parser.c

   1 /* parser.c   source line parser for the Netwide Assembler
   2  *
   3  * The Netwide Assembler is copyright (C) 1996 Simon Tatham and
   4  * Julian Hall. All rights reserved. The software is
   5  * redistributable under the licence given in the file "Licence"
   6  * distributed in the NASM archive.
   7  *
   8  * initial version 27/iii/95 by Simon Tatham
   9  */
  10
  11 #include "compiler.h"
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <stddef.h>
  16 #include <string.h>
  17 #include <ctype.h>
  18 #include <inttypes.h>
  19
  20 #include "nasm.h"
  21 #include "insns.h"
  22 #include "nasmlib.h"
  23 #include "stdscan.h"
  24 #include "parser.h"
  25 #include "float.h"
  26
  27 extern int in_abs_seg;          /* ABSOLUTE segment flag */
  28 extern int32_t abs_seg;            /* ABSOLUTE segment */
  29 extern int32_t abs_offset;         /* ABSOLUTE segment offset */
  30
  31 #include "regflags.c"           /* List of register flags */
  32
  33 static int is_comma_next(void);
  34
  35 static int i;
  36 static struct tokenval tokval;
  37 static efunc error;
  38 static struct ofmt *outfmt;     /* Structure of addresses of output routines */
  39 static struct location *location;         /* Pointer to current line's segment,offset */
  40
  41 void parser_global_info(struct ofmt *output, struct location * locp)
  42 {
  43     outfmt = output;
  44     location = locp;
  45 }
  46
  47 static int prefix_slot(enum prefixes prefix)
  48 {
  49     switch (prefix) {
  50     case R_CS:
  51     case R_DS:
  52     case R_SS:
  53     case R_ES:
  54     case R_FS:
  55     case R_GS:
  56         return PPS_SEG;
  57     case P_LOCK:
  58     case P_REP:
  59     case P_REPE:
  60     case P_REPZ:
  61     case P_REPNE:
  62     case P_REPNZ:
  63         return PPS_LREP;
  64     case P_O16:
  65     case P_O32:
  66     case P_O64:
  67     case P_OSP:
  68         return PPS_OSIZE;
  69     case P_A16:
  70     case P_A32:
  71     case P_A64:
  72     case P_ASP:
  73         return PPS_ASIZE;
  74     default:
  75         error(ERR_PANIC, "Invalid value %d passed to prefix_slot()", prefix);
  76         return -1;
  77     }
  78 }
  79
  80 static void process_size_override(insn * result, int operand)
  81 {
  82     if (tasm_compatible_mode) {
  83         switch ((int)tokval.t_integer) {
  84             /* For TASM compatibility a size override inside the
  85              * brackets changes the size of the operand, not the
  86              * address type of the operand as it does in standard
  87              * NASM syntax. Hence:
  88              *
  89              *  mov     eax,[DWORD val]
  90              *
  91              * is valid syntax in TASM compatibility mode. Note that
  92              * you lose the ability to override the default address
  93              * type for the instruction, but we never use anything
  94              * but 32-bit flat model addressing in our code.
  95              */
  96         case S_BYTE:
  97             result->oprs[operand].type |= BITS8;
  98             break;
  99         case S_WORD:
 100             result->oprs[operand].type |= BITS16;
 101             break;
 102         case S_DWORD:
 103         case S_LONG:
 104             result->oprs[operand].type |= BITS32;
 105             break;
 106         case S_QWORD:
 107             result->oprs[operand].type |= BITS64;
 108             break;
 109         case S_TWORD:
 110             result->oprs[operand].type |= BITS80;
 111             break;
 112         case S_OWORD:
 113             result->oprs[operand].type |= BITS128;
 114             break;
 115         default:
 116             error(ERR_NONFATAL,
 117                   "invalid operand size specification");
 118             break;
 119         }
 120     } else {
 121         /* Standard NASM compatible syntax */
 122         switch ((int)tokval.t_integer) {
 123         case S_NOSPLIT:
 124             result->oprs[operand].eaflags |= EAF_TIMESTWO;
 125             break;
 126         case S_REL:
 127             result->oprs[operand].eaflags |= EAF_REL;
 128             break;
 129         case S_ABS:
 130             result->oprs[operand].eaflags |= EAF_ABS;
 131             break;
 132         case S_BYTE:
 133             result->oprs[operand].disp_size = 8;
 134             result->oprs[operand].eaflags |= EAF_BYTEOFFS;
 135             break;
 136         case P_A16:
 137         case P_A32:
 138         case P_A64:
 139             if (result->prefixes[PPS_ASIZE] &&
 140                 result->prefixes[PPS_ASIZE] != tokval.t_integer)
 141                 error(ERR_NONFATAL,
 142                       "conflicting address size specifications");
 143             else
 144                 result->prefixes[PPS_ASIZE] = tokval.t_integer;
 145             break;
 146         case S_WORD:
 147             result->oprs[operand].disp_size = 16;
 148             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 149             break;
 150         case S_DWORD:
 151         case S_LONG:
 152             result->oprs[operand].disp_size = 32;
 153             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 154             break;
 155         case S_QWORD:
 156             result->oprs[operand].disp_size = 64;
 157             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 158             break;
 159         default:
 160             error(ERR_NONFATAL, "invalid size specification in"
 161                   " effective address");
 162             break;
 163         }
 164     }
 165 }
 166
 167 insn *parse_line(int pass, char *buffer, insn * result,
 168                  efunc errfunc, evalfunc evaluate, ldfunc ldef)
 169 {
 170     int operand;
 171     int critical;
 172     struct eval_hints hints;
 173     int j;
 174     bool first;
 175     bool insn_is_label = false;
 176
 177 restart_parse:
 178     first = true;
 179     result->forw_ref = false;
 180     error = errfunc;
 181
 182     stdscan_reset();
 183     stdscan_bufptr = buffer;
 184     i = stdscan(NULL, &tokval);
 185
 186     result->label = NULL;       /* Assume no label */
 187     result->eops = NULL;        /* must do this, whatever happens */
 188     result->operands = 0;       /* must initialize this */
 189
 190     if (i == 0) {               /* blank line - ignore */
 191         result->opcode = -1;    /* and no instruction either */
 192         return result;
 193     }
 194     if (i != TOKEN_ID && i != TOKEN_INSN && i != TOKEN_PREFIX &&
 195         (i != TOKEN_REG || (REG_SREG & ~reg_flags[tokval.t_integer]))) {
 196         error(ERR_NONFATAL, "label or instruction expected"
 197               " at start of line");
 198         result->opcode = -1;
 199         return result;
 200     }
 201
 202     if (i == TOKEN_ID || (insn_is_label && i == TOKEN_INSN)) {
 203         /* there's a label here */
 204         first = false;
 205         result->label = tokval.t_charptr;
 206         i = stdscan(NULL, &tokval);
 207         if (i == ':') {         /* skip over the optional colon */
 208             i = stdscan(NULL, &tokval);
 209         } else if (i == 0) {
 210             error(ERR_WARNING | ERR_WARN_OL | ERR_PASS1,
 211                   "label alone on a line without a colon might be in error");
 212         }
 213         if (i != TOKEN_INSN || tokval.t_integer != I_EQU) {
 214             /*
 215              * FIXME: location->segment could be NO_SEG, in which case
 216              * it is possible we should be passing 'abs_seg'. Look into this.
 217              * Work out whether that is *really* what we should be doing.
 218              * Generally fix things. I think this is right as it is, but
 219              * am still not certain.
 220              */
 221             ldef(result->label, in_abs_seg ? abs_seg : location->segment,
 222                  location->offset, NULL, true, false, outfmt, errfunc);
 223         }
 224     }
 225
 226     if (i == 0) {
 227         result->opcode = -1;    /* this line contains just a label */
 228         return result;
 229     }
 230
 231     for (j = 0; j < MAXPREFIX; j++)
 232         result->prefixes[j] = P_none;
 233     result->times = 1L;
 234
 235     while (i == TOKEN_PREFIX ||
 236            (i == TOKEN_REG && !(REG_SREG & ~reg_flags[tokval.t_integer])))
 237     {
 238         first = false;
 239
 240         /*
 241          * Handle special case: the TIMES prefix.
 242          */
 243         if (i == TOKEN_PREFIX && tokval.t_integer == P_TIMES) {
 244             expr *value;
 245
 246             i = stdscan(NULL, &tokval);
 247             value =
 248                 evaluate(stdscan, NULL, &tokval, NULL, pass0, error, NULL);
 249             i = tokval.t_type;
 250             if (!value) {       /* but, error in evaluator */
 251                 result->opcode = -1;    /* unrecoverable parse error: */
 252                 return result;  /* ignore this instruction */
 253             }
 254             if (!is_simple(value)) {
 255                 error(ERR_NONFATAL,
 256                       "non-constant argument supplied to TIMES");
 257                 result->times = 1L;
 258             } else {
 259                 result->times = value->value;
 260                 if (value->value < 0) {
 261                     error(ERR_NONFATAL, "TIMES value %d is negative",
 262                           value->value);
 263                     result->times = 0;
 264                 }
 265             }
 266         } else {
 267             int slot = prefix_slot(tokval.t_integer);
 268             if (result->prefixes[slot]) {
 269                if (result->prefixes[slot] == tokval.t_integer)
 270                     error(ERR_WARNING,
 271                       "instruction has redundant prefixes");
 272                else
 273                     error(ERR_NONFATAL,
 274                       "instruction has conflicting prefixes");
 275             }
 276             result->prefixes[slot] = tokval.t_integer;
 277             i = stdscan(NULL, &tokval);
 278         }
 279     }
 280
 281     if (i != TOKEN_INSN) {
 282         int j;
 283         enum prefixes pfx;
 284
 285         for (j = 0; j < MAXPREFIX; j++)
 286             if ((pfx = result->prefixes[j]) != P_none)
 287                 break;
 288
 289         if (i == 0 && pfx != P_none) {
 290             /*
 291              * Instruction prefixes are present, but no actual
 292              * instruction. This is allowed: at this point we
 293              * invent a notional instruction of RESB 0.
 294              */
 295             result->opcode = I_RESB;
 296             result->operands = 1;
 297             result->oprs[0].type = IMMEDIATE;
 298             result->oprs[0].offset = 0L;
 299             result->oprs[0].segment = result->oprs[0].wrt = NO_SEG;
 300             return result;
 301         } else {
 302             error(ERR_NONFATAL, "parser: instruction expected");
 303             result->opcode = -1;
 304             return result;
 305         }
 306     }
 307
 308     result->opcode = tokval.t_integer;
 309     result->condition = tokval.t_inttwo;
 310
 311     /*
 312      * RESB, RESW and RESD cannot be satisfied with incorrectly
 313      * evaluated operands, since the correct values _must_ be known
 314      * on the first pass. Hence, even in pass one, we set the
 315      * `critical' flag on calling evaluate(), so that it will bomb
 316      * out on undefined symbols. Nasty, but there's nothing we can
 317      * do about it.
 318      *
 319      * For the moment, EQU has the same difficulty, so we'll
 320      * include that.
 321      */
 322     if (result->opcode == I_RESB || result->opcode == I_RESW ||
 323         result->opcode == I_RESD || result->opcode == I_RESQ ||
 324         result->opcode == I_REST || result->opcode == I_RESO ||
 325         result->opcode == I_EQU || result->opcode == I_INCBIN) {
 326         critical = pass0;
 327     } else
 328         critical = (pass == 2 ? 2 : 0);
 329
 330     if (result->opcode == I_DB || result->opcode == I_DW ||
 331         result->opcode == I_DD || result->opcode == I_DQ ||
 332         result->opcode == I_DT || result->opcode == I_DO ||
 333         result->opcode == I_INCBIN) {
 334         extop *eop, **tail = &result->eops, **fixptr;
 335         int oper_num = 0;
 336
 337         result->eops_float = false;
 338
 339         /*
 340          * Begin to read the DB/DW/DD/DQ/DT/DO/INCBIN operands.
 341          */
 342         while (1) {
 343             i = stdscan(NULL, &tokval);
 344             if (i == 0)
 345                 break;
 346             else if (first && i == ':') {
 347                 insn_is_label = true;
 348                 goto restart_parse;
 349             }
 350             first = false;
 351             fixptr = tail;
 352             eop = *tail = nasm_malloc(sizeof(extop));
 353             tail = &eop->next;
 354             eop->next = NULL;
 355             eop->type = EOT_NOTHING;
 356             oper_num++;
 357
 358             if (i == TOKEN_NUM && tokval.t_charptr && is_comma_next()) {
 359                 eop->type = EOT_DB_STRING;
 360                 eop->stringval = tokval.t_charptr;
 361                 eop->stringlen = tokval.t_inttwo;
 362                 i = stdscan(NULL, &tokval);     /* eat the comma */
 363                 continue;
 364             }
 365
 366             if ((i == TOKEN_FLOAT && is_comma_next())
 367                 || i == '-' || i == '+') {
 368                 int32_t sign = +1;
 369
 370                 if (i == '+' || i == '-') {
 371                     char *save = stdscan_bufptr;
 372                     int token = i;
 373                     sign = (i == '-') ? -1 : 1;
 374                     i = stdscan(NULL, &tokval);
 375                     if (i != TOKEN_FLOAT || !is_comma_next()) {
 376                         stdscan_bufptr = save;
 377                         i = tokval.t_type = token;
 378                     }
 379                 }
 380
 381                 if (i == TOKEN_FLOAT) {
 382                     eop->type = EOT_DB_STRING;
 383                     result->eops_float = true;
 384                     switch (result->opcode) {
 385                     case I_DB:
 386                         eop->stringlen = 1;
 387                         break;
 388                     case I_DW:
 389                         eop->stringlen = 2;
 390                         break;
 391                     case I_DD:
 392                         eop->stringlen = 4;
 393                         break;
 394                     case I_DQ:
 395                         eop->stringlen = 8;
 396                         break;
 397                     case I_DT:
 398                         eop->stringlen = 10;
 399                         break;
 400                     case I_DO:
 401                         eop->stringlen = 16;
 402                         break;
 403                     default:
 404                         error(ERR_NONFATAL, "floating-point constant"
 405                               " encountered in unknown instruction");
 406                         /*
 407                          * fix suggested by Pedro Gimeno... original line
 408                          * was:
 409                          * eop->type = EOT_NOTHING;
 410                          */
 411                         eop->stringlen = 0;
 412                         break;
 413                     }
 414                     eop = nasm_realloc(eop, sizeof(extop) + eop->stringlen);
 415                     tail = &eop->next;
 416                     *fixptr = eop;
 417                     eop->stringval = (char *)eop + sizeof(extop);
 418                     if (!eop->stringlen ||
 419                         !float_const(tokval.t_charptr, sign,
 420                                      (uint8_t *)eop->stringval,
 421                                      eop->stringlen, error))
 422                         eop->type = EOT_NOTHING;
 423                     i = stdscan(NULL, &tokval); /* eat the comma */
 424                     continue;
 425                 }
 426             }
 427
 428             /* anything else */
 429             {
 430                 expr *value;
 431                 value = evaluate(stdscan, NULL, &tokval, NULL,
 432                                  critical, error, NULL);
 433                 i = tokval.t_type;
 434                 if (!value) {   /* error in evaluator */
 435                     result->opcode = -1;        /* unrecoverable parse error: */
 436                     return result;      /* ignore this instruction */
 437                 }
 438                 if (is_unknown(value)) {
 439                     eop->type = EOT_DB_NUMBER;
 440                     eop->offset = 0;    /* doesn't matter what we put */
 441                     eop->segment = eop->wrt = NO_SEG;   /* likewise */
 442                 } else if (is_reloc(value)) {
 443                     eop->type = EOT_DB_NUMBER;
 444                     eop->offset = reloc_value(value);
 445                     eop->segment = reloc_seg(value);
 446                     eop->wrt = reloc_wrt(value);
 447                 } else {
 448                     error(ERR_NONFATAL,
 449                           "operand %d: expression is not simple"
 450                           " or relocatable", oper_num);
 451                 }
 452             }
 453
 454             /*
 455              * We're about to call stdscan(), which will eat the
 456              * comma that we're currently sitting on between
 457              * arguments. However, we'd better check first that it
 458              * _is_ a comma.
 459              */
 460             if (i == 0)         /* also could be EOL */
 461                 break;
 462             if (i != ',') {
 463                 error(ERR_NONFATAL, "comma expected after operand %d",
 464                       oper_num);
 465                 result->opcode = -1;    /* unrecoverable parse error: */
 466                 return result;  /* ignore this instruction */
 467             }
 468         }
 469
 470         if (result->opcode == I_INCBIN) {
 471             /*
 472              * Correct syntax for INCBIN is that there should be
 473              * one string operand, followed by one or two numeric
 474              * operands.
 475              */
 476             if (!result->eops || result->eops->type != EOT_DB_STRING)
 477                 error(ERR_NONFATAL, "`incbin' expects a file name");
 478             else if (result->eops->next &&
 479                      result->eops->next->type != EOT_DB_NUMBER)
 480                 error(ERR_NONFATAL, "`incbin': second parameter is",
 481                       " non-numeric");
 482             else if (result->eops->next && result->eops->next->next &&
 483                      result->eops->next->next->type != EOT_DB_NUMBER)
 484                 error(ERR_NONFATAL, "`incbin': third parameter is",
 485                       " non-numeric");
 486             else if (result->eops->next && result->eops->next->next &&
 487                      result->eops->next->next->next)
 488                 error(ERR_NONFATAL,
 489                       "`incbin': more than three parameters");
 490             else
 491                 return result;
 492             /*
 493              * If we reach here, one of the above errors happened.
 494              * Throw the instruction away.
 495              */
 496             result->opcode = -1;
 497             return result;
 498         } else /* DB ... */ if (oper_num == 0)
 499             error(ERR_WARNING | ERR_PASS1,
 500                   "no operand for data declaration");
 501         else
 502             result->operands = oper_num;
 503
 504         return result;
 505     }
 506
 507     /* right. Now we begin to parse the operands. There may be up to four
 508      * of these, separated by commas, and terminated by a zero token. */
 509
 510     for (operand = 0; operand < MAX_OPERANDS; operand++) {
 511         expr *value;            /* used most of the time */
 512         int mref;               /* is this going to be a memory ref? */
 513         int bracket;            /* is it a [] mref, or a & mref? */
 514         int setsize = 0;
 515
 516         result->oprs[operand].disp_size = 0;    /* have to zero this whatever */
 517         result->oprs[operand].eaflags = 0;      /* and this */
 518         result->oprs[operand].opflags = 0;
 519
 520         i = stdscan(NULL, &tokval);
 521         if (i == 0)
 522             break;              /* end of operands: get out of here */
 523         else if (first && i == ':') {
 524             insn_is_label = true;
 525             goto restart_parse;
 526         }
 527         first = false;
 528         result->oprs[operand].type = 0; /* so far, no override */
 529         while (i == TOKEN_SPECIAL) {    /* size specifiers */
 530             switch ((int)tokval.t_integer) {
 531             case S_BYTE:
 532                 if (!setsize)   /* we want to use only the first */
 533                     result->oprs[operand].type |= BITS8;
 534                 setsize = 1;
 535                 break;
 536             case S_WORD:
 537                 if (!setsize)
 538                     result->oprs[operand].type |= BITS16;
 539                 setsize = 1;
 540                 break;
 541             case S_DWORD:
 542             case S_LONG:
 543                 if (!setsize)
 544                     result->oprs[operand].type |= BITS32;
 545                 setsize = 1;
 546                 break;
 547             case S_QWORD:
 548                 if (!setsize)
 549                     result->oprs[operand].type |= BITS64;
 550                 setsize = 1;
 551                 break;
 552             case S_TWORD:
 553                 if (!setsize)
 554                     result->oprs[operand].type |= BITS80;
 555                 setsize = 1;
 556                 break;
 557             case S_OWORD:
 558                 if (!setsize)
 559                     result->oprs[operand].type |= BITS128;
 560                 setsize = 1;
 561                 break;
 562             case S_TO:
 563                 result->oprs[operand].type |= TO;
 564                 break;
 565             case S_STRICT:
 566                 result->oprs[operand].type |= STRICT;
 567                 break;
 568             case S_FAR:
 569                 result->oprs[operand].type |= FAR;
 570                 break;
 571             case S_NEAR:
 572                 result->oprs[operand].type |= NEAR;
 573                 break;
 574             case S_SHORT:
 575                 result->oprs[operand].type |= SHORT;
 576                 break;
 577             default:
 578                 error(ERR_NONFATAL, "invalid operand size specification");
 579             }
 580             i = stdscan(NULL, &tokval);
 581         }
 582
 583         if (i == '[' || i == '&') {     /* memory reference */
 584             mref = true;
 585             bracket = (i == '[');
 586             i = stdscan(NULL, &tokval); /* then skip the colon */
 587             while (i == TOKEN_SPECIAL || i == TOKEN_PREFIX) {
 588                 process_size_override(result, operand);
 589                 i = stdscan(NULL, &tokval);
 590             }
 591         } else {                /* immediate operand, or register */
 592             mref = false;
 593             bracket = false;    /* placate optimisers */
 594         }
 595
 596         if ((result->oprs[operand].type & FAR) && !mref &&
 597             result->opcode != I_JMP && result->opcode != I_CALL) {
 598             error(ERR_NONFATAL, "invalid use of FAR operand specifier");
 599         }
 600
 601         value = evaluate(stdscan, NULL, &tokval,
 602                          &result->oprs[operand].opflags,
 603                          critical, error, &hints);
 604         i = tokval.t_type;
 605         if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
 606             result->forw_ref = true;
 607         }
 608         if (!value) {           /* error in evaluator */
 609             result->opcode = -1;        /* unrecoverable parse error: */
 610             return result;      /* ignore this instruction */
 611         }
 612         if (i == ':' && mref) { /* it was seg:offset */
 613             /*
 614              * Process the segment override.
 615              */
 616             if (value[1].type != 0 || value->value != 1 ||
 617                 REG_SREG & ~reg_flags[value->type])
 618                 error(ERR_NONFATAL, "invalid segment override");
 619             else if (result->prefixes[PPS_SEG])
 620                 error(ERR_NONFATAL,
 621                       "instruction has conflicting segment overrides");
 622             else {
 623                 result->prefixes[PPS_SEG] = value->type;
 624                 if (!(REG_FSGS & ~reg_flags[value->type]))
 625                     result->oprs[operand].eaflags |= EAF_FSGS;
 626             }
 627
 628             i = stdscan(NULL, &tokval); /* then skip the colon */
 629             while (i == TOKEN_SPECIAL || i == TOKEN_PREFIX) {
 630                 process_size_override(result, operand);
 631                 i = stdscan(NULL, &tokval);
 632             }
 633             value = evaluate(stdscan, NULL, &tokval,
 634                              &result->oprs[operand].opflags,
 635                              critical, error, &hints);
 636             i = tokval.t_type;
 637             if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
 638                 result->forw_ref = true;
 639             }
 640             /* and get the offset */
 641             if (!value) {       /* but, error in evaluator */
 642                 result->opcode = -1;    /* unrecoverable parse error: */
 643                 return result;  /* ignore this instruction */
 644             }
 645         }
 646         if (mref && bracket) {  /* find ] at the end */
 647             if (i != ']') {
 648                 error(ERR_NONFATAL, "parser: expecting ]");
 649                 do {            /* error recovery again */
 650                     i = stdscan(NULL, &tokval);
 651                 } while (i != 0 && i != ',');
 652             } else              /* we got the required ] */
 653                 i = stdscan(NULL, &tokval);
 654         } else {                /* immediate operand */
 655             if (i != 0 && i != ',' && i != ':') {
 656                 error(ERR_NONFATAL, "comma or end of line expected");
 657                 do {            /* error recovery */
 658                     i = stdscan(NULL, &tokval);
 659                 } while (i != 0 && i != ',');
 660             } else if (i == ':') {
 661                 result->oprs[operand].type |= COLON;
 662             }
 663         }
 664
 665         /* now convert the exprs returned from evaluate() into operand
 666          * descriptions... */
 667
 668         if (mref) {             /* it's a memory reference */
 669             expr *e = value;
 670             int b, i, s;        /* basereg, indexreg, scale */
 671             int64_t o;             /* offset */
 672
 673             b = i = -1, o = s = 0;
 674             result->oprs[operand].hintbase = hints.base;
 675             result->oprs[operand].hinttype = hints.type;
 676
 677             if (e->type && e->type <= EXPR_REG_END) {   /* this bit's a register */
 678                 if (e->value == 1)      /* in fact it can be basereg */
 679                     b = e->type;
 680                 else            /* no, it has to be indexreg */
 681                     i = e->type, s = e->value;
 682                 e++;
 683             }
 684             if (e->type && e->type <= EXPR_REG_END) {   /* it's a 2nd register */
 685                 if (b != -1)    /* If the first was the base, ... */
 686                     i = e->type, s = e->value;  /* second has to be indexreg */
 687
 688                 else if (e->value != 1) {       /* If both want to be index */
 689                     error(ERR_NONFATAL,
 690                           "beroset-p-592-invalid effective address");
 691                     result->opcode = -1;
 692                     return result;
 693                 } else
 694                     b = e->type;
 695                 e++;
 696             }
 697             if (e->type != 0) { /* is there an offset? */
 698                 if (e->type <= EXPR_REG_END) {  /* in fact, is there an error? */
 699                     error(ERR_NONFATAL,
 700                           "beroset-p-603-invalid effective address");
 701                     result->opcode = -1;
 702                     return result;
 703                 } else {
 704                     if (e->type == EXPR_UNKNOWN) {
 705                         o = 0;  /* doesn't matter what */
 706                         result->oprs[operand].wrt = NO_SEG;     /* nor this */
 707                         result->oprs[operand].segment = NO_SEG; /* or this */
 708                         while (e->type)
 709                             e++;        /* go to the end of the line */
 710                     } else {
 711                         if (e->type == EXPR_SIMPLE) {
 712                             o = e->value;
 713                             e++;
 714                         }
 715                         if (e->type == EXPR_WRT) {
 716                             result->oprs[operand].wrt = e->value;
 717                             e++;
 718                         } else
 719                             result->oprs[operand].wrt = NO_SEG;
 720                         /*
 721                          * Look for a segment base type.
 722                          */
 723                         if (e->type && e->type < EXPR_SEGBASE) {
 724                             error(ERR_NONFATAL,
 725                                   "beroset-p-630-invalid effective address");
 726                             result->opcode = -1;
 727                             return result;
 728                         }
 729                         while (e->type && e->value == 0)
 730                             e++;
 731                         if (e->type && e->value != 1) {
 732                             error(ERR_NONFATAL,
 733                                   "beroset-p-637-invalid effective address");
 734                             result->opcode = -1;
 735                             return result;
 736                         }
 737                         if (e->type) {
 738                             result->oprs[operand].segment =
 739                                 e->type - EXPR_SEGBASE;
 740                             e++;
 741                         } else
 742                             result->oprs[operand].segment = NO_SEG;
 743                         while (e->type && e->value == 0)
 744                             e++;
 745                         if (e->type) {
 746                             error(ERR_NONFATAL,
 747                                   "beroset-p-650-invalid effective address");
 748                             result->opcode = -1;
 749                             return result;
 750                         }
 751                     }
 752                 }
 753             } else {
 754                 o = 0;
 755                 result->oprs[operand].wrt = NO_SEG;
 756                 result->oprs[operand].segment = NO_SEG;
 757             }
 758
 759             if (e->type != 0) { /* there'd better be nothing left! */
 760                 error(ERR_NONFATAL,
 761                       "beroset-p-663-invalid effective address");
 762                 result->opcode = -1;
 763                 return result;
 764             }
 765
 766             /* It is memory, but it can match any r/m operand */
 767             result->oprs[operand].type |= MEMORY_ANY;
 768
 769             if (b == -1 && (i == -1 || s == 0)) {
 770                 int is_rel = globalbits == 64 &&
 771                     !(result->oprs[operand].eaflags & EAF_ABS) &&
 772                     ((globalrel &&
 773                       !(result->oprs[operand].eaflags & EAF_FSGS)) ||
 774                      (result->oprs[operand].eaflags & EAF_REL));
 775
 776                 result->oprs[operand].type |= is_rel ? IP_REL : MEM_OFFS;
 777             }
 778             result->oprs[operand].basereg = b;
 779             result->oprs[operand].indexreg = i;
 780             result->oprs[operand].scale = s;
 781             result->oprs[operand].offset = o;
 782         } else {                /* it's not a memory reference */
 783
 784             if (is_just_unknown(value)) {       /* it's immediate but unknown */
 785                 result->oprs[operand].type |= IMMEDIATE;
 786                 result->oprs[operand].offset = 0;       /* don't care */
 787                 result->oprs[operand].segment = NO_SEG; /* don't care again */
 788                 result->oprs[operand].wrt = NO_SEG;     /* still don't care */
 789             } else if (is_reloc(value)) {       /* it's immediate */
 790                 result->oprs[operand].type |= IMMEDIATE;
 791                 result->oprs[operand].offset = reloc_value(value);
 792                 result->oprs[operand].segment = reloc_seg(value);
 793                 result->oprs[operand].wrt = reloc_wrt(value);
 794                 if (is_simple(value)) {
 795                     if (reloc_value(value) == 1)
 796                         result->oprs[operand].type |= UNITY;
 797                     if (optimizing >= 0 &&
 798                         !(result->oprs[operand].type & STRICT)) {
 799                         if (reloc_value(value) >= -128 &&
 800                             reloc_value(value) <= 127)
 801                             result->oprs[operand].type |= SBYTE;
 802                     }
 803                 }
 804             } else {            /* it's a register */
 805
 806                 if (value->type >= EXPR_SIMPLE || value->value != 1) {
 807                     error(ERR_NONFATAL, "invalid operand type");
 808                     result->opcode = -1;
 809                     return result;
 810                 }
 811
 812                 /*
 813                  * check that its only 1 register, not an expression...
 814                  */
 815                 for (i = 1; value[i].type; i++)
 816                     if (value[i].value) {
 817                         error(ERR_NONFATAL, "invalid operand type");
 818                         result->opcode = -1;
 819                         return result;
 820                     }
 821
 822                 /* clear overrides, except TO which applies to FPU regs */
 823                 if (result->oprs[operand].type & ~TO) {
 824                     /*
 825                      * we want to produce a warning iff the specified size
 826                      * is different from the register size
 827                      */
 828                     i = result->oprs[operand].type & SIZE_MASK;
 829                 } else
 830                     i = 0;
 831
 832                 result->oprs[operand].type &= TO;
 833                 result->oprs[operand].type |= REGISTER;
 834                 result->oprs[operand].type |= reg_flags[value->type];
 835                 result->oprs[operand].basereg = value->type;
 836
 837                 if (i && (result->oprs[operand].type & SIZE_MASK) != i)
 838                     error(ERR_WARNING | ERR_PASS1,
 839                           "register size specification ignored");
 840             }
 841         }
 842     }
 843
 844     result->operands = operand; /* set operand count */
 845
 846 /* clear remaining operands */
 847 while (operand < MAX_OPERANDS)
 848     result->oprs[operand++].type = 0;
 849
 850     /*
 851      * Transform RESW, RESD, RESQ, REST, RESO into RESB.
 852      */
 853     switch (result->opcode) {
 854     case I_RESW:
 855         result->opcode = I_RESB;
 856         result->oprs[0].offset *= 2;
 857         break;
 858     case I_RESD:
 859         result->opcode = I_RESB;
 860         result->oprs[0].offset *= 4;
 861         break;
 862     case I_RESQ:
 863         result->opcode = I_RESB;
 864         result->oprs[0].offset *= 8;
 865         break;
 866     case I_REST:
 867         result->opcode = I_RESB;
 868         result->oprs[0].offset *= 10;
 869         break;
 870     case I_RESO:
 871         result->opcode = I_RESB;
 872         result->oprs[0].offset *= 16;
 873         break;
 874     default:
 875         break;
 876     }
 877
 878     return result;
 879 }
 880
 881 static int is_comma_next(void)
 882 {
 883     char *p;
 884     int i;
 885     struct tokenval tv;
 886
 887     p = stdscan_bufptr;
 888     i = stdscan(NULL, &tv);
 889     stdscan_bufptr = p;
 890     return (i == ',' || i == ';' || !i);
 891 }
 892
 893 void cleanup_insn(insn * i)
 894 {
 895     extop *e;
 896
 897     while (i->eops) {
 898         e = i->eops;
 899         i->eops = i->eops->next;
 900         nasm_free(e);
 901     }
 902 }