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     { "laddeq0sp",      REG_EAX,              REG_EAXY                       },
 128     { "laddeqysp",      REG_EAXY,             REG_EAXY                       },
 129     { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
 130     { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
 131     { "ldax0sp",        REG_NONE,             REG_AXY                        },
 132     { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
 133     { "ldaxidx",        REG_AXY,              REG_AXY | REG_PTR1             },
 134     { "ldaxysp",        REG_Y,                REG_AXY                        },
 135     { "ldeax0sp",       REG_NONE,             REG_EAXY                       },
 136     { "ldeaxi",         REG_AX,               REG_EAXY | REG_PTR1            },
 137     { "ldeaxidx",       REG_AXY,              REG_EAXY | REG_PTR1            },
 138     { "ldeaxysp",       REG_Y,                REG_EAXY                       },
 139     { "leaasp",         REG_A,                REG_AX                         },
 140     { "lsubeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 141     { "lsubeq0sp",      REG_EAX,              REG_EAXY                       },
 142     { "lsubeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 143     { "lsubeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 144     { "lsubeqysp",      REG_EAXY,             REG_EAXY                       },
 145     { "lsubeq0sp",      REG_EAX,              REG_EAXY                       },
 146     { "negax",          REG_AX,               REG_AX                         },
 147     { "push0",          REG_NONE,             REG_AXY                        },
 148     { "push1",          REG_NONE,             REG_AXY                        },
 149     { "push2",          REG_NONE,             REG_AXY                        },
 150     { "push3",          REG_NONE,             REG_AXY                        },
 151     { "push4",          REG_NONE,             REG_AXY                        },
 152     { "push5",          REG_NONE,             REG_AXY                        },
 153     { "push6",          REG_NONE,             REG_AXY                        },
 154     { "push7",          REG_NONE,             REG_AXY                        },
 155     { "pusha",          REG_A,                REG_Y                          },
 156     { "pusha0",         REG_A,                REG_XY                         },
 157     { "pushax",         REG_AX,               REG_Y                          },
 158     { "pusha0sp",       REG_NONE,             REG_AY                         },
 159     { "pushaysp",       REG_Y,                REG_AY                         },
 160     { "pushc0",         REG_NONE,             REG_A | REG_Y                  },
 161     { "pushc1",         REG_NONE,             REG_A | REG_Y                  },
 162     { "pushc2",         REG_NONE,             REG_A | REG_Y                  },
 163     { "pusheax",        REG_EAX,              REG_Y                          },
 164     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 165     { "pushwysp",       REG_Y,                REG_AXY                        },
 166     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 167     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 168     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 169     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 170     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 171     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 172     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 173     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 174     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 175     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 176     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 177     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 178     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 179     { "stax0sp",        REG_AX,               REG_Y                          },
 180     { "staxysp",        REG_AXY,              REG_Y                          },
 181     { "steax0sp",       REG_EAX,              REG_Y                          },
 182     { "steaxysp",       REG_EAXY,             REG_Y                          },
 183     { "subeq0sp",       REG_AX,               REG_AXY                        },
 184     { "subeqysp",       REG_AXY,              REG_AXY                        },
 185     { "tosadda0",       REG_A,                REG_AXY                        },
 186     { "tosaddax",       REG_AX,               REG_AXY                        },
 187     { "tosanda0",       REG_A,                REG_AXY                        },
 188     { "tosandax",       REG_AX,               REG_AXY                        },
 189     { "tosdiva0",       REG_AY,               REG_ALL                        },
 190     { "tosdivax",       REG_AXY,              REG_ALL                        },
 191     { "tosdiveax",      REG_EAXY,             REG_ALL                        },
 192     { "toseqeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 193     { "tosgeeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 194     { "tosgteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 195     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 196     { "toslcmp",        REG_EAX,              REG_A | REG_Y | REG_PTR1       },
 197     { "tosleeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 198     { "toslteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 199     { "tosmula0",       REG_AX,               REG_ALL                        },
 200     { "tosmulax",       REG_AX,               REG_ALL                        },
 201     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 202     { "tosneeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 203     { "tosshreax",      REG_EAX,              REG_EAXY | REG_PTR1 | REG_PTR2 },
 204     { "tossuba0",       REG_A,                REG_AXY                        },
 205     { "tossubax",       REG_AX,               REG_AXY                        },
 206     { "tossubeax",      REG_EAX,              REG_EAXY                       },
 207     { "tosugeeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 208     { "tosugteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 209     { "tosuleeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 210     { "tosulteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 211     { "tosumula0",      REG_AX,               REG_ALL                        },
 212     { "tosumulax",      REG_AX,               REG_ALL                        },
 213     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 214     { "tsteax",         REG_EAX,              REG_Y                          },
 215     { "utsteax",        REG_EAX,              REG_Y                          },
 216 };
 217 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 218
 219 /* Table with names of zero page locations used by the compiler */
 220 static const ZPInfo ZPInfoTable[] = {
 221     {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
 222     {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
 223     {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
 224     {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
 225     {   4, "ptr3",      REG_NONE,       REG_NONE        },
 226     {   4, "ptr4",      REG_NONE,       REG_NONE        },
 227     {   7, "regbank",   REG_NONE,       REG_NONE        },
 228     {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
 229     {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
 230     {   0, "sp",        REG_SP_LO,      REG_SP          },
 231     {   0, "sp+1",      REG_SP_HI,      REG_SP          },
 232     {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
 233     {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
 234     {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
 235     {   0, "tmp2",      REG_NONE,       REG_NONE        },
 236     {   0, "tmp3",      REG_NONE,       REG_NONE        },
 237     {   0, "tmp4",      REG_NONE,       REG_NONE        },
 238 };
 239 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 240
 241
 242
 243 /*****************************************************************************/
 244 /*                                   Code                                    */
 245 /*****************************************************************************/
 246
 247
 248
 249 static int CompareFuncInfo (const void* Key, const void* Info)
 250 /* Compare function for bsearch */
 251 {
 252     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 253 }
 254
 255
 256
 257 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 258 /* For the given function, lookup register information and store it into
 259  * the given variables. If the function is unknown, assume it will use and
 260  * load all registers.
 261  */
 262 {
 263     /* If the function name starts with an underline, it is an external
 264      * function. Search for it in the symbol table. If the function does
 265      * not start with an underline, it may be a runtime support function.
 266      * Search for it in the list of builtin functions.
 267      */
 268     if (Name[0] == '_') {
 269
 270         /* Search in the symbol table, skip the leading underscore */
 271         SymEntry* E = FindGlobalSym (Name+1);
 272
 273         /* Did we find it in the top level table? */
 274         if (E && IsTypeFunc (E->Type)) {
 275
 276             /* A function may use the A or A/X registers if it is a fastcall
 277              * function. If it is not a fastcall function but a variadic one,
 278              * it will use the Y register (the parameter size is passed here).
 279              * In all other cases, no registers are used. However, we assume
 280              * that any function will destroy all registers.
 281              */
 282             FuncDesc* D = E->V.F.Func;
 283             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 284                 /* Will use registers depending on the last param */
 285                 SymEntry* LastParam = D->SymTab->SymTail;
 286                 unsigned LastParamSize = CheckedSizeOf (LastParam->Type);
 287                 if (LastParamSize == 1) {
 288                     *Use = REG_A;
 289                 } else if (LastParamSize == 2) {
 290                     *Use = REG_AX;
 291                 } else {
 292                     *Use = REG_EAX;
 293                 }
 294             } else if ((D->Flags & FD_VARIADIC) != 0) {
 295                 *Use = REG_Y;
 296             } else {
 297                 /* Will not use any registers */
 298                 *Use = REG_NONE;
 299             }
 300
 301             /* Will destroy all registers */
 302             *Chg = REG_ALL;
 303
 304             /* Done */
 305             return;
 306         }
 307
 308     } else {
 309
 310         /* Search for the function in the list of builtin functions */
 311         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 312                                         sizeof(FuncInfo), CompareFuncInfo);
 313
 314         /* Do we know the function? */
 315         if (Info) {
 316             /* Use the information we have */
 317             *Use = Info->Use;
 318             *Chg = Info->Chg;
 319             return;
 320         }
 321     }
 322
 323     /* Function not found - assume that the primary register is input, and all
 324      * registers are changed
 325      */
 326     *Use = REG_EAXY;
 327     *Chg = REG_ALL;
 328 }
 329
 330
 331
 332 static int CompareZPInfo (const void* Name, const void* Info)
 333 /* Compare function for bsearch */
 334 {
 335     /* Cast the pointers to the correct data type */
 336     const char* N   = (const char*) Name;
 337     const ZPInfo* E = (const ZPInfo*) Info;
 338
 339     /* Do the compare. Be careful because of the length (Info may contain
 340      * more than just the zeropage name).
 341      */
 342     if (E->Len == 0) {
 343         /* Do a full compare */
 344         return strcmp (N, E->Name);
 345     } else {
 346         /* Only compare the first part */
 347         int Res = strncmp (N, E->Name, E->Len);
 348         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 349             /* Name is actually longer than Info->Name */
 350             Res = -1;
 351         }
 352         return Res;
 353     }
 354 }
 355
 356
 357
 358 const ZPInfo* GetZPInfo (const char* Name)
 359 /* If the given name is a zero page symbol, return a pointer to the info
 360  * struct for this symbol, otherwise return NULL.
 361  */
 362 {
 363     /* Search for the zp location in the list */
 364     return bsearch (Name, ZPInfoTable, ZPInfoCount,
 365                     sizeof(ZPInfo), CompareZPInfo);
 366 }
 367
 368
 369
 370 static unsigned GetRegInfo2 (CodeSeg* S,
 371                              CodeEntry* E,
 372                              int Index,
 373                              Collection* Visited,
 374                              unsigned Used,
 375                              unsigned Unused,
 376                              unsigned Wanted)
 377 /* Recursively called subfunction for GetRegInfo. */
 378 {
 379     /* Follow the instruction flow recording register usage. */
 380     while (1) {
 381
 382         unsigned R;
 383
 384         /* Check if we have already visited the current code entry. If so,
 385          * bail out.
 386          */
 387         if (CE_HasMark (E)) {
 388             break;
 389         }
 390
 391         /* Mark this entry as already visited */
 392         CE_SetMark (E);
 393         CollAppend (Visited, E);
 394
 395         /* Evaluate the used registers */
 396         R = E->Use;
 397         if (E->OPC == OP65_RTS ||
 398             ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
 399             /* This instruction will leave the function */
 400             R |= S->ExitRegs;
 401         }
 402         if (R != REG_NONE) {
 403             /* We are not interested in the use of any register that has been
 404              * used before.
 405              */
 406             R &= ~Unused;
 407             /* Remember the remaining registers */
 408             Used |= R;
 409         }
 410
 411         /* Evaluate the changed registers */
 412         if ((R = E->Chg) != REG_NONE) {
 413             /* We are not interested in the use of any register that has been
 414              * used before.
 415              */
 416             R &= ~Used;
 417             /* Remember the remaining registers */
 418             Unused |= R;
 419         }
 420
 421         /* If we know about all registers now, bail out */
 422         if (((Used | Unused) & Wanted) == Wanted) {
 423             break;
 424         }
 425
 426         /* If the instruction is an RTS or RTI, we're done */
 427         if ((E->Info & OF_RET) != 0) {
 428             break;
 429         }
 430
 431         /* If we have an unconditional branch, follow this branch if possible,
 432          * otherwise we're done.
 433          */
 434         if ((E->Info & OF_UBRA) != 0) {
 435
 436             /* Does this jump have a valid target? */
 437             if (E->JumpTo) {
 438
 439                 /* Unconditional jump */
 440                 E     = E->JumpTo->Owner;
 441                 Index = -1;             /* Invalidate */
 442
 443             } else {
 444                 /* Jump outside means we're done */
 445                 break;
 446             }
 447
 448         /* In case of conditional branches, follow the branch if possible and
 449          * follow the normal flow (branch not taken) afterwards. If we cannot
 450          * follow the branch, we're done.
 451          */
 452         } else if ((E->Info & OF_CBRA) != 0) {
 453
 454             if (E->JumpTo) {
 455
 456                 /* Recursively determine register usage at the branch target */
 457                 unsigned U1;
 458                 unsigned U2;
 459
 460                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 461                 if (U1 == REG_ALL) {
 462                     /* All registers used, no need for second call */
 463                     return REG_AXY;
 464                 }
 465                 if (Index < 0) {
 466                     Index = CS_GetEntryIndex (S, E);
 467                 }
 468                 if ((E = CS_GetEntry (S, ++Index)) == 0) {
 469                     Internal ("GetRegInfo2: No next entry!");
 470                 }
 471                 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 472                 return U1 | U2;         /* Used in any of the branches */
 473
 474             } else {
 475                 /* Jump to global symbol */
 476                 break;
 477             }
 478
 479         } else {
 480
 481             /* Just go to the next instruction */
 482             if (Index < 0) {
 483                 Index = CS_GetEntryIndex (S, E);
 484             }
 485             E = CS_GetEntry (S, ++Index);
 486             if (E == 0) {
 487                 /* No next entry */
 488                 Internal ("GetRegInfo2: No next entry!");
 489             }
 490
 491         }
 492
 493     }
 494
 495     /* Return to the caller the complement of all unused registers */
 496     return Used;
 497 }
 498
 499
 500
 501 static unsigned GetRegInfo1 (CodeSeg* S,
 502                              CodeEntry* E,
 503                              int Index,
 504                              Collection* Visited,
 505                              unsigned Used,
 506                              unsigned Unused,
 507                              unsigned Wanted)
 508 /* Recursively called subfunction for GetRegInfo. */
 509 {
 510     /* Remember the current count of the line collection */
 511     unsigned Count = CollCount (Visited);
 512
 513     /* Call the worker routine */
 514     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 515
 516     /* Restore the old count, unmarking all new entries */
 517     unsigned NewCount = CollCount (Visited);
 518     while (NewCount-- > Count) {
 519         CodeEntry* E = CollAt (Visited, NewCount);
 520         CE_ResetMark (E);
 521         CollDelete (Visited, NewCount);
 522     }
 523
 524     /* Return the registers used */
 525     return R;
 526 }
 527
 528
 529
 530 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 531 /* Determine register usage information for the instructions starting at the
 532  * given index.
 533  */
 534 {
 535     CodeEntry*      E;
 536     Collection      Visited;    /* Visited entries */
 537     unsigned        R;
 538
 539     /* Get the code entry for the given index */
 540     if (Index >= CS_GetEntryCount (S)) {
 541         /* There is no such code entry */
 542         return REG_NONE;
 543     }
 544     E = CS_GetEntry (S, Index);
 545
 546     /* Initialize the data structure used to collection information */
 547     InitCollection (&Visited);
 548
 549     /* Call the recursive subfunction */
 550     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 551
 552     /* Delete the line collection */
 553     DoneCollection (&Visited);
 554
 555     /* Return the registers used */
 556     return R;
 557 }
 558
 559
 560
 561 int RegAUsed (struct CodeSeg* S, unsigned Index)
 562 /* Check if the value in A is used. */
 563 {
 564     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 565 }
 566
 567
 568
 569 int RegXUsed (struct CodeSeg* S, unsigned Index)
 570 /* Check if the value in X is used. */
 571 {
 572     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 573 }
 574
 575
 576
 577 int RegYUsed (struct CodeSeg* S, unsigned Index)
 578 /* Check if the value in Y is used. */
 579 {
 580     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 581 }
 582
 583
 584
 585 int RegAXUsed (struct CodeSeg* S, unsigned Index)
 586 /* Check if the value in A or(!) the value in X are used. */
 587 {
 588     return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
 589 }
 590
 591
 592
 593 int RegEAXUsed (struct CodeSeg* S, unsigned Index)
 594 /* Check if any of the four bytes in EAX are used. */
 595 {
 596     return (GetRegInfo (S, Index, REG_EAX) & REG_EAX) != 0;
 597 }
 598
 599
 600
 601 unsigned GetKnownReg (unsigned Use, const RegContents* RC)
 602 /* Return the register or zero page location from the set in Use, thats
 603  * contents are known. If Use does not contain any register, or if the
 604  * register in question does not have a known value, return REG_NONE.
 605  */
 606 {
 607     if ((Use & REG_A) != 0) {
 608         return (RC == 0 || RC->RegA >= 0)? REG_A : REG_NONE;
 609     } else if ((Use & REG_X) != 0) {
 610         return (RC == 0 || RC->RegX >= 0)? REG_X : REG_NONE;
 611     } else if ((Use & REG_Y) != 0) {
 612         return (RC == 0 || RC->RegY >= 0)? REG_Y : REG_NONE;
 613     } else if ((Use & REG_TMP1) != 0) {
 614         return (RC == 0 || RC->Tmp1 >= 0)? REG_TMP1 : REG_NONE;
 615     } else if ((Use & REG_SREG_LO) != 0) {
 616         return (RC == 0 || RC->SRegLo >= 0)? REG_SREG_LO : REG_NONE;
 617     } else if ((Use & REG_SREG_HI) != 0) {
 618         return (RC == 0 || RC->SRegHi >= 0)? REG_SREG_HI : REG_NONE;
 619     } else {
 620         return REG_NONE;
 621     }
 622 }
 623
 624
 625
 626 static cmp_t FindCmpCond (const char* Code, unsigned CodeLen)
 627 /* Search for a compare condition by the given code using the given length */
 628 {
 629     unsigned I;
 630
 631     /* Linear search */
 632     for (I = 0; I < sizeof (CmpSuffixTab) / sizeof (CmpSuffixTab [0]); ++I) {
 633         if (strncmp (Code, CmpSuffixTab [I], CodeLen) == 0) {
 634             /* Found */
 635             return I;
 636         }
 637     }
 638
 639     /* Not found */
 640     return CMP_INV;
 641 }
 642
 643
 644
 645 cmp_t FindBoolCmpCond (const char* Name)
 646 /* Check if the given string is the name of one of the boolean transformer
 647  * subroutine, and if so, return the condition that is evaluated by this
 648  * routine. Return CMP_INV if the condition is not recognised.
 649  */
 650 {
 651     /* Check for the correct subroutine name */
 652     if (strncmp (Name, "bool", 4) == 0) {
 653         /* Name is ok, search for the code in the table */
 654         return FindCmpCond (Name+4, strlen(Name)-4);
 655     } else {
 656         /* Not found */
 657         return CMP_INV;
 658     }
 659 }
 660
 661
 662
 663 cmp_t FindTosCmpCond (const char* Name)
 664 /* Check if this is a call to one of the TOS compare functions (tosgtax).
 665  * Return the condition code or CMP_INV on failure.
 666  */
 667 {
 668     unsigned Len = strlen (Name);
 669
 670     /* Check for the correct subroutine name */
 671     if (strncmp (Name, "tos", 3) == 0 && strcmp (Name+Len-2, "ax") == 0) {
 672         /* Name is ok, search for the code in the table */
 673         return FindCmpCond (Name+3, Len-3-2);
 674     } else {
 675         /* Not found */
 676         return CMP_INV;
 677     }
 678 }
 679
 680
 681