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     { "pusha0sp",       REG_NONE,             REG_AY                         },
 158     { "pushax",         REG_AX,               REG_Y                          },
 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     { "pushw",          REG_AX,               REG_AXY | REG_PTR1             },
 165     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 166     { "pushwidx",       REG_AXY,              REG_AXY | REG_PTR1             },
 167     { "pushwysp",       REG_Y,                REG_AXY                        },
 168     { "regswap",        REG_AXY,              REG_AXY | REG_TMP1             },
 169     { "regswap1",       REG_XY,               REG_A                          },
 170     { "regswap2",       REG_XY,               REG_A | REG_Y                  },
 171     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 172     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 173     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 174     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 175     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 176     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 177     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 178     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 179     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 180     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 181     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 182     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 183     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 184     { "stax0sp",        REG_AX,               REG_Y                          },
 185     { "staxysp",        REG_AXY,              REG_Y                          },
 186     { "steax0sp",       REG_EAX,              REG_Y                          },
 187     { "steaxysp",       REG_EAXY,             REG_Y                          },
 188     { "subeq0sp",       REG_AX,               REG_AXY                        },
 189     { "subeqysp",       REG_AXY,              REG_AXY                        },
 190     { "tosadda0",       REG_A,                REG_AXY                        },
 191     { "tosaddax",       REG_AX,               REG_AXY                        },
 192     { "tosanda0",       REG_A,                REG_AXY                        },
 193     { "tosandax",       REG_AX,               REG_AXY                        },
 194     { "tosdiva0",       REG_AY,               REG_ALL                        },
 195     { "tosdivax",       REG_AXY,              REG_ALL                        },
 196     { "tosdiveax",      REG_EAXY,             REG_ALL                        },
 197     { "toseqeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 198     { "tosgeeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 199     { "tosgteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 200     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 201     { "toslcmp",        REG_EAX,              REG_A | REG_Y | REG_PTR1       },
 202     { "tosleeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 203     { "toslteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 204     { "tosmula0",       REG_AX,               REG_ALL                        },
 205     { "tosmulax",       REG_AX,               REG_ALL                        },
 206     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 207     { "tosneeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 208     { "tosshreax",      REG_EAX,              REG_EAXY | REG_PTR1 | REG_PTR2 },
 209     { "tossuba0",       REG_A,                REG_AXY                        },
 210     { "tossubax",       REG_AX,               REG_AXY                        },
 211     { "tossubeax",      REG_EAX,              REG_EAXY                       },
 212     { "tosugeeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 213     { "tosugteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 214     { "tosuleeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 215     { "tosulteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 216     { "tosumula0",      REG_AX,               REG_ALL                        },
 217     { "tosumulax",      REG_AX,               REG_ALL                        },
 218     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 219     { "tsteax",         REG_EAX,              REG_Y                          },
 220     { "utsteax",        REG_EAX,              REG_Y                          },
 221 };
 222 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 223
 224 /* Table with names of zero page locations used by the compiler */
 225 static const ZPInfo ZPInfoTable[] = {
 226     {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
 227     {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
 228     {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
 229     {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
 230     {   4, "ptr3",      REG_NONE,       REG_NONE        },
 231     {   4, "ptr4",      REG_NONE,       REG_NONE        },
 232     {   7, "regbank",   REG_NONE,       REG_NONE        },
 233     {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
 234     {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
 235     {   0, "sp",        REG_SP_LO,      REG_SP          },
 236     {   0, "sp+1",      REG_SP_HI,      REG_SP          },
 237     {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
 238     {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
 239     {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
 240     {   0, "tmp2",      REG_NONE,       REG_NONE        },
 241     {   0, "tmp3",      REG_NONE,       REG_NONE        },
 242     {   0, "tmp4",      REG_NONE,       REG_NONE        },
 243 };
 244 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 245
 246
 247
 248 /*****************************************************************************/
 249 /*                                   Code                                    */
 250 /*****************************************************************************/
 251
 252
 253
 254 static int CompareFuncInfo (const void* Key, const void* Info)
 255 /* Compare function for bsearch */
 256 {
 257     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 258 }
 259
 260
 261
 262 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 263 /* For the given function, lookup register information and store it into
 264  * the given variables. If the function is unknown, assume it will use and
 265  * load all registers.
 266  */
 267 {
 268     /* If the function name starts with an underline, it is an external
 269      * function. Search for it in the symbol table. If the function does
 270      * not start with an underline, it may be a runtime support function.
 271      * Search for it in the list of builtin functions.
 272      */
 273     if (Name[0] == '_') {
 274
 275         /* Search in the symbol table, skip the leading underscore */
 276         SymEntry* E = FindGlobalSym (Name+1);
 277
 278         /* Did we find it in the top level table? */
 279         if (E && IsTypeFunc (E->Type)) {
 280
 281             /* A function may use the A or A/X registers if it is a fastcall
 282              * function. If it is not a fastcall function but a variadic one,
 283              * it will use the Y register (the parameter size is passed here).
 284              * In all other cases, no registers are used. However, we assume
 285              * that any function will destroy all registers.
 286              */
 287             FuncDesc* D = E->V.F.Func;
 288             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 289                 /* Will use registers depending on the last param */
 290                 unsigned LastParamSize = CheckedSizeOf (D->LastParam->Type);
 291                 if (LastParamSize == 1) {
 292                     *Use = REG_A;
 293                 } else if (LastParamSize == 2) {
 294                     *Use = REG_AX;
 295                 } else {
 296                     *Use = REG_EAX;
 297                 }
 298             } else if ((D->Flags & FD_VARIADIC) != 0) {
 299                 *Use = REG_Y;
 300             } else {
 301                 /* Will not use any registers */
 302                 *Use = REG_NONE;
 303             }
 304
 305             /* Will destroy all registers */
 306             *Chg = REG_ALL;
 307
 308             /* Done */
 309             return;
 310         }
 311
 312     } else {
 313
 314         /* Search for the function in the list of builtin functions */
 315         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 316                                         sizeof(FuncInfo), CompareFuncInfo);
 317
 318         /* Do we know the function? */
 319         if (Info) {
 320             /* Use the information we have */
 321             *Use = Info->Use;
 322             *Chg = Info->Chg;
 323             return;
 324         }
 325     }
 326
 327     /* Function not found - assume that the primary register is input, and all
 328      * registers are changed
 329      */
 330     *Use = REG_EAXY;
 331     *Chg = REG_ALL;
 332 }
 333
 334
 335
 336 static int CompareZPInfo (const void* Name, const void* Info)
 337 /* Compare function for bsearch */
 338 {
 339     /* Cast the pointers to the correct data type */
 340     const char* N   = (const char*) Name;
 341     const ZPInfo* E = (const ZPInfo*) Info;
 342
 343     /* Do the compare. Be careful because of the length (Info may contain
 344      * more than just the zeropage name).
 345      */
 346     if (E->Len == 0) {
 347         /* Do a full compare */
 348         return strcmp (N, E->Name);
 349     } else {
 350         /* Only compare the first part */
 351         int Res = strncmp (N, E->Name, E->Len);
 352         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 353             /* Name is actually longer than Info->Name */
 354             Res = -1;
 355         }
 356         return Res;
 357     }
 358 }
 359
 360
 361
 362 const ZPInfo* GetZPInfo (const char* Name)
 363 /* If the given name is a zero page symbol, return a pointer to the info
 364  * struct for this symbol, otherwise return NULL.
 365  */
 366 {
 367     /* Search for the zp location in the list */
 368     return bsearch (Name, ZPInfoTable, ZPInfoCount,
 369                     sizeof(ZPInfo), CompareZPInfo);
 370 }
 371
 372
 373
 374 static unsigned GetRegInfo2 (CodeSeg* S,
 375                              CodeEntry* E,
 376                              int Index,
 377                              Collection* Visited,
 378                              unsigned Used,
 379                              unsigned Unused,
 380                              unsigned Wanted)
 381 /* Recursively called subfunction for GetRegInfo. */
 382 {
 383     /* Follow the instruction flow recording register usage. */
 384     while (1) {
 385
 386         unsigned R;
 387
 388         /* Check if we have already visited the current code entry. If so,
 389          * bail out.
 390          */
 391         if (CE_HasMark (E)) {
 392             break;
 393         }
 394
 395         /* Mark this entry as already visited */
 396         CE_SetMark (E);
 397         CollAppend (Visited, E);
 398
 399         /* Evaluate the used registers */
 400         R = E->Use;
 401         if (E->OPC == OP65_RTS ||
 402             ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
 403             /* This instruction will leave the function */
 404             R |= S->ExitRegs;
 405         }
 406         if (R != REG_NONE) {
 407             /* We are not interested in the use of any register that has been
 408              * used before.
 409              */
 410             R &= ~Unused;
 411             /* Remember the remaining registers */
 412             Used |= R;
 413         }
 414
 415         /* Evaluate the changed registers */
 416         if ((R = E->Chg) != REG_NONE) {
 417             /* We are not interested in the use of any register that has been
 418              * used before.
 419              */
 420             R &= ~Used;
 421             /* Remember the remaining registers */
 422             Unused |= R;
 423         }
 424
 425         /* If we know about all registers now, bail out */
 426         if (((Used | Unused) & Wanted) == Wanted) {
 427             break;
 428         }
 429
 430         /* If the instruction is an RTS or RTI, we're done */
 431         if ((E->Info & OF_RET) != 0) {
 432             break;
 433         }
 434
 435         /* If we have an unconditional branch, follow this branch if possible,
 436          * otherwise we're done.
 437          */
 438         if ((E->Info & OF_UBRA) != 0) {
 439
 440             /* Does this jump have a valid target? */
 441             if (E->JumpTo) {
 442
 443                 /* Unconditional jump */
 444                 E     = E->JumpTo->Owner;
 445                 Index = -1;             /* Invalidate */
 446
 447             } else {
 448                 /* Jump outside means we're done */
 449                 break;
 450             }
 451
 452         /* In case of conditional branches, follow the branch if possible and
 453          * follow the normal flow (branch not taken) afterwards. If we cannot
 454          * follow the branch, we're done.
 455          */
 456         } else if ((E->Info & OF_CBRA) != 0) {
 457
 458             if (E->JumpTo) {
 459
 460                 /* Recursively determine register usage at the branch target */
 461                 unsigned U1;
 462                 unsigned U2;
 463
 464                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 465                 if (U1 == REG_ALL) {
 466                     /* All registers used, no need for second call */
 467                     return REG_AXY;
 468                 }
 469                 if (Index < 0) {
 470                     Index = CS_GetEntryIndex (S, E);
 471                 }
 472                 if ((E = CS_GetEntry (S, ++Index)) == 0) {
 473                     Internal ("GetRegInfo2: No next entry!");
 474                 }
 475                 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 476                 return U1 | U2;         /* Used in any of the branches */
 477
 478             } else {
 479                 /* Jump to global symbol */
 480                 break;
 481             }
 482
 483         } else {
 484
 485             /* Just go to the next instruction */
 486             if (Index < 0) {
 487                 Index = CS_GetEntryIndex (S, E);
 488             }
 489             E = CS_GetEntry (S, ++Index);
 490             if (E == 0) {
 491                 /* No next entry */
 492                 Internal ("GetRegInfo2: No next entry!");
 493             }
 494
 495         }
 496
 497     }
 498
 499     /* Return to the caller the complement of all unused registers */
 500     return Used;
 501 }
 502
 503
 504
 505 static unsigned GetRegInfo1 (CodeSeg* S,
 506                              CodeEntry* E,
 507                              int Index,
 508                              Collection* Visited,
 509                              unsigned Used,
 510                              unsigned Unused,
 511                              unsigned Wanted)
 512 /* Recursively called subfunction for GetRegInfo. */
 513 {
 514     /* Remember the current count of the line collection */
 515     unsigned Count = CollCount (Visited);
 516
 517     /* Call the worker routine */
 518     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 519
 520     /* Restore the old count, unmarking all new entries */
 521     unsigned NewCount = CollCount (Visited);
 522     while (NewCount-- > Count) {
 523         CodeEntry* E = CollAt (Visited, NewCount);
 524         CE_ResetMark (E);
 525         CollDelete (Visited, NewCount);
 526     }
 527
 528     /* Return the registers used */
 529     return R;
 530 }
 531
 532
 533
 534 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 535 /* Determine register usage information for the instructions starting at the
 536  * given index.
 537  */
 538 {
 539     CodeEntry*      E;
 540     Collection      Visited;    /* Visited entries */
 541     unsigned        R;
 542
 543     /* Get the code entry for the given index */
 544     if (Index >= CS_GetEntryCount (S)) {
 545         /* There is no such code entry */
 546         return REG_NONE;
 547     }
 548     E = CS_GetEntry (S, Index);
 549
 550     /* Initialize the data structure used to collection information */
 551     InitCollection (&Visited);
 552
 553     /* Call the recursive subfunction */
 554     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 555
 556     /* Delete the line collection */
 557     DoneCollection (&Visited);
 558
 559     /* Return the registers used */
 560     return R;
 561 }
 562
 563
 564
 565 int RegAUsed (struct CodeSeg* S, unsigned Index)
 566 /* Check if the value in A is used. */
 567 {
 568     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 569 }
 570
 571
 572
 573 int RegXUsed (struct CodeSeg* S, unsigned Index)
 574 /* Check if the value in X is used. */
 575 {
 576     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 577 }
 578
 579
 580
 581 int RegYUsed (struct CodeSeg* S, unsigned Index)
 582 /* Check if the value in Y is used. */
 583 {
 584     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 585 }
 586
 587
 588
 589 int RegAXUsed (struct CodeSeg* S, unsigned Index)
 590 /* Check if the value in A or(!) the value in X are used. */
 591 {
 592     return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
 593 }
 594
 595
 596
 597 int RegEAXUsed (struct CodeSeg* S, unsigned Index)
 598 /* Check if any of the four bytes in EAX are used. */
 599 {
 600     return (GetRegInfo (S, Index, REG_EAX) & REG_EAX) != 0;
 601 }
 602
 603
 604
 605 unsigned GetKnownReg (unsigned Use, const RegContents* RC)
 606 /* Return the register or zero page location from the set in Use, thats
 607  * contents are known. If Use does not contain any register, or if the
 608  * register in question does not have a known value, return REG_NONE.
 609  */
 610 {
 611     if ((Use & REG_A) != 0) {
 612         return (RC == 0 || RC->RegA >= 0)? REG_A : REG_NONE;
 613     } else if ((Use & REG_X) != 0) {
 614         return (RC == 0 || RC->RegX >= 0)? REG_X : REG_NONE;
 615     } else if ((Use & REG_Y) != 0) {
 616         return (RC == 0 || RC->RegY >= 0)? REG_Y : REG_NONE;
 617     } else if ((Use & REG_TMP1) != 0) {
 618         return (RC == 0 || RC->Tmp1 >= 0)? REG_TMP1 : REG_NONE;
 619     } else if ((Use & REG_SREG_LO) != 0) {
 620         return (RC == 0 || RC->SRegLo >= 0)? REG_SREG_LO : REG_NONE;
 621     } else if ((Use & REG_SREG_HI) != 0) {
 622         return (RC == 0 || RC->SRegHi >= 0)? REG_SREG_HI : REG_NONE;
 623     } else {
 624         return REG_NONE;
 625     }
 626 }
 627
 628
 629
 630 static cmp_t FindCmpCond (const char* Code, unsigned CodeLen)
 631 /* Search for a compare condition by the given code using the given length */
 632 {
 633     unsigned I;
 634
 635     /* Linear search */
 636     for (I = 0; I < sizeof (CmpSuffixTab) / sizeof (CmpSuffixTab [0]); ++I) {
 637         if (strncmp (Code, CmpSuffixTab [I], CodeLen) == 0) {
 638             /* Found */
 639             return I;
 640         }
 641     }
 642
 643     /* Not found */
 644     return CMP_INV;
 645 }
 646
 647
 648
 649 cmp_t FindBoolCmpCond (const char* Name)
 650 /* Check if the given string is the name of one of the boolean transformer
 651  * subroutine, and if so, return the condition that is evaluated by this
 652  * routine. Return CMP_INV if the condition is not recognised.
 653  */
 654 {
 655     /* Check for the correct subroutine name */
 656     if (strncmp (Name, "bool", 4) == 0) {
 657         /* Name is ok, search for the code in the table */
 658         return FindCmpCond (Name+4, strlen(Name)-4);
 659     } else {
 660         /* Not found */
 661         return CMP_INV;
 662     }
 663 }
 664
 665
 666
 667 cmp_t FindTosCmpCond (const char* Name)
 668 /* Check if this is a call to one of the TOS compare functions (tosgtax).
 669  * Return the condition code or CMP_INV on failure.
 670  */
 671 {
 672     unsigned Len = strlen (Name);
 673
 674     /* Check for the correct subroutine name */
 675     if (strncmp (Name, "tos", 3) == 0 && strcmp (Name+Len-2, "ax") == 0) {
 676         /* Name is ok, search for the code in the table */
 677         return FindCmpCond (Name+3, Len-3-2);
 678     } else {
 679         /* Not found */
 680         return CMP_INV;
 681     }
 682 }
 683
 684
 685