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) 2001-2006, Ullrich von Bassewitz                                      */
  10 /*                Römerstraße 52                                             */
  11 /*                D-70794 Filderstadt                                        */
  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 "chartype.h"
  41 #include "coll.h"
  42 #include "debugflag.h"
  43
  44 /* cc65 */
  45 #include "codeent.h"
  46 #include "codeseg.h"
  47 #include "datatype.h"
  48 #include "error.h"
  49 #include "reginfo.h"
  50 #include "symtab.h"
  51 #include "codeinfo.h"
  52
  53
  54
  55 /*****************************************************************************/
  56 /*                                   Data                                    */
  57 /*****************************************************************************/
  58
  59
  60
  61 /* Table with the compare suffixes */
  62 static const char CmpSuffixTab [][4] = {
  63     "eq", "ne", "gt", "ge", "lt", "le", "ugt", "uge", "ult", "ule"
  64 };
  65
  66 /* Table listing the function names and code info values for known internally
  67  * used functions. This table should get auto-generated in the future.
  68  */
  69 typedef struct FuncInfo FuncInfo;
  70 struct FuncInfo {
  71     const char*     Name;       /* Function name */
  72     unsigned short  Use;        /* Register usage */
  73     unsigned short  Chg;        /* Changed/destroyed registers */
  74 };
  75
  76 static const FuncInfo FuncInfoTable[] = {
  77     { "addeq0sp",       REG_AX,               REG_AXY                        },
  78     { "addeqysp",       REG_AXY,              REG_AXY                        },
  79     { "addysp",         REG_Y,                REG_NONE                       },
  80     { "aslax1",         REG_AX,               REG_AX | REG_TMP1              },
  81     { "aslax2",         REG_AX,               REG_AX | REG_TMP1              },
  82     { "aslax3",         REG_AX,               REG_AX | REG_TMP1              },
  83     { "aslax4",         REG_AX,               REG_AX | REG_TMP1              },
  84     { "bnega",          REG_A,                REG_AX                         },
  85     { "bnegax",         REG_AX,               REG_AX                         },
  86     { "bnegeax",        REG_EAX,              REG_EAX                        },
  87     { "booleq",         REG_NONE,             REG_AX                         },
  88     { "boolge",         REG_NONE,             REG_AX                         },
  89     { "boolgt",         REG_NONE,             REG_AX                         },
  90     { "boolle",         REG_NONE,             REG_AX                         },
  91     { "boollt",         REG_NONE,             REG_AX                         },
  92     { "boolne",         REG_NONE,             REG_AX                         },
  93     { "booluge",        REG_NONE,             REG_AX                         },
  94     { "boolugt",        REG_NONE,             REG_AX                         },
  95     { "boolule",        REG_NONE,             REG_AX                         },
  96     { "boolult",        REG_NONE,             REG_AX                         },
  97     { "complax",        REG_AX,               REG_AX                         },
  98     { "decax1",         REG_AX,               REG_AX                         },
  99     { "decax2",         REG_AX,               REG_AX                         },
 100     { "decax3",         REG_AX,               REG_AX                         },
 101     { "decax4",         REG_AX,               REG_AX                         },
 102     { "decax5",         REG_AX,               REG_AX                         },
 103     { "decax6",         REG_AX,               REG_AX                         },
 104     { "decax7",         REG_AX,               REG_AX                         },
 105     { "decax8",         REG_AX,               REG_AX                         },
 106     { "decaxy",         REG_AXY,              REG_AX | REG_TMP1              },
 107     { "deceaxy",        REG_EAXY,             REG_EAX                        },
 108     { "decsp1",         REG_NONE,             REG_Y                          },
 109     { "decsp2",         REG_NONE,             REG_A                          },
 110     { "decsp3",         REG_NONE,             REG_A                          },
 111     { "decsp4",         REG_NONE,             REG_A                          },
 112     { "decsp5",         REG_NONE,             REG_A                          },
 113     { "decsp6",         REG_NONE,             REG_A                          },
 114     { "decsp7",         REG_NONE,             REG_A                          },
 115     { "decsp8",         REG_NONE,             REG_A                          },
 116     { "incax1",         REG_AX,               REG_AX                         },
 117     { "incax2",         REG_AX,               REG_AX                         },
 118     { "incax3",         REG_AX,               REG_AX                         },
 119     { "incax4",         REG_AX,               REG_AX                         },
 120     { "incax5",         REG_AX,               REG_AX                         },
 121     { "incax6",         REG_AX,               REG_AX                         },
 122     { "incax7",         REG_AX,               REG_AX                         },
 123     { "incax8",         REG_AX,               REG_AX                         },
 124     { "incsp1",         REG_NONE,             REG_NONE                       },
 125     { "incsp2",         REG_NONE,             REG_Y                          },
 126     { "incsp3",         REG_NONE,             REG_Y                          },
 127     { "incsp4",         REG_NONE,             REG_Y                          },
 128     { "incsp5",         REG_NONE,             REG_Y                          },
 129     { "incsp6",         REG_NONE,             REG_Y                          },
 130     { "incsp7",         REG_NONE,             REG_Y                          },
 131     { "incsp8",         REG_NONE,             REG_Y                          },
 132     { "laddeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 133     { "laddeq0sp",      REG_EAX,              REG_EAXY                       },
 134     { "laddeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 135     { "laddeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 136     { "laddeqysp",      REG_EAXY,             REG_EAXY                       },
 137     { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
 138     { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
 139     { "ldax0sp",        REG_NONE,             REG_AXY                        },
 140     { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
 141     { "ldaxidx",        REG_AXY,              REG_AXY | REG_PTR1             },
 142     { "ldaxysp",        REG_Y,                REG_AXY                        },
 143     { "ldeax0sp",       REG_NONE,             REG_EAXY                       },
 144     { "ldeaxi",         REG_AX,               REG_EAXY | REG_PTR1            },
 145     { "ldeaxidx",       REG_AXY,              REG_EAXY | REG_PTR1            },
 146     { "ldeaxysp",       REG_Y,                REG_EAXY                       },
 147     { "leaasp",         REG_A,                REG_AX                         },
 148     { "lsubeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 149     { "lsubeq0sp",      REG_EAX,              REG_EAXY                       },
 150     { "lsubeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 151     { "lsubeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 152     { "lsubeqysp",      REG_EAXY,             REG_EAXY                       },
 153     { "negax",          REG_AX,               REG_AX                         },
 154     { "push0",          REG_NONE,             REG_AXY                        },
 155     { "push1",          REG_NONE,             REG_AXY                        },
 156     { "push2",          REG_NONE,             REG_AXY                        },
 157     { "push3",          REG_NONE,             REG_AXY                        },
 158     { "push4",          REG_NONE,             REG_AXY                        },
 159     { "push5",          REG_NONE,             REG_AXY                        },
 160     { "push6",          REG_NONE,             REG_AXY                        },
 161     { "push7",          REG_NONE,             REG_AXY                        },
 162     { "pusha",          REG_A,                REG_Y                          },
 163     { "pusha0",         REG_A,                REG_XY                         },
 164     { "pusha0sp",       REG_NONE,             REG_AY                         },
 165     { "pushax",         REG_AX,               REG_Y                          },
 166     { "pushaysp",       REG_Y,                REG_AY                         },
 167     { "pushc0",         REG_NONE,             REG_A | REG_Y                  },
 168     { "pushc1",         REG_NONE,             REG_A | REG_Y                  },
 169     { "pushc2",         REG_NONE,             REG_A | REG_Y                  },
 170     { "pusheax",        REG_EAX,              REG_Y                          },
 171     { "pushw",          REG_AX,               REG_AXY | REG_PTR1             },
 172     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 173     { "pushwidx",       REG_AXY,              REG_AXY | REG_PTR1             },
 174     { "pushwysp",       REG_Y,                REG_AXY                        },
 175     { "regswap",        REG_AXY,              REG_AXY | REG_TMP1             },
 176     { "regswap1",       REG_XY,               REG_A                          },
 177     { "regswap2",       REG_XY,               REG_A | REG_Y                  },
 178     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 179     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 180     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 181     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 182     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 183     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 184     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 185     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 186     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 187     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 188     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 189     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 190     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 191     { "stax0sp",        REG_AX,               REG_Y                          },
 192     { "staxspidx",      REG_AXY,              REG_TMP1 | REG_PTR1            },
 193     { "staxysp",        REG_AXY,              REG_Y                          },
 194     { "steax0sp",       REG_EAX,              REG_Y                          },
 195     { "steaxysp",       REG_EAXY,             REG_Y                          },
 196     { "subeq0sp",       REG_AX,               REG_AXY                        },
 197     { "subeqysp",       REG_AXY,              REG_AXY                        },
 198     { "tosadda0",       REG_A,                REG_AXY                        },
 199     { "tosaddax",       REG_AX,               REG_AXY                        },
 200     { "tosanda0",       REG_A,                REG_AXY                        },
 201     { "tosandax",       REG_AX,               REG_AXY                        },
 202     { "tosaslax",       REG_A,                REG_AXY | REG_TMP1             },
 203     { "tosasleax",      REG_A,                REG_EAXY | REG_TMP1            },
 204     { "tosasrax",       REG_A,                REG_AXY | REG_TMP1             },
 205     { "tosasreax",      REG_A,                REG_EAXY | REG_TMP1            },
 206     { "tosdiva0",       REG_AY,               REG_ALL                        },
 207     { "tosdivax",       REG_AXY,              REG_ALL                        },
 208     { "tosdiveax",      REG_EAXY,             REG_ALL                        },
 209     { "toseqeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 210     { "tosgeeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 211     { "tosgteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 212     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 213     { "toslcmp",        REG_EAX,              REG_A | REG_Y | REG_PTR1       },
 214     { "tosleeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 215     { "toslteax",       REG_EAX,              REG_AXY | REG_PTR1             },
 216     { "tosmula0",       REG_AX,               REG_ALL                        },
 217     { "tosmulax",       REG_AX,               REG_ALL                        },
 218     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 219     { "tosneeax",       REG_EAX,              REG_AXY | REG_PTR1             },
 220     { "tosshlax",       REG_A,                REG_AXY | REG_TMP1             },
 221     { "tosshleax",      REG_A,                REG_EAXY | REG_TMP1            },
 222     { "tosshrax",       REG_A,                REG_AXY | REG_TMP1             },
 223     { "tosshreax",      REG_A,                REG_EAXY | REG_TMP1            },
 224     { "tossuba0",       REG_A,                REG_AXY                        },
 225     { "tossubax",       REG_AX,               REG_AXY                        },
 226     { "tossubeax",      REG_EAX,              REG_EAXY                       },
 227     { "tosugeeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 228     { "tosugteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 229     { "tosuleeax",      REG_EAX,              REG_AXY | REG_PTR1             },
 230     { "tosulteax",      REG_EAX,              REG_AXY | REG_PTR1             },
 231     { "tosumula0",      REG_AX,               REG_ALL                        },
 232     { "tosumulax",      REG_AX,               REG_ALL                        },
 233     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 234     { "tsteax",         REG_EAX,              REG_Y                          },
 235     { "utsteax",        REG_EAX,              REG_Y                          },
 236 };
 237 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 238
 239 /* Table with names of zero page locations used by the compiler */
 240 static const ZPInfo ZPInfoTable[] = {
 241     {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
 242     {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
 243     {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
 244     {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
 245     {   4, "ptr3",      REG_NONE,       REG_NONE        },
 246     {   4, "ptr4",      REG_NONE,       REG_NONE        },
 247     {   7, "regbank",   REG_NONE,       REG_NONE        },
 248     {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
 249     {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
 250     {   0, "sp",        REG_SP_LO,      REG_SP          },
 251     {   0, "sp+1",      REG_SP_HI,      REG_SP          },
 252     {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
 253     {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
 254     {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
 255     {   0, "tmp2",      REG_NONE,       REG_NONE        },
 256     {   0, "tmp3",      REG_NONE,       REG_NONE        },
 257     {   0, "tmp4",      REG_NONE,       REG_NONE        },
 258 };
 259 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 260
 261
 262
 263 /*****************************************************************************/
 264 /*                                   Code                                    */
 265 /*****************************************************************************/
 266
 267
 268
 269 static int CompareFuncInfo (const void* Key, const void* Info)
 270 /* Compare function for bsearch */
 271 {
 272     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 273 }
 274
 275
 276
 277 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 278 /* For the given function, lookup register information and store it into
 279  * the given variables. If the function is unknown, assume it will use and
 280  * load all registers.
 281  */
 282 {
 283     /* If the function name starts with an underline, it is an external
 284      * function. Search for it in the symbol table. If the function does
 285      * not start with an underline, it may be a runtime support function.
 286      * Search for it in the list of builtin functions.
 287      */
 288     if (Name[0] == '_') {
 289
 290         /* Search in the symbol table, skip the leading underscore */
 291         SymEntry* E = FindGlobalSym (Name+1);
 292
 293         /* Did we find it in the top level table? */
 294         if (E && IsTypeFunc (E->Type)) {
 295
 296             /* A function may use the A or A/X registers if it is a fastcall
 297              * function. If it is not a fastcall function but a variadic one,
 298              * it will use the Y register (the parameter size is passed here).
 299              * In all other cases, no registers are used. However, we assume
 300              * that any function will destroy all registers.
 301              */
 302             FuncDesc* D = E->V.F.Func;
 303             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 304                 /* Will use registers depending on the last param */
 305                 unsigned LastParamSize = CheckedSizeOf (D->LastParam->Type);
 306                 if (LastParamSize == 1) {
 307                     *Use = REG_A;
 308                 } else if (LastParamSize == 2) {
 309                     *Use = REG_AX;
 310                 } else {
 311                     *Use = REG_EAX;
 312                 }
 313             } else if ((D->Flags & FD_VARIADIC) != 0) {
 314                 *Use = REG_Y;
 315             } else {
 316                 /* Will not use any registers */
 317                 *Use = REG_NONE;
 318             }
 319
 320             /* Will destroy all registers */
 321             *Chg = REG_ALL;
 322
 323             /* Done */
 324             return;
 325         }
 326
 327     } else if (IsDigit (Name[0]) || Name[0] == '$') {
 328
 329         /* A call to a numeric address. Assume that anything gets used and
 330          * destroyed. This is not a real problem, since numeric addresses
 331          * are used mostly in inline assembly anyway.
 332          */
 333         *Use = REG_ALL;
 334         *Chg = REG_ALL;
 335         return;
 336
 337     } else {
 338
 339         /* Search for the function in the list of builtin functions */
 340         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 341                                         sizeof(FuncInfo), CompareFuncInfo);
 342
 343         /* Do we know the function? */
 344         if (Info) {
 345             /* Use the information we have */
 346             *Use = Info->Use;
 347             *Chg = Info->Chg;
 348         } else {
 349             /* It's an internal function we have no information for. If in
 350              * debug mode, output an additional warning, so we have a chance
 351              * to fix it. Otherwise assume that the internal function will
 352              * use and change all registers.
 353              */
 354             if (Debug) {
 355                 fprintf (stderr, "No info about internal function `%s'", Name);
 356             }
 357             *Use = REG_ALL;
 358             *Chg = REG_ALL;
 359         }
 360         return;
 361     }
 362
 363     /* Function not found - assume that the primary register is input, and all
 364      * registers are changed
 365      */
 366     *Use = REG_EAXY;
 367     *Chg = REG_ALL;
 368 }
 369
 370
 371
 372 static int CompareZPInfo (const void* Name, const void* Info)
 373 /* Compare function for bsearch */
 374 {
 375     /* Cast the pointers to the correct data type */
 376     const char* N   = (const char*) Name;
 377     const ZPInfo* E = (const ZPInfo*) Info;
 378
 379     /* Do the compare. Be careful because of the length (Info may contain
 380      * more than just the zeropage name).
 381      */
 382     if (E->Len == 0) {
 383         /* Do a full compare */
 384         return strcmp (N, E->Name);
 385     } else {
 386         /* Only compare the first part */
 387         int Res = strncmp (N, E->Name, E->Len);
 388         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 389             /* Name is actually longer than Info->Name */
 390             Res = -1;
 391         }
 392         return Res;
 393     }
 394 }
 395
 396
 397
 398 const ZPInfo* GetZPInfo (const char* Name)
 399 /* If the given name is a zero page symbol, return a pointer to the info
 400  * struct for this symbol, otherwise return NULL.
 401  */
 402 {
 403     /* Search for the zp location in the list */
 404     return bsearch (Name, ZPInfoTable, ZPInfoCount,
 405                     sizeof(ZPInfo), CompareZPInfo);
 406 }
 407
 408
 409
 410 static unsigned GetRegInfo2 (CodeSeg* S,
 411                              CodeEntry* E,
 412                              int Index,
 413                              Collection* Visited,
 414                              unsigned Used,
 415                              unsigned Unused,
 416                              unsigned Wanted)
 417 /* Recursively called subfunction for GetRegInfo. */
 418 {
 419     /* Follow the instruction flow recording register usage. */
 420     while (1) {
 421
 422         unsigned R;
 423
 424         /* Check if we have already visited the current code entry. If so,
 425          * bail out.
 426          */
 427         if (CE_HasMark (E)) {
 428             break;
 429         }
 430
 431         /* Mark this entry as already visited */
 432         CE_SetMark (E);
 433         CollAppend (Visited, E);
 434
 435         /* Evaluate the used registers */
 436         R = E->Use;
 437         if (E->OPC == OP65_RTS ||
 438             ((E->Info & OF_UBRA) != 0 && E->JumpTo == 0)) {
 439             /* This instruction will leave the function */
 440             R |= S->ExitRegs;
 441         }
 442         if (R != REG_NONE) {
 443             /* We are not interested in the use of any register that has been
 444              * used before.
 445              */
 446             R &= ~Unused;
 447             /* Remember the remaining registers */
 448             Used |= R;
 449         }
 450
 451         /* Evaluate the changed registers */
 452         if ((R = E->Chg) != REG_NONE) {
 453             /* We are not interested in the use of any register that has been
 454              * used before.
 455              */
 456             R &= ~Used;
 457             /* Remember the remaining registers */
 458             Unused |= R;
 459         }
 460
 461         /* If we know about all registers now, bail out */
 462         if (((Used | Unused) & Wanted) == Wanted) {
 463             break;
 464         }
 465
 466         /* If the instruction is an RTS or RTI, we're done */
 467         if ((E->Info & OF_RET) != 0) {
 468             break;
 469         }
 470
 471         /* If we have an unconditional branch, follow this branch if possible,
 472          * otherwise we're done.
 473          */
 474         if ((E->Info & OF_UBRA) != 0) {
 475
 476             /* Does this jump have a valid target? */
 477             if (E->JumpTo) {
 478
 479                 /* Unconditional jump */
 480                 E     = E->JumpTo->Owner;
 481                 Index = -1;             /* Invalidate */
 482
 483             } else {
 484                 /* Jump outside means we're done */
 485                 break;
 486             }
 487
 488         /* In case of conditional branches, follow the branch if possible and
 489          * follow the normal flow (branch not taken) afterwards. If we cannot
 490          * follow the branch, we're done.
 491          */
 492         } else if ((E->Info & OF_CBRA) != 0) {
 493
 494             /* Recursively determine register usage at the branch target */
 495             unsigned U1;
 496             unsigned U2;
 497
 498             if (E->JumpTo) {
 499
 500                 /* Jump to internal label */
 501                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 502
 503             } else {
 504
 505                 /* Jump to external label. This will effectively exit the
 506                  * function, so we use the exitregs information here.
 507                  */
 508                 U1 = S->ExitRegs;
 509
 510             }
 511
 512             /* Get the next entry */
 513             if (Index < 0) {
 514                 Index = CS_GetEntryIndex (S, E);
 515             }
 516             if ((E = CS_GetEntry (S, ++Index)) == 0) {
 517                 Internal ("GetRegInfo2: No next entry!");
 518             }
 519
 520             /* Follow flow if branch not taken */
 521             U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 522
 523             /* Registers are used if they're use in any of the branches */
 524             return U1 | U2;
 525
 526         } else {
 527
 528             /* Just go to the next instruction */
 529             if (Index < 0) {
 530                 Index = CS_GetEntryIndex (S, E);
 531             }
 532             E = CS_GetEntry (S, ++Index);
 533             if (E == 0) {
 534                 /* No next entry */
 535                 Internal ("GetRegInfo2: No next entry!");
 536             }
 537
 538         }
 539
 540     }
 541
 542     /* Return to the caller the complement of all unused registers */
 543     return Used;
 544 }
 545
 546
 547
 548 static unsigned GetRegInfo1 (CodeSeg* S,
 549                              CodeEntry* E,
 550                              int Index,
 551                              Collection* Visited,
 552                              unsigned Used,
 553                              unsigned Unused,
 554                              unsigned Wanted)
 555 /* Recursively called subfunction for GetRegInfo. */
 556 {
 557     /* Remember the current count of the line collection */
 558     unsigned Count = CollCount (Visited);
 559
 560     /* Call the worker routine */
 561     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 562
 563     /* Restore the old count, unmarking all new entries */
 564     unsigned NewCount = CollCount (Visited);
 565     while (NewCount-- > Count) {
 566         CodeEntry* E = CollAt (Visited, NewCount);
 567         CE_ResetMark (E);
 568         CollDelete (Visited, NewCount);
 569     }
 570
 571     /* Return the registers used */
 572     return R;
 573 }
 574
 575
 576
 577 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 578 /* Determine register usage information for the instructions starting at the
 579  * given index.
 580  */
 581 {
 582     CodeEntry*      E;
 583     Collection      Visited;    /* Visited entries */
 584     unsigned        R;
 585
 586     /* Get the code entry for the given index */
 587     if (Index >= CS_GetEntryCount (S)) {
 588         /* There is no such code entry */
 589         return REG_NONE;
 590     }
 591     E = CS_GetEntry (S, Index);
 592
 593     /* Initialize the data structure used to collection information */
 594     InitCollection (&Visited);
 595
 596     /* Call the recursive subfunction */
 597     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 598
 599     /* Delete the line collection */
 600     DoneCollection (&Visited);
 601
 602     /* Return the registers used */
 603     return R;
 604 }
 605
 606
 607
 608 int RegAUsed (struct CodeSeg* S, unsigned Index)
 609 /* Check if the value in A is used. */
 610 {
 611     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 612 }
 613
 614
 615
 616 int RegXUsed (struct CodeSeg* S, unsigned Index)
 617 /* Check if the value in X is used. */
 618 {
 619     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 620 }
 621
 622
 623
 624 int RegYUsed (struct CodeSeg* S, unsigned Index)
 625 /* Check if the value in Y is used. */
 626 {
 627     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 628 }
 629
 630
 631
 632 int RegAXUsed (struct CodeSeg* S, unsigned Index)
 633 /* Check if the value in A or(!) the value in X are used. */
 634 {
 635     return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
 636 }
 637
 638
 639
 640 int RegEAXUsed (struct CodeSeg* S, unsigned Index)
 641 /* Check if any of the four bytes in EAX are used. */
 642 {
 643     return (GetRegInfo (S, Index, REG_EAX) & REG_EAX) != 0;
 644 }
 645
 646
 647
 648 unsigned GetKnownReg (unsigned Use, const RegContents* RC)
 649 /* Return the register or zero page location from the set in Use, thats
 650  * contents are known. If Use does not contain any register, or if the
 651  * register in question does not have a known value, return REG_NONE.
 652  */
 653 {
 654     if ((Use & REG_A) != 0) {
 655         return (RC == 0 || RC->RegA >= 0)? REG_A : REG_NONE;
 656     } else if ((Use & REG_X) != 0) {
 657         return (RC == 0 || RC->RegX >= 0)? REG_X : REG_NONE;
 658     } else if ((Use & REG_Y) != 0) {
 659         return (RC == 0 || RC->RegY >= 0)? REG_Y : REG_NONE;
 660     } else if ((Use & REG_TMP1) != 0) {
 661         return (RC == 0 || RC->Tmp1 >= 0)? REG_TMP1 : REG_NONE;
 662     } else if ((Use & REG_PTR1_LO) != 0) {
 663         return (RC == 0 || RC->Ptr1Lo >= 0)? REG_PTR1_LO : REG_NONE;
 664     } else if ((Use & REG_PTR1_HI) != 0) {
 665         return (RC == 0 || RC->Ptr1Hi >= 0)? REG_PTR1_HI : REG_NONE;
 666     } else if ((Use & REG_SREG_LO) != 0) {
 667         return (RC == 0 || RC->SRegLo >= 0)? REG_SREG_LO : REG_NONE;
 668     } else if ((Use & REG_SREG_HI) != 0) {
 669         return (RC == 0 || RC->SRegHi >= 0)? REG_SREG_HI : REG_NONE;
 670     } else {
 671         return REG_NONE;
 672     }
 673 }
 674
 675
 676
 677 static cmp_t FindCmpCond (const char* Code, unsigned CodeLen)
 678 /* Search for a compare condition by the given code using the given length */
 679 {
 680     unsigned I;
 681
 682     /* Linear search */
 683     for (I = 0; I < sizeof (CmpSuffixTab) / sizeof (CmpSuffixTab [0]); ++I) {
 684         if (strncmp (Code, CmpSuffixTab [I], CodeLen) == 0) {
 685             /* Found */
 686             return I;
 687         }
 688     }
 689
 690     /* Not found */
 691     return CMP_INV;
 692 }
 693
 694
 695
 696 cmp_t FindBoolCmpCond (const char* Name)
 697 /* Check if the given string is the name of one of the boolean transformer
 698  * subroutine, and if so, return the condition that is evaluated by this
 699  * routine. Return CMP_INV if the condition is not recognised.
 700  */
 701 {
 702     /* Check for the correct subroutine name */
 703     if (strncmp (Name, "bool", 4) == 0) {
 704         /* Name is ok, search for the code in the table */
 705         return FindCmpCond (Name+4, strlen(Name)-4);
 706     } else {
 707         /* Not found */
 708         return CMP_INV;
 709     }
 710 }
 711
 712
 713
 714 cmp_t FindTosCmpCond (const char* Name)
 715 /* Check if this is a call to one of the TOS compare functions (tosgtax).
 716  * Return the condition code or CMP_INV on failure.
 717  */
 718 {
 719     unsigned Len = strlen (Name);
 720
 721     /* Check for the correct subroutine name */
 722     if (strncmp (Name, "tos", 3) == 0 && strcmp (Name+Len-2, "ax") == 0) {
 723         /* Name is ok, search for the code in the table */
 724         return FindCmpCond (Name+3, Len-3-2);
 725     } else {
 726         /* Not found */
 727         return CMP_INV;
 728     }
 729 }
 730
 731
 732