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 { "bnega", REG_A, REG_AX },
71 { "bnegax", REG_AX, REG_AX },
72 { "bnegeax", REG_AX, REG_AX },
73 { "booleq", REG_NONE, REG_AX },
74 { "boolge", REG_NONE, REG_AX },
75 { "boolgt", REG_NONE, REG_AX },
76 { "boolle", REG_NONE, REG_AX },
77 { "boollt", REG_NONE, REG_AX },
78 { "boolne", REG_NONE, REG_AX },
79 { "booluge", REG_NONE, REG_AX },
80 { "boolugt", REG_NONE, REG_AX },
81 { "boolule", REG_NONE, REG_AX },
82 { "boolult", REG_NONE, REG_AX },
83 { "complax", REG_AX, REG_AX },
84 { "decax1", REG_AX, REG_AX },
85 { "decax2", REG_AX, REG_AX },
86 { "decax3", REG_AX, REG_AX },
87 { "decax4", REG_AX, REG_AX },
88 { "decax5", REG_AX, REG_AX },
89 { "decax6", REG_AX, REG_AX },
90 { "decax7", REG_AX, REG_AX },
91 { "decax8", REG_AX, REG_AX },
92 { "decaxy", REG_AXY, REG_AX },
93 { "decsp1", REG_NONE, REG_Y },
94 { "decsp2", REG_NONE, REG_A },
95 { "decsp3", REG_NONE, REG_A },
96 { "decsp4", REG_NONE, REG_A },
97 { "decsp5", REG_NONE, REG_A },
98 { "decsp6", REG_NONE, REG_A },
99 { "decsp7", REG_NONE, REG_A },
100 { "decsp8", REG_NONE, REG_A },
101 { "incax1", REG_AX, REG_AX },
102 { "incax2", REG_AX, REG_AX },
103 { "incsp1", REG_NONE, REG_NONE },
104 { "incsp2", REG_NONE, REG_Y },
105 { "incsp3", REG_NONE, REG_Y },
106 { "incsp4", REG_NONE, REG_Y },
107 { "incsp5", REG_NONE, REG_Y },
108 { "incsp6", REG_NONE, REG_Y },
109 { "incsp7", REG_NONE, REG_Y },
110 { "incsp8", REG_NONE, REG_Y },
111 { "ldaui", REG_AX, REG_AXY },
112 { "ldauidx", REG_AXY, REG_AX },
113 { "ldax0sp", REG_Y, REG_AX },
114 { "ldaxi", REG_AX, REG_AXY },
115 { "ldaxidx", REG_AXY, REG_AX },
116 { "ldaxysp", REG_Y, REG_AX },
117 { "leaasp", REG_A, REG_AX },
118 { "negax", REG_AX, REG_AX },
119 { "pusha", REG_A, REG_Y },
120 { "pusha0", REG_A, REG_XY },
121 { "pushax", REG_AX, REG_Y },
122 { "pusheax", REG_AX, REG_Y },
123 { "pushw0sp", REG_NONE, REG_AXY },
124 { "pushwysp", REG_Y, REG_AXY },
125 { "shrax1", REG_AX, REG_AX },
126 { "shrax2", REG_AX, REG_AX },
127 { "shrax3", REG_AX, REG_AX },
128 { "shreax1", REG_AX, REG_AX },
129 { "shreax2", REG_AX, REG_AX },
130 { "shreax3", REG_AX, REG_AX },
131 { "staspidx", REG_A | REG_Y, REG_Y },
132 { "tosicmp", REG_AX, REG_AXY },
133 { "tosdiva0", REG_AX, REG_AXY },
134 { "tosdivax", REG_AX, REG_AXY },
135 { "tosdiveax", REG_AX, REG_AXY },
136 { "tosmula0", REG_AX, REG_AXY },
137 { "tosmulax", REG_AX, REG_AXY },
138 { "tosmuleax", REG_AX, REG_AXY },
139 { "tosshreax", REG_AX, REG_AXY },
140 { "tosumula0", REG_AX, REG_AXY },
141 { "tosumulax", REG_AX, REG_AXY },
142 { "tosumuleax", REG_AX, REG_AXY },
144 #define FuncInfoCount (sizeof(FuncInfoTable) / sizeof(FuncInfoTable[0]))
146 /* Table with names of zero page locations used by the compiler */
147 typedef struct ZPInfo ZPInfo;
149 unsigned char Len; /* Length of the following string */
150 char Name[11]; /* Name of zero page symbol */
152 static const ZPInfo ZPInfoTable[] = {
160 #define ZPInfoCount (sizeof(ZPInfoTable) / sizeof(ZPInfoTable[0]))
163 /*****************************************************************************/
165 /*****************************************************************************/
169 static int CompareFuncInfo (const void* Key, const void* Info)
170 /* Compare function for bsearch */
172 return strcmp (Key, ((const FuncInfo*) Info)->Name);
177 void GetFuncInfo (const char* Name, unsigned char* Use, unsigned char* Chg)
178 /* For the given function, lookup register information and store it into
179 * the given variables. If the function is unknown, assume it will use and
180 * load all registers.
183 /* If the function name starts with an underline, it is an external
184 * function. Search for it in the symbol table. If the function does
185 * not start with an underline, it may be a runtime support function.
186 * Search for it in the list of builtin functions.
188 if (Name[0] == '_') {
190 /* Search in the symbol table, skip the leading underscore */
191 SymEntry* E = FindGlobalSym (Name+1);
193 /* Did we find it in the top level table? */
194 if (E && IsTypeFunc (E->Type)) {
196 /* A function may use the A or A/X registers if it is a fastcall
197 * function. If it is not a fastcall function but a variadic one,
198 * it will use the Y register (the parameter size is passed here).
199 * In all other cases, no registers are used. However, we assume
200 * that any function will destroy all registers.
202 FuncDesc* D = E->V.F.Func;
203 if ((D->Flags & FD_FASTCALL) != 0 && D->ParamCount > 0) {
204 /* Will use registers depending on the last param */
205 SymEntry* LastParam = D->SymTab->SymTail;
206 if (SizeOf (LastParam->Type) == 1) {
211 } else if ((D->Flags & FD_VARIADIC) != 0) {
214 /* Will not use any registers */
218 /* Will destroy all registers */
227 /* Search for the function in the list of builtin functions */
228 const FuncInfo* Info = bsearch (Name, FuncInfoTable, FuncInfoCount,
229 sizeof(FuncInfo), CompareFuncInfo);
231 /* Do we know the function? */
233 /* Use the information we have */
240 /* Function not found - assume all registers used */
247 int IsZPName (const char* Name)
248 /* Return true if the given name is a zero page symbol */
253 /* Because of the low number of symbols, we do a linear search here */
254 for (I = 0, Info = ZPInfoTable; I < ZPInfoCount; ++I, ++Info) {
255 if (strncmp (Name, Info->Name, Info->Len) == 0 &&
256 (Name[Info->Len] == '\0' || Name[Info->Len] == '+')) {
268 static unsigned char GetRegInfo2 (CodeSeg* S,
273 unsigned char Unused)
274 /* Recursively called subfunction for GetRegInfo. */
276 /* Follow the instruction flow recording register usage. */
281 /* Check if we have already visited the current code entry. If so,
284 if (CE_HasMark (E)) {
288 /* Mark this entry as already visited */
290 CollAppend (Visited, E);
292 /* Evaluate the used registers */
294 if (E->OPC == OP65_RTS ||
295 ((E->Info & OF_BRA) != 0 && E->JumpTo == 0)) {
296 /* This instruction will leave the function */
300 /* We are not interested in the use of any register that has been
304 /* Remember the remaining registers */
308 /* Evaluate the changed registers */
309 if ((R = E->Chg) != REG_NONE) {
310 /* We are not interested in the use of any register that has been
314 /* Remember the remaining registers */
318 /* If we know about all registers now, bail out */
319 if ((Used | Unused) == REG_AXY) {
323 /* If the instruction is an RTS or RTI, we're done */
324 if ((E->Info & OF_RET) != 0) {
328 /* If we have an unconditional branch, follow this branch if possible,
329 * otherwise we're done.
331 if ((E->Info & OF_UBRA) != 0) {
333 /* Does this jump have a valid target? */
336 /* Unconditional jump */
337 E = E->JumpTo->Owner;
338 Index = -1; /* Invalidate */
341 /* Jump outside means we're done */
345 /* In case of conditional branches, follow the branch if possible and
346 * follow the normal flow (branch not taken) afterwards. If we cannot
347 * follow the branch, we're done.
349 } else if ((E->Info & OF_CBRA) != 0) {
353 /* Recursively determine register usage at the branch target */
357 U1 = GetRegInfo2 (S, E->JumpTo->Owner, -1, Visited, Used, Unused);
359 /* All registers used, no need for second call */
363 Index = CS_GetEntryIndex (S, E);
365 if ((E = CS_GetEntry (S, ++Index)) == 0) {
366 Internal ("GetRegInfo2: No next entry!");
368 U2 = GetRegInfo2 (S, E, Index, Visited, Used, Unused);
369 return U1 | U2; /* Used in any of the branches */
372 /* Jump to global symbol */
378 /* Just go to the next instruction */
380 Index = CS_GetEntryIndex (S, E);
382 E = CS_GetEntry (S, ++Index);
385 Internal ("GetRegInfo2: No next entry!");
392 /* Return to the caller the complement of all unused registers */
398 static unsigned char GetRegInfo1 (CodeSeg* S,
403 unsigned char Unused)
404 /* Recursively called subfunction for GetRegInfo. */
406 /* Remember the current count of the line collection */
407 unsigned Count = CollCount (Visited);
409 /* Call the worker routine */
410 unsigned char R = GetRegInfo2 (S, E, Index, Visited, Used, Unused);
412 /* Restore the old count, unmarking all new entries */
413 unsigned NewCount = CollCount (Visited);
414 while (NewCount-- > Count) {
415 CodeEntry* E = CollAt (Visited, NewCount);
417 CollDelete (Visited, NewCount);
420 /* Return the registers used */
426 unsigned char GetRegInfo (struct CodeSeg* S, unsigned Index)
427 /* Determine register usage information for the instructions starting at the
432 Collection Visited; /* Visited entries */
435 /* Get the code entry for the given index */
436 if (Index >= CS_GetEntryCount (S)) {
437 /* There is no such code entry */
440 E = CS_GetEntry (S, Index);
442 /* Initialize the data structure used to collection information */
443 InitCollection (&Visited);
445 /* Call the recursive subfunction */
446 R = GetRegInfo1 (S, E, Index, &Visited, REG_NONE, REG_NONE);
448 /* Delete the line collection */
449 DoneCollection (&Visited);
451 /* Return the registers used */
457 int RegAUsed (struct CodeSeg* S, unsigned Index)
458 /* Check if the value in A is used. */
460 return (GetRegInfo (S, Index) & REG_A) != 0;
465 int RegXUsed (struct CodeSeg* S, unsigned Index)
466 /* Check if the value in X is used. */
468 return (GetRegInfo (S, Index) & REG_X) != 0;
473 int RegYUsed (struct CodeSeg* S, unsigned Index)
474 /* Check if the value in Y is used. */
476 return (GetRegInfo (S, Index) & REG_Y) != 0;