Shamusworld >> Repos - rmac/blob - expr.c

   1 //
   2 // RMAC - Reboot's Macro Assembler for the Atari Jaguar Console System
   3 // EXPR.C - Expression Analyzer
   4 // Copyright (C) 199x Landon Dyer, 2011 Reboot and Friends
   5 // RMAC derived from MADMAC v1.07 Written by Landon Dyer, 1986
   6 // Source Utilised with the Kind Permission of Landon Dyer
   7 //
   8
   9 #include "expr.h"
  10 #include "direct.h"
  11 #include "error.h"
  12 #include "listing.h"
  13 #include "mach.h"
  14 #include "procln.h"
  15 #include "riscasm.h"
  16 #include "sect.h"
  17 #include "symbol.h"
  18 #include "token.h"
  19
  20 #define DEF_KW                                                  // Declare keyword values
  21 #include "kwtab.h"                                              // Incl generated keyword tables & defs
  22
  23 static char tokenClass[128];                                    // Generated table of token classes
  24 static VALUE evstk[EVSTACKSIZE];                // Evaluator value stack
  25 static WORD evattr[EVSTACKSIZE];                // Evaluator attribute stack
  26
  27 // Token-class initialization list
  28 char itokcl[] = {
  29         0,                                                                      // END
  30         CONST, SYMBOL, 0,                                       // ID
  31         '(', '[', '{', 0,                                       // OPAR
  32         ')', ']', '}', 0,                                       // CPAR
  33         CR_DEFINED, CR_REFERENCED,                      // SUNARY (special unary)
  34         CR_STREQ, CR_MACDEF,
  35         CR_DATE, CR_TIME, 0,
  36         '!', '~', UNMINUS, 0,                           // UNARY
  37         '*', '/', '%', 0,                                       // MULT
  38         '+', '-', 0,                                            // ADD
  39         SHL, SHR, 0,                                            // SHIFT
  40         LE, GE, '<', '>', NE, '=', 0,           // REL
  41         '&', 0,                                                         // AND
  42         '^', 0,                                                         // XOR
  43         '|', 0,                                                         // OR
  44         1                                                                       // (the end)
  45 };
  46
  47 const char missym_error[] = "missing symbol";
  48 const char str_error[] = "missing symbol or string";
  49
  50 // Convert expression to postfix
  51 static TOKEN * evalTokenBuffer;                 // Deposit tokens here (this is really a
  52                                                                                 // pointer to exprbuf from direct.c)
  53                                                                                 // (Can also be from others, like riscasm.c)
  54 static symbolNum;                                               // Pointer to the entry in symbolPtr[]
  55
  56
  57 //
  58 // Obtain a String Value
  59 //
  60 static VALUE str_value(char * p)
  61 {
  62         VALUE v;
  63
  64         for(v=0; *p; p++)
  65                 v = (v << 8) | (*p & 0xFF);
  66
  67         return v;
  68 }
  69
  70
  71 //
  72 // Initialize Expression Analyzer
  73 //
  74 void InitExpression(void)
  75 {
  76         int i;                                                                  // Iterator
  77         char * p;                                                               // Token pointer
  78
  79         // Initialize token-class table (all set to END)
  80         for(i=0; i<128; i++)
  81                 tokenClass[i] = END;
  82
  83         for(i=0, p=itokcl; *p!=1; p++)
  84         {
  85                 if (*p == 0)
  86                         i++;
  87                 else
  88                         tokenClass[(int)(*p)] = (char)i;
  89         }
  90
  91         symbolNum = 0;
  92 }
  93
  94
  95 //
  96 // Binary operators (all the same precedence)
  97 //
  98 int expr0(void)
  99 {
 100         TOKEN t;
 101
 102         if (expr1() != OK)
 103                 return ERROR;
 104
 105         while (tokenClass[*tok] >= MULT)
 106         {
 107                 t = *tok++;
 108
 109                 if (expr1() != OK)
 110                         return ERROR;
 111
 112                 *evalTokenBuffer++ = t;
 113         }
 114
 115         return OK;
 116 }
 117
 118
 119 //
 120 // Unary operators (detect unary '-')
 121 //
 122 int expr1(void)
 123 {
 124         int class;
 125         TOKEN t;
 126         SYM * sy;
 127         char * p, * p2;
 128         WORD w;
 129         int j;
 130
 131         class = tokenClass[*tok];
 132
 133         if (*tok == '-' || class == UNARY)
 134         {
 135                 t = *tok++;
 136
 137                 if (expr2() != OK)
 138                         return ERROR;
 139
 140                 if (t == '-')
 141                         t = UNMINUS;
 142
 143                 *evalTokenBuffer++ = t;
 144         }
 145         else if (class == SUNARY)
 146         {
 147                 switch ((int)*tok++)
 148                 {
 149                 case CR_TIME:
 150                         *evalTokenBuffer++ = CONST;
 151                         *evalTokenBuffer++ = dos_time();
 152                         break;
 153                 case CR_DATE:
 154                         *evalTokenBuffer++ = CONST;
 155                         *evalTokenBuffer++ = dos_date();
 156                         break;
 157                 case CR_MACDEF:                                    // ^^macdef <macro-name>
 158                         if (*tok++ != SYMBOL)
 159                                 return error(missym_error);
 160
 161                         p = string[*tok++];
 162                         w = (lookup(p, MACRO, 0) == NULL ? 0 : 1);
 163                         *evalTokenBuffer++ = CONST;
 164                         *evalTokenBuffer++ = (TOKEN)w;
 165                         break;
 166                 case CR_DEFINED:
 167                         w = DEFINED;
 168                         goto getsym;
 169                 case CR_REFERENCED:
 170                         w = REFERENCED;
 171 getsym:
 172                         if (*tok++ != SYMBOL)
 173                                 return error(missym_error);
 174
 175                         p = string[*tok++];
 176                         j = (*p == '.' ? curenv : 0);
 177                         w = ((sy = lookup(p, LABEL, j)) != NULL && (sy->sattr & w) ? 1 : 0);
 178                         *evalTokenBuffer++ = CONST;
 179                         *evalTokenBuffer++ = (TOKEN)w;
 180                         break;
 181                 case CR_STREQ:
 182                         if (*tok != SYMBOL && *tok != STRING)
 183                                 return error(str_error);
 184
 185                         p = string[tok[1]];
 186                         tok +=2;
 187
 188                         if (*tok++ != ',')
 189                                 return error(comma_error);
 190
 191                         if (*tok != SYMBOL && *tok != STRING)
 192                                 return error(str_error);
 193
 194                         p = string[tok[1]];
 195                         tok += 2;
 196
 197                         w = (WORD)(!strcmp(p, p2));
 198                         *evalTokenBuffer++ = CONST;
 199                         *evalTokenBuffer++ = (TOKEN)w;
 200                         break;
 201                 }
 202         }
 203         else
 204                 return expr2();
 205
 206         return OK;
 207 }
 208
 209
 210 //
 211 // Terminals (CONSTs) and parenthesis grouping
 212 //
 213 int expr2(void)
 214 {
 215         char * p;
 216         SYM * sy;
 217         int j;
 218
 219         switch ((int)*tok++)
 220         {
 221         case CONST:
 222                 *evalTokenBuffer++ = CONST;
 223                 *evalTokenBuffer++ = *tok++;
 224                 break;
 225         case SYMBOL:
 226                 p = string[*tok++];
 227                 j = (*p == '.' ? curenv : 0);
 228                 sy = lookup(p, LABEL, j);
 229
 230                 if (sy == NULL)
 231                         sy = NewSymbol(p, LABEL, j);
 232
 233                 // Check register bank usage
 234                 if (sy->sattre & EQUATEDREG)
 235                 {
 236                         if ((regbank == BANK_0) && (sy->sattre & BANK_1) && !altbankok)
 237                                 warns("equated symbol \'%s\' cannot be used in register bank 0", sy->sname);
 238
 239                         if ((regbank == BANK_1) && (sy->sattre & BANK_0) && !altbankok)
 240                                 warns("equated symbol \'%s\' cannot be used in register bank 1", sy->sname);
 241                 }
 242
 243                 *evalTokenBuffer++ = SYMBOL;
 244                 *evalTokenBuffer++ = symbolNum;
 245                 symbolPtr[symbolNum] = sy;
 246                 symbolNum++;
 247                 break;
 248         case STRING:
 249                 *evalTokenBuffer++ = CONST;
 250                 *evalTokenBuffer++ = str_value(string[*tok++]);
 251                 break;
 252         case '(':
 253                 if (expr0() != OK)
 254                         return ERROR;
 255
 256                 if (*tok++ != ')')
 257                         return error("missing close parenthesis ')'");
 258
 259                 break;
 260         case '[':
 261                 if (expr0() != OK)
 262                         return ERROR;
 263
 264                 if (*tok++ != ']')
 265                         return error("missing close parenthesis ']'");
 266
 267                 break;
 268         case '$':
 269                 *evalTokenBuffer++ = ACONST;                            // Attributed const
 270                 *evalTokenBuffer++ = sloc;                                      // Current location
 271                 *evalTokenBuffer++ = cursect | DEFINED;         // Store attribs
 272                 break;
 273         case '*':
 274                 *evalTokenBuffer++ = ACONST;                            // Attributed const
 275
 276 #if 0
 277                 if (orgactive)
 278                         *evalTokenBuffer++ = orgaddr;
 279                 else
 280                         *evalTokenBuffer++ = pcloc;                             // Location at start of line
 281 #else
 282                 // pcloc == location at start of line
 283                 *evalTokenBuffer++ = (orgactive ? orgaddr : pcloc);
 284 #endif
 285
 286                 *evalTokenBuffer++ = ABS | DEFINED;                     // Store attribs
 287                 break;
 288         default:
 289                 return error("bad expression");
 290         }
 291
 292         return OK;
 293 }
 294
 295
 296 //
 297 // Recursive-descent expression analyzer (with some simple speed hacks)
 298 //
 299 int expr(TOKEN * otk, VALUE * a_value, WORD * a_attr, SYM ** a_esym)
 300 {
 301         // Passed in values (once derefenced, that is) can all be zero. They are
 302         // there so that the expression analyzer can fill them in as needed. The
 303         // expression analyzer gets its input from the global token pointer "tok",
 304         // and not from anything passed in by the user.
 305         SYM * symbol;
 306         char * p;
 307         int j;
 308
 309         evalTokenBuffer = otk;  // Set token pointer to 'exprbuf' (direct.c)
 310                                                         // Also set in various other places too (riscasm.c, e.g.)
 311
 312 //printf("expr(): tokens 0-2: %i %i %i (%c %c %c); tc[2] = %i\n", tok[0], tok[1], tok[2], tok[0], tok[1], tok[2], tokenClass[tok[2]]);
 313         // Optimize for single constant or single symbol.
 314         // Shamus: Subtle bug here. EOL token is 101; if you have a constant token
 315         //         followed by the value 101, it will trigger a bad evaluation here.
 316         //         This is probably a really bad assumption to be making here...!
 317         //         (assuming tok[1] == EOL is a single token that is)
 318 //      if ((tok[1] == EOL)
 319         if ((tok[1] == EOL && tok[0] != CONST)
 320                 || (((*tok == CONST || *tok == SYMBOL) || (*tok >= KW_R0 && *tok <= KW_R31))
 321                 && (tokenClass[tok[2]] < UNARY)))
 322         {
 323                 if (*tok >= KW_R0 && *tok <= KW_R31)
 324                 {
 325                         *evalTokenBuffer++ = CONST;
 326                         *evalTokenBuffer++ = *a_value = (*tok - KW_R0);
 327                         *a_attr = ABS | DEFINED;
 328
 329                         if (a_esym != NULL)
 330                                 *a_esym = NULL;
 331
 332                         tok++;
 333                 }
 334                 else if (*tok == CONST)
 335                 {
 336                         *evalTokenBuffer++ = CONST;
 337                         *evalTokenBuffer++ = *a_value = tok[1];
 338                         *a_attr = ABS | DEFINED;
 339
 340                         if (a_esym != NULL)
 341                                 *a_esym = NULL;
 342
 343                         tok += 2;
 344 //printf("Quick eval in expr(): CONST = %i, tokenClass[tok[2]] = %i\n", *a_value, tokenClass[*tok]);
 345                 }
 346                 else if (*tok == '*')
 347                 {
 348                         *evalTokenBuffer++ = CONST;
 349
 350                         if (orgactive)
 351                                 *evalTokenBuffer++ = *a_value = orgaddr;
 352                         else
 353                                 *evalTokenBuffer++ = *a_value = pcloc;
 354
 355                         *a_attr = ABS | DEFINED;
 356
 357                         if (a_esym != NULL)
 358                                 *a_esym = NULL;
 359
 360                         tok++;
 361                 }
 362                 else if (*tok == STRING || *tok == SYMBOL)
 363                 {
 364                         p = string[tok[1]];
 365                         j = (*p == '.' ? curenv : 0);
 366                         symbol = lookup(p, LABEL, j);
 367
 368                         if (symbol == NULL)
 369                                 symbol = NewSymbol(p, LABEL, j);
 370
 371                         symbol->sattr |= REFERENCED;
 372
 373                         // Check for undefined register equates
 374                         if (symbol->sattre & UNDEF_EQUR)
 375                         {
 376                                 errors("undefined register equate '%s'", symbol->sname);
 377 //if we return right away, it returns some spurious errors...
 378 //                              return ERROR;
 379                         }
 380
 381                         // Check register bank usage
 382                         if (symbol->sattre & EQUATEDREG)
 383                         {
 384                                 if ((regbank == BANK_0) && (symbol->sattre & BANK_1) && !altbankok)
 385                                         warns("equated symbol '%s' cannot be used in register bank 0", symbol->sname);
 386
 387                                 if ((regbank == BANK_1) && (symbol->sattre & BANK_0) && !altbankok)
 388                                         warns("equated symbol '%s' cannot be used in register bank 1", symbol->sname);
 389                         }
 390
 391                         *evalTokenBuffer++ = SYMBOL;
 392 #if 0
 393                         *evalTokenBuffer++ = (TOKEN)symbol;
 394 #else
 395 /*
 396 While this approach works, it's wasteful. It would be better to use something
 397 that's already available, like the symbol "order defined" table (which needs to
 398 be converted from a linked list into an array).
 399 */
 400                         *evalTokenBuffer++ = symbolNum;
 401                         symbolPtr[symbolNum] = symbol;
 402                         symbolNum++;
 403 #endif
 404
 405                         if (symbol->sattr & DEFINED)
 406                                 *a_value = symbol->svalue;
 407                         else
 408                                 *a_value = 0;
 409
 410 /*
 411 All that extra crap that was put into the svalue when doing the equr stuff is
 412 thrown away right here. What the hell is it for?
 413 */
 414                         if (symbol->sattre & EQUATEDREG)
 415                                 *a_value &= 0x1F;
 416
 417                         *a_attr = (WORD)(symbol->sattr & ~GLOBAL);
 418
 419                         if ((symbol->sattr & (GLOBAL | DEFINED)) == GLOBAL && a_esym != NULL)
 420                                 *a_esym = symbol;
 421
 422                         tok += 2;
 423                 }
 424                 else
 425                 {
 426                         // Unknown type here... Alert the user!
 427                         error("undefined RISC register in expression");
 428                         // Prevent spurious error reporting...
 429                         tok++;
 430                         return ERROR;
 431                 }
 432
 433                 *evalTokenBuffer++ = ENDEXPR;
 434                 return OK;
 435         }
 436
 437         if (expr0() != OK)
 438                 return ERROR;
 439
 440         *evalTokenBuffer++ = ENDEXPR;
 441         return evexpr(otk, a_value, a_attr, a_esym);
 442 }
 443
 444
 445 //
 446 // Evaluate expression.
 447 // If the expression involves only ONE external symbol, the expression is
 448 // UNDEFINED, but it's value includes everything but the symbol value, and
 449 // `a_esym' is set to the external symbol.
 450 //
 451 int evexpr(TOKEN * tk, VALUE * a_value, WORD * a_attr, SYM ** a_esym)
 452 {
 453         WORD * sattr;
 454         VALUE * sval;
 455         WORD attr;
 456         SYM * sy;
 457         SYM * esym;
 458         WORD sym_seg;
 459
 460         sval = evstk;                                                   // (Empty) initial stack
 461         sattr = evattr;
 462         esym = NULL;                                                    // No external symbol involved
 463         sym_seg = 0;
 464
 465         while (*tk != ENDEXPR)
 466         {
 467                 switch ((int)*tk++)
 468                 {
 469                 case SYMBOL:
 470 //printf("evexpr(): SYMBOL\n");
 471                         sy = symbolPtr[*tk++];
 472                         sy->sattr |= REFERENCED;                // Set "referenced" bit
 473
 474                         if (!(sy->sattr & DEFINED))
 475                         {
 476                                 // Reference to undefined symbol
 477                                 if (!(sy->sattr & GLOBAL))
 478                                 {
 479                                         *a_attr = 0;
 480                                         *a_value = 0;
 481                                         return OK;
 482                                 }
 483
 484                                 if (esym != NULL)                       // Check for multiple externals
 485                                         return error(seg_error);
 486
 487                                 esym = sy;
 488                         }
 489
 490                         if (sy->sattr & DEFINED)
 491                         {
 492                                 *++sval = sy->svalue;           // Push symbol's value
 493                         }
 494                         else
 495                         {
 496                                 *++sval = 0;                            // 0 for undefined symbols
 497                         }
 498
 499                         *++sattr = (WORD)(sy->sattr & ~GLOBAL); // Push attribs
 500                         sym_seg = (WORD)(sy->sattr & (TEXT | DATA | BSS));
 501                         break;
 502                 case CONST:
 503 //printf("evexpr(): CONST = %i\n", *tk);
 504                         *++sval = *tk++;                                // Push value
 505                         *++sattr = ABS | DEFINED;               // Push simple attribs
 506                         break;
 507                 case ACONST:
 508 //printf("evexpr(): ACONST = %i\n", *tk);
 509                         *++sval = *tk++;                                // Push value
 510                         *++sattr = (WORD)*tk++;                 // Push attribs
 511                         break;
 512
 513                         // Binary "+" and "-" matrix:
 514                         //
 515                         //                ABS    Sect     Other
 516                         //     ----------------------------
 517                         //   ABS     |  ABS   |  Sect  |  Other |
 518                         //   Sect    |  Sect  |  [1]   |  Error |
 519                         //   Other   |  Other |  Error |  [1]   |
 520                         //      ----------------------------
 521                         //
 522                         //   [1] + : Error
 523                         //       - : ABS
 524                 case '+':
 525 //printf("evexpr(): +\n");
 526                         --sval;                                                 // Pop value
 527                         --sattr;                                                // Pop attrib
 528                         *sval += sval[1];                               // Compute value
 529
 530                         if (!(*sattr & (TEXT | DATA | BSS)))
 531                                 *sattr = sattr[1];
 532                         else if (sattr[1] & (TEXT | DATA | BSS))
 533                                 return error(seg_error);
 534
 535                         break;
 536                 case '-':
 537 //printf("evexpr(): -\n");
 538                         --sval;                                                 // Pop value
 539                         --sattr;                                                // Pop attrib
 540                         *sval -= sval[1];                               // Compute value
 541
 542                         attr = (WORD)(*sattr & (TEXT | DATA | BSS));
 543
 544                         if (!attr)
 545                                 *sattr = sattr[1];
 546                         else if (sattr[1] & (TEXT | DATA | BSS))
 547                         {
 548                                 if (!(attr & sattr[1]))
 549                                         return error(seg_error);
 550                                 else
 551                                         *sattr &= ~(TEXT | DATA | BSS);
 552                         }
 553
 554                         break;
 555                 // Unary operators only work on ABS items
 556                 case UNMINUS:
 557 //printf("evexpr(): UNMINUS\n");
 558                         if (*sattr & (TEXT | DATA | BSS))
 559                                 error(seg_error);
 560
 561                         *sval = -(int)*sval;
 562                         *sattr = ABS | DEFINED;                 // Expr becomes absolute
 563                         break;
 564                 case '!':
 565 //printf("evexpr(): !\n");
 566                         if (*sattr & (TEXT | DATA | BSS))
 567                                 error(seg_error);
 568
 569                         *sval = !*sval;
 570                         *sattr = ABS | DEFINED;                 // Expr becomes absolute
 571                         break;
 572                 case '~':
 573 //printf("evexpr(): ~\n");
 574                         if (*sattr & (TEXT | DATA | BSS))
 575                                 error(seg_error);
 576
 577                         *sval = ~*sval;
 578                         *sattr = ABS | DEFINED;                 // Expr becomes absolute
 579                         break;
 580                 // Comparison operators must have two values that
 581                 // are in the same segment, but that's the only requirement.
 582                 case LE:
 583 //printf("evexpr(): LE\n");
 584                         --sattr;
 585                         --sval;
 586
 587                         if ((*sattr & TDB) != (sattr[1] & TDB))
 588                                 error(seg_error);
 589
 590                         *sattr = ABS | DEFINED;
 591                         *sval = *sval <= sval[1];
 592                         break;
 593                 case GE:
 594 //printf("evexpr(): GE\n");
 595                         --sattr;
 596                         --sval;
 597
 598                         if ((*sattr & TDB) != (sattr[1] & TDB))
 599                                 error(seg_error);
 600
 601                         *sattr = ABS | DEFINED;
 602                         *sval = *sval >= sval[1];
 603                         break;
 604                 case '>':
 605 //printf("evexpr(): >\n");
 606                         --sattr;
 607                         --sval;
 608
 609                         if ((*sattr & TDB) != (sattr[1] & TDB))
 610                                 error(seg_error);
 611
 612                         *sattr = ABS | DEFINED;
 613                         *sval = *sval > sval[1];
 614                         break;
 615                 case '<':
 616 //printf("evexpr(): <\n");
 617                         --sattr;
 618                         --sval;
 619
 620                         if ((*sattr & TDB) != (sattr[1] & TDB))
 621                                 error(seg_error);
 622
 623                         *sattr = ABS | DEFINED;
 624                         *sval = *sval < sval[1];
 625                         break;
 626                 case NE:
 627 //printf("evexpr(): NE\n");
 628                         --sattr;
 629                         --sval;
 630
 631                         if ((*sattr & TDB) != (sattr[1] & TDB))
 632                                 error(seg_error);
 633
 634                         *sattr = ABS | DEFINED;
 635                         *sval = *sval != sval[1];
 636                         break;
 637                 case '=':
 638 //printf("evexpr(): =\n");
 639                         --sattr;
 640                         --sval;
 641
 642                         if ((*sattr & TDB) != (sattr[1] & TDB))
 643                                 error(seg_error);
 644
 645                         *sattr = ABS | DEFINED;
 646                         *sval = *sval == sval[1];
 647                         break;
 648                 // All other binary operators must have two ABS items
 649                 // to work with.  They all produce an ABS value.
 650                 default:
 651 //printf("evexpr(): default\n");
 652                         // GH - Removed for v1.0.15 as part of the fix for indexed loads.
 653                         //if ((*sattr & (TEXT|DATA|BSS)) || (*--sattr & (TEXT|DATA|BSS)))
 654                         //error(seg_error);
 655                         *sattr = ABS | DEFINED;                 // Expr becomes absolute
 656
 657                         switch ((int)tk[-1])
 658                         {
 659                         case '*':
 660                                 --sval;
 661                                 --sattr;                                        // Pop attrib
 662                                 *sval *= sval[1];
 663                                 break;
 664                         case '/':
 665                                 --sval;
 666                                 --sattr;                                        // Pop attrib
 667
 668                                 if (sval[1] == 0)
 669                                         return error("divide by zero");
 670
 671                                 *sval /= sval[1];
 672                                 break;
 673                         case '%':
 674                                 --sval;
 675                                 --sattr;                                        // Pop attrib
 676
 677                                 if (sval[1] == 0)
 678                                         return error("mod (%) by zero");
 679
 680                                 *sval %= sval[1];
 681                                 break;
 682                         case SHL:
 683                                 --sval;
 684                                 --sattr;                                        // Pop attrib
 685                                 *sval <<= sval[1];
 686                                 break;
 687                         case SHR:
 688                                 --sval;
 689                                 --sattr;                                        // Pop attrib
 690                                 *sval >>= sval[1];
 691                                 break;
 692                         case '&':
 693                                 --sval;
 694                                 --sattr;                                        // Pop attrib
 695                                 *sval &= sval[1];
 696                                 break;
 697                         case '^':
 698                                 --sval;
 699                                 --sattr;                                        // Pop attrib
 700                                 *sval ^= sval[1];
 701                                 break;
 702                         case '|':
 703                                 --sval;
 704                                 --sattr;                                        // Pop attrib
 705                                 *sval |= sval[1];
 706                                 break;
 707                         default:
 708                                 interror(5);                            // Bad operator in expression stream
 709                         }
 710                 }
 711         }
 712
 713         if (esym != NULL)
 714                 *sattr &= ~DEFINED;
 715
 716         if (a_esym != NULL)
 717                 *a_esym = esym;
 718
 719         // sym_seg added in 1.0.16 to solve a problem with forward symbols in
 720         // expressions where absolute values also existed. The absolutes were
 721         // overiding the symbol segments and not being included :(
 722         //*a_attr = *sattr | sym_seg;                                        // Copy value + attrib
 723
 724         *a_attr = *sattr;                                               // Copy value + attrib
 725         *a_value = *sval;
 726
 727         return OK;
 728 }