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

   1 //
   2 // RMAC - Reboot's Macro Assembler for the Atari Jaguar Console System
   3 // PROCLN.C - Line Processing
   4 // Copyright (C) 199x Landon Dyer, 2017 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 "procln.h"
  10 #include "6502.h"
  11 #include "amode.h"
  12 #include "direct.h"
  13 #include "error.h"
  14 #include "expr.h"
  15 #include "listing.h"
  16 #include "mach.h"
  17 #include "macro.h"
  18 #include "riscasm.h"
  19 #include "sect.h"
  20 #include "symbol.h"
  21
  22 #define DEF_KW                                  // Declare keyword values
  23 #include "kwtab.h"                              // Incl generated keyword tables & defs
  24
  25 #define DEF_MN                                  // Incl 68k keyword definitions
  26 #define DECL_MN                                 // Incl 68k keyword state machine tables
  27 #include "mntab.h"
  28
  29 #define DEF_MR
  30 #define DECL_MR
  31 #include "risckw.h"
  32
  33 #define DEF_MP                                  // Include 6502 keyword definitions
  34 #define DECL_MP                                 // Include 6502 keyword state machine tables
  35 #include "6502kw.h"
  36
  37 IFENT * ifent;                                  // Current ifent
  38 static IFENT ifent0;                    // Root ifent
  39 static IFENT * f_ifent;                 // Freelist of ifents
  40 static int disabled;                    // Assembly conditionally disabled
  41 int just_bss;                                   // 1, ds.b in microprocessor mode
  42 VALUE pcloc;                                    // Value of "PC" at beginning of line
  43 SYM * lab_sym;                                  // Label on line (or NULL)
  44 int bfparam1;                                   // bfxxx instruction parameters
  45 int bfparam2;                                   // bfxxx instruction parameters
  46
  47 const char extra_stuff[] = "extra (unexpected) text found after addressing mode";
  48 const char comma_error[] = "missing comma";
  49 const char syntax_error[] = "syntax error";
  50 const char locgl_error[] = "cannot GLOBL local symbol";
  51 const char lab_ignored[] = "label ignored";
  52
  53 // Table to convert an addressing-mode number to a bitmask.
  54 LONG amsktab[0124] = {
  55         M_DREG, M_DREG, M_DREG, M_DREG,
  56         M_DREG, M_DREG, M_DREG, M_DREG,
  57
  58         M_AREG, M_AREG, M_AREG, M_AREG,
  59         M_AREG, M_AREG, M_AREG, M_AREG,
  60
  61         M_AIND, M_AIND, M_AIND, M_AIND,
  62         M_AIND, M_AIND, M_AIND, M_AIND,
  63
  64         M_APOSTINC, M_APOSTINC, M_APOSTINC, M_APOSTINC,
  65         M_APOSTINC, M_APOSTINC, M_APOSTINC, M_APOSTINC,
  66
  67         M_APREDEC, M_APREDEC, M_APREDEC, M_APREDEC,
  68         M_APREDEC, M_APREDEC, M_APREDEC, M_APREDEC,
  69
  70         M_ADISP, M_ADISP, M_ADISP, M_ADISP,
  71         M_ADISP, M_ADISP, M_ADISP, M_ADISP,
  72
  73         M_AINDEXED, M_AINDEXED, M_AINDEXED, M_AINDEXED,
  74         M_AINDEXED, M_AINDEXED, M_AINDEXED, M_AINDEXED,
  75
  76         M_ABSW,                                                                                 // 070
  77         M_ABSL,                                                                                 // 071
  78         M_PCDISP,                                                                               // 072
  79         M_PCINDEXED,                                                                    // 073
  80         M_IMMED,                                                                                // 074
  81         0L,                                                                                             // 075
  82         0L,                                                                                             // 076
  83         0L,                                                                                             // 077
  84         M_ABASE,                                                                                // 0100
  85         M_MEMPOST,                                                                              // 0101
  86         M_MEMPRE,                                                                               // 0102
  87         M_PCBASE,                                                                               // 0103
  88         M_PCMPOST,                                                                              // 0104
  89         M_PCMPRE,                                                                               // 0105
  90         M_AM_USP,                                                                               // 0106
  91         M_AM_SR,                                                                                // 0107
  92         M_AM_CCR,                                                                               // 0110
  93         M_AM_NONE,                                                                              // 0111
  94         0x30,                                                                                   // 0112
  95         0x30,                                                                                   // 0113
  96         0L,                                                                                         // 0114
  97         0L,                                                                                         // 0115
  98         0L,                                                                                         // 0116
  99         0L,                                                                                         // 0117
 100         M_CREG,                                                                             // 0120 (caches - TODO: is this correct or does it need its own bitfield?)
 101         M_CREG,                                                                             // 0121
 102         M_FREG,                                         // 0122
 103         M_FPSCR                                         // 0123
 104 };                                                                                                      // 0123 length
 105
 106
 107 // Function prototypes
 108 int HandleLabel(char *, int);
 109
 110
 111 //
 112 // Initialize line processor
 113 //
 114 void InitLineProcessor(void)
 115 {
 116         disabled = 0;
 117         ifent = &ifent0;
 118         f_ifent = ifent0.if_prev = NULL;
 119         ifent0.if_state = 0;
 120 }
 121
 122
 123 //
 124 // Line processor
 125 //
 126 void Assemble(void)
 127 {
 128         int state;                                      // Keyword machine state (output)
 129         int j;                                          // Random int, must be fast
 130         char * p;                                       // Random char ptr, must be fast
 131         TOKEN * tk;                                     // First token in line
 132         char * label;                           // Symbol (or NULL)
 133         char * equate;                          // Symbol (or NULL)
 134         int labtyp = 0;                         // Label type (':', DCOLON)
 135         int equtyp = 0;                         // Equ type ('=', DEQUALS)
 136         VALUE eval;                                     // Expression value
 137         WORD eattr;                                     // Expression attributes
 138         SYM * esym;                                     // External symbol involved in expr.
 139         WORD siz = 0;                           // Size suffix to mnem/diretve/macro
 140         LONG amsk0, amsk1;                      // Address-type masks for ea0, ea1
 141         MNTAB * m;                                      // Code generation table pointer
 142         SYM * sy, * sy2;                        // Symbol (temp usage)
 143         char * opname = NULL;           // Name of dirctve/mnemonic/macro
 144         int listflag;                           // 0: Don't call listeol()
 145         WORD rmask;                                     // Register list, for REG
 146         int registerbank;                       // RISC register bank
 147         int riscreg;                            // RISC register
 148         listflag = 0;                           // Initialise listing flag
 149
 150 loop:                                                   // Line processing loop label
 151
 152         // Get another line of tokens
 153         if (TokenizeLine() == TKEOF)
 154         {
 155 if (debug) printf("Assemble: Found TKEOF flag...\n");
 156                 if (list_flag && listflag)                      // Flush last line of source
 157                         listeol();
 158
 159                 if (ifent->if_prev != NULL)                     // Check conditional token
 160                         error("hit EOF without finding matching .endif");
 161
 162                 return;
 163         }
 164
 165         DEBUG DumpTokenBuffer();
 166
 167         if (list_flag)
 168         {
 169                 if (listflag && listing > 0)
 170                         listeol();                                              // Tell listing generator about EOL
 171
 172                 lstout((char)(disabled ? '-' : lntag)); // Prepare new line for listing
 173                 listflag = 1;                                           // OK to call `listeol' now
 174                 just_bss = 0;                                           // Reset just_bss mode
 175         }
 176
 177         state = -3;                                                             // No keyword (just EOL)
 178         label = NULL;                                                   // No label
 179         lab_sym = NULL;                                                 // No (exported) label
 180         equate = NULL;                                                  // No equate
 181         tk = tok;                                                               // Save first token in line
 182         pcloc = (VALUE)sloc;                                    // Set beginning-of-line PC
 183
 184 loop1:                                                                          // Internal line processing loop
 185
 186         if (*tok == EOL)                                                // Restart loop if end-of-line
 187                 goto loop;
 188
 189         // First token MUST be a symbol (Shamus: not sure why :-/)
 190         if (*tok != SYMBOL)
 191         {
 192         if (*tok>=KW_D0 && *tok<=KW_R31)
 193             error("cannot use reserved keyword as label name or .equ");
 194         else
 195                 error("syntax error; expected symbol");
 196                 goto loop;
 197         }
 198
 199         j = (int)tok[2];                                                // Skip equates (normal statements)
 200
 201         if (j == '=' || j == DEQUALS || j == SET || j == REG || j == EQUREG || j == CCDEF)
 202         {
 203                 equate = string[tok[1]];
 204                 equtyp = j;
 205                 tok += 3;
 206                 goto normal;
 207         }
 208
 209         // Skip past label (but record it)
 210         if (j == ':' || j == DCOLON)
 211         {
 212 as68label:
 213                 label = string[tok[1]];                         // Get label name
 214                 labtyp = tok[2];                                        // Get label type
 215                 tok += 3;                                                       // Go to next line token
 216
 217                 // AS68 MODE:
 218                 // Looks like another label follows the previous one, so handle
 219                 // the previous one until there aren't any more
 220                 if (as68_flag && (*tok == SYMBOL && tok[2] == ':'))
 221                 {
 222                         if (HandleLabel(label, labtyp) != 0)
 223                                 goto loop;
 224
 225                         goto as68label;
 226                 }
 227         }
 228
 229         // EOL is legal here...
 230         if (*tok == EOL)
 231                 goto normal;
 232
 233         // Next token MUST be a symbol
 234         if (*tok++ != SYMBOL)
 235         {
 236                 error("syntax error; expected symbol");
 237                 goto loop;
 238         }
 239
 240         opname = p = string[*tok++];
 241
 242         // Check to see if the SYMBOL is a keyword (a mnemonic or directive).
 243         // On output, `state' will have one of the values:
 244         //    -3          there was no symbol (EOL)
 245         //    -2..-1      the symbol didn't match any keyword
 246         //    0..499      vanilla directives (dc, ds, etc.)
 247         //    500..999    electric directives (macro, rept, etc.)
 248         //    1000..+     mnemonics (move, lsr, etc.)
 249         for(state=0; state>=0;)
 250         {
 251                 j = mnbase[state] + (int)tolowertab[*p];
 252
 253                 // Reject, character doesn't match
 254                 if (mncheck[j] != state)
 255                 {
 256                         state = -1;                                             // No match
 257                         break;
 258                 }
 259
 260                 // Must accept or reject at EOS
 261                 if (!*++p)
 262                 {
 263                         state = mnaccept[j];                    // (-1 on no terminal match)
 264                         break;
 265                 }
 266
 267                 state = mntab[j];
 268         }
 269
 270         // Check for ".b" ".w" ".l" after directive, macro or mnemonic.
 271         siz = SIZN;
 272
 273         if (*tok == DOTW)
 274                 siz = SIZW, tok++;
 275         else if (*tok == DOTL)
 276                 siz = SIZL, tok++;
 277         else if (*tok == DOTB)
 278                 siz = SIZB, tok++;
 279         else if(*tok == DOTD)
 280                 siz = SIZD, tok++;
 281         else if(*tok == DOTP)
 282                 siz = SIZP, tok++;
 283         else if(*tok == DOTQ)
 284                 siz = SIZQ, tok++;
 285         else if(*tok == DOTS)
 286                 siz = SIZS, tok++;
 287         else if(*tok == DOTX)
 288                 siz = SIZX, tok++;
 289
 290
 291         // Do special directives (500..999) (These must be handled in "real time")
 292         if (state >= 500 && state < 1000)
 293         {
 294                 switch (state)
 295                 {
 296                 case MN_IF:
 297                         d_if();
 298                 goto loop;
 299                 case MN_ELSE:
 300                         d_else();
 301                         goto loop;
 302                 case MN_ENDIF:
 303                         d_endif();
 304                         goto loop;
 305                 case MN_IIF:                                            // .iif --- immediate if
 306                         if (disabled || expr(exprbuf, &eval, &eattr, &esym) != OK)
 307                                 goto loop;
 308
 309                         if (!(eattr & DEFINED))
 310                         {
 311                                 error(undef_error);
 312                                 goto loop;
 313                         }
 314
 315                         if (*tok++ != ',')
 316                         {
 317                                 error(comma_error);
 318                                 goto loop;
 319                         }
 320
 321                         if (eval == 0)
 322                                 goto loop;
 323
 324                         goto loop1;
 325                 case MN_MACRO:                                          // .macro --- macro definition
 326                         if (!disabled)
 327                         {
 328                                 // Label on a macro definition is bad mojo... Warn the user
 329                                 if (label != NULL)
 330                                         warn(lab_ignored);
 331
 332                                 DefineMacro();
 333                         }
 334
 335                         goto loop;
 336                 case MN_EXITM:                                          // .exitm --- exit macro
 337                 case MN_ENDM:                                           // .endm --- same as .exitm
 338                         if (!disabled)
 339                         {
 340                                 if (label != NULL)
 341                                         warn(lab_ignored);
 342
 343                                 ExitMacro();
 344                         }
 345
 346                         goto loop;
 347                 case MN_REPT:
 348                         if (!disabled)
 349                         {
 350                                 // Handle labels on REPT directive lines...
 351                                 if (label)
 352                                 {
 353                                         if (HandleLabel(label, labtyp) != 0)
 354                                                 goto loop;
 355                                 }
 356
 357                                 defrept();
 358                         }
 359
 360                         goto loop;
 361                 case MN_ENDR:
 362                         if (!disabled)
 363                                 error("mis-nested .endr");
 364
 365                         goto loop;
 366                 }
 367         }
 368
 369 normal:
 370         if (disabled)                                                   // Conditionally disabled code
 371                 goto loop;
 372
 373         // Do equates
 374         if (equate != NULL)
 375         {
 376                 // Pick global or local symbol enviroment
 377                 j = (*equate == '.' ? curenv : 0);
 378                 sy = lookup(equate, LABEL, j);
 379
 380                 if (sy == NULL)
 381                 {
 382                         sy = NewSymbol(equate, LABEL, j);
 383                         sy->sattr = 0;
 384
 385                         if (equtyp == DEQUALS)
 386                         {
 387                                 // Can't GLOBAL a local symbol
 388                                 if (j)
 389                                 {
 390                                         error(locgl_error);
 391                                         goto loop;
 392                                 }
 393
 394                                 sy->sattr = GLOBAL;
 395                         }
 396                 }
 397                 else if ((sy->sattr & DEFINED) && equtyp != SET)
 398                 {
 399                         if ((equtyp == EQUREG) && (sy->sattre & UNDEF_EQUR))
 400                         {
 401 //REALLY?                               sy->sattre |= ~UNDEF_EQUR;
 402                                 sy->sattre &= ~UNDEF_EQUR;
 403                                 sy->svalue = 0;
 404                         }
 405                         else if ((equtyp == CCDEF) && (sy->sattre & UNDEF_CC))
 406                         {
 407 //REALLY?                               sy->sattre |= ~UNDEF_CC;
 408                                 sy->sattre &= ~UNDEF_CC;
 409                                 sy->svalue = 0;
 410                         }
 411                         else
 412                         {
 413                                 errors("multiple equate to '%s'", sy->sname);
 414                                 goto loop;
 415                         }
 416                 }
 417
 418                 // Put symbol in "order of definition" list if it's not already there
 419                 AddToSymbolDeclarationList(sy);
 420
 421                 // Parse value to equate symbol to;
 422                 // o  .equr
 423                 // o  .reg
 424                 // o  everything else
 425                 if (equtyp == EQUREG)
 426                 {
 427 //Linko's request to issue a warning on labels that equated to the same
 428 //register would go here. Not sure how to implement it though. :-/
 429 /*
 430 Maybe like this way:
 431 have an array of bools with 64 entries. Whenever a register is equated, set the
 432 corresponding register bool to true. Whenever it's undef'ed, set it to false.
 433 When checking to see if it's already been equated, issue a warning.
 434 */
 435                         // Check that we are in a RISC section
 436                         if (!rgpu && !rdsp)
 437                         {
 438                                 error(".equr/.regequ must be defined in .gpu/.dsp section");
 439                                 goto loop;
 440                         }
 441
 442                         // Check for register to equate to
 443                         if ((*tok >= KW_R0) && (*tok <= KW_R31))
 444                         {
 445 //                              sy->sattre  = EQUATEDREG | RISCSYM;     // Mark as equated register
 446                                 sy->sattre  = EQUATEDREG;       // Mark as equated register
 447                                 riscreg = (*tok - KW_R0);
 448 //is there any reason to do this, since we're putting this in svalue?
 449 //i'm thinking, no. Let's test that out! :-D
 450 //                              sy->sattre |= (riscreg << 8);           // Store register number
 451 //everything seems to build fine without it... We'll leave it here Just In Case(tm)
 452
 453 #define DEBODGE_REGBANK
 454 #ifdef DEBODGE_REGBANK
 455                                 // Default is current state of "regbank"
 456                                 registerbank = regbank;
 457 #else
 458                                 // Default is no register bank specified
 459                                 registerbank = BANK_N;
 460 #endif
 461
 462                                 // Check for ",<bank #>" override notation
 463                                 if ((tok[1] == ',') && (tok[2] == CONST))
 464                                 {
 465                                         // Advance token pointer to the constant
 466                                         tok += 3;
 467
 468                                         // Anything other than a 0 or a 1 will result in "No Bank"
 469                                         if (*tok == 0)
 470                                                 registerbank = BANK_0;
 471                                         else if (*tok == 1)
 472                                                 registerbank = BANK_1;
 473                                 }
 474
 475 #ifdef DEBODGE_REGBANK
 476                                 sy->sattre |= registerbank;     // Store register bank
 477 #else
 478 // What needs to happen here is to prime registerbank with regbank, then use
 479 // registerbank down below for the bank marking.
 480 #warning "!!! regbank <-> registerbank confusion here !!!"
 481 // The question here is why, if we're allowed to override the ".regbankN" rules
 482 // above, then why is it using the one set by the directive in the extended
 483 // attributes and not in what ends up in symbol->svalue?
 484 // ".regbankN" is not an original Madmac directive, so it's suspect
 485                                 sy->sattre |= regbank;          // Store register bank
 486 #endif
 487                                 eattr = ABS | DEFINED | GLOBAL;
 488 // & what does this $80000080 constant mean???
 489 //                              eval = 0x80000080 + (riscreg) + (registerbank << 8);
 490                                 eval = riscreg;
 491                                 tok++;
 492                         }
 493                         // Checking for a register symbol
 494                         else if (tok[0] == SYMBOL)
 495                         {
 496                                 sy2 = lookup(string[tok[1]], LABEL, j);
 497
 498                                 // Make sure symbol is a valid equreg
 499                                 if (!sy2 || !(sy2->sattre & EQUATEDREG))
 500                                 {
 501                                         error("invalid GPU/DSP .equr/.regequ definition");
 502                                         goto loop;
 503                                 }
 504                                 else
 505                                 {
 506                                         eattr = ABS | DEFINED | GLOBAL; // Copy symbols attributes
 507                                         sy->sattre = sy2->sattre;
 508                                         eval = (sy2->svalue & 0xFFFFF0FF);
 509                                         tok += 2;
 510                                 }
 511                         }
 512                         else
 513                         {
 514                                 error("invalid GPU/DSP .equr/.regequ definition");
 515                                 goto loop;
 516                         }
 517                 }
 518                 else if (equtyp == REG)
 519                 {
 520                         if (reglist(&rmask) < 0)
 521                                 goto loop;
 522
 523                         eval = (VALUE)rmask;
 524                         eattr = ABS | DEFINED;
 525                 }
 526                 else if (equtyp == CCDEF)
 527                 {
 528                         sy->sattre |= EQUATEDCC;
 529                         eattr = ABS | DEFINED | GLOBAL;
 530
 531                         if (tok[0] == SYMBOL)
 532                         {
 533                                 sy2 = lookup(string[tok[1]], LABEL, j);
 534
 535                                 if (!sy2 || !(sy2->sattre & EQUATEDCC))
 536                                 {
 537                                         error("invalid gpu/dsp .ccdef definition");
 538                                         goto loop;
 539                                 }
 540                                 else
 541                                 {
 542                                         eattr = ABS | DEFINED | GLOBAL;
 543                                         sy->sattre = sy2->sattre;
 544                                         eval = sy2->svalue;
 545                                         tok += 2;
 546                                 }
 547                         }
 548                         else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 549                                 goto loop;
 550                 }
 551                 //equ a equr
 552                 else if (*tok == SYMBOL)
 553                 {
 554                         sy2 = lookup(string[tok[1]], LABEL, j);
 555
 556                         if (sy2 && (sy2->sattre & EQUATEDREG))
 557                         {
 558                                 sy->stype = sy2->stype;
 559                                 sy->sattr = sy2->sattr;
 560                                 sy->sattre = sy2->sattre;
 561 //ICK                           sy->svalue = (sy2->svalue & 0xFFFFF0FF);
 562                                 sy->svalue = sy2->svalue;
 563                                 goto loop;
 564                         }
 565                         else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 566                                 goto loop;
 567                 }
 568                 else if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 569                         goto loop;
 570
 571                 if (!(eattr & DEFINED))
 572                 {
 573                         error(undef_error);
 574                         goto loop;
 575                 }
 576
 577                 sy->sattr |= eattr | EQUATED;   // Symbol inherits value and attributes
 578                 sy->svalue = eval;
 579
 580                 if (list_flag)                                  // Put value in listing
 581                         listvalue(eval);
 582
 583                 at_eol();                                               // Must be at EOL now
 584                 goto loop;
 585         }
 586
 587         // Do labels
 588         if (label != NULL)
 589         {
 590                 // Non-zero == error occurred
 591                 if (HandleLabel(label, labtyp) != 0)
 592                         goto loop;
 593         }
 594
 595         // Punt on EOL
 596         if (state == -3)
 597                 goto loop;
 598
 599         // If we're in 6502 mode and are still in need of a mnemonic, then search
 600         // for valid 6502 mnemonic.
 601         if (m6502 && (state < 0 || state >= 1000))
 602         {
 603 #ifdef ST
 604                 state = kmatch(opname, mpbase, mpcheck, mptab, mpaccept);
 605 #else
 606                 for(state=0, p=opname; state>= 0; )
 607                 {
 608                         j = mpbase[state] + tolowertab[*p];
 609
 610                         if (mpcheck[j] != state)        // Reject, character doesn't match
 611                         {
 612                                 state = -1;             // No match
 613                                 break;
 614                         }
 615
 616                         if (!*++p)
 617                         {                       // Must accept or reject at EOS
 618                                 state = mpaccept[j];    // (-1 on no terminal match)
 619                                 break;
 620                         }
 621
 622                         state = mptab[j];
 623                 }
 624 #endif
 625
 626                 // Call 6502 code generator if we found a mnemonic
 627                 if (state >= 2000)
 628                 {
 629                         m6502cg(state - 2000);
 630                         goto loop;
 631                 }
 632         }
 633
 634         // If we are in GPU or DSP mode and still in need of a mnemonic then search
 635         // for one
 636         if ((rgpu || rdsp) && (state < 0 || state >= 1000))
 637         {
 638                 for(state=0, p=opname; state>=0;)
 639                 {
 640                         j = mrbase[state] + (int)tolowertab[*p];
 641
 642                         // Reject, character doesn't match
 643                         if (mrcheck[j] != state)
 644                         {
 645                                 state = -1;                                     // No match
 646                                 break;
 647                         }
 648
 649                         // Must accept or reject at EOS
 650                         if (!*++p)
 651                         {
 652                                 state = mraccept[j];            // (-1 on no terminal match)
 653                                 break;
 654                         }
 655
 656                         state = mrtab[j];
 657                 }
 658
 659                 // Call RISC code generator if we found a mnemonic
 660                 if (state >= 3000)
 661                 {
 662                         GenerateRISCCode(state);
 663                         goto loop;
 664                 }
 665         }
 666
 667         // Invoke macro or complain about bad mnemonic
 668         if (state < 0)
 669         {
 670                 if ((sy = lookup(opname, MACRO, 0)) != NULL)
 671                         InvokeMacro(sy, siz);
 672                 else
 673                         errors("unknown op '%s'", opname);
 674
 675                 goto loop;
 676         }
 677
 678         // Call directive handlers
 679         if (state < 500)
 680         {
 681                 (*dirtab[state])(siz);
 682                 goto loop;
 683         }
 684
 685         // Do mnemonics
 686         // o  can't deposit instrs in BSS or ABS
 687         // o  do automatic .EVEN for instrs
 688         // o  allocate space for largest possible instr
 689         // o  can't do ".b" operations with an address register
 690         if (scattr & SBSS)
 691         {
 692                 error("cannot initialize non-storage (BSS) section");
 693                 goto loop;
 694         }
 695
 696         if (sloc & 1)                                   // Automatic .even
 697                 auto_even();
 698
 699         if (challoc - ch_size < 18)             // Make sure have space in current chunk
 700                 chcheck(0);
 701
 702         m = &machtab[state - 1000];
 703
 704         // Call special-mode handler
 705         if (m->mnattr & CGSPECIAL)
 706         {
 707                 (*m->mnfunc)(m->mninst, siz);
 708                 goto loop;
 709         }
 710
 711         if (amode(1) < 0)                               // Parse 0, 1 or 2 addr modes
 712                 goto loop;
 713
 714         if (*tok != EOL)
 715                 error(extra_stuff);
 716
 717         amsk0 = amsktab[am0];
 718         amsk1 = amsktab[am1];
 719
 720         // Catch attempts to use ".B" with an address register (yes, this check
 721         // does work at this level)
 722         if (siz == SIZB && (am0 == AREG || am1 == AREG))
 723         {
 724                 error("cannot use '.b' with an address register");
 725                 goto loop;
 726         }
 727
 728         // Keep a backup of chptr (used for optimisations during codegen)
 729         chptr_opcode = chptr;
 730
 731         for(;;)
 732         {
 733                 if ((m->mnattr & siz) && (amsk0 & m->mn0) != 0 && (amsk1 & m->mn1) != 0)
 734                 {
 735                         (*m->mnfunc)(m->mninst, siz);
 736                         goto loop;
 737                 }
 738
 739                 m = &machtab[m->mncont];
 740         }
 741 }
 742
 743
 744 //
 745 // Handle the creation of labels
 746 //
 747 int HandleLabel(char * label, int labelType)
 748 {
 749         // Check for dot in front of label; means this is a local label if present
 750         int environment = (*label == '.' ? curenv : 0);
 751         SYM * symbol = lookup(label, LABEL, environment);
 752
 753         if (symbol == NULL)
 754         {
 755                 symbol = NewSymbol(label, LABEL, environment);
 756                 symbol->sattr = 0;
 757 //              symbol->sattre = RISCSYM;
 758                 symbol->sattre = 0;
 759         }
 760         else if (symbol->sattr & DEFINED)
 761                 return errors("multiply-defined label '%s'", label);
 762
 763         // Put symbol in "order of definition" list if it's not already in it
 764         AddToSymbolDeclarationList(symbol);
 765
 766         if (orgactive)
 767         {
 768                 symbol->svalue = orgaddr;
 769                 symbol->sattr |= ABS | DEFINED | EQUATED;
 770         }
 771         else
 772         {
 773                 symbol->svalue = sloc;
 774                 symbol->sattr |= DEFINED | cursect;
 775         }
 776
 777         lab_sym = symbol;
 778
 779         if (0 == environment)
 780                 curenv++;
 781
 782         // Make label global if it has a double colon
 783         if (labelType == DCOLON)
 784         {
 785                 if (environment != 0)
 786                         return error(locgl_error);
 787
 788                 symbol->sattr |= GLOBAL;
 789         }
 790
 791         return 0;
 792 }
 793
 794
 795 //
 796 // .if, Start conditional assembly
 797 //
 798 int d_if(void)
 799 {
 800         IFENT * rif;
 801         WORD eattr;
 802         VALUE eval;
 803         SYM * esym;
 804
 805         // Alloc an IFENTRY
 806         if ((rif = f_ifent) == NULL)
 807                 rif = (IFENT *)malloc(sizeof(IFENT));
 808         else
 809                 f_ifent = rif->if_prev;
 810
 811         rif->if_prev = ifent;
 812         ifent = rif;
 813
 814         if (!disabled)
 815         {
 816                 if (expr(exprbuf, &eval, &eattr, &esym) != OK)
 817                         return 0;
 818
 819                 if ((eattr & DEFINED) == 0)
 820                         return error(undef_error);
 821
 822                 disabled = !eval;
 823         }
 824
 825         rif->if_state = (WORD)disabled;
 826         return 0;
 827 }
 828
 829
 830 //
 831 // .else, Do alternate case for .if
 832 //
 833 int d_else(void)
 834 {
 835         IFENT * rif = ifent;
 836
 837         if (rif->if_prev == NULL)
 838                 return error("mismatched .else");
 839
 840         if (disabled)
 841                 disabled = rif->if_prev->if_state;
 842         else
 843                 disabled = 1;
 844
 845         rif->if_state = (WORD)disabled;
 846         return 0;
 847 }
 848
 849
 850 //
 851 // .endif, End of conditional assembly block
 852 // This is also called by fpop() to pop levels of IFENTs in case a macro or
 853 // include file exits early with `exitm' or `end'.
 854 //
 855 int d_endif (void)
 856 {
 857         IFENT * rif = ifent;
 858
 859         if (rif->if_prev == NULL)
 860                 return error("mismatched .endif");
 861
 862         ifent = rif->if_prev;
 863         disabled = rif->if_prev->if_state;
 864         rif->if_prev = f_ifent;
 865         f_ifent = rif;
 866         return 0;
 867 }
 868