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      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 "symtab.h"
  48 #include "codeinfo.h"
  49
  50
  51
  52 /*****************************************************************************/
  53 /*                                   Data                                    */
  54 /*****************************************************************************/
  55
  56
  57
  58 /* Table listing the function names and code info values for known internally
  59  * used functions. This table should get auto-generated in the future.
  60  */
  61 typedef struct FuncInfo FuncInfo;
  62 struct FuncInfo {
  63     const char*     Name;       /* Function name */
  64     unsigned short  Use;        /* Register usage */
  65     unsigned short  Chg;        /* Changed/destroyed registers */
  66 };
  67
  68 static const FuncInfo FuncInfoTable[] = {
  69     { "addysp",         REG_Y,                REG_NONE                       },
  70     { "aslax1",         REG_AX,               REG_AX | REG_TMP1              },
  71     { "aslax2",         REG_AX,               REG_AX | REG_TMP1              },
  72     { "aslax3",         REG_AX,               REG_AX | REG_TMP1              },
  73     { "aslax4",         REG_AX,               REG_AX | REG_TMP1              },
  74     { "bnega",          REG_A,                REG_AX                         },
  75     { "bnegax",         REG_AX,               REG_AX                         },
  76     { "bnegeax",        REG_EAX,              REG_EAX                        },
  77     { "booleq",         REG_NONE,             REG_AX                         },
  78     { "boolge",         REG_NONE,             REG_AX                         },
  79     { "boolgt",         REG_NONE,             REG_AX                         },
  80     { "boolle",         REG_NONE,             REG_AX                         },
  81     { "boollt",         REG_NONE,             REG_AX                         },
  82     { "boolne",         REG_NONE,             REG_AX                         },
  83     { "booluge",        REG_NONE,             REG_AX                         },
  84     { "boolugt",        REG_NONE,             REG_AX                         },
  85     { "boolule",        REG_NONE,             REG_AX                         },
  86     { "boolult",        REG_NONE,             REG_AX                         },
  87     { "complax",        REG_AX,               REG_AX                         },
  88     { "decax1",         REG_AX,               REG_AX                         },
  89     { "decax2",         REG_AX,               REG_AX                         },
  90     { "decax3",         REG_AX,               REG_AX                         },
  91     { "decax4",         REG_AX,               REG_AX                         },
  92     { "decax5",         REG_AX,               REG_AX                         },
  93     { "decax6",         REG_AX,               REG_AX                         },
  94     { "decax7",         REG_AX,               REG_AX                         },
  95     { "decax8",         REG_AX,               REG_AX                         },
  96     { "decaxy",         REG_AXY,              REG_AX | REG_TMP1              },
  97     { "decsp1",         REG_NONE,             REG_Y                          },
  98     { "decsp2",         REG_NONE,             REG_A                          },
  99     { "decsp3",         REG_NONE,             REG_A                          },
 100     { "decsp4",         REG_NONE,             REG_A                          },
 101     { "decsp5",         REG_NONE,             REG_A                          },
 102     { "decsp6",         REG_NONE,             REG_A                          },
 103     { "decsp7",         REG_NONE,             REG_A                          },
 104     { "decsp8",         REG_NONE,             REG_A                          },
 105     { "incax1",         REG_AX,               REG_AX                         },
 106     { "incax2",         REG_AX,               REG_AX                         },
 107     { "incsp1",         REG_NONE,             REG_NONE                       },
 108     { "incsp2",         REG_NONE,             REG_Y                          },
 109     { "incsp3",         REG_NONE,             REG_Y                          },
 110     { "incsp4",         REG_NONE,             REG_Y                          },
 111     { "incsp5",         REG_NONE,             REG_Y                          },
 112     { "incsp6",         REG_NONE,             REG_Y                          },
 113     { "incsp7",         REG_NONE,             REG_Y                          },
 114     { "incsp8",         REG_NONE,             REG_Y                          },
 115     { "laddeq",         REG_EAXY|REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 116     { "laddeq1",        REG_Y | REG_PTR1_LO,  REG_EAXY | REG_PTR1_HI         },
 117     { "laddeqa",        REG_AY | REG_PTR1_LO, REG_EAXY | REG_PTR1_HI         },
 118     { "ldaidx",         REG_AXY,              REG_AX | REG_PTR1              },
 119     { "ldauidx",        REG_AXY,              REG_AX | REG_PTR1              },
 120     { "ldax0sp",        REG_Y,                REG_AX                         },
 121     { "ldaxi",          REG_AX,               REG_AXY | REG_PTR1             },
 122     { "ldaxidx",        REG_AXY,              REG_AX | REG_PTR1              },
 123     { "ldaxysp",        REG_Y,                REG_AX                         },
 124     { "leaasp",         REG_A,                REG_AX                         },
 125     { "negax",          REG_AX,               REG_AX                         },
 126     { "pusha",          REG_A,                REG_Y                          },
 127     { "pusha0",         REG_A,                REG_XY                         },
 128     { "pushax",         REG_AX,               REG_Y                          },
 129     { "pusheax",        REG_EAX,              REG_Y                          },
 130     { "pushw0sp",       REG_NONE,             REG_AXY                        },
 131     { "pushwysp",       REG_Y,                REG_AXY                        },
 132     { "shlax1",         REG_AX,               REG_AX | REG_TMP1              },
 133     { "shlax2",         REG_AX,               REG_AX | REG_TMP1              },
 134     { "shlax3",         REG_AX,               REG_AX | REG_TMP1              },
 135     { "shlax4",         REG_AX,               REG_AX | REG_TMP1              },
 136     { "shrax1",         REG_AX,               REG_AX | REG_TMP1              },
 137     { "shrax2",         REG_AX,               REG_AX | REG_TMP1              },
 138     { "shrax3",         REG_AX,               REG_AX | REG_TMP1              },
 139     { "shrax4",         REG_AX,               REG_AX | REG_TMP1              },
 140     { "shreax1",        REG_EAX,              REG_AX | REG_TMP1              },
 141     { "shreax2",        REG_EAX,              REG_AX | REG_TMP1              },
 142     { "shreax3",        REG_EAX,              REG_AX | REG_TMP1              },
 143     { "shreax4",        REG_EAX,              REG_AX | REG_TMP1              },
 144     { "staspidx",       REG_A | REG_Y,        REG_Y | REG_TMP1 | REG_PTR1    },
 145     { "stax0sp",        REG_AX,               REG_Y                          },
 146     { "staxysp",        REG_AXY,              REG_Y                          },
 147     { "tosadda0",       REG_A,                REG_AXY                        },
 148     { "tosaddax",       REG_AX,               REG_AXY                        },
 149     { "tosicmp",        REG_AX,               REG_AXY | REG_SREG             },
 150     { "tosdiva0",       REG_AX,               REG_ALL                        },
 151     { "tosdivax",       REG_AX,               REG_ALL                        },
 152     { "tosdiveax",      REG_EAX,              REG_ALL                        },
 153     { "tosmula0",       REG_AX,               REG_ALL                        },
 154     { "tosmulax",       REG_AX,               REG_ALL                        },
 155     { "tosmuleax",      REG_EAX,              REG_ALL                        },
 156     { "tosshreax",      REG_EAX,              REG_EAXY | REG_PTR1 | REG_PTR2 },
 157     { "tosumula0",      REG_AX,               REG_ALL                        },
 158     { "tosumulax",      REG_AX,               REG_ALL                        },
 159     { "tosumuleax",     REG_EAX,              REG_ALL                        },
 160 };
 161 #define FuncInfoCount   (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
 162
 163 /* Table with names of zero page locations used by the compiler */
 164 static const ZPInfo ZPInfoTable[] = {
 165     {   0, "ptr1",      REG_PTR1_LO,    REG_PTR1        },
 166     {   0, "ptr1+1",    REG_PTR1_HI,    REG_PTR1        },
 167     {   0, "ptr2",      REG_PTR2_LO,    REG_PTR2        },
 168     {   0, "ptr2+1",    REG_PTR2_HI,    REG_PTR2        },
 169     {   4, "ptr3",      REG_NONE,       REG_NONE        },
 170     {   4, "ptr4",      REG_NONE,       REG_NONE        },
 171     {   7, "regbank",   REG_NONE,       REG_NONE        },
 172     {   0, "regsave",   REG_SAVE_LO,    REG_SAVE        },
 173     {   0, "regsave+1", REG_SAVE_HI,    REG_SAVE        },
 174     {   0, "sp",        REG_SP_LO,      REG_SP          },
 175     {   0, "sp+1",      REG_SP_HI,      REG_SP          },
 176     {   0, "sreg",      REG_SREG_LO,    REG_SREG        },
 177     {   0, "sreg+1",    REG_SREG_HI,    REG_SREG        },
 178     {   0, "tmp1",      REG_TMP1,       REG_TMP1        },
 179     {   0, "tmp2",      REG_NONE,       REG_NONE        },
 180     {   0, "tmp3",      REG_NONE,       REG_NONE        },
 181     {   0, "tmp4",      REG_NONE,       REG_NONE        },
 182 };
 183 #define ZPInfoCount     (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
 184
 185
 186
 187 /*****************************************************************************/
 188 /*                                   Code                                    */
 189 /*****************************************************************************/
 190
 191
 192
 193 static int CompareFuncInfo (const void* Key, const void* Info)
 194 /* Compare function for bsearch */
 195 {
 196     return strcmp (Key, ((const FuncInfo*) Info)->Name);
 197 }
 198
 199
 200
 201 void GetFuncInfo (const char* Name, unsigned short* Use, unsigned short* Chg)
 202 /* For the given function, lookup register information and store it into
 203  * the given variables. If the function is unknown, assume it will use and
 204  * load all registers.
 205  */
 206 {
 207     /* If the function name starts with an underline, it is an external
 208      * function. Search for it in the symbol table. If the function does
 209      * not start with an underline, it may be a runtime support function.
 210      * Search for it in the list of builtin functions.
 211      */
 212     if (Name[0] == '_') {
 213
 214         /* Search in the symbol table, skip the leading underscore */
 215         SymEntry* E = FindGlobalSym (Name+1);
 216
 217         /* Did we find it in the top level table? */
 218         if (E && IsTypeFunc (E->Type)) {
 219
 220             /* A function may use the A or A/X registers if it is a fastcall
 221              * function. If it is not a fastcall function but a variadic one,
 222              * it will use the Y register (the parameter size is passed here).
 223              * In all other cases, no registers are used. However, we assume
 224              * that any function will destroy all registers.
 225              */
 226             FuncDesc* D = E->V.F.Func;
 227             if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
 228                 /* Will use registers depending on the last param */
 229                 SymEntry* LastParam = D->SymTab->SymTail;
 230                 if (SizeOf (LastParam->Type) == 1) {
 231                     *Use = REG_A;
 232                 } else {
 233                     *Use = REG_AX;
 234                 }
 235             } else if ((D->Flags & FD_VARIADIC) != 0) {
 236                 *Use = REG_Y;
 237             } else {
 238                 /* Will not use any registers */
 239                 *Use = REG_NONE;
 240             }
 241
 242             /* Will destroy all registers */
 243             *Chg = REG_ALL;
 244
 245             /* Done */
 246             return;
 247         }
 248
 249     } else {
 250
 251         /* Search for the function in the list of builtin functions */
 252         const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
 253                                         sizeof(FuncInfo), CompareFuncInfo);
 254
 255         /* Do we know the function? */
 256         if (Info) {
 257             /* Use the information we have */
 258             *Use = Info->Use;
 259             *Chg = Info->Chg;
 260             return;
 261         }
 262     }
 263
 264     /* Function not found - assume that the primary register is input, and all
 265      * registers are changed
 266      */
 267     *Use = REG_EAXY;
 268     *Chg = REG_ALL;
 269 }
 270
 271
 272
 273 static int CompareZPInfo (const void* Name, const void* Info)
 274 /* Compare function for bsearch */
 275 {
 276     /* Cast the pointers to the correct data type */
 277     const char* N   = (const char*) Name;
 278     const ZPInfo* E = (const ZPInfo*) Info;
 279
 280     /* Do the compare. Be careful because of the length (Info may contain
 281      * more than just the zeropage name).
 282      */
 283     if (E->Len == 0) {
 284         /* Do a full compare */
 285         return strcmp (N, E->Name);
 286     } else {
 287         /* Only compare the first part */
 288         int Res = strncmp (N, E->Name, E->Len);
 289         if (Res == 0 && (N[E->Len] != '\0' && N[E->Len] != '+')) {
 290             /* Name is actually longer than Info->Name */
 291             Res = -1;
 292         }
 293         return Res;
 294     }
 295 }
 296
 297
 298
 299 const ZPInfo* GetZPInfo (const char* Name)
 300 /* If the given name is a zero page symbol, return a pointer to the info
 301  * struct for this symbol, otherwise return NULL.
 302  */
 303 {
 304     /* Search for the zp location in the list */
 305     return bsearch (Name, ZPInfoTable, ZPInfoCount,
 306                     sizeof(ZPInfo), CompareZPInfo);
 307 }
 308
 309
 310
 311 static unsigned GetRegInfo2 (CodeSeg* S,
 312                              CodeEntry* E,
 313                              int Index,
 314                              Collection* Visited,
 315                              unsigned Used,
 316                              unsigned Unused,
 317                              unsigned Wanted)
 318 /* Recursively called subfunction for GetRegInfo. */
 319 {
 320     /* Follow the instruction flow recording register usage. */
 321     while (1) {
 322
 323         unsigned R;
 324
 325         /* Check if we have already visited the current code entry. If so,
 326          * bail out.
 327          */
 328         if (CE_HasMark (E)) {
 329             break;
 330         }
 331
 332         /* Mark this entry as already visited */
 333         CE_SetMark (E);
 334         CollAppend (Visited, E);
 335
 336         /* Evaluate the used registers */
 337         R = E->Use;
 338         if (E->OPC == OP65_RTS ||
 339             ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
 340             /* This instruction will leave the function */
 341             R |= S->ExitRegs;
 342         }
 343         if (R != REG_NONE) {
 344             /* We are not interested in the use of any register that has been
 345              * used before.
 346              */
 347             R &= ~Unused;
 348             /* Remember the remaining registers */
 349             Used |= R;
 350         }
 351
 352         /* Evaluate the changed registers */
 353         if ((R = E->Chg) != REG_NONE) {
 354             /* We are not interested in the use of any register that has been
 355              * used before.
 356              */
 357             R &= ~Used;
 358             /* Remember the remaining registers */
 359             Unused |= R;
 360         }
 361
 362         /* If we know about all registers now, bail out */
 363         if (((Used | Unused) & Wanted) == Wanted) {
 364             break;
 365         }
 366
 367         /* If the instruction is an RTS or RTI, we're done */
 368         if ((E->Info & OF_RET) != 0) {
 369             break;
 370         }
 371
 372         /* If we have an unconditional branch, follow this branch if possible,
 373          * otherwise we're done.
 374          */
 375         if ((E->Info & OF_UBRA) != 0) {
 376
 377             /* Does this jump have a valid target? */
 378             if (E->JumpTo) {
 379
 380                 /* Unconditional jump */
 381                 E     = E->JumpTo->Owner;
 382                 Index = -1;             /* Invalidate */
 383
 384             } else {
 385                 /* Jump outside means we're done */
 386                 break;
 387             }
 388
 389         /* In case of conditional branches, follow the branch if possible and
 390          * follow the normal flow (branch not taken) afterwards. If we cannot
 391          * follow the branch, we're done.
 392          */
 393         } else if ((E->Info & OF_CBRA) != 0) {
 394
 395             if (E->JumpTo) {
 396
 397                 /* Recursively determine register usage at the branch target */
 398                 unsigned U1;
 399                 unsigned U2;
 400
 401                 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused, Wanted);
 402                 if (U1 == REG_ALL) {
 403                     /* All registers used, no need for second call */
 404                     return REG_AXY;
 405                 }
 406                 if (Index < 0) {
 407                     Index = CS_GetEntryIndex (S, E);
 408                 }
 409                 if ((E = CS_GetEntry (S, ++Index)) == 0) {
 410                     Internal ("GetRegInfo2: No next entry!");
 411                 }
 412                 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 413                 return U1 | U2;         /* Used in any of the branches */
 414
 415             } else {
 416                 /* Jump to global symbol */
 417                 break;
 418             }
 419
 420         } else {
 421
 422             /* Just go to the next instruction */
 423             if (Index < 0) {
 424                 Index = CS_GetEntryIndex (S, E);
 425             }
 426             E = CS_GetEntry (S, ++Index);
 427             if (E == 0) {
 428                 /* No next entry */
 429                 Internal ("GetRegInfo2: No next entry!");
 430             }
 431
 432         }
 433
 434     }
 435
 436     /* Return to the caller the complement of all unused registers */
 437     return Used;
 438 }
 439
 440
 441
 442 static unsigned GetRegInfo1 (CodeSeg* S,
 443                              CodeEntry* E,
 444                              int Index,
 445                              Collection* Visited,
 446                              unsigned Used,
 447                              unsigned Unused,
 448                              unsigned Wanted)
 449 /* Recursively called subfunction for GetRegInfo. */
 450 {
 451     /* Remember the current count of the line collection */
 452     unsigned Count = CollCount (Visited);
 453
 454     /* Call the worker routine */
 455     unsigned R = GetRegInfo2 (S, E, Index, Visited, Used, Unused, Wanted);
 456
 457     /* Restore the old count, unmarking all new entries */
 458     unsigned NewCount = CollCount (Visited);
 459     while (NewCount-- > Count) {
 460         CodeEntry* E = CollAt (Visited, NewCount);
 461         CE_ResetMark (E);
 462         CollDelete (Visited, NewCount);
 463     }
 464
 465     /* Return the registers used */
 466     return R;
 467 }
 468
 469
 470
 471 unsigned GetRegInfo (struct CodeSeg* S, unsigned Index, unsigned Wanted)
 472 /* Determine register usage information for the instructions starting at the
 473  * given index.
 474  */
 475 {
 476     CodeEntry*      E;
 477     Collection      Visited;    /* Visited entries */
 478     unsigned        R;
 479
 480     /* Get the code entry for the given index */
 481     if (Index >= CS_GetEntryCount (S)) {
 482         /* There is no such code entry */
 483         return REG_NONE;
 484     }
 485     E = CS_GetEntry (S, Index);
 486
 487     /* Initialize the data structure used to collection information */
 488     InitCollection (&Visited);
 489
 490     /* Call the recursive subfunction */
 491     R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE, Wanted);
 492
 493     /* Delete the line collection */
 494     DoneCollection (&Visited);
 495
 496     /* Return the registers used */
 497     return R;
 498 }
 499
 500
 501
 502 int RegAUsed (struct CodeSeg* S, unsigned Index)
 503 /* Check if the value in A is used. */
 504 {
 505     return (GetRegInfo (S, Index, REG_A) & REG_A) != 0;
 506 }
 507
 508
 509
 510 int RegXUsed (struct CodeSeg* S, unsigned Index)
 511 /* Check if the value in X is used. */
 512 {
 513     return (GetRegInfo (S, Index, REG_X) & REG_X) != 0;
 514 }
 515
 516
 517
 518 int RegYUsed (struct CodeSeg* S, unsigned Index)
 519 /* Check if the value in Y is used. */
 520 {
 521     return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
 522 }
 523
 524
 525
 526
 527