1 /*****************************************************************************/
5 /* Additional information about 6502 code */
9 /* (C) 2001 Ullrich von Bassewitz */
11 /* D-70597 Stuttgart */
12 /* EMail: uz@cc65.org */
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. */
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: */
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 */
32 /*****************************************************************************/
52 /*****************************************************************************/
54 /*****************************************************************************/
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.
61 typedef struct FuncInfo FuncInfo;
63 const char* Name; /* Function name */
64 unsigned char Use; /* Register usage */
65 unsigned char Chg; /* Changed/destroyed registers */
68 static const FuncInfo FuncInfoTable[] = {
69 { "addysp", REG_Y, REG_NONE },
70 { "booleq", REG_NONE, REG_AX },
71 { "boolge", REG_NONE, REG_AX },
72 { "boolgt", REG_NONE, REG_AX },
73 { "boolle", REG_NONE, REG_AX },
74 { "boollt", REG_NONE, REG_AX },
75 { "boolne", REG_NONE, REG_AX },
76 { "booluge", REG_NONE, REG_AX },
77 { "boolugt", REG_NONE, REG_AX },
78 { "boolule", REG_NONE, REG_AX },
79 { "boolult", REG_NONE, REG_AX },
80 { "decax1", REG_AX, REG_AX },
81 { "decax2", REG_AX, REG_AX },
82 { "decax3", REG_AX, REG_AX },
83 { "decax4", REG_AX, REG_AX },
84 { "decax5", REG_AX, REG_AX },
85 { "decax6", REG_AX, REG_AX },
86 { "decax7", REG_AX, REG_AX },
87 { "decax8", REG_AX, REG_AX },
88 { "decaxy", REG_AXY, REG_AX },
89 { "decsp2", REG_NONE, REG_A },
90 { "decsp3", REG_NONE, REG_A },
91 { "decsp4", REG_NONE, REG_A },
92 { "decsp5", REG_NONE, REG_A },
93 { "decsp6", REG_NONE, REG_A },
94 { "decsp7", REG_NONE, REG_A },
95 { "decsp8", REG_NONE, REG_A },
96 { "incsp1", REG_NONE, REG_NONE },
97 { "incsp2", REG_NONE, REG_Y },
98 { "incsp3", REG_NONE, REG_Y },
99 { "incsp4", REG_NONE, REG_Y },
100 { "incsp5", REG_NONE, REG_Y },
101 { "incsp6", REG_NONE, REG_Y },
102 { "incsp7", REG_NONE, REG_Y },
103 { "incsp8", REG_NONE, REG_Y },
104 { "ldax0sp", REG_Y, REG_AX },
105 { "ldaxysp", REG_Y, REG_AX },
106 { "pusha", REG_A, REG_Y },
107 { "pusha0", REG_A, REG_XY },
108 { "pushax", REG_AX, REG_Y },
109 { "pushw0sp", REG_NONE, REG_AXY },
110 { "pushwysp", REG_Y, REG_AXY },
111 { "tosicmp", REG_AX, REG_AXY },
113 #define FuncInfoCount (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
115 /* Table with names of zero page locations used by the compiler */
116 typedef struct ZPInfo ZPInfo;
118 unsigned char Len; /* Length of the following string */
119 char Name[11]; /* Name of zero page symbol */
121 static const ZPInfo ZPInfoTable[] = {
129 #define ZPInfoCount (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
132 /*****************************************************************************/
134 /*****************************************************************************/
138 static int CompareFuncInfo (const void* Key, const void* Info)
139 /* Compare function for bsearch */
141 return strcmp (Key, ((const FuncInfo*) Info)->Name);
146 void GetFuncInfo (const char* Name, unsigned char* Use, unsigned char* Chg)
147 /* For the given function, lookup register information and store it into
148 * the given variables. If the function is unknown, assume it will use and
149 * load all registers.
152 /* If the function name starts with an underline, it is an external
153 * function. Search for it in the symbol table. If the function does
154 * not start with an underline, it may be a runtime support function.
155 * Search for it in the list of builtin functions.
157 if (Name[0] == '_') {
159 /* Search in the symbol table, skip the leading underscore */
160 SymEntry* E = FindSym (Name+1);
162 /* Did we find it in the top level table? */
163 if (E && E->Owner->PrevTab == 0 && IsTypeFunc (E->Type)) {
165 /* A function may use the A or A/X registers if it is a fastcall
166 * function. If it is not a fastcall function but a variadic one,
167 * it will use the Y register (the parameter size is passed here).
168 * In all other cases, no registers are used. However, we assume
169 * that any function will destroy all registers.
171 FuncDesc* D = E->V.F.Func;
172 if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
173 /* Will use registers depending on the last param */
174 SymEntry* LastParam = D->SymTab->SymTail;
175 if (SizeOf (LastParam->Type) == 1) {
180 } else if ((D->Flags & FD_VARIADIC) != 0) {
183 /* Will not use any registers */
187 /* Will destroy all registers */
196 /* Search for the function in the list of builtin functions */
197 const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
198 sizeof(FuncInfo), CompareFuncInfo);
200 /* Do we know the function? */
202 /* Use the information we have */
209 /* Function not found - assume all registers used */
216 int IsZPName (const char* Name)
217 /* Return true if the given name is a zero page symbol */
222 /* Because of the low number of symbols, we do a linear search here */
223 for (I = 0, Info = ZPInfoTable; I < ZPInfoCount; ++I, ++Info) {
224 if (strncmp (Name, Info->Name, Info->Len) == 0 &&
225 (Name[Info->Len] == '\0' || Name[Info->Len] == '+')) {
237 static unsigned char GetRegInfo2 (CodeSeg* S,
242 unsigned char Unused)
243 /* Recursively called subfunction for GetRegInfo. */
245 /* Follow the instruction flow recording register usage. */
250 /* Check if we have already visited the current code entry. If so,
253 if (CodeEntryHasMark (E)) {
257 /* Mark this entry as already visited */
258 CodeEntrySetMark (E);
259 CollAppend (Visited, E);
261 /* Evaluate the used registers */
263 if (E->OPC == OPC_RTS ||
264 ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
265 /* This instruction will leave the function */
269 /* We are not interested in the use of any register that has been
273 /* Remember the remaining registers */
277 /* Evaluate the changed registers */
278 if ((R = E->Chg) != REG_NONE) {
279 /* We are not interested in the use of any register that has been
283 /* Remember the remaining registers */
287 /* If we know about all registers now, bail out */
288 if ((Used | Unused) == REG_AXY) {
292 /* If the instruction is an RTS or RTI, we're done */
293 if (E->OPC == OPC_RTS || E->OPC == OPC_RTI) {
297 /* If we have an unconditional branch, follow this branch if possible,
298 * otherwise we're done.
300 if ((E->Info & OF_UBRA) != 0) {
302 /* Does this jump have a valid target? */
305 /* Unconditional jump */
306 E = E->JumpTo->Owner;
307 Index = -1; /* Invalidate */
310 /* Jump outside means we're done */
314 /* In case of conditional branches, follow the branch if possible and
315 * follow the normal flow (branch not taken) afterwards. If we cannot
316 * follow the branch, we're done.
318 } else if ((E->Info & OF_CBRA) != 0) {
322 /* Recursively determine register usage at the branch target */
326 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused);
328 /* All registers used, no need for second call */
332 Index = GetCodeEntryIndex (S, E);
334 if ((E = GetCodeEntry (S, ++Index)) == 0) {
335 Internal ("GetRegInfo2: No next entry!");
337 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused);
338 return U1 | U2; /* Used in any of the branches */
341 /* Jump to global symbol */
347 /* Just go to the next instruction */
349 Index = GetCodeEntryIndex (S, E);
351 E = GetCodeEntry (S, ++Index);
354 Internal ("GetRegInfo2: No next entry!");
361 /* Return to the caller the complement of all unused registers */
367 static unsigned char GetRegInfo1 (CodeSeg* S,
372 unsigned char Unused)
373 /* Recursively called subfunction for GetRegInfo. */
375 /* Remember the current count of the line collection */
376 unsigned Count = CollCount (Visited);
378 /* Call the worker routine */
379 unsigned char R = GetRegInfo2 (S, E, Index, Visited, Used, Unused);
381 /* Restore the old count, unmarking all new entries */
382 unsigned NewCount = CollCount (Visited);
383 while (NewCount-- > Count) {
384 CodeEntry* E = CollAt (Visited, NewCount);
385 CodeEntryResetMark (E);
386 CollDelete (Visited, NewCount);
389 /* Return the registers used */
395 unsigned char GetRegInfo (struct CodeSeg* S, unsigned Index)
396 /* Determine register usage information for the instructions starting at the
401 Collection Visited; /* Visited entries */
404 /* Get the code entry for the given index */
405 if (Index >= GetCodeEntryCount (S)) {
406 /* There is no such code entry */
409 E = GetCodeEntry (S, Index);
411 /* Initialize the data structure used to collection information */
412 InitCollection (&Visited);
414 /* Call the recursive subfunction */
415 R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE);
417 /* Delete the line collection */
418 DoneCollection (&Visited);
420 /* Return the registers used */
426 int RegAUsed (struct CodeSeg* S, unsigned Index)
427 /* Check if the value in A is used. */
429 return (GetRegInfo (S, Index) & REG_A) != 0;
434 int RegXUsed (struct CodeSeg* S, unsigned Index)
435 /* Check if the value in X is used. */
437 return (GetRegInfo (S, Index) & REG_X) != 0;
442 int RegYUsed (struct CodeSeg* S, unsigned Index)
443 /* Check if the value in Y is used. */
445 return (GetRegInfo (S, Index) & REG_Y) != 0;