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

   1 //
   2 // RMAC - Renamed Macro Assembler for all Atari computers
   3 // RISCA.C - GPU/DSP Assembler
   4 // Copyright (C) 199x Landon Dyer, 2011-2021 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 "riscasm.h"
  10 #include "amode.h"
  11 #include "direct.h"
  12 #include "error.h"
  13 #include "expr.h"
  14 #include "mark.h"
  15 #include "procln.h"
  16 #include "rmac.h"
  17 #include "sect.h"
  18 #include "token.h"
  19
  20 #define DEF_MR                          // Declare keyword values
  21 #include "risckw.h"                     // Incl. generated risc keywords
  22
  23 #define DEF_KW                          // Declare keyword values
  24 #include "kwtab.h"                      // Incl. generated keyword tables & defs
  25
  26 #define MAXINTERNCC 26          // Maximum internal condition codes
  27
  28 // Useful macros
  29 #define EVAL_REG_RETURN_IF_ERROR(x, y) \
  30 x = EvaluateRegisterFromTokenStream(y); \
  31 \
  32 if (x == ERROR) \
  33         return ERROR;
  34
  35 #define EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(x, y) \
  36 x = EvaluateRegisterFromTokenStream(y); \
  37 \
  38 if ((x == ERROR) || (ErrorIfNotAtEOL() == ERROR)) \
  39         return ERROR;
  40
  41 #define CHECK_EOL \
  42 if (ErrorIfNotAtEOL() == ERROR) \
  43         return ERROR;
  44
  45 unsigned altbankok = 0;         // Ok to use alternate register bank
  46 unsigned orgactive = 0;         // RISC/6502 org directive active
  47 unsigned orgaddr = 0;           // Org'd address
  48 unsigned orgwarning = 0;        // Has an ORG warning been issued
  49 int lastOpcode = -1;            // Last RISC opcode assembled
  50 uint8_t riscImmTokenSeen;       // The '#' (immediate) token was seen
  51
  52 static const char reg_err[] = "missing register R0...R31";
  53
  54 // Jaguar jump condition names
  55 static const char condname[MAXINTERNCC][5] = {
  56         "NZ", "Z", "NC", "NCNZ", "NCZ", "C", "CNZ", "CZ", "NN", "NNNZ", "NNZ",
  57         "N", "N_NZ", "N_Z", "T", "A", "NE", "EQ", "CC", "HS", "HI", "CS", "LO",
  58         "PL", "MI", "F"
  59 };
  60
  61 // Jaguar jump condition numbers
  62 static const char condnumber[] = {
  63         1, 2, 4, 5, 6, 8, 9, 10, 20, 21, 22, 24, 25, 26,
  64         0, 0, 1, 2, 4, 4, 5,  8,  8, 20, 24, 31
  65 };
  66
  67 // Opcode Specific Data
  68 struct opcoderecord {
  69         uint16_t state;         // Opcode Name (unused)
  70         uint16_t type;          // Opcode Type
  71         uint16_t param;         // Opcode Parameter
  72 };
  73
  74 static const struct opcoderecord roptbl[] = {
  75         { MR_ADD,     RI_TWO,    0 },
  76         { MR_ADDC,    RI_TWO,    1 },
  77         { MR_ADDQ,    RI_NUM_32, 2 },
  78         { MR_ADDQT,   RI_NUM_32, 3 },
  79         { MR_SUB,     RI_TWO,    4 },
  80         { MR_SUBC,    RI_TWO,    5 },
  81         { MR_SUBQ,    RI_NUM_32, 6 },
  82         { MR_SUBQT,   RI_NUM_32, 7 },
  83         { MR_NEG,     RI_ONE,    8 },
  84         { MR_AND,     RI_TWO,    9 },
  85         { MR_OR,      RI_TWO,    10 },
  86         { MR_XOR,     RI_TWO,    11 },
  87         { MR_NOT,     RI_ONE,    12 },
  88         { MR_BTST,    RI_NUM_31, 13 },
  89         { MR_BSET,    RI_NUM_31, 14 },
  90         { MR_BCLR,    RI_NUM_31, 15 },
  91         { MR_MULT,    RI_TWO,    16 },
  92         { MR_IMULT,   RI_TWO,    17 },
  93         { MR_IMULTN,  RI_TWO,    18 },
  94         { MR_RESMAC,  RI_ONE,    19 },
  95         { MR_IMACN,   RI_TWO,    20 },
  96         { MR_DIV,     RI_TWO,    21 },
  97         { MR_ABS,     RI_ONE,    22 },
  98         { MR_SH,      RI_TWO,    23 },
  99         { MR_SHLQ,    RI_NUM_32, 24 + SUB32 },
 100         { MR_SHRQ,    RI_NUM_32, 25 },
 101         { MR_SHA,     RI_TWO,    26 },
 102         { MR_SHARQ,   RI_NUM_32, 27 },
 103         { MR_ROR,     RI_TWO,    28 },
 104         { MR_RORQ,    RI_NUM_32, 29 },
 105         { MR_ROLQ,    RI_NUM_32, 29 + SUB32 },
 106         { MR_CMP,     RI_TWO,    30 },
 107         { MR_CMPQ,    RI_NUM_15, 31 },
 108         { MR_SAT8,    RI_ONE,    32 + GPUONLY },
 109         { MR_SUBQMOD, RI_NUM_32, 32 + DSPONLY },
 110         { MR_SAT16,   RI_ONE,    33 + GPUONLY },
 111         { MR_SAT16S,  RI_ONE,    33 + DSPONLY },
 112         { MR_MOVEQ,   RI_NUM_31, 35 },
 113         { MR_MOVETA,  RI_TWO,    36 },
 114         { MR_MOVEFA,  RI_TWO,    37 },
 115         { MR_MOVEI,   RI_MOVEI,  38 },
 116         { MR_LOADB,   RI_LOADN,  39 },
 117         { MR_LOADW,   RI_LOADN,  40 },
 118         { MR_LOADP,   RI_LOADN,  42 + GPUONLY },
 119         { MR_SAT32S,  RI_ONE,    42 + DSPONLY },
 120         { MR_STOREB,  RI_STOREN, 45 },
 121         { MR_STOREW,  RI_STOREN, 46 },
 122         { MR_STOREP,  RI_STOREN, 48 + GPUONLY },
 123         { MR_MIRROR,  RI_ONE,    48 + DSPONLY },
 124         { MR_JUMP,    RI_JUMP,   52 },
 125         { MR_JR,      RI_JR,     53 },
 126         { MR_MMULT,   RI_TWO,    54 },
 127         { MR_MTOI,    RI_TWO,    55 },
 128         { MR_NORMI,   RI_TWO,    56 },
 129         { MR_NOP,     RI_NONE,   57 },
 130         { MR_SAT24,   RI_ONE,    62 },
 131         { MR_UNPACK,  RI_ONE,    63 + GPUONLY | (0 << 6) },
 132         { MR_PACK,    RI_ONE,    63 + GPUONLY | (1 << 6) },
 133         { MR_ADDQMOD, RI_NUM_32, 63 + DSPONLY },
 134         { MR_MOVE,    RI_MOVE,   0 },
 135         { MR_LOAD,    RI_LOAD,   0 },
 136         { MR_STORE,   RI_STORE,  0 }
 137 };
 138
 139 #define MALF_NUM                0
 140 #define MALF_EXPR               1
 141 #define MALF_LPAREN             2
 142 #define MALF_RPAREN             3
 143
 144 static const char malform1[] = "missing '#'";
 145 static const char malform2[] = "bad expression";
 146 static const char malform3[] = "missing ')'";
 147 static const char malform4[] = "missing '('";
 148
 149 static const char * malformErr[] = {
 150         malform1, malform2, malform3, malform4
 151 };
 152
 153 //
 154 // Function to return "malformed expression" error
 155 // This is done mainly to remove a bunch of GOTO statements in the parser
 156 //
 157 static inline int MalformedOpcode(int signal)
 158 {
 159         return error("Malformed opcode, %s", malformErr[signal]);
 160 }
 161
 162 //
 163 // Function to return "Illegal Indexed Register" error
 164 // Anyone trying to index something other than R14 or R15
 165 //
 166 static inline int IllegalIndexedRegister(int reg)
 167 {
 168         return error("Attempted index reference with non-indexable register (r%d)", reg - KW_R0);
 169 }
 170
 171 //
 172 // Function to return "Illegal Indexed Register" error for EQUR scenarios
 173 // Trying to use register value within EQUR that isn't 14 or 15
 174 //
 175 static inline int IllegalIndexedRegisterEqur(SYM * sy)
 176 {
 177         return error("Attempted index reference with non-indexable register within EQUR (%s = r%d)", sy->sname, sy->svalue);
 178 }
 179
 180 //
 181 // Build up & deposit RISC instruction word
 182 //
 183 static void DepositRISCInstructionWord(uint16_t opcode, int reg1, int reg2)
 184 {
 185         // Check for absolute address setting
 186         if (!orgwarning && !orgactive)
 187         {
 188                 warn("RISC code generated with no origin defined");
 189                 orgwarning = 1;
 190         }
 191
 192         int value = ((opcode & 0x3F) << 10) + ((reg1 & 0x1F) << 5) + (reg2 & 0x1F);
 193         D_word(value);
 194 }
 195
 196 //
 197 // Evaluate the RISC register from the token stream. Passed in value is the
 198 // FIXUP attribute to use if the expression comes back as undefined.
 199 //
 200 static int EvaluateRegisterFromTokenStream(uint32_t fixup)
 201 {
 202         // Firstly, check to see if it's a register token and return that.  No
 203         // need to invoke expr() for easy cases like this.
 204         int reg = *tok & 255;
 205         if (reg >= KW_R0 && reg <= KW_R31)
 206         {
 207                 // Check register bank usage in the case of .equr register
 208                 // (encoded as bits 30 and 31 in *tok).
 209                 // (I still think that this is superfluous and should be taken out, see my note in token.c)
 210                 if (*tok & 0x80000000)
 211                 {
 212                         // Oops, with all the evaluation in token.c we now lost the equated symbol reference, so we
 213                         // don't know its name or anything else. Oh well...
 214                         if ((regbank == BANK_0) && (*tok & 0x40000000) && !altbankok)
 215                                 return error("equated symbol cannot be used in register bank 0");
 216
 217                         if ((regbank == BANK_1) && !(*tok & 0x40000000) && !altbankok)
 218                                 return error("equated symbol cannot be used in register bank 1");
 219                 }
 220                 reg -= KW_R0;
 221                 tok++;
 222                 return reg;
 223         }
 224
 225         if (*tok != SYMBOL)
 226         {
 227                 // If at this point we don't have a symbol then it's garbage.  Punt.
 228                 return error("Expected register number or EQUREG");
 229         }
 230
 231         uint64_t eval;                          // Expression value
 232         WORD eattr;                                     // Expression attributes
 233         SYM * esym;                                     // External symbol involved in expr.
 234         TOKEN r_expr[EXPRSIZE];         // Expression token list
 235
 236         // Evaluate what's in the global "tok" buffer
 237         // N.B.: We should either get a fixup or a register name from EQUR
 238         if (expr(r_expr, &eval, &eattr, &esym) != OK)
 239                 return ERROR;
 240
 241         if (!(eattr & DEFINED))
 242         {
 243                 AddFixup(FU_WORD | fixup, sloc, r_expr);
 244                 return 0;
 245         }
 246
 247         // We shouldn't get here, that should not be legal
 248         interror(9);
 249
 250         // If we got a register in range (0-31), return it
 251         //if (eattr & RISCREG)
 252         //      return (int)eval - KW_R0;
 253
 254         //// Otherwise, it's out of range & we flag an error
 255         //return error(reg_err);
 256 }
 257
 258 //
 259 // Do RISC code generation
 260 //
 261 int GenerateRISCCode(int state)
 262 {
 263         int reg1;                                       // Register 1
 264         int reg2;                                       // Register 2
 265         int val = 0;                            // Constructed value
 266         char scratch[80];
 267         SYM * ccsym;
 268         SYM * sy;
 269         int i, commaFound;
 270         TOKEN * t;
 271         uint16_t attrflg;
 272         int indexed;                            // Indexed register flag
 273
 274         uint64_t eval;                          // Expression value
 275         uint16_t eattr;                         // Expression attributes
 276         SYM * esym = NULL;                      // External symbol involved in expr.
 277         TOKEN r_expr[EXPRSIZE];         // Expression token list
 278
 279         // Get opcode parameter and type
 280         uint16_t parm = roptbl[state - 3000].param;
 281         uint16_t type = roptbl[state - 3000].type;
 282         riscImmTokenSeen = 0;           // Set to "token not seen yet"
 283
 284         // Detect whether the opcode parmeter passed determines that the opcode is
 285         // specific to only one of the RISC processors and ensure it is legal in
 286         // the current code section. If not then show error and return.
 287         if (((parm & GPUONLY) && rdsp) || ((parm & DSPONLY) && rgpu))
 288                 return error("Opcode is not valid in this code section");
 289
 290         // Process RISC opcode
 291         switch (type)
 292         {
 293         // No operand instructions
 294         // NOP (57)
 295         case RI_NONE:
 296                 DepositRISCInstructionWord(parm, 0, 0);
 297                 break;
 298
 299         // Single operand instructions (Rd)
 300         // ABS, MIRROR, NEG, NOT, PACK, RESMAC, SAT8, SAT16, SAT16S, SAT24, SAT32S,
 301         // UNPACK
 302         case RI_ONE:
 303                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 304                 DepositRISCInstructionWord(parm, parm >> 6, reg2);
 305                 break;
 306
 307         // Two operand instructions (Rs,Rd)
 308         // ADD, ADDC, AND, CMP, DIV, IMACN, IMULT, IMULTN, MOVEFA, MOVETA, MULT,
 309         // MMULT, MTOI, NORMI, OR, ROR, SH, SHA, SUB, SUBC, XOR
 310         case RI_TWO:
 311                 if (parm == 37)
 312                         altbankok = 1;                      // MOVEFA
 313
 314                 EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 315                 CHECK_COMMA;
 316
 317                 if (parm == 36)
 318                         altbankok = 1;                      // MOVETA
 319
 320                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 321                 DepositRISCInstructionWord(parm, reg1, reg2);
 322                 break;
 323
 324         // Numeric operand (n,Rd) where n = -16..+15
 325         // CMPQ
 326         case RI_NUM_15:
 327
 328         // Numeric operand (n,Rd) where n = 0..31
 329         // BCLR, BSET, BTST, MOVEQ
 330         case RI_NUM_31:
 331
 332         // Numeric operand (n,Rd) where n = 1..32
 333         // ADDQ, ADDQMOD, ADDQT, SHARQ, SHLQ, SHRQ, SUBQ, SUBQMOD, SUBQT, ROLQ,
 334         // RORQ
 335         case RI_NUM_32:
 336                 switch (type)
 337                 {
 338                 case RI_NUM_15:
 339                         reg1 = -16; reg2 = 15; attrflg = FU_NUM15;
 340                         break;
 341                 default:
 342                 case RI_NUM_31:
 343                         reg1 =   0; reg2 = 31; attrflg = FU_NUM31;
 344                         break;
 345                 case RI_NUM_32:
 346                         reg1 =   1; reg2 = 32; attrflg = FU_NUM32;
 347                         break;
 348                 }
 349
 350                 if (parm & SUB32)
 351                         attrflg |= FU_SUB32;
 352
 353                 if (*tok != '#')
 354                         return MalformedOpcode(MALF_NUM);
 355
 356                 tok++;
 357                 riscImmTokenSeen = 1;
 358
 359                 if (expr(r_expr, &eval, &eattr, &esym) != OK)
 360                         return MalformedOpcode(MALF_EXPR);
 361
 362                 if (!(eattr & DEFINED))
 363                 {
 364                         AddFixup((WORD)(FU_WORD | attrflg), sloc, r_expr);
 365                         reg1 = 0;
 366                 }
 367                 else
 368                 {
 369                         if (esym && (esym->sattre & EQUATEDREG))
 370                                 return error("equated register seen for immediate value");
 371
 372                         if (eattr & RISCREG)
 373                                 return error("register seen for immediate value");
 374
 375                         if (((int)eval < reg1) || ((int)eval > reg2))
 376                                 return error("constant out of range (%d to %d)", reg1, reg2);
 377
 378                         if (parm & SUB32)
 379                                 reg1 = 32 - (int)eval;
 380                         else if (type == RI_NUM_32)
 381                                 reg1 = (reg1 == 32 ? 0 : (int)eval);
 382                         else
 383                                 reg1 = (int)eval;
 384                 }
 385
 386                 CHECK_COMMA;
 387                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 388                 DepositRISCInstructionWord(parm, reg1, reg2);
 389                 break;
 390
 391         // Move Immediate--n,Rn--n in Second Word
 392         case RI_MOVEI:
 393                 if (*tok != '#')
 394                         return MalformedOpcode(MALF_NUM);
 395
 396                 tok++;
 397                 riscImmTokenSeen = 1;
 398
 399                 // Check for equated register after # and return error if so
 400                 if (*tok == SYMBOL)
 401                 {
 402                         sy = lookup(string[tok[1]], LABEL, 0);
 403
 404                         if (sy && (sy->sattre & EQUATEDREG))
 405                                 return error("equated register in 1st operand of MOVEI instruction");
 406                 }
 407
 408                 if (expr(r_expr, &eval, &eattr, &esym) != OK)
 409                         return MalformedOpcode(MALF_EXPR);
 410
 411                 if ((lastOpcode == RI_JUMP) || (lastOpcode == RI_JR))
 412                 {
 413                         if (legacy_flag)
 414                         {
 415                                 // User doesn't care, emit a NOP to fix
 416                                 DepositRISCInstructionWord(57, 0, 0);
 417                                 warn("MOVEI following JUMP, inserting NOP to fix your BROKEN CODE");
 418                         }
 419                         else
 420                                 warn("MOVEI immediately follows JUMP");
 421                 }
 422
 423                 if (!(eattr & DEFINED))
 424                 {
 425                         AddFixup(FU_LONG | FU_MOVEI, sloc + 2, r_expr);
 426                         eval = 0;
 427                 }
 428                 else
 429                 {
 430                         if (eattr & TDB)
 431                                 MarkRelocatable(cursect, sloc + 2, (eattr & TDB), (MLONG | MMOVEI), NULL);
 432                 }
 433
 434                 CHECK_COMMA;
 435                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 436
 437                 DepositRISCInstructionWord(parm, 0, reg2);
 438                 val = WORDSWAP32(eval);
 439                 D_long(val);
 440                 break;
 441
 442         // PC,Rd or Rs,Rd
 443         case RI_MOVE:
 444                 if (*tok == KW_PC)
 445                 {
 446                         parm = 51;
 447                         reg1 = 0;
 448                         tok++;
 449                 }
 450                 else
 451                 {
 452                         parm = 34;
 453                         EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 454                 }
 455
 456                 CHECK_COMMA;
 457                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 458                 DepositRISCInstructionWord(parm, reg1, reg2);
 459                 break;
 460
 461         // (Rn),Rn = 41 / (R14/R15+n),Rn = 43/44 / (R14/R15+Rn),Rn = 58/59
 462         case RI_LOAD:
 463                 indexed = 0;
 464                 parm = 41;
 465
 466                 if (*tok != '(')
 467                         return MalformedOpcode(MALF_LPAREN);
 468
 469                 tok++;
 470
 471         if ((tok[1] == '+') || (tok[1] == '-'))
 472                 {
 473                         // Trying to make indexed call
 474                         // Note: no bank check for .equr symbol here, but the original code for .equr
 475                         //       below also didn't check for banks. Even more reasons to throw away
 476                         //       bank checks.
 477                         if (((*tok & 0xff) == KW_R14) || ((*tok &0xff) == KW_R15))
 478                                 indexed = ((*tok & 0xff) - KW_R0);
 479                         else
 480                                 return IllegalIndexedRegister(*tok);
 481                 }
 482
 483                 //if (*tok == SYMBOL)
 484                 //{
 485                 //      sy = lookup(string[tok[1]], LABEL, 0);
 486                 //
 487                 //      if (!sy)
 488                 //      {
 489                 //              error(reg_err);
 490                 //              return ERROR;
 491                 //      }
 492                 //
 493                 //      if (sy->sattre & EQUATEDREG)
 494                 //      {
 495                 //              if ((tok[2] == '+') || (tok[2] == '-'))
 496                 //              {
 497                 //                      if ((sy->svalue - KW_R0) == 14 || (sy->svalue - KW_R0) == 15) {
 498                 //                              indexed = (sy->svalue - KW_R0);
 499                 //                              tok++;
 500                 //                      }
 501                 //                      else
 502                 //                              return IllegalIndexedRegisterEqur(sy);
 503                 //              }
 504                 //      }
 505                 //}
 506
 507                 if (!indexed)
 508                 {
 509                         EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 510                 }
 511                 else
 512                 {
 513                         reg1 = indexed;
 514                         indexed = 0;
 515                         tok++;
 516
 517                         if (*tok == '+')
 518                         {
 519                                 parm = (WORD)(reg1 - 14 + 58);
 520                                 tok++;
 521
 522                                 if (((*tok & 0xff) >= KW_R0) && ((*tok & 0xff) <= KW_R31))
 523                                         indexed = 1;
 524
 525                                 if (*tok == SYMBOL)
 526                                 {
 527                                         sy = lookup(string[tok[1]], LABEL, 0);
 528
 529                                         if (!sy)
 530                                         {
 531                                                 error(reg_err);
 532                                                 return ERROR;
 533                                         }
 534
 535                                         if (sy->sattre & EQUATEDREG)
 536                                                 indexed = 1;
 537                                 }
 538
 539                                 if (indexed)
 540                                 {
 541                                         EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 542                                 }
 543                                 else
 544                                 {
 545                                         if (expr(r_expr, &eval, &eattr, &esym) != OK)
 546                                                 return MalformedOpcode(MALF_EXPR);
 547
 548                                         if (!(eattr & DEFINED))
 549                                                 return error("constant expected after '+'");
 550
 551                                         reg1 = (int)eval;
 552
 553                                         if (reg1 == 0)
 554                                         {
 555                                                 reg1 = 14 + (parm - 58);
 556                                                 parm = 41;
 557                                                 warn("NULL offset in LOAD ignored");
 558                                         }
 559                                         else
 560                                         {
 561                                                 if ((reg1 < 1) || (reg1 > 32))
 562                                                         return error("constant in LOAD out of range (1-32)");
 563
 564                                                 if (reg1 == 32)
 565                                                         reg1 = 0;
 566
 567                                                 parm = (WORD)(parm - 58 + 43);
 568                                         }
 569                                 }
 570                         }
 571                         else
 572                         {
 573                                 EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 574                         }
 575                 }
 576
 577                 if (*tok != ')')
 578                         return MalformedOpcode(MALF_RPAREN);
 579
 580                 tok++;
 581                 CHECK_COMMA;
 582                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 583                 DepositRISCInstructionWord(parm, reg1, reg2);
 584                 break;
 585
 586         // Rn,(Rn) = 47 / Rn,(R14/R15+n) = 49/50 / Rn,(R14/R15+Rn) = 60/61
 587         case RI_STORE:
 588                 parm = 47;
 589                 EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 590                 CHECK_COMMA;
 591
 592                 if (*tok != '(')
 593                         return MalformedOpcode(MALF_LPAREN);
 594
 595                 tok++;
 596                 indexed = 0;
 597
 598                 // Again, no bank checks here or in the original code.
 599                 // This check has more holes than a very hole-y thing.
 600                 if ((((*tok & 0xff) == KW_R14) || ((*tok & 0xff) == KW_R15)) && (tok[1] != ')'))
 601                         indexed = (*tok & 0xff) - KW_R0;
 602
 603                 //if (*tok == SYMBOL)
 604                 //{
 605                 //      sy = lookup(string[tok[1]], LABEL, 0);
 606                 //
 607                 //      if (!sy)
 608                 //      {
 609                 //              error(reg_err);
 610                 //              return ERROR;
 611                 //      }
 612                 //
 613                 //      if (sy->sattre & EQUATEDREG)
 614                 //      {
 615                 //              if (((sy->svalue - KW_R0) == 14 || (sy->svalue - KW_R0) == 15)
 616                 //                      && (tok[2] != ')'))
 617                 //              {
 618                 //                      indexed = (sy->svalue - KW_R0);
 619                 //                      tok++;
 620                 //              }
 621                 //      }
 622                 //}
 623
 624                 if (!indexed)
 625                 {
 626                         EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 627                 }
 628                 else
 629                 {
 630                         reg2 = indexed;
 631                         indexed = 0;
 632                         tok++;
 633
 634                         if (*tok == '+')
 635                         {
 636                                 parm = (WORD)(reg2 - 14 + 60);
 637                                 tok++;
 638
 639                                 if (((*tok & 0xff) >= KW_R0) && ((*tok & 0xff) <= KW_R31))
 640                                         indexed = 1;
 641
 642                                 if (*tok == SYMBOL)
 643                                 {
 644                                         sy = lookup(string[tok[1]], LABEL, 0);
 645
 646                                         if (!sy)
 647                                         {
 648                                                 error(reg_err);
 649                                                 return ERROR;
 650                                         }
 651
 652                                         if (sy->sattre & EQUATEDREG)
 653                                                 indexed = 1;
 654                                 }
 655
 656                                 if (indexed)
 657                                 {
 658                                         EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 659                                 }
 660                                 else
 661                                 {
 662                                         if (expr(r_expr, &eval, &eattr, &esym) != OK)
 663                                                 return MalformedOpcode(MALF_EXPR);
 664
 665                                         if (!(eattr & DEFINED))
 666                                         {
 667                                                 AddFixup(FU_WORD | FU_REGTWO, sloc, r_expr);
 668                                                 reg2 = 0;
 669                                         }
 670                                         else
 671                                         {
 672                                                 reg2 = (int)eval;
 673
 674                                                 if (reg2 == 0)
 675                                                 {
 676                                                         reg2 = 14 + (parm - 60);
 677                                                         parm = 47;
 678                                                         warn("NULL offset in STORE ignored");
 679                                                 }
 680                                                 else
 681                                                 {
 682                                                         if ((reg2 < 1) || (reg2 > 32))
 683                                                                 return error("constant in STORE out of range (1-32)");
 684
 685                                                         if (reg2 == 32)
 686                                                                 reg2 = 0;
 687
 688                                                         parm = (WORD)(parm - 60 + 49);
 689                                                 }
 690                                         }
 691                                 }
 692                         }
 693                         else
 694                         {
 695                                 EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 696                         }
 697                 }
 698
 699                 if (*tok != ')')
 700                         return MalformedOpcode(MALF_RPAREN);
 701
 702                 tok++;
 703                 CHECK_EOL;
 704                 DepositRISCInstructionWord(parm, reg2, reg1);
 705                 break;
 706
 707         // LOADB/LOADP/LOADW (Rn),Rn
 708         case RI_LOADN:
 709                 if (*tok != '(')
 710                         return MalformedOpcode(MALF_LPAREN);
 711
 712                 tok++;
 713                 EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 714
 715                 if (*tok != ')')
 716                         return MalformedOpcode(MALF_RPAREN);
 717
 718                 tok++;
 719                 CHECK_COMMA;
 720                 EVAL_REG_RETURN_IF_ERROR_OR_NO_EOL(reg2, FU_REGTWO);
 721                 DepositRISCInstructionWord(parm, reg1, reg2);
 722                 break;
 723
 724         // STOREB/STOREP/STOREW Rn,(Rn)
 725         case RI_STOREN:
 726                 EVAL_REG_RETURN_IF_ERROR(reg1, FU_REGONE);
 727                 CHECK_COMMA;
 728
 729                 if (*tok != '(')
 730                         return MalformedOpcode(MALF_LPAREN);
 731
 732                 tok++;
 733                 EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 734
 735                 if (*tok != ')')
 736                         return MalformedOpcode(MALF_RPAREN);
 737
 738                 tok++;
 739                 CHECK_EOL;
 740                 DepositRISCInstructionWord(parm, reg2, reg1);
 741                 break;
 742
 743         // Jump Relative - cc,n - n=-16..+15 words, reg2=cc
 744         case RI_JR:
 745
 746         // Jump Absolute - cc,(Rs) - reg2=cc
 747         case RI_JUMP:
 748                 // Check to see if there is a comma in the token string. If not then
 749                 // the JR or JUMP should default to 0, Jump Always
 750                 commaFound = 0;
 751
 752                 for(t=tok; *t!=EOL; t++)
 753                 {
 754                         if (*t == ',')
 755                         {
 756                                 commaFound = 1;
 757                                 break;
 758                         }
 759                 }
 760
 761                 if (commaFound)
 762                 {
 763                         if (*tok == CONST)
 764                         {
 765                                 // CC using a constant number (O_o)
 766                                 PTR tp;
 767                                 tp.tk = tok + 1;
 768                                 val = *tp.i64++;
 769                                 tok = tp.tk;
 770                                 CHECK_COMMA;
 771                         }
 772                         else if (*tok == SYMBOL)
 773                         {
 774                                 val = 9999;
 775                                 strcpy(scratch, string[tok[1]]);
 776                                 strtoupper(scratch);
 777
 778                                 for(i=0; i<MAXINTERNCC; i++)
 779                                 {
 780                                         // Look for the condition code & break if found
 781                                         if (strcmp(condname[i], scratch) == 0)
 782                                         {
 783                                                 val = condnumber[i];
 784                                                 break;
 785                                         }
 786                                 }
 787
 788                                 // Standard CC was not found, look for an equated one
 789                                 if (val == 9999)
 790                                 {
 791                                         ccsym = lookup(string[tok[1]], LABEL, 0);
 792
 793                                         if (ccsym && (ccsym->sattre & EQUATEDCC) && !(ccsym->sattre & UNDEF_CC))
 794                                                 val = (int)ccsym->svalue;
 795                                         else
 796                                                 return error("unknown condition code");
 797                                 }
 798
 799                                 tok += 2;
 800                                 CHECK_COMMA;
 801                         }
 802                         else if (*tok == '(')
 803                         {
 804                                 // Set CC to "Jump Always"
 805                                 val = 0;
 806                         }
 807                 }
 808                 else
 809                 {
 810                         // Set CC to "Jump Always"
 811                         val = 0;
 812                 }
 813
 814                 if ((val < 0) || (val > 31))
 815                         return error("condition constant out of range");
 816
 817                 // Store condition code
 818                 reg1 = val;
 819
 820                 if (type == RI_JR)
 821                 {
 822                         // JR cc,n
 823                         if (expr(r_expr, &eval, &eattr, &esym) != OK)
 824                                 return MalformedOpcode(MALF_EXPR);
 825
 826                         if (!(eattr & DEFINED))
 827                         {
 828                                 AddFixup(FU_WORD | FU_JR, sloc, r_expr);
 829                                 reg2 = 0;
 830                         }
 831                         else
 832                         {
 833                                 reg2 = ((int)(eval - ((orgactive ? orgaddr : sloc) + 2))) / 2;
 834
 835                                 if ((reg2 < -16) || (reg2 > 15))
 836                                         error("PC relative overflow in JR (outside of -16 to 15)");
 837                         }
 838                 }
 839                 else
 840                 {
 841                         // JUMP cc, (Rn)
 842                         if (*tok != '(')
 843                                 return MalformedOpcode(MALF_LPAREN);
 844
 845                         tok++;
 846                         EVAL_REG_RETURN_IF_ERROR(reg2, FU_REGTWO);
 847
 848                         if (*tok != ')')
 849                                 return MalformedOpcode(MALF_RPAREN);
 850
 851                         tok++;
 852                         CHECK_EOL;
 853                 }
 854
 855                 DepositRISCInstructionWord(parm, reg2, reg1);
 856                 break;
 857
 858         // We should never get here. If we do, somebody done fucked up. :-D
 859         default:
 860                 return error("Unknown RISC opcode type");
 861         }
 862
 863         lastOpcode = type;
 864         return 0;
 865 }