output/outas86.c

   1 /* outas86.c    output routines for the Netwide Assembler to produce
   2  *              Linux as86 (bin86-0.3) object 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 license given in the file "LICENSE"
   7  * distributed in the NASM archive.
   8  */
   9
  10 #include "compiler.h"
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <ctype.h>
  16 #include <inttypes.h>
  17
  18 #include "nasm.h"
  19 #include "nasmlib.h"
  20 #include "saa.h"
  21 #include "raa.h"
  22 #include "outform.h"
  23 #include "outlib.h"
  24
  25 #ifdef OF_AS86
  26
  27 struct Piece {
  28     struct Piece *next;
  29     int type;                   /* 0 = absolute, 1 = seg, 2 = sym */
  30     int32_t offset;             /* relative offset */
  31     int number;                 /* symbol/segment number (4=bss) */
  32     int32_t bytes;              /* size of reloc or of absolute data */
  33     bool relative;              /* relative address? */
  34 };
  35
  36 struct Symbol {
  37     int32_t strpos;             /* string table position of name */
  38     int flags;                  /* symbol flags */
  39     int segment;                /* 4=bss at this point */
  40     int32_t value;              /* address, or COMMON variable size */
  41 };
  42
  43 /*
  44  * Section IDs - used in Piece.number and Symbol.segment.
  45  */
  46 #define SECT_TEXT 0             /* text section */
  47 #define SECT_DATA 3             /* data section */
  48 #define SECT_BSS 4              /* bss section */
  49
  50 /*
  51  * Flags used in Symbol.flags.
  52  */
  53 #define SYM_ENTRY (1<<8)
  54 #define SYM_EXPORT (1<<7)
  55 #define SYM_IMPORT (1<<6)
  56 #define SYM_ABSOLUTE (1<<4)
  57
  58 struct Section {
  59     struct SAA *data;
  60     uint32_t datalen, size, len;
  61     int32_t index;
  62     struct Piece *head, *last, **tail;
  63 };
  64
  65 static char as86_module[FILENAME_MAX];
  66
  67 static struct Section stext, sdata;
  68 static uint32_t bsslen;
  69 static int32_t bssindex;
  70
  71 static struct SAA *syms;
  72 static uint32_t nsyms;
  73
  74 static struct RAA *bsym;
  75
  76 static struct SAA *strs;
  77 static uint32_t strslen;
  78
  79 static int as86_reloc_size;
  80
  81 static FILE *as86fp;
  82 static efunc error;
  83
  84 static void as86_write(void);
  85 static void as86_write_section(struct Section *, int);
  86 static int as86_add_string(char *name);
  87 static void as86_sect_write(struct Section *, const uint8_t *,
  88                             uint32_t);
  89
  90 static void as86_init(FILE * fp, efunc errfunc, ldfunc ldef, evalfunc eval)
  91 {
  92     as86fp = fp;
  93     error = errfunc;
  94     (void)ldef;                 /* placate optimisers */
  95     (void)eval;
  96     stext.data = saa_init(1L);
  97     stext.datalen = 0L;
  98     stext.head = stext.last = NULL;
  99     stext.tail = &stext.head;
 100     sdata.data = saa_init(1L);
 101     sdata.datalen = 0L;
 102     sdata.head = sdata.last = NULL;
 103     sdata.tail = &sdata.head;
 104     bsslen =
 105         stext.len = stext.datalen = stext.size =
 106         sdata.len = sdata.datalen = sdata.size = 0;
 107     stext.index = seg_alloc();
 108     sdata.index = seg_alloc();
 109     bssindex = seg_alloc();
 110     syms = saa_init((int32_t)sizeof(struct Symbol));
 111     nsyms = 0;
 112     bsym = raa_init();
 113     strs = saa_init(1L);
 114     strslen = 0;
 115
 116     as86_add_string(as86_module);
 117 }
 118
 119 static void as86_cleanup(int debuginfo)
 120 {
 121     struct Piece *p;
 122
 123     (void)debuginfo;
 124
 125     as86_write();
 126     fclose(as86fp);
 127     saa_free(stext.data);
 128     while (stext.head) {
 129         p = stext.head;
 130         stext.head = stext.head->next;
 131         nasm_free(p);
 132     }
 133     saa_free(sdata.data);
 134     while (sdata.head) {
 135         p = sdata.head;
 136         sdata.head = sdata.head->next;
 137         nasm_free(p);
 138     }
 139     saa_free(syms);
 140     raa_free(bsym);
 141     saa_free(strs);
 142 }
 143
 144 static int32_t as86_section_names(char *name, int pass, int *bits)
 145 {
 146
 147     (void)pass;
 148
 149     /*
 150      * Default is 16 bits.
 151      */
 152     if (!name)
 153         *bits = 16;
 154
 155     if (!name)
 156         return stext.index;
 157
 158     if (!strcmp(name, ".text"))
 159         return stext.index;
 160     else if (!strcmp(name, ".data"))
 161         return sdata.index;
 162     else if (!strcmp(name, ".bss"))
 163         return bssindex;
 164     else
 165         return NO_SEG;
 166 }
 167
 168 static int as86_add_string(char *name)
 169 {
 170     int pos = strslen;
 171     int length = strlen(name);
 172
 173     saa_wbytes(strs, name, (int32_t)(length + 1));
 174     strslen += 1 + length;
 175
 176     return pos;
 177 }
 178
 179 static void as86_deflabel(char *name, int32_t segment, int64_t offset,
 180                           int is_global, char *special)
 181 {
 182     struct Symbol *sym;
 183
 184     if (special)
 185         error(ERR_NONFATAL, "as86 format does not support any"
 186               " special symbol types");
 187
 188     if (name[0] == '.' && name[1] == '.' && name[2] != '@') {
 189         error(ERR_NONFATAL, "unrecognised special symbol `%s'", name);
 190         return;
 191     }
 192
 193     sym = saa_wstruct(syms);
 194
 195     sym->strpos = as86_add_string(name);
 196     sym->flags = 0;
 197     if (segment == NO_SEG)
 198         sym->flags |= SYM_ABSOLUTE, sym->segment = 0;
 199     else if (segment == stext.index)
 200         sym->segment = SECT_TEXT;
 201     else if (segment == sdata.index)
 202         sym->segment = SECT_DATA;
 203     else if (segment == bssindex)
 204         sym->segment = SECT_BSS;
 205     else {
 206         sym->flags |= SYM_IMPORT;
 207         sym->segment = 15;
 208     }
 209
 210     if (is_global == 2)
 211         sym->segment = 3;       /* already have IMPORT */
 212
 213     if (is_global && !(sym->flags & SYM_IMPORT))
 214         sym->flags |= SYM_EXPORT;
 215
 216     sym->value = offset;
 217
 218     /*
 219      * define the references from external-symbol segment numbers
 220      * to these symbol records.
 221      */
 222     if (segment != NO_SEG && segment != stext.index &&
 223         segment != sdata.index && segment != bssindex)
 224         bsym = raa_write(bsym, segment, nsyms);
 225
 226     nsyms++;
 227 }
 228
 229 static void as86_add_piece(struct Section *sect, int type, int32_t offset,
 230                            int32_t segment, int32_t bytes, int relative)
 231 {
 232     struct Piece *p;
 233
 234     sect->len += bytes;
 235
 236     if (type == 0 && sect->last && sect->last->type == 0) {
 237         sect->last->bytes += bytes;
 238         return;
 239     }
 240
 241     p = sect->last = *sect->tail = nasm_malloc(sizeof(struct Piece));
 242     sect->tail = &p->next;
 243     p->next = NULL;
 244
 245     p->type = type;
 246     p->offset = offset;
 247     p->bytes = bytes;
 248     p->relative = relative;
 249
 250     if (type == 1 && segment == stext.index)
 251         p->number = SECT_TEXT;
 252     else if (type == 1 && segment == sdata.index)
 253         p->number = SECT_DATA;
 254     else if (type == 1 && segment == bssindex)
 255         p->number = SECT_BSS;
 256     else if (type == 1)
 257         p->number = raa_read(bsym, segment), p->type = 2;
 258 }
 259
 260 static void as86_out(int32_t segto, const void *data,
 261                      enum out_type type, uint64_t size,
 262                      int32_t segment, int32_t wrt)
 263 {
 264     struct Section *s;
 265     int32_t offset;
 266     uint8_t mydata[4], *p;
 267
 268     if (wrt != NO_SEG) {
 269         wrt = NO_SEG;           /* continue to do _something_ */
 270         error(ERR_NONFATAL, "WRT not supported by as86 output format");
 271     }
 272
 273     /*
 274      * handle absolute-assembly (structure definitions)
 275      */
 276     if (segto == NO_SEG) {
 277         if (type != OUT_RESERVE)
 278             error(ERR_NONFATAL, "attempt to assemble code in [ABSOLUTE]"
 279                   " space");
 280         return;
 281     }
 282
 283     if (segto == stext.index)
 284         s = &stext;
 285     else if (segto == sdata.index)
 286         s = &sdata;
 287     else if (segto == bssindex)
 288         s = NULL;
 289     else {
 290         error(ERR_WARNING, "attempt to assemble code in"
 291               " segment %d: defaulting to `.text'", segto);
 292         s = &stext;
 293     }
 294
 295     if (!s && type != OUT_RESERVE) {
 296         error(ERR_WARNING, "attempt to initialize memory in the"
 297               " BSS section: ignored");
 298         bsslen += realsize(type, size);
 299         return;
 300     }
 301
 302     if (type == OUT_RESERVE) {
 303         if (s) {
 304             error(ERR_WARNING, "uninitialized space declared in"
 305                   " %s section: zeroing",
 306                   (segto == stext.index ? "code" : "data"));
 307             as86_sect_write(s, NULL, size);
 308             as86_add_piece(s, 0, 0L, 0L, size, 0);
 309         } else
 310             bsslen += size;
 311     } else if (type == OUT_RAWDATA) {
 312         if (segment != NO_SEG)
 313             error(ERR_PANIC, "OUT_RAWDATA with other than NO_SEG");
 314         as86_sect_write(s, data, size);
 315         as86_add_piece(s, 0, 0L, 0L, size, 0);
 316     } else if (type == OUT_ADDRESS) {
 317         if (segment != NO_SEG) {
 318             if (segment % 2) {
 319                 error(ERR_NONFATAL, "as86 format does not support"
 320                       " segment base references");
 321             } else {
 322                 offset = *(int64_t *)data;
 323                 as86_add_piece(s, 1, offset, segment, size, 0);
 324             }
 325         } else {
 326             p = mydata;
 327             WRITELONG(p, *(int64_t *)data);
 328             as86_sect_write(s, data, size);
 329             as86_add_piece(s, 0, 0L, 0L, size, 0);
 330         }
 331     } else if (type == OUT_REL2ADR) {
 332         if (segment == segto)
 333             error(ERR_PANIC, "intra-segment OUT_REL2ADR");
 334         if (segment != NO_SEG) {
 335             if (segment % 2) {
 336                 error(ERR_NONFATAL, "as86 format does not support"
 337                       " segment base references");
 338             } else {
 339                 offset = *(int64_t *)data;
 340                 as86_add_piece(s, 1, offset - size + 2, segment, 2L,
 341                                1);
 342             }
 343         }
 344     } else if (type == OUT_REL4ADR) {
 345         if (segment == segto)
 346             error(ERR_PANIC, "intra-segment OUT_REL4ADR");
 347         if (segment != NO_SEG) {
 348             if (segment % 2) {
 349                 error(ERR_NONFATAL, "as86 format does not support"
 350                       " segment base references");
 351             } else {
 352                 offset = *(int64_t *)data;
 353                 as86_add_piece(s, 1, offset - size + 4, segment, 4L,
 354                                1);
 355             }
 356         }
 357     }
 358 }
 359
 360 static void as86_write(void)
 361 {
 362     uint32_t i;
 363     int32_t symlen, seglen, segsize;
 364
 365     /*
 366      * First, go through the symbol records working out how big
 367      * each will be. Also fix up BSS references at this time, and
 368      * set the flags words up completely.
 369      */
 370     symlen = 0;
 371     saa_rewind(syms);
 372     for (i = 0; i < nsyms; i++) {
 373         struct Symbol *sym = saa_rstruct(syms);
 374         if (sym->segment == SECT_BSS)
 375             sym->segment = SECT_DATA, sym->value += sdata.len;
 376         sym->flags |= sym->segment;
 377         if (sym->value == 0)
 378             sym->flags |= 0 << 14, symlen += 4;
 379         else if (sym->value >= 0 && sym->value <= 255)
 380             sym->flags |= 1 << 14, symlen += 5;
 381         else if (sym->value >= 0 && sym->value <= 65535L)
 382             sym->flags |= 2 << 14, symlen += 6;
 383         else
 384             sym->flags |= 3 << 14, symlen += 8;
 385     }
 386
 387     /*
 388      * Now do the same for the segments, and get the segment size
 389      * descriptor word at the same time.
 390      */
 391     seglen = segsize = 0;
 392     if ((uint32_t)stext.len > 65535L)
 393         segsize |= 0x03000000L, seglen += 4;
 394     else
 395         segsize |= 0x02000000L, seglen += 2;
 396     if ((uint32_t)sdata.len > 65535L)
 397         segsize |= 0xC0000000L, seglen += 4;
 398     else
 399         segsize |= 0x80000000L, seglen += 2;
 400
 401     /*
 402      * Emit the as86 header.
 403      */
 404     fwriteint32_t(0x000186A3L, as86fp);
 405     fputc(0x2A, as86fp);
 406     fwriteint32_t(27 + symlen + seglen + strslen, as86fp); /* header length */
 407     fwriteint32_t(stext.len + sdata.len + bsslen, as86fp);
 408     fwriteint16_t(strslen, as86fp);
 409     fwriteint16_t(0, as86fp);     /* class = revision = 0 */
 410     fwriteint32_t(0x55555555L, as86fp);    /* segment max sizes: always this */
 411     fwriteint32_t(segsize, as86fp);        /* segment size descriptors */
 412     if (segsize & 0x01000000L)
 413         fwriteint32_t(stext.len, as86fp);
 414     else
 415         fwriteint16_t(stext.len, as86fp);
 416     if (segsize & 0x40000000L)
 417         fwriteint32_t(sdata.len + bsslen, as86fp);
 418     else
 419         fwriteint16_t(sdata.len + bsslen, as86fp);
 420     fwriteint16_t(nsyms, as86fp);
 421
 422     /*
 423      * Write the symbol table.
 424      */
 425     saa_rewind(syms);
 426     for (i = 0; i < nsyms; i++) {
 427         struct Symbol *sym = saa_rstruct(syms);
 428         fwriteint16_t(sym->strpos, as86fp);
 429         fwriteint16_t(sym->flags, as86fp);
 430         switch (sym->flags & (3 << 14)) {
 431         case 0 << 14:
 432             break;
 433         case 1 << 14:
 434             fputc(sym->value, as86fp);
 435             break;
 436         case 2 << 14:
 437             fwriteint16_t(sym->value, as86fp);
 438             break;
 439         case 3 << 14:
 440             fwriteint32_t(sym->value, as86fp);
 441             break;
 442         }
 443     }
 444
 445     /*
 446      * Write out the string table.
 447      */
 448     saa_fpwrite(strs, as86fp);
 449
 450     /*
 451      * Write the program text.
 452      */
 453     as86_reloc_size = -1;
 454     as86_write_section(&stext, SECT_TEXT);
 455     as86_write_section(&sdata, SECT_DATA);
 456     /*
 457      * Append the BSS section to the .data section
 458      */
 459     if (bsslen > 65535L) {
 460         fputc(0x13, as86fp);
 461         fwriteint32_t(bsslen, as86fp);
 462     } else if (bsslen > 255) {
 463         fputc(0x12, as86fp);
 464         fwriteint16_t(bsslen, as86fp);
 465     } else if (bsslen) {
 466         fputc(0x11, as86fp);
 467         fputc(bsslen, as86fp);
 468     }
 469
 470     fputc(0, as86fp);           /* termination */
 471 }
 472
 473 static void as86_set_rsize(int size)
 474 {
 475     if (as86_reloc_size != size) {
 476         switch (as86_reloc_size = size) {
 477         case 1:
 478             fputc(0x01, as86fp);
 479             break;
 480         case 2:
 481             fputc(0x02, as86fp);
 482             break;
 483         case 4:
 484             fputc(0x03, as86fp);
 485             break;
 486         default:
 487             error(ERR_PANIC, "bizarre relocation size %d", size);
 488         }
 489     }
 490 }
 491
 492 static void as86_write_section(struct Section *sect, int index)
 493 {
 494     struct Piece *p;
 495     uint32_t s;
 496     int32_t length;
 497
 498     fputc(0x20 + index, as86fp);        /* select the right section */
 499
 500     saa_rewind(sect->data);
 501
 502     for (p = sect->head; p; p = p->next)
 503         switch (p->type) {
 504         case 0:
 505             /*
 506              * Absolute data. Emit it in chunks of at most 64
 507              * bytes.
 508              */
 509             length = p->bytes;
 510             do {
 511                 char buf[64];
 512                 int32_t tmplen = (length > 64 ? 64 : length);
 513                 fputc(0x40 | (tmplen & 0x3F), as86fp);
 514                 saa_rnbytes(sect->data, buf, tmplen);
 515                 fwrite(buf, 1, tmplen, as86fp);
 516                 length -= tmplen;
 517             } while (length > 0);
 518             break;
 519         case 1:
 520             /*
 521              * A segment-type relocation. First fix up the BSS.
 522              */
 523             if (p->number == SECT_BSS)
 524                 p->number = SECT_DATA, p->offset += sdata.len;
 525             as86_set_rsize(p->bytes);
 526             fputc(0x80 | (p->relative ? 0x20 : 0) | p->number, as86fp);
 527             if (as86_reloc_size == 2)
 528                 fwriteint16_t(p->offset, as86fp);
 529             else
 530                 fwriteint32_t(p->offset, as86fp);
 531             break;
 532         case 2:
 533             /*
 534              * A symbol-type relocation.
 535              */
 536             as86_set_rsize(p->bytes);
 537             s = p->offset;
 538             if (s > 65535L)
 539                 s = 3;
 540             else if (s > 255)
 541                 s = 2;
 542             else if (s > 0)
 543                 s = 1;
 544             else
 545                 s = 0;
 546             fputc(0xC0 |
 547                   (p->relative ? 0x20 : 0) |
 548                   (p->number > 255 ? 0x04 : 0) | s, as86fp);
 549             if (p->number > 255)
 550                 fwriteint16_t(p->number, as86fp);
 551             else
 552                 fputc(p->number, as86fp);
 553             switch ((int)s) {
 554             case 0:
 555                 break;
 556             case 1:
 557                 fputc(p->offset, as86fp);
 558                 break;
 559             case 2:
 560                 fwriteint16_t(p->offset, as86fp);
 561                 break;
 562             case 3:
 563                 fwriteint32_t(p->offset, as86fp);
 564                 break;
 565             }
 566             break;
 567         }
 568 }
 569
 570 static void as86_sect_write(struct Section *sect,
 571                             const uint8_t *data, uint32_t len)
 572 {
 573     saa_wbytes(sect->data, data, len);
 574     sect->datalen += len;
 575 }
 576
 577 static int32_t as86_segbase(int32_t segment)
 578 {
 579     return segment;
 580 }
 581
 582 static int as86_directive(char *directive, char *value, int pass)
 583 {
 584     (void)directive;
 585     (void)value;
 586     (void)pass;
 587     return 0;
 588 }
 589
 590 static void as86_filename(char *inname, char *outname, efunc error)
 591 {
 592     char *p;
 593
 594     if ((p = strrchr(inname, '.')) != NULL) {
 595         strncpy(as86_module, inname, p - inname);
 596         as86_module[p - inname] = '\0';
 597     } else
 598         strcpy(as86_module, inname);
 599
 600     standard_extension(inname, outname, ".o", error);
 601 }
 602
 603 extern macros_t as86_stdmac[];
 604
 605 static int as86_set_info(enum geninfo type, char **val)
 606 {
 607     (void)type;
 608     (void)val;
 609     return 0;
 610 }
 611 void as86_linenumber(char *name, int32_t segment, int32_t offset, int is_main,
 612                      int lineno)
 613 {
 614     (void)name;
 615     (void)segment;
 616     (void)offset;
 617     (void)is_main;
 618     (void)lineno;
 619 }
 620 struct ofmt of_as86 = {
 621     "Linux as86 (bin86 version 0.3) object files",
 622     "as86",
 623     NULL,
 624     null_debug_arr,
 625     &null_debug_form,
 626     as86_stdmac,
 627     as86_init,
 628     as86_set_info,
 629     as86_out,
 630     as86_deflabel,
 631     as86_section_names,
 632     as86_segbase,
 633     as86_directive,
 634     as86_filename,
 635     as86_cleanup
 636 };
 637
 638 #endif                          /* OF_AS86 */