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