git.sur5r.net Git - cc65/blob - src/cc65/codeinfo.c

   1 /*****************************************************************************/
   2 /*                                                                           */
   3 /*                                codeinfo.c                                 */
   4 /*                                                                           */
   5 /*                  Additional information about 6502 code                   */
   6 /*                                                                           */
   7 /*                                                                           */
   8 /*                                                                           */
   9 /* (C) 2001-2002 Ullrich von Bassewitz                                       */
  10 /*               Wacholderweg 14                                             */
  11 /*               D-70597 Stuttgart                                           */
  12 /* EMail:        uz@cc65.org                                                 */
  13 /*                                                                           */
  14 /*                                                                           */
  15 /* This software is provided 'as-is', without any expressed or implied       */
  16 /* warranty.  In no event will the authors be held liable for any damages    */
  17 /* arising from the use of this software.                                    */
  18 /*                                                                           */
  19 /* Permission is granted to anyone to use this software for any purpose,     */
  20 /* including commercial applications, and to alter it and redistribute it    */
  21 /* freely, subject to the following restrictions:                            */
  22 /*                                                                           */
  23 /* 1. The origin of this software must not be misrepresented; you must not   */
  24 /*    claim that you wrote the original software. If you use this software   */
  25 /*    in a product, an acknowledgment in the product documentation would be  */
  26 /*    appreciated but is not required.                                       */
  27 /* 2. Altered source versions must be plainly marked as such, and must not   */
  28 /*    be misrepresented as being the original software.                      */
  29 /* 3. This notice may not be removed or altered from any source              */
  30 /*    distribution.                                                          */
  31 /*                                                                           */
  32 /*****************************************************************************/
  33
  34
  35
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 /* common */
  40 #include "coll.h"
  41
  42 /* cc65 */
  43 #include "codeent.h"
  44 #include "codeseg.h"
  45 #include "datatype.h"
  46 #include "error.h"
  47 #include "reginfo.h"
  48 #include "symtab.h"
  49 #include "codeinfo.h"
  50
  51
  52
  53 /*****************************************************************************/
  54 /*                                   Data                                    */
  55 /*****************************************************************************/
  56
  57
  58
  59 /* Table with the compare suffixes */
  60 static const char CmpSuffixTab [][4] = {
  61     "eq", "ne", "gt", "ge", "lt", "le", "ugt", "uge", "ult", "ule"
  62 };
  63
  64 /* Table listing the function names and code info values for known internally
  65  * used functions. This table should get auto-generated in the future.
  66  */
  67 typedef struct FuncInfo FuncInfo;
  68 struct FuncInfo {
  69     const char*     Name;       /* Function name */
  70     unsigned short  Use;        /* Register usage */
  71     unsigned short  Chg;        /* Changed/destroyed registers */
  72 };
  73
  74 static const FuncInfo FuncInfoTable[] = {
  75     { "addeq0sp",       REG_AX,               REG_AXY                        },
  76     { "addeqysp",       REG_AXY,              REG_AXY                        },
  77     { "addysp",         REG_Y,                REG_NONE                       },
  78     { "aslax1",         REG_AX,               REG_AX | REG_TMP1              },
  79     { "aslax2",         REG_AX,               REG_AX | REG_TMP1              },
  80     { "aslax3",         REG_AX,               REG_AX | REG_TMP1              },
  81     { "aslax4",         REG_AX,               REG_AX | REG_TMP1              },
  82     { "bnega",          REG_A,                REG_AX                         },
  83     { "bnegax",         REG_AX,               REG_AX                         },
  84     { "bnegeax",        REG_EAX,              REG_EAX                        },
  85     { "booleq",         REG_NONE,             REG_AX                         },
  86     { "boolge",         REG_NONE,             REG_AX                         },
  87     { "boolgt",         REG_NONE,             REG_AX                         },
  88     { "boolle",         REG_NONE,             REG_AX                         },
  89     { "boollt",         REG_NONE,             REG_AX                         },
  90     { "boolne",         REG_NONE,             REG_AX                         },
  91     { "booluge",        REG_NONE,             REG_AX                         },
  92     { "boolugt",        REG_NONE,             REG_AX                         },
  93     { "boolule",        REG_NONE,             REG_AX                         },
  94     { "boolult",        REG_NONE,             REG_AX                         },
  95     { "complax",        REG_AX,               REG_AX                         },
  96     { "decax1",         REG_AX,               REG_AX                         },
  97     { "decax2",         REG_AX,               REG_AX                         },
  98     { "decax3",         REG_AX,               REG_AX                         },
  99     { "decax4",         REG_AX,               REG_AX                         },
 100     { "decax5",         REG_AX,               REG_AX                         },
 101     { "decax6",         REG_AX,               REG_AX                         },
 102     { "decax7",         REG_AX,               REG_AX                         },
 103     { "decax8",         REG_AX,               REG_AX                         },
 104     { "decaxy",         REG_AXY,              REG_AX | REG_TMP1              },
 105     { "deceaxy",        REG_EAXY,             REG_EAX                        },
 106     { "decsp1",         REG_NONE,             REG_Y                          },
 107     { "decsp2",         REG_NONE,             REG_A                          },
 108     { "decsp3",         REG_NONE,             REG_A                          },
 109     { "decsp4",         REG_NONE,             REG_A                          },
 110     { "decsp5",         REG_NONE,             REG_A                          },
 111     { "decsp6",         REG_NONE,             REG_A                          },
 112     { "decsp7",         REG_NONE,             REG_A                          },
 113     { "decsp8",         REG_NONE,             REG_A                          },
 114     { "incax1",         REG_AX,               REG_AX                         },
 115     { "incax2",         REG_AX,               REG_AX                         },
 116     { "incsp1",         REG_NONE,             REG_NONE                       },
 117     { "incsp2",         REG_NONE,             REG_Y                          },
 118     { "incsp3",         REG_NONE,             REG_Y                          },
 119     { "incsp4",         REG_NONE,             REG_Y                          },
 120     { "incsp5",         REG_NONE,             REG_Y                          },
 121     { "incsp6",         REG_NONE,             REG_Y                          },
 122     { "incsp7",         REG_NONE,             REG_Y                          },
 123     { "incsp8",         REG_NONE,             REG_Y                          },
 124     { "laddeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 125     { "laddeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 126     { "laddeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 127     { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
 128     { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
 129     { "ldax0sp",        REG_NONE,             REG_AXY                        },
 130     { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
 131     { "ldaxidx",        REG_AXY,              REG_AXY | REG_PTR1             },
 132     { "ldaxysp",        REG_Y,                REG_AXY                        },
 133     { "leaasp",         REG_A,                REG_AX                         },
 134     { "lsubeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 135     { "lsubeq0sp",      REG_EAX,              REG_EAXY                       },
 136     { "lsubeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 137     { "lsubeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 138     { "lsubeqysp",      REG_EAXY,             REG_EAXY                       },
 139     { "negax",          REG_AX,               REG_AX                         },
 140     { "push0",          REG_NONE,             REG_AXY                        },
 141     { "push1",          REG_NONE,             REG_AXY                        },
 142     { "push2",          REG_NONE,             REG_AXY                        },
 143     { "push3",          REG_NONE,             REG_AXY                        },
 144     { "push4",          REG_NONE,             REG_AXY                        },
 145     { "push5",          REG_NONE,             REG_AXY                        },
 146     { "push6",          REG_NONE,             REG_AXY                        },
 147     { "push7",          REG_NONE,             REG_AXY                        },
 148     { "pusha",          REG_A,                REG_Y                          },
 149     { "pusha0",         REG_A,                REG_XY                         },
 150     { "pushax",         REG_AX,               REG_Y                          },
 151     { "pushc0",         REG_NONE,             REG_A | REG_Y                  },
 152     { "pushc1",         REG_NONE,             REG_A | REG_Y                  },
 153     { "pushc2",         REG_NONE,             REG_A | REG_Y                  },
 154     { "pusheax",        REG_EAX,              REG_Y                          },
 155     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 156     { "pushwysp",       REG_Y,                REG_AXY                        },
 157     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 158     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 159     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 160     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 161     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 162     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 163     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 164     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 165     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 166     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 167     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 168     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 169     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 170     { "stax0sp",        REG_AX,               REG_Y                          },
 171     { "staxysp",        REG_AXY,              REG_Y                          },
 172     { "subeq0sp",       REG_AX,               REG_AXY                        },
 173     { "subeqysp",       REG_AXY,              REG_AXY                        },
 174     { "tosadda0",       REG_A,                REG_AXY                        },
 175     { "tosaddax",       REG_AX,               REG_AXY                        },
 176     { "tosdiva0",       REG_AX,               REG_ALL                        },
 177     { "tosdivax",       REG_AX,               REG_ALL                        },
 178     { "tosdiveax",      REG_EAX,              REG_ALL                        },
 179     { "toseqeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 180     { "tosgeeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 181     { "tosgteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 182     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 183     { "toslcmp",        REG_EAX,              REG_A | REG_Y | REG_PTR1       },
 184     { "tosleeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 185     { "toslteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 186     { "tosmula0",       REG_AX,               REG_ALL                        },
 187     { "tosmulax",       REG_AX,               REG_ALL                        },
 188     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 189     { "tosneeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 190     { "tosshreax",      REG_EAX,              REG_EAXY | REG_PTR1 | REG_PTR2 },
 191     { "tossuba0",       REG_A,                REG_AXY                        },
 192     { "tossubax",       REG_AX,               REG_AXY                        },
 193     { "tossubeax",      REG_EAX,              REG_EAXY                       },
 194     { "tosugeeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 195     { "tosugteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 196     { "tosuleeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 197     { "tosulteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 198     { "tosumula0",      REG_AX,               REG_ALL                        },
 199     { "tosumulax",      REG_AX,               REG_ALL                        },
 200     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 201     { "tsteax",         REG_EAX,              REG_Y                          },
 202     { "utsteax",        REG_EAX,              REG_Y                          },
 203 };
 204 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 205
 206 /* Table with names of zero page locations used by the compiler */
 207 static const ZPInfo ZPInfoTable[] = {
 208     {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
 209     {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
 210     {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
 211     {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
 212     {   4, "ptr3",      REG_NONE,       REG_NONE        },
 213     {   4, "ptr4",      REG_NONE,       REG_NONE        },
 214     {   7, "regbank",   REG_NONE,       REG_NONE        },
 215     {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
 216     {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
 217     {   0, "sp",        REG_SP_LO,      REG_SP          },
 218     {   0, "sp+1",      REG_SP_HI,      REG_SP          },
 219     {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
 220     {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
 221     {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
 222     {   0, "tmp2",      REG_NONE,       REG_NONE        },
 223     {   0, "tmp3",      REG_NONE,       REG_NONE        },
 224     {   0, "tmp4",      REG_NONE,       REG_NONE        },
 225 };
 226 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 227
 228
 229
 230 /*****************************************************************************/
 231 /*                                   Code                                    */
 232 /*****************************************************************************/
 233
 234
 235
 236 static int CompareFuncInfo (const void* Key, const void* Info)
 237 /* Compare function for bsearch */
 238 {
 239     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 240 }
 241
 242
 243
 244 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 245 /* For the given function, lookup register information and store it into
 246  * the given variables. If the function is unknown, assume it will use and
 247  * load all registers.
 248  */
 249 {
 250     /* If the function name starts with an underline, it is an external
 251      * function. Search for it in the symbol table. If the function does
 252      * not start with an underline, it may be a runtime support function.
 253      * Search for it in the list of builtin functions.
 254      */
 255     if (Name[0] == '_') {
 256
 257         /* Search in the symbol table, skip the leading underscore */
 258         SymEntry* E = FindGlobalSym (Name+1);
 259
 260         /* Did we find it in the top level table? */
 261         if (E && IsTypeFunc (E->Type)) {
 262
 263             /* A function may use the A or A/X registers if it is a fastcall
 264              * function. If it is not a fastcall function but a variadic one,
 265              * it will use the Y register (the parameter size is passed here).
 266              * In all other cases, no registers are used. However, we assume
 267              * that any function will destroy all registers.
 268              */
 269             FuncDesc* D = E->V.F.Func;
 270             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 271                 /* Will use registers depending on the last param */
 272                 SymEntry* LastParam = D->SymTab->SymTail;
 273                 unsigned LastParamSize = CheckedSizeOf (LastParam->Type);
 274                 if (LastParamSize == 1) {
 275                     *Use = REG_A;
 276                 } else if (LastParamSize == 2) {
 277                     *Use = REG_AX;
 278                 } else {
 279                     *Use = REG_EAX;
 280                 }
 281             } else if ((D->Flags & FD_VARIADIC) != 0) {
 282                 *Use = REG_Y;
 283             } else {
 284                 /* Will not use any registers */
 285                 *Use = REG_NONE;
 286             }
 287
 288             /* Will destroy all registers */
 289             *Chg = REG_ALL;
 290
 291             /* Done */
 292             return;
 293         }
 294
 295     } else {
 296
 297         /* Search for the function in the list of builtin functions */
 298         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 299                                         sizeof(FuncInfo), CompareFuncInfo);
 300
 301         /* Do we know the function? */
 302         if (Info) {
 303             /* Use the information we have */
 304             *Use = Info->Use;
 305             *Chg = Info->Chg;
 306             return;
 307         }
 308     }
 309
 310     /* Function not found - assume that the primary register is input, and all
 311      * registers are changed
 312      */
 313     *Use = REG_EAXY;
 314     *Chg = REG_ALL;
 315 }
 316
 317
 318
 319 static int CompareZPInfo (const void* Name, const void* Info)
 320 /* Compare function for bsearch */
 321 {
 322     /* Cast the pointers to the correct data type */
 323     const char* N   = (const char*) Name;
 324     const ZPInfo* E = (const ZPInfo*) Info;
 325
 326     /* Do the compare. Be careful because of the length (Info may contain
 327      * more than just the zeropage name).
 328      */
 329     if (E->Len == 0) {
 330         /* Do a full compare */
 331         return strcmp (N, E->Name);
 332     } else {
 333         /* Only compare the first part */
 334         int Res = strncmp (N, E->Name, E->Len);
 335         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 336             /* Name is actually longer than Info->Name */
 337             Res = -1;
 338         }
 339         return Res;
 340     }
 341 }
 342
 343
 344
 345 const ZPInfo* GetZPInfo (const char* Name)
 346 /* If the given name is a zero page symbol, return a pointer to the info
 347  * struct for this symbol, otherwise return NULL.
 348  */
 349 {
 350     /* Search for the zp location in the list */
 351     return bsearch (Name, ZPInfoTable, ZPInfoCount,
 352                     sizeof(ZPInfo), CompareZPInfo);
 353 }
 354
 355
 356
 357 static unsigned GetRegInfo2 (CodeSeg* S,
 358                              CodeEntry* E,
 359                              int Index,
 360                              Collection* Visited,
 361                              unsigned Used,
 362                              unsigned Unused,
 363                              unsigned Wanted)
 364 /* Recursively called subfunction for GetRegInfo. */
 365 {
 366     /* Follow the instruction flow recording register usage. */
 367     while (1) {
 368
 369         unsigned R;
 370
 371         /* Check if we have already visited the current code entry. If so,
 372          * bail out.
 373          */
 374         if (CE_HasMark (E)) {
 375             break;
 376         }
 377
 378         /* Mark this entry as already visited */
 379         CE_SetMark (E);
 380         CollAppend (Visited, E);
 381
 382         /* Evaluate the used registers */
 383         R = E->Use;
 384         if (E->OPC == OP65_RTS ||
 385             ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
 386             /* This instruction will leave the function */
 387             R |= S->ExitRegs;
 388         }
 389         if (R != REG_NONE) {
 390             /* We are not interested in the use of any register that has been
 391              * used before.
 392              */
 393             R &= ~Unused;
 394             /* Remember the remaining registers */
 395             Used |= R;
 396         }
 397
 398         /* Evaluate the changed registers */
 399         if ((R = E->Chg) != REG_NONE) {
 400             /* We are not interested in the use of any register that has been
 401              * used before.
 402              */
 403             R &= ~Used;
 404             /* Remember the remaining registers */
 405             Unused |= R;
 406         }
 407
 408         /* If we know about all registers now, bail out */
 409         if (((Used | Unused) & Wanted) == Wanted) {
 410             break;
 411         }
 412
 413         /* If the instruction is an RTS or RTI, we're done */
 414         if ((E->Info & OF_RET) != 0) {
 415             break;
 416         }
 417
 418         /* If we have an unconditional branch, follow this branch if possible,
 419          * otherwise we're done.
 420          */
 421         if ((E->Info & OF_UBRA) != 0) {
 422
 423             /* Does this jump have a valid target? */
 424             if (E->JumpTo) {
 425
 426                 /* Unconditional jump */
 427                 E     = E->JumpTo->Owner;
 428                 Index = -1;             /* Invalidate */
 429
 430             } else {
 431                 /* Jump outside means we're done */
 432                 break;
 433             }
 434
 435         /* In case of conditional branches, follow the branch if possible and
 436          * follow the normal flow (branch not taken) afterwards. If we cannot
 437          * follow the branch, we're done.
 438          */
 439         } else if ((E->Info & OF_CBRA) != 0) {
 440
 441             if (E->JumpTo) {
 442
 443                 /* Recursively determine register usage at the branch target */
 444                 unsigned U1;
 445                 unsigned U2;
 446
 447                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 448                 if (U1 == REG_ALL) {
 449                     /* All registers used, no need for second call */
 450                     return REG_AXY;
 451                 }
 452                 if (Index < 0) {
 453                     Index = CS_GetEntryIndex (S, E);
 454                 }
 455                 if ((E = CS_GetEntry (S, ++Index)) == 0) {
 456                     Internal ("GetRegInfo2: No next entry!");
 457                 }
 458                 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 459                 return U1 | U2;         /* Used in any of the branches */
 460
 461             } else {
 462                 /* Jump to global symbol */
 463                 break;
 464             }
 465
 466         } else {
 467
 468             /* Just go to the next instruction */
 469             if (Index < 0) {
 470                 Index = CS_GetEntryIndex (S, E);
 471             }
 472             E = CS_GetEntry (S, ++Index);
 473             if (E == 0) {
 474                 /* No next entry */
 475                 Internal ("GetRegInfo2: No next entry!");
 476             }
 477
 478         }
 479
 480     }
 481
 482     /* Return to the caller the complement of all unused registers */
 483     return Used;
 484 }
 485
 486
 487
 488 static unsigned GetRegInfo1 (CodeSeg* S,
 489                              CodeEntry* E,
 490                              int Index,
 491                              Collection* Visited,
 492                              unsigned Used,
 493                              unsigned Unused,
 494                              unsigned Wanted)
 495 /* Recursively called subfunction for GetRegInfo. */
 496 {
 497     /* Remember the current count of the line collection */
 498     unsigned Count = CollCount (Visited);
 499
 500     /* Call the worker routine */
 501     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 502
 503     /* Restore the old count, unmarking all new entries */
 504     unsigned NewCount = CollCount (Visited);
 505     while (NewCount-- > Count) {
 506         CodeEntry* E = CollAt (Visited, NewCount);
 507         CE_ResetMark (E);
 508         CollDelete (Visited, NewCount);
 509     }
 510
 511     /* Return the registers used */
 512     return R;
 513 }
 514
 515
 516
 517 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 518 /* Determine register usage information for the instructions starting at the
 519  * given index.
 520  */
 521 {
 522     CodeEntry*      E;
 523     Collection      Visited;    /* Visited entries */
 524     unsigned        R;
 525
 526     /* Get the code entry for the given index */
 527     if (Index >= CS_GetEntryCount (S)) {
 528         /* There is no such code entry */
 529         return REG_NONE;
 530     }
 531     E = CS_GetEntry (S, Index);
 532
 533     /* Initialize the data structure used to collection information */
 534     InitCollection (&Visited);
 535
 536     /* Call the recursive subfunction */
 537     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 538
 539     /* Delete the line collection */
 540     DoneCollection (&Visited);
 541
 542     /* Return the registers used */
 543     return R;
 544 }
 545
 546
 547
 548 int RegAUsed (struct CodeSeg* S, unsigned Index)
 549 /* Check if the value in A is used. */
 550 {
 551     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 552 }
 553
 554
 555
 556 int RegXUsed (struct CodeSeg* S, unsigned Index)
 557 /* Check if the value in X is used. */
 558 {
 559     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 560 }
 561
 562
 563
 564 int RegYUsed (struct CodeSeg* S, unsigned Index)
 565 /* Check if the value in Y is used. */
 566 {
 567     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 568 }
 569
 570
 571
 572 int RegAXUsed (struct CodeSeg* S, unsigned Index)
 573 /* Check if the value in A or(!) the value in X are used. */
 574 {
 575     return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
 576 }
 577
 578
 579
 580 unsigned GetKnownReg (unsigned Use, const RegContents* RC)
 581 /* Return the register or zero page location from the set in Use, thats
 582  * contents are known. If Use does not contain any register, or if the
 583  * register in question does not have a known value, return REG_NONE.
 584  */
 585 {
 586     if ((Use & REG_A) != 0) {
 587         return (RC == 0 || RC->RegA >= 0)? REG_A : REG_NONE;
 588     } else if ((Use & REG_X) != 0) {
 589         return (RC == 0 || RC->RegX >= 0)? REG_X : REG_NONE;
 590     } else if ((Use & REG_Y) != 0) {
 591         return (RC == 0 || RC->RegY >= 0)? REG_Y : REG_NONE;
 592     } else if ((Use & REG_TMP1) != 0) {
 593         return (RC == 0 || RC->Tmp1 >= 0)? REG_TMP1 : REG_NONE;
 594     } else if ((Use & REG_SREG_LO) != 0) {
 595         return (RC == 0 || RC->SRegLo >= 0)? REG_SREG_LO : REG_NONE;
 596     } else if ((Use & REG_SREG_HI) != 0) {
 597         return (RC == 0 || RC->SRegHi >= 0)? REG_SREG_HI : REG_NONE;
 598     } else {
 599         return REG_NONE;
 600     }
 601 }
 602
 603
 604
 605 static cmp_t FindCmpCond (const char* Code, unsigned CodeLen)
 606 /* Search for a compare condition by the given code using the given length */
 607 {
 608     unsigned I;
 609
 610     /* Linear search */
 611     for (I = 0; I < sizeof (CmpSuffixTab) / sizeof (CmpSuffixTab [0]); ++I) {
 612         if (strncmp (Code, CmpSuffixTab [I], CodeLen) == 0) {
 613             /* Found */
 614             return I;
 615         }
 616     }
 617
 618     /* Not found */
 619     return CMP_INV;
 620 }
 621
 622
 623
 624 cmp_t FindBoolCmpCond (const char* Name)
 625 /* Check if the given string is the name of one of the boolean transformer
 626  * subroutine, and if so, return the condition that is evaluated by this
 627  * routine. Return CMP_INV if the condition is not recognised.
 628  */
 629 {
 630     /* Check for the correct subroutine name */
 631     if (strncmp (Name, "bool", 4) == 0) {
 632         /* Name is ok, search for the code in the table */
 633         return FindCmpCond (Name+4, strlen(Name)-4);
 634     } else {
 635         /* Not found */
 636         return CMP_INV;
 637     }
 638 }
 639
 640
 641
 642 cmp_t FindTosCmpCond (const char* Name)
 643 /* Check if this is a call to one of the TOS compare functions (tosgtax).
 644  * Return the condition code or CMP_INV on failure.
 645  */
 646 {
 647     unsigned Len = strlen (Name);
 648
 649     /* Check for the correct subroutine name */
 650     if (strncmp (Name, "tos", 3) == 0 && strcmp (Name+Len-2, "ax") == 0) {
 651         /* Name is ok, search for the code in the table */
 652         return FindCmpCond (Name+3, Len-3-2);
 653     } else {
 654         /* Not found */
 655         return CMP_INV;
 656     }
 657 }
 658
 659
 660