parser.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  * parser.c   source line parser for the Netwide Assembler
  36  */
  37
  38 #include "compiler.h"
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <stddef.h>
  43 #include <string.h>
  44 #include <ctype.h>
  45 #include <inttypes.h>
  46
  47 #include "nasm.h"
  48 #include "insns.h"
  49 #include "nasmlib.h"
  50 #include "stdscan.h"
  51 #include "eval.h"
  52 #include "parser.h"
  53 #include "float.h"
  54 #include "tables.h"
  55
  56 extern int in_abs_seg;          /* ABSOLUTE segment flag */
  57 extern int32_t abs_seg;         /* ABSOLUTE segment */
  58 extern int32_t abs_offset;      /* ABSOLUTE segment offset */
  59
  60 static int is_comma_next(void);
  61
  62 static int i;
  63 static struct tokenval tokval;
  64 static struct location *location;       /* Pointer to current line's segment,offset */
  65
  66 void parser_global_info(struct location * locp)
  67 {
  68     location = locp;
  69 }
  70
  71 static int prefix_slot(enum prefixes prefix)
  72 {
  73     switch (prefix) {
  74     case P_WAIT:
  75         return PPS_WAIT;
  76     case R_CS:
  77     case R_DS:
  78     case R_SS:
  79     case R_ES:
  80     case R_FS:
  81     case R_GS:
  82         return PPS_SEG;
  83     case P_LOCK:
  84     case P_REP:
  85     case P_REPE:
  86     case P_REPZ:
  87     case P_REPNE:
  88     case P_REPNZ:
  89         return PPS_LREP;
  90     case P_O16:
  91     case P_O32:
  92     case P_O64:
  93     case P_OSP:
  94         return PPS_OSIZE;
  95     case P_A16:
  96     case P_A32:
  97     case P_A64:
  98     case P_ASP:
  99         return PPS_ASIZE;
 100     default:
 101         nasm_error(ERR_PANIC, "Invalid value %d passed to prefix_slot()", prefix);
 102         return -1;
 103     }
 104 }
 105
 106 static void process_size_override(insn *result, int operand)
 107 {
 108     if (tasm_compatible_mode) {
 109         switch ((int)tokval.t_integer) {
 110             /* For TASM compatibility a size override inside the
 111              * brackets changes the size of the operand, not the
 112              * address type of the operand as it does in standard
 113              * NASM syntax. Hence:
 114              *
 115              *  mov     eax,[DWORD val]
 116              *
 117              * is valid syntax in TASM compatibility mode. Note that
 118              * you lose the ability to override the default address
 119              * type for the instruction, but we never use anything
 120              * but 32-bit flat model addressing in our code.
 121              */
 122         case S_BYTE:
 123             result->oprs[operand].type |= BITS8;
 124             break;
 125         case S_WORD:
 126             result->oprs[operand].type |= BITS16;
 127             break;
 128         case S_DWORD:
 129         case S_LONG:
 130             result->oprs[operand].type |= BITS32;
 131             break;
 132         case S_QWORD:
 133             result->oprs[operand].type |= BITS64;
 134             break;
 135         case S_TWORD:
 136             result->oprs[operand].type |= BITS80;
 137             break;
 138         case S_OWORD:
 139             result->oprs[operand].type |= BITS128;
 140             break;
 141         default:
 142             nasm_error(ERR_NONFATAL,
 143                        "invalid operand size specification");
 144             break;
 145         }
 146     } else {
 147         /* Standard NASM compatible syntax */
 148         switch ((int)tokval.t_integer) {
 149         case S_NOSPLIT:
 150             result->oprs[operand].eaflags |= EAF_TIMESTWO;
 151             break;
 152         case S_REL:
 153             result->oprs[operand].eaflags |= EAF_REL;
 154             break;
 155         case S_ABS:
 156             result->oprs[operand].eaflags |= EAF_ABS;
 157             break;
 158         case S_BYTE:
 159             result->oprs[operand].disp_size = 8;
 160             result->oprs[operand].eaflags |= EAF_BYTEOFFS;
 161             break;
 162         case P_A16:
 163         case P_A32:
 164         case P_A64:
 165             if (result->prefixes[PPS_ASIZE] &&
 166                 result->prefixes[PPS_ASIZE] != tokval.t_integer)
 167                 nasm_error(ERR_NONFATAL,
 168                            "conflicting address size specifications");
 169             else
 170                 result->prefixes[PPS_ASIZE] = tokval.t_integer;
 171             break;
 172         case S_WORD:
 173             result->oprs[operand].disp_size = 16;
 174             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 175             break;
 176         case S_DWORD:
 177         case S_LONG:
 178             result->oprs[operand].disp_size = 32;
 179             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 180             break;
 181         case S_QWORD:
 182             result->oprs[operand].disp_size = 64;
 183             result->oprs[operand].eaflags |= EAF_WORDOFFS;
 184             break;
 185         default:
 186             nasm_error(ERR_NONFATAL, "invalid size specification in"
 187                        " effective address");
 188             break;
 189         }
 190     }
 191 }
 192
 193 insn *parse_line(int pass, char *buffer, insn *result, ldfunc ldef)
 194 {
 195     int operand;
 196     int critical;
 197     struct eval_hints hints;
 198     int j;
 199     bool first;
 200     bool insn_is_label = false;
 201     bool recover;
 202
 203 restart_parse:
 204     first = true;
 205     result->forw_ref = false;
 206
 207     stdscan_reset();
 208     stdscan_set(buffer);
 209     i = stdscan(NULL, &tokval);
 210
 211     result->label = NULL;       /* Assume no label */
 212     result->eops = NULL;        /* must do this, whatever happens */
 213     result->operands = 0;       /* must initialize this */
 214
 215     if (i == 0) {               /* blank line - ignore */
 216         result->opcode = I_none;    /* and no instruction either */
 217         return result;
 218     }
 219     if (i != TOKEN_ID && i != TOKEN_INSN && i != TOKEN_PREFIX &&
 220         (i != TOKEN_REG || (REG_SREG & ~nasm_reg_flags[tokval.t_integer]))) {
 221         nasm_error(ERR_NONFATAL, "label or instruction expected"
 222               " at start of line");
 223         result->opcode = I_none;
 224         return result;
 225     }
 226
 227     if (i == TOKEN_ID || (insn_is_label && i == TOKEN_INSN)) {
 228         /* there's a label here */
 229         first = false;
 230         result->label = tokval.t_charptr;
 231         i = stdscan(NULL, &tokval);
 232         if (i == ':') {         /* skip over the optional colon */
 233             i = stdscan(NULL, &tokval);
 234         } else if (i == 0) {
 235             nasm_error(ERR_WARNING | ERR_WARN_OL | ERR_PASS1,
 236                   "label alone on a line without a colon might be in error");
 237         }
 238         if (i != TOKEN_INSN || tokval.t_integer != I_EQU) {
 239             /*
 240              * FIXME: location->segment could be NO_SEG, in which case
 241              * it is possible we should be passing 'abs_seg'. Look into this.
 242              * Work out whether that is *really* what we should be doing.
 243              * Generally fix things. I think this is right as it is, but
 244              * am still not certain.
 245              */
 246             ldef(result->label, in_abs_seg ? abs_seg : location->segment,
 247                  location->offset, NULL, true, false);
 248         }
 249     }
 250
 251     if (i == 0) {
 252         result->opcode = I_none;    /* this line contains just a label */
 253         return result;
 254     }
 255
 256     for (j = 0; j < MAXPREFIX; j++)
 257         result->prefixes[j] = P_none;
 258     result->times = 1L;
 259
 260     while (i == TOKEN_PREFIX ||
 261            (i == TOKEN_REG && !(REG_SREG & ~nasm_reg_flags[tokval.t_integer])))
 262     {
 263         first = false;
 264
 265         /*
 266          * Handle special case: the TIMES prefix.
 267          */
 268         if (i == TOKEN_PREFIX && tokval.t_integer == P_TIMES) {
 269             expr *value;
 270
 271             i = stdscan(NULL, &tokval);
 272             value =
 273                 evaluate(stdscan, NULL, &tokval, NULL, pass0, nasm_error, NULL);
 274             i = tokval.t_type;
 275             if (!value) {       /* but, error in evaluator */
 276                 result->opcode = I_none;    /* unrecoverable parse error: */
 277                 return result;  /* ignore this instruction */
 278             }
 279             if (!is_simple(value)) {
 280                 nasm_error(ERR_NONFATAL,
 281                       "non-constant argument supplied to TIMES");
 282                 result->times = 1L;
 283             } else {
 284                 result->times = value->value;
 285                 if (value->value < 0 && pass0 == 2) {
 286                     nasm_error(ERR_NONFATAL, "TIMES value %"PRId64" is negative",
 287                           value->value);
 288                     result->times = 0;
 289                 }
 290             }
 291         } else {
 292             int slot = prefix_slot(tokval.t_integer);
 293             if (result->prefixes[slot]) {
 294                if (result->prefixes[slot] == tokval.t_integer)
 295                     nasm_error(ERR_WARNING,
 296                                "instruction has redundant prefixes");
 297                else
 298                     nasm_error(ERR_NONFATAL,
 299                                "instruction has conflicting prefixes");
 300             }
 301             result->prefixes[slot] = tokval.t_integer;
 302             i = stdscan(NULL, &tokval);
 303         }
 304     }
 305
 306     if (i != TOKEN_INSN) {
 307         int j;
 308         enum prefixes pfx;
 309
 310         for (j = 0; j < MAXPREFIX; j++)
 311             if ((pfx = result->prefixes[j]) != P_none)
 312                 break;
 313
 314         if (i == 0 && pfx != P_none) {
 315             /*
 316              * Instruction prefixes are present, but no actual
 317              * instruction. This is allowed: at this point we
 318              * invent a notional instruction of RESB 0.
 319              */
 320             result->opcode = I_RESB;
 321             result->operands = 1;
 322             result->oprs[0].type = IMMEDIATE;
 323             result->oprs[0].offset = 0L;
 324             result->oprs[0].segment = result->oprs[0].wrt = NO_SEG;
 325             return result;
 326         } else {
 327             nasm_error(ERR_NONFATAL, "parser: instruction expected");
 328             result->opcode = I_none;
 329             return result;
 330         }
 331     }
 332
 333     result->opcode = tokval.t_integer;
 334     result->condition = tokval.t_inttwo;
 335
 336     /*
 337      * INCBIN cannot be satisfied with incorrectly
 338      * evaluated operands, since the correct values _must_ be known
 339      * on the first pass. Hence, even in pass one, we set the
 340      * `critical' flag on calling evaluate(), so that it will bomb
 341      * out on undefined symbols.
 342      */
 343     if (result->opcode == I_INCBIN) {
 344         critical = (pass0 < 2 ? 1 : 2);
 345
 346     } else
 347         critical = (pass == 2 ? 2 : 0);
 348
 349     if (result->opcode == I_DB || result->opcode == I_DW ||
 350         result->opcode == I_DD || result->opcode == I_DQ ||
 351         result->opcode == I_DT || result->opcode == I_DO ||
 352         result->opcode == I_DY || result->opcode == I_INCBIN) {
 353         extop *eop, **tail = &result->eops, **fixptr;
 354         int oper_num = 0;
 355         int32_t sign;
 356
 357         result->eops_float = false;
 358
 359         /*
 360          * Begin to read the DB/DW/DD/DQ/DT/DO/INCBIN operands.
 361          */
 362         while (1) {
 363             i = stdscan(NULL, &tokval);
 364             if (i == 0)
 365                 break;
 366             else if (first && i == ':') {
 367                 insn_is_label = true;
 368                 goto restart_parse;
 369             }
 370             first = false;
 371             fixptr = tail;
 372             eop = *tail = nasm_malloc(sizeof(extop));
 373             tail = &eop->next;
 374             eop->next = NULL;
 375             eop->type = EOT_NOTHING;
 376             oper_num++;
 377             sign = +1;
 378
 379             /*
 380              * is_comma_next() here is to distinguish this from
 381              * a string used as part of an expression...
 382              */
 383             if (i == TOKEN_STR && is_comma_next()) {
 384                 eop->type = EOT_DB_STRING;
 385                 eop->stringval = tokval.t_charptr;
 386                 eop->stringlen = tokval.t_inttwo;
 387                 i = stdscan(NULL, &tokval);     /* eat the comma */
 388             } else if (i == TOKEN_STRFUNC) {
 389                 bool parens = false;
 390                 const char *funcname = tokval.t_charptr;
 391                 enum strfunc func = tokval.t_integer;
 392                 i = stdscan(NULL, &tokval);
 393                 if (i == '(') {
 394                     parens = true;
 395                     i = stdscan(NULL, &tokval);
 396                 }
 397                 if (i != TOKEN_STR) {
 398                     nasm_error(ERR_NONFATAL,
 399                                "%s must be followed by a string constant",
 400                                funcname);
 401                         eop->type = EOT_NOTHING;
 402                 } else {
 403                     eop->type = EOT_DB_STRING_FREE;
 404                     eop->stringlen =
 405                         string_transform(tokval.t_charptr, tokval.t_inttwo,
 406                                          &eop->stringval, func);
 407                     if (eop->stringlen == (size_t)-1) {
 408                         nasm_error(ERR_NONFATAL, "invalid string for transform");
 409                         eop->type = EOT_NOTHING;
 410                     }
 411                 }
 412                 if (parens && i && i != ')') {
 413                     i = stdscan(NULL, &tokval);
 414                     if (i != ')') {
 415                         nasm_error(ERR_NONFATAL, "unterminated %s function",
 416                                    funcname);
 417                     }
 418                 }
 419                 if (i && i != ',')
 420                     i = stdscan(NULL, &tokval);
 421             } else if (i == '-' || i == '+') {
 422                 char *save = stdscan_get();
 423                 int token = i;
 424                 sign = (i == '-') ? -1 : 1;
 425                 i = stdscan(NULL, &tokval);
 426                 if (i != TOKEN_FLOAT) {
 427                     stdscan_set(save);
 428                     i = tokval.t_type = token;
 429                     goto is_expression;
 430                 } else {
 431                     goto is_float;
 432                 }
 433             } else if (i == TOKEN_FLOAT) {
 434 is_float:
 435                 eop->type = EOT_DB_STRING;
 436                 result->eops_float = true;
 437
 438                 eop->stringlen = idata_bytes(result->opcode);
 439                 if (eop->stringlen > 16) {
 440                     nasm_error(ERR_NONFATAL, "floating-point constant"
 441                                " encountered in DY instruction");
 442                     eop->stringlen = 0;
 443                 } else if (eop->stringlen < 1) {
 444                     nasm_error(ERR_NONFATAL, "floating-point constant"
 445                                " encountered in unknown instruction");
 446                     /*
 447                      * fix suggested by Pedro Gimeno... original line was:
 448                      * eop->type = EOT_NOTHING;
 449                      */
 450                     eop->stringlen = 0;
 451                 }
 452
 453                 eop = nasm_realloc(eop, sizeof(extop) + eop->stringlen);
 454                 tail = &eop->next;
 455                 *fixptr = eop;
 456                 eop->stringval = (char *)eop + sizeof(extop);
 457                 if (!eop->stringlen ||
 458                     !float_const(tokval.t_charptr, sign,
 459                                  (uint8_t *)eop->stringval,
 460                                  eop->stringlen, nasm_error))
 461                     eop->type = EOT_NOTHING;
 462                 i = stdscan(NULL, &tokval); /* eat the comma */
 463             } else {
 464                 /* anything else, assume it is an expression */
 465                 expr *value;
 466
 467 is_expression:
 468                 value = evaluate(stdscan, NULL, &tokval, NULL,
 469                                  critical, nasm_error, NULL);
 470                 i = tokval.t_type;
 471                 if (!value) {   /* error in evaluator */
 472                     result->opcode = I_none;        /* unrecoverable parse error: */
 473                     return result;      /* ignore this instruction */
 474                 }
 475                 if (is_unknown(value)) {
 476                     eop->type = EOT_DB_NUMBER;
 477                     eop->offset = 0;    /* doesn't matter what we put */
 478                     eop->segment = eop->wrt = NO_SEG;   /* likewise */
 479                 } else if (is_reloc(value)) {
 480                     eop->type = EOT_DB_NUMBER;
 481                     eop->offset = reloc_value(value);
 482                     eop->segment = reloc_seg(value);
 483                     eop->wrt = reloc_wrt(value);
 484                 } else {
 485                     nasm_error(ERR_NONFATAL,
 486                           "operand %d: expression is not simple"
 487                           " or relocatable", oper_num);
 488                 }
 489             }
 490
 491             /*
 492              * We're about to call stdscan(), which will eat the
 493              * comma that we're currently sitting on between
 494              * arguments. However, we'd better check first that it
 495              * _is_ a comma.
 496              */
 497             if (i == 0)         /* also could be EOL */
 498                 break;
 499             if (i != ',') {
 500                 nasm_error(ERR_NONFATAL, "comma expected after operand %d",
 501                       oper_num);
 502                 result->opcode = I_none;    /* unrecoverable parse error: */
 503                 return result;  /* ignore this instruction */
 504             }
 505         }
 506
 507         if (result->opcode == I_INCBIN) {
 508             /*
 509              * Correct syntax for INCBIN is that there should be
 510              * one string operand, followed by one or two numeric
 511              * operands.
 512              */
 513             if (!result->eops || result->eops->type != EOT_DB_STRING)
 514                 nasm_error(ERR_NONFATAL, "`incbin' expects a file name");
 515             else if (result->eops->next &&
 516                      result->eops->next->type != EOT_DB_NUMBER)
 517                 nasm_error(ERR_NONFATAL, "`incbin': second parameter is"
 518                       " non-numeric");
 519             else if (result->eops->next && result->eops->next->next &&
 520                      result->eops->next->next->type != EOT_DB_NUMBER)
 521                 nasm_error(ERR_NONFATAL, "`incbin': third parameter is"
 522                       " non-numeric");
 523             else if (result->eops->next && result->eops->next->next &&
 524                      result->eops->next->next->next)
 525                 nasm_error(ERR_NONFATAL,
 526                       "`incbin': more than three parameters");
 527             else
 528                 return result;
 529             /*
 530              * If we reach here, one of the above errors happened.
 531              * Throw the instruction away.
 532              */
 533             result->opcode = I_none;
 534             return result;
 535         } else /* DB ... */ if (oper_num == 0)
 536             nasm_error(ERR_WARNING | ERR_PASS1,
 537                   "no operand for data declaration");
 538         else
 539             result->operands = oper_num;
 540
 541         return result;
 542     }
 543
 544     /* right. Now we begin to parse the operands. There may be up to four
 545      * of these, separated by commas, and terminated by a zero token. */
 546
 547     for (operand = 0; operand < MAX_OPERANDS; operand++) {
 548         expr *value;            /* used most of the time */
 549         int mref;               /* is this going to be a memory ref? */
 550         int bracket;            /* is it a [] mref, or a & mref? */
 551         int setsize = 0;
 552
 553         result->oprs[operand].disp_size = 0;    /* have to zero this whatever */
 554         result->oprs[operand].eaflags = 0;      /* and this */
 555         result->oprs[operand].opflags = 0;
 556
 557         i = stdscan(NULL, &tokval);
 558         if (i == 0)
 559             break;              /* end of operands: get out of here */
 560         else if (first && i == ':') {
 561             insn_is_label = true;
 562             goto restart_parse;
 563         }
 564         first = false;
 565         result->oprs[operand].type = 0; /* so far, no override */
 566         while (i == TOKEN_SPECIAL) {    /* size specifiers */
 567             switch ((int)tokval.t_integer) {
 568             case S_BYTE:
 569                 if (!setsize)   /* we want to use only the first */
 570                     result->oprs[operand].type |= BITS8;
 571                 setsize = 1;
 572                 break;
 573             case S_WORD:
 574                 if (!setsize)
 575                     result->oprs[operand].type |= BITS16;
 576                 setsize = 1;
 577                 break;
 578             case S_DWORD:
 579             case S_LONG:
 580                 if (!setsize)
 581                     result->oprs[operand].type |= BITS32;
 582                 setsize = 1;
 583                 break;
 584             case S_QWORD:
 585                 if (!setsize)
 586                     result->oprs[operand].type |= BITS64;
 587                 setsize = 1;
 588                 break;
 589             case S_TWORD:
 590                 if (!setsize)
 591                     result->oprs[operand].type |= BITS80;
 592                 setsize = 1;
 593                 break;
 594             case S_OWORD:
 595                 if (!setsize)
 596                     result->oprs[operand].type |= BITS128;
 597                 setsize = 1;
 598                 break;
 599             case S_YWORD:
 600                 if (!setsize)
 601                     result->oprs[operand].type |= BITS256;
 602                 setsize = 1;
 603                 break;
 604             case S_TO:
 605                 result->oprs[operand].type |= TO;
 606                 break;
 607             case S_STRICT:
 608                 result->oprs[operand].type |= STRICT;
 609                 break;
 610             case S_FAR:
 611                 result->oprs[operand].type |= FAR;
 612                 break;
 613             case S_NEAR:
 614                 result->oprs[operand].type |= NEAR;
 615                 break;
 616             case S_SHORT:
 617                 result->oprs[operand].type |= SHORT;
 618                 break;
 619             default:
 620                 nasm_error(ERR_NONFATAL, "invalid operand size specification");
 621             }
 622             i = stdscan(NULL, &tokval);
 623         }
 624
 625         if (i == '[' || i == '&') {     /* memory reference */
 626             mref = true;
 627             bracket = (i == '[');
 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         } else {                /* immediate operand, or register */
 634             mref = false;
 635             bracket = false;    /* placate optimisers */
 636         }
 637
 638         if ((result->oprs[operand].type & FAR) && !mref &&
 639             result->opcode != I_JMP && result->opcode != I_CALL) {
 640             nasm_error(ERR_NONFATAL, "invalid use of FAR operand specifier");
 641         }
 642
 643         value = evaluate(stdscan, NULL, &tokval,
 644                          &result->oprs[operand].opflags,
 645                          critical, nasm_error, &hints);
 646         i = tokval.t_type;
 647         if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
 648             result->forw_ref = true;
 649         }
 650         if (!value) {           /* nasm_error in evaluator */
 651             result->opcode = I_none;        /* unrecoverable parse error: */
 652             return result;      /* ignore this instruction */
 653         }
 654         if (i == ':' && mref) { /* it was seg:offset */
 655             /*
 656              * Process the segment override.
 657              */
 658             if (value[1].type != 0 || value->value != 1 ||
 659                 REG_SREG & ~nasm_reg_flags[value->type])
 660                 nasm_error(ERR_NONFATAL, "invalid segment override");
 661             else if (result->prefixes[PPS_SEG])
 662                 nasm_error(ERR_NONFATAL,
 663                       "instruction has conflicting segment overrides");
 664             else {
 665                 result->prefixes[PPS_SEG] = value->type;
 666                 if (!(REG_FSGS & ~nasm_reg_flags[value->type]))
 667                     result->oprs[operand].eaflags |= EAF_FSGS;
 668             }
 669
 670             i = stdscan(NULL, &tokval); /* then skip the colon */
 671             while (i == TOKEN_SPECIAL || i == TOKEN_PREFIX) {
 672                 process_size_override(result, operand);
 673                 i = stdscan(NULL, &tokval);
 674             }
 675             value = evaluate(stdscan, NULL, &tokval,
 676                              &result->oprs[operand].opflags,
 677                              critical, nasm_error, &hints);
 678             i = tokval.t_type;
 679             if (result->oprs[operand].opflags & OPFLAG_FORWARD) {
 680                 result->forw_ref = true;
 681             }
 682             /* and get the offset */
 683             if (!value) {       /* but, error in evaluator */
 684                 result->opcode = I_none;    /* unrecoverable parse error: */
 685                 return result;  /* ignore this instruction */
 686             }
 687         }
 688
 689         recover = false;
 690         if (mref && bracket) {  /* find ] at the end */
 691             if (i != ']') {
 692                 nasm_error(ERR_NONFATAL, "parser: expecting ]");
 693                 recover = true;
 694             } else {            /* we got the required ] */
 695                 i = stdscan(NULL, &tokval);
 696                 if (i != 0 && i != ',') {
 697                     nasm_error(ERR_NONFATAL, "comma or end of line expected");
 698                     recover = true;
 699                 }
 700             }
 701         } else {                /* immediate operand */
 702             if (i != 0 && i != ',' && i != ':') {
 703                 nasm_error(ERR_NONFATAL, "comma, colon or end of line expected");
 704                 recover = true;
 705             } else if (i == ':') {
 706                 result->oprs[operand].type |= COLON;
 707             }
 708         }
 709         if (recover) {
 710             do {                /* error recovery */
 711                 i = stdscan(NULL, &tokval);
 712             } while (i != 0 && i != ',');
 713         }
 714
 715         /*
 716          * now convert the exprs returned from evaluate()
 717          * into operand descriptions...
 718          */
 719
 720         if (mref) {             /* it's a memory reference */
 721             expr *e = value;
 722             int b, i, s;        /* basereg, indexreg, scale */
 723             int64_t o;          /* offset */
 724
 725             b = i = -1, o = s = 0;
 726             result->oprs[operand].hintbase = hints.base;
 727             result->oprs[operand].hinttype = hints.type;
 728
 729             if (e->type && e->type <= EXPR_REG_END) {   /* this bit's a register */
 730                 if (e->value == 1)      /* in fact it can be basereg */
 731                     b = e->type;
 732                 else            /* no, it has to be indexreg */
 733                     i = e->type, s = e->value;
 734                 e++;
 735             }
 736             if (e->type && e->type <= EXPR_REG_END) {   /* it's a 2nd register */
 737                 if (b != -1)    /* If the first was the base, ... */
 738                     i = e->type, s = e->value;  /* second has to be indexreg */
 739
 740                 else if (e->value != 1) {       /* If both want to be index */
 741                     nasm_error(ERR_NONFATAL,
 742                           "beroset-p-592-invalid effective address");
 743                     result->opcode = I_none;
 744                     return result;
 745                 } else
 746                     b = e->type;
 747                 e++;
 748             }
 749             if (e->type != 0) { /* is there an offset? */
 750                 if (e->type <= EXPR_REG_END) {  /* in fact, is there an error? */
 751                     nasm_error(ERR_NONFATAL,
 752                           "beroset-p-603-invalid effective address");
 753                     result->opcode = I_none;
 754                     return result;
 755                 } else {
 756                     if (e->type == EXPR_UNKNOWN) {
 757                         result->oprs[operand].opflags |= OPFLAG_UNKNOWN;
 758                         o = 0;  /* doesn't matter what */
 759                         result->oprs[operand].wrt = NO_SEG;     /* nor this */
 760                         result->oprs[operand].segment = NO_SEG; /* or this */
 761                         while (e->type)
 762                             e++;        /* go to the end of the line */
 763                     } else {
 764                         if (e->type == EXPR_SIMPLE) {
 765                             o = e->value;
 766                             e++;
 767                         }
 768                         if (e->type == EXPR_WRT) {
 769                             result->oprs[operand].wrt = e->value;
 770                             e++;
 771                         } else
 772                             result->oprs[operand].wrt = NO_SEG;
 773                         /*
 774                          * Look for a segment base type.
 775                          */
 776                         if (e->type && e->type < EXPR_SEGBASE) {
 777                             nasm_error(ERR_NONFATAL,
 778                                   "beroset-p-630-invalid effective address");
 779                             result->opcode = I_none;
 780                             return result;
 781                         }
 782                         while (e->type && e->value == 0)
 783                             e++;
 784                         if (e->type && e->value != 1) {
 785                             nasm_error(ERR_NONFATAL,
 786                                   "beroset-p-637-invalid effective address");
 787                             result->opcode = I_none;
 788                             return result;
 789                         }
 790                         if (e->type) {
 791                             result->oprs[operand].segment =
 792                                 e->type - EXPR_SEGBASE;
 793                             e++;
 794                         } else
 795                             result->oprs[operand].segment = NO_SEG;
 796                         while (e->type && e->value == 0)
 797                             e++;
 798                         if (e->type) {
 799                             nasm_error(ERR_NONFATAL,
 800                                   "beroset-p-650-invalid effective address");
 801                             result->opcode = I_none;
 802                             return result;
 803                         }
 804                     }
 805                 }
 806             } else {
 807                 o = 0;
 808                 result->oprs[operand].wrt = NO_SEG;
 809                 result->oprs[operand].segment = NO_SEG;
 810             }
 811
 812             if (e->type != 0) { /* there'd better be nothing left! */
 813                 nasm_error(ERR_NONFATAL,
 814                       "beroset-p-663-invalid effective address");
 815                 result->opcode = I_none;
 816                 return result;
 817             }
 818
 819             /* It is memory, but it can match any r/m operand */
 820             result->oprs[operand].type |= MEMORY_ANY;
 821
 822             if (b == -1 && (i == -1 || s == 0)) {
 823                 int is_rel = globalbits == 64 &&
 824                     !(result->oprs[operand].eaflags & EAF_ABS) &&
 825                     ((globalrel &&
 826                       !(result->oprs[operand].eaflags & EAF_FSGS)) ||
 827                      (result->oprs[operand].eaflags & EAF_REL));
 828
 829                 result->oprs[operand].type |= is_rel ? IP_REL : MEM_OFFS;
 830             }
 831             result->oprs[operand].basereg = b;
 832             result->oprs[operand].indexreg = i;
 833             result->oprs[operand].scale = s;
 834             result->oprs[operand].offset = o;
 835         } else {                /* it's not a memory reference */
 836             if (is_just_unknown(value)) {       /* it's immediate but unknown */
 837                 result->oprs[operand].type |= IMMEDIATE;
 838                 result->oprs[operand].opflags |= OPFLAG_UNKNOWN;
 839                 result->oprs[operand].offset = 0;       /* don't care */
 840                 result->oprs[operand].segment = NO_SEG; /* don't care again */
 841                 result->oprs[operand].wrt = NO_SEG;     /* still don't care */
 842
 843                 if(optimizing >= 0 && !(result->oprs[operand].type & STRICT))
 844                 {
 845                     /* Be optimistic */
 846                     result->oprs[operand].type |=
 847                         SBYTE16 | SBYTE32 | SBYTE64 | UDWORD64 | SDWORD64;
 848                 }
 849             } else if (is_reloc(value)) {       /* it's immediate */
 850                 result->oprs[operand].type |= IMMEDIATE;
 851                 result->oprs[operand].offset = reloc_value(value);
 852                 result->oprs[operand].segment = reloc_seg(value);
 853                 result->oprs[operand].wrt = reloc_wrt(value);
 854                 if (is_simple(value)) {
 855                     if (reloc_value(value) == 1)
 856                         result->oprs[operand].type |= UNITY;
 857                     if (optimizing >= 0 &&
 858                         !(result->oprs[operand].type & STRICT)) {
 859                         int64_t v64 = reloc_value(value);
 860                         int32_t v32 = (int32_t)v64;
 861                         int16_t v16 = (int16_t)v32;
 862
 863                         if (v64 >= -128 && v64 <= 127)
 864                             result->oprs[operand].type |= SBYTE64;
 865                         if (v32 >= -128 && v32 <= 127)
 866                             result->oprs[operand].type |= SBYTE32;
 867                         if (v16 >= -128 && v16 <= 127)
 868                             result->oprs[operand].type |= SBYTE16;
 869                         if ((uint64_t)v64 <= UINT64_C(0xffffffff))
 870                             result->oprs[operand].type |= UDWORD64;
 871                         if (v64 >= -INT64_C(0x80000000) &&
 872                             v64 <=  INT64_C(0x7fffffff))
 873                             result->oprs[operand].type |= SDWORD64;
 874                     }
 875                 }
 876             } else {            /* it's a register */
 877                 unsigned int rs;
 878
 879                 if (value->type >= EXPR_SIMPLE || value->value != 1) {
 880                     nasm_error(ERR_NONFATAL, "invalid operand type");
 881                     result->opcode = I_none;
 882                     return result;
 883                 }
 884
 885                 /*
 886                  * check that its only 1 register, not an expression...
 887                  */
 888                 for (i = 1; value[i].type; i++)
 889                     if (value[i].value) {
 890                         nasm_error(ERR_NONFATAL, "invalid operand type");
 891                         result->opcode = I_none;
 892                         return result;
 893                     }
 894
 895                 /* clear overrides, except TO which applies to FPU regs */
 896                 if (result->oprs[operand].type & ~TO) {
 897                     /*
 898                      * we want to produce a warning iff the specified size
 899                      * is different from the register size
 900                      */
 901                     rs = result->oprs[operand].type & SIZE_MASK;
 902                 } else
 903                     rs = 0;
 904
 905                 result->oprs[operand].type &= TO;
 906                 result->oprs[operand].type |= REGISTER;
 907                 result->oprs[operand].type |= nasm_reg_flags[value->type];
 908                 result->oprs[operand].basereg = value->type;
 909
 910                 if (rs && (result->oprs[operand].type & SIZE_MASK) != rs)
 911                     nasm_error(ERR_WARNING | ERR_PASS1,
 912                           "register size specification ignored");
 913             }
 914         }
 915     }
 916
 917     result->operands = operand; /* set operand count */
 918
 919     /* clear remaining operands */
 920     while (operand < MAX_OPERANDS)
 921         result->oprs[operand++].type = 0;
 922
 923     /*
 924      * Transform RESW, RESD, RESQ, REST, RESO, RESY into RESB.
 925      */
 926     switch (result->opcode) {
 927     case I_RESW:
 928         result->opcode = I_RESB;
 929         result->oprs[0].offset *= 2;
 930         break;
 931     case I_RESD:
 932         result->opcode = I_RESB;
 933         result->oprs[0].offset *= 4;
 934         break;
 935     case I_RESQ:
 936         result->opcode = I_RESB;
 937         result->oprs[0].offset *= 8;
 938         break;
 939     case I_REST:
 940         result->opcode = I_RESB;
 941         result->oprs[0].offset *= 10;
 942         break;
 943     case I_RESO:
 944         result->opcode = I_RESB;
 945         result->oprs[0].offset *= 16;
 946         break;
 947     case I_RESY:
 948         result->opcode = I_RESB;
 949         result->oprs[0].offset *= 32;
 950         break;
 951     default:
 952         break;
 953     }
 954
 955     return result;
 956 }
 957
 958 static int is_comma_next(void)
 959 {
 960     char *p;
 961     int i;
 962     struct tokenval tv;
 963
 964     p = stdscan_get();
 965     i = stdscan(NULL, &tv);
 966     stdscan_set(p);
 967     return (i == ',' || i == ';' || !i);
 968 }
 969
 970 void cleanup_insn(insn * i)
 971 {
 972     extop *e;
 973
 974     while ((e = i->eops)) {
 975         i->eops = e->next;
 976         if (e->type == EOT_DB_STRING_FREE)
 977             nasm_free(e->stringval);
 978         nasm_free(e);
 979     }
 980 }