flags |= SYM_ABSOLUTE, sym->segment = 0;
 237     else if (segment == stext.index)
 238         sym->segment = SECT_TEXT;
 239     else if (segment == sdata.index)
 240         sym->segment = SECT_DATA;
 241     else if (segment == bssindex)
 242         sym->segment = SECT_BSS;
 243     else {
 244         sym->flags |= SYM_IMPORT;
 245         sym->segment = 15;
 246     }
 247
 248     if (is_global == 2)
 249         sym->segment = 3;       /* already have IMPORT */
 250
 251     if (is_global && !(sym->flags & SYM_IMPORT))
 252         sym->flags |= SYM_EXPORT;
 253
 254     sym->value = offset;
 255
 256     /*
 257      * define the references from external-symbol segment numbers
 258      * to these symbol records.
 259      */
 260     if (segment != NO_SEG && segment != stext.index &&
 261         segment != sdata.index && segment != bssindex)
 262         bsym = raa_write(bsym, segment, nsyms);
 263
 264     nsyms++;
 265 }
 266
 267 static void as86_add_piece(struct Section *sect, int type, int32_t offset,
 268                            int32_t segment, int32_t bytes, int relative)
 269 {
 270     struct Piece *p;
 271
 272     sect->len += bytes;
 273
 274     if (type == 0 && sect->last && sect->last->type == 0) {
 275         sect->last->bytes += bytes;
 276         return;
 277     }
 278
 279     p = sect->last = *sect->tail = nasm_malloc(sizeof(struct Piece));
 280     sect->tail = &p->next;
 281     p->next = NULL;
 282
 283     p->type = type;
 284     p->offset = offset;
 285     p->bytes = bytes;
 286     p->relative = relative;
 287
 288     if (type == 1 && segment == stext.index)
 289         p->number = SECT_TEXT;
 290     else if (type == 1 && segment == sdata.index)
 291         p->number = SECT_DATA;
 292     else if (type == 1 && segment == bssindex)
 293         p->number = SECT_BSS;
 294     else if (type == 1)
 295         p->number = raa_read(bsym, segment), p->type = 2;
 296 }
 297
 298 static void as86_out(int32_t segto, const void *data,
 299                      enum out_type type, uint64_t size,
 300                      int32_t segment, int32_t wrt)
 301 {
 302     struct Section *s;
 303     int32_t offset;
 304     uint8_t mydata[4], *p;
 305
 306     if (wrt != NO_SEG) {
 307         wrt = NO_SEG;           /* continue to do _something_ */
 308         error(ERR_NONFATAL, "WRT not supported by as86 output format");
 309     }
 310
 311     /*
 312      * handle absolute-assembly (structure definitions)
 313      */
 314     if (segto == NO_SEG) {
 315         if (type != OUT_RESERVE)
 316             error(ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
 317                   " space");
 318         return;
 319     }
 320
 321     if (segto == stext.index)
 322         s = &stext;
 323     else if (segto == sdata.index)
 324         s = &sdata;
 325     else if (segto == bssindex)
 326         s = NULL;
 327     else {
 328         error(ERR_WARNING, "attempt to assemble code in"
 329               " segment %d: defaulting to `.text'", segto);
 330         s = &stext;
 331     }
 332
 333     if (!s && type != OUT_RESERVE) {
 334         error(ERR_WARNING, "attempt to initialize memory in the"
 335               " BSS section: ignored");
 336         bsslen += realsize(type, size);
 337         return;
 338     }
 339
 340     if (type == OUT_RESERVE) {
 341         if (s) {
 342             error(ERR_WARNING, "uninitialized space declared in"
 343                   " %s section: zeroing",
 344                   (segto == stext.index ? "code" : "data"));
 345             as86_sect_write(s, NULL, size);
 346             as86_add_piece(s, 0, 0L, 0L, size, 0);
 347         } else
 348             bsslen += size;
 349     } else if (type == OUT_RAWDATA) {
 350         if (segment != NO_SEG)
 351             error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
 352         as86_sect_write(s, data, size);
 353         as86_add_piece(s, 0, 0L, 0L, size, 0);
 354     } else if (type == OUT_ADDRESS) {
 355         if (segment != NO_SEG) {
 356             if (segment % 2) {
 357                 error(ERR_NONFATAL, "as86 format does not support"
 358                       " segment base references");
 359             } else {
 360                 offset = *(int64_t *)data;
 361                 as86_add_piece(s, 1, offset, segment, size, 0);
 362             }
 363         } else {
 364             p = mydata;
 365             WRITELONG(p, *(int64_t *)data);
 366             as86_sect_write(s, data, size);
 367             as86_add_piece(s, 0, 0L, 0L, size, 0);
 368         }
 369     } else if (type == OUT_REL2ADR) {
 370         if (segment == segto)
 371             error(ERR_PANIC, "intra-segment OUT_REL2ADR");
 372         if (segment != NO_SEG) {
 373             if (segment % 2) {
 374                 error(ERR_NONFATAL, "as86 format does not support"
 375                       " segment base references");
 376             } else {
 377                 offset = *(int64_t *)data;
 378                 as86_add_piece(s, 1, offset - size + 2, segment, 2L,
 379                                1);
 380             }
 381         }
 382     } else if (type == OUT_REL4ADR) {
 383         if (segment == segto)
 384             error(ERR_PANIC, "intra-segment OUT_REL4ADR");
 385         if (segment != NO_SEG) {
 386             if (segment % 2) {
 387                 error(ERR_NONFATAL, "as86 format does not support"
 388                       " segment base references");
 389             } else {
 390                 offset = *(int64_t *)data;
 391                 as86_add_piece(s, 1, offset - size + 4, segment, 4L,
 392                                1);
 393             }
 394         }
 395     }
 396 }
 397
 398 static void as86_write(void)
 399 {
 400     uint32_t i;
 401     int32_t symlen, seglen, segsize;
 402
 403     /*
 404      * First, go through the symbol records working out how big
 405      * each will be. Also fix up BSS references at this time, and
 406      * set the flags words up completely.
 407      */
 408     symlen = 0;
 409     saa_rewind(syms);
 410     for (i = 0; i < nsyms; i++) {
 411         struct Symbol *sym = saa_rstruct(syms);
 412         if (sym->segment == SECT_BSS)
 413             sym->segment = SECT_DATA, sym->value += sdata.len;
 414         sym->flags |= sym->segment;
 415         if (sym->value == 0)
 416             sym->flags |= 0 << 14, symlen += 4;
 417         else if (sym->value >= 0 && sym->value <= 255)
 418             sym->flags |= 1 << 14, symlen += 5;
 419         else if (sym->value >= 0 && sym->value <= 65535L)
 420             sym->flags |= 2 << 14, symlen += 6;
 421         else
 422             sym->flags |= 3 << 14, symlen += 8;
 423     }
 424
 425     /*
 426      * Now do the same for the segments, and get the segment size
 427      * descriptor word at the same time.
 428      */
 429     seglen = segsize = 0;
 430     if ((uint32_t)stext.len > 65535L)
 431         segsize |= 0x03000000L, seglen += 4;
 432     else
 433         segsize |= 0x02000000L, seglen += 2;
 434     if ((uint32_t)sdata.len > 65535L)
 435         segsize |= 0xC0000000L, seglen += 4;
 436     else
 437         segsize |= 0x80000000L, seglen += 2;
 438
 439     /*
 440      * Emit the as86 header.
 441      */
 442     fwriteint32_t(0x000186A3L, as86fp);
 443     fputc(0x2A, as86fp);
 444     fwriteint32_t(27 + symlen + seglen + strslen, as86fp); /* header length */
 445     fwriteint32_t(stext.len + sdata.len + bsslen, as86fp);
 446     fwriteint16_t(strslen, as86fp);
 447     fwriteint16_t(0, as86fp);     /* class = revision = 0 */
 448     fwriteint32_t(0x55555555L, as86fp);    /* segment max sizes: always this */
 449     fwriteint32_t(segsize, as86fp);        /* segment size descriptors */
 450     if (segsize & 0x01000000L)
 451         fwriteint32_t(stext.len, as86fp);
 452     else
 453         fwriteint16_t(stext.len, as86fp);
 454     if (segsize & 0x40000000L)
 455         fwriteint32_t(sdata.len + bsslen, as86fp);
 456     else
 457         fwriteint16_t(sdata.len + bsslen, as86fp);
 458     fwriteint16_t(nsyms, as86fp);
 459
 460     /*
 461      * Write the symbol table.
 462      */
 463     saa_rewind(syms);
 464     for (i = 0; i < nsyms; i++) {
 465         struct Symbol *sym = saa_rstruct(syms);
 466         fwriteint16_t(sym->strpos, as86fp);
 467         fwriteint16_t(sym->flags, as86fp);
 468         switch (sym->flags & (3 << 14)) {
 469         case 0 << 14:
 470             break;
 471         case 1 << 14:
 472             fputc(sym->value, as86fp);
 473             break;
 474         case 2 << 14:
 475             fwriteint16_t(sym->value, as86fp);
 476             break;
 477         case 3 << 14:
 478             fwriteint32_t(sym->value, as86fp);
 479             break;
 480         }
 481     }
 482
 483     /*
 484      * Write out the string table.
 485      */
 486     saa_fpwrite(strs, as86fp);
 487
 488     /*
 489      * Write the program text.
 490      */
 491     as86_reloc_size = -1;
 492     as86_write_section(&stext, SECT_TEXT);
 493     as86_write_section(&sdata, SECT_DATA);
 494     /*
 495      * Append the BSS section to the .data section
 496      */
 497     if (bsslen > 65535L) {
 498         fputc(0x13, as86fp);
 499         fwriteint32_t(bsslen, as86fp);
 500     } else if (bsslen > 255) {
 501         fputc(0x12, as86fp);
 502         fwriteint16_t(bsslen, as86fp);
 503     } else if (bsslen) {
 504         fputc(0x11, as86fp);
 505         fputc(bsslen, as86fp);
 506     }
 507
 508     fputc(0, as86fp);           /* termination */
 509 }
 510
 511 static void as86_set_rsize(int size)
 512 {
 513     if (as86_reloc_size != size) {
 514         switch (as86_reloc_size = size) {
 515         case 1:
 516             fputc(0x01, as86fp);
 517             break;
 518         case 2:
 519             fputc(0x02, as86fp);
 520             break;
 521         case 4:
 522             fputc(0x03, as86fp);
 523             break;
 524         default:
 525             error(ERR_PANIC, "bizarre relocation size %d", size);
 526         }
 527     }
 528 }
 529
 530 static void as86_write_section(struct Section *sect, int index)
 531 {
 532     struct Piece *p;
 533     uint32_t s;
 534     int32_t length;
 535
 536     fputc(0x20 + index, as86fp);        /* select the right section */
 537
 538     saa_rewind(sect->data);
 539
 540     for (p = sect->head; p; p = p->next)
 541         switch (p->type) {
 542         case 0:
 543             /*
 544              * Absolute data. Emit it in chunks of at most 64
 545              * bytes.
 546              */
 547             length = p->bytes;
 548             do {
 549                 char buf[64];
 550                 int32_t tmplen = (length > 64 ? 64 : length);
 551                 fputc(0x40 | (tmplen & 0x3F), as86fp);
 552                 saa_rnbytes(sect->data, buf, tmplen);
 553                 fwrite(buf, 1, tmplen, as86fp);
 554                 length -= tmplen;
 555             } while (length > 0);
 556             break;
 557         case 1:
 558             /*
 559              * A segment-type relocation. First fix up the BSS.
 560              */
 561             if (p->number == SECT_BSS)
 562                 p->number = SECT_DATA, p->offset += sdata.len;
 563             as86_set_rsize(p->bytes);
 564             fputc(0x80 | (p->relative ? 0x20 : 0) | p->number, as86fp);
 565             if (as86_reloc_size == 2)
 566                 fwriteint16_t(p->offset, as86fp);
 567             else
 568                 fwriteint32_t(p->offset, as86fp);
 569             break;
 570         case 2:
 571             /*
 572              * A symbol-type relocation.
 573              */
 574             as86_set_rsize(p->bytes);
 575             s = p->offset;
 576             if (s > 65535L)
 577                 s = 3;
 578             else if (s > 255)
 579                 s = 2;
 580             else if (s > 0)
 581                 s = 1;
 582             else
 583                 s = 0;
 584             fputc(0xC0 |
 585                   (p->relative ? 0x20 : 0) |
 586                   (p->number > 255 ? 0x04 : 0) | s, as86fp);
 587             if (p->number > 255)
 588                 fwriteint16_t(p->number, as86fp);
 589             else
 590                 fputc(p->number, as86fp);
 591             switch ((int)s) {
 592             case 0:
 593                 break;
 594             case 1:
 595                 fputc(p->offset, as86fp);
 596                 break;
 597             case 2:
 598                 fwriteint16_t(p->offset, as86fp);
 599                 break;
 600             case 3:
 601                 fwriteint32_t(p->offset, as86fp);
 602                 break;
 603             }
 604             break;
 605         }
 606 }
 607
 608 static void as86_sect_write(struct Section *sect,
 609                             const uint8_t *data, uint32_t len)
 610 {
 611     saa_wbytes(sect->data, data, len);
 612     sect->datalen += len;
 613 }
 614
 615 static int32_t as86_segbase(int32_t segment)
 616 {
 617     return segment;
 618 }
 619
 620 static int as86_directive(char *directive, char *value, int pass)
 621 {
 622     (void)directive;
 623     (void)value;
 624     (void)pass;
 625     return 0;
 626 }
 627
 628 static void as86_filename(char *inname, char *outname, efunc error)
 629 {
 630     char *p;
 631
 632     if ((p = strrchr(inname, '.')) != NULL) {
 633         strncpy(as86_module, inname, p - inname);
 634         as86_module[p - inname] = '\0';
 635     } else
 636         strcpy(as86_module, inname);
 637
 638     standard_extension(inname, outname, ".o", error);
 639 }
 640
 641 extern macros_t as86_stdmac[];
 642
 643 static int as86_set_info(enum geninfo type, char **val)
 644 {
 645     (void)type;
 646     (void)val;
 647     return 0;
 648 }
 649 void as86_linenumber(char *name, int32_t segment, int32_t offset, int is_main,
 650                      int lineno)
 651 {
 652     (void)name;
 653     (void)segment;
 654     (void)offset;
 655     (void)is_main;
 656     (void)lineno;
 657 }
 658 struct ofmt of_as86 = {
 659     "Linux as86 (bin86 version 0.3) object files",
 660     "as86",
 661     0,
 662     null_debug_arr,
 663     &null_debug_form,
 664     as86_stdmac,
 665     as86_init,
 666     as86_set_info,
 667     as86_out,
 668     as86_deflabel,
 669     as86_section_names,
 670     as86_segbase,
 671     as86_directive,
 672     as86_filename,
 673     as86_cleanup
 674 };
 675
 676 #endif                          /* OF_AS86 */