1 /*****************************************************************************/
5 /* Size optimizations */
9 /* (C) 2002 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 /*****************************************************************************/
48 /*****************************************************************************/
50 /*****************************************************************************/
54 typedef struct CallDesc CallDesc;
56 const char* LongFunc; /* Long function name */
57 short A, X, Y; /* Register contents */
58 const char* ShortFunc; /* Short function name */
61 /* Note: The table is sorted. If there is more than one entry with the same
62 * name, entries are sorted best match first, so when searching linear for
63 * a match, the first one can be used because it is also the best one (or
64 * at least none of the following ones are better).
66 static const CallDesc CallTable [] = {
67 { "addeqysp", -1, -1, 0, "addeq0sp" },
68 { "laddeqysp", -1, -1, 0, "laddeq0sp" },
69 { "ldaxidx", -1, -1, 1, "ldaxi" },
70 { "ldaxysp", -1, -1, 1, "ldax0sp" },
71 { "ldeaxidx", -1, -1, 3, "ldeaxi" },
72 { "ldeaxysp", -1, -1, 3, "ldeax0sp" },
73 { "pusha", 0, -1, -1, "pushc0" },
74 { "pusha", 1, -1, -1, "pushc1" },
75 { "pusha", 2, -1, -1, "pushc2" },
76 { "pushax", 0, 0, -1, "push0" },
77 { "pushax", 1, 0, -1, "push1" },
78 { "pushax", 2, 0, -1, "push2" },
79 { "pushax", 3, 0, -1, "push3" },
80 { "pushax", 4, 0, -1, "push4" },
81 { "pushax", 5, 0, -1, "push5" },
82 { "pushax", 6, 0, -1, "push6" },
83 { "pushax", 7, 0, -1, "push7" },
84 { "pushax", -1, 0, -1, "pusha0" },
85 { "pushax", -1, 0xFF, -1, "pushaFF" },
86 { "pushaysp", -1, -1, 0, "pusha0sp" },
87 { "pushwidx", -1, -1, 1, "pushw" },
88 { "pushwysp", -1, -1, 3, "pushw0sp" },
89 { "staxysp", -1, -1, 0, "stax0sp" },
90 { "tosaddax", -1, 0, -1, "tosadda0" },
91 { "tosandax", -1, 0, -1, "tosanda0" },
92 { "tosdivax", -1, 0, -1, "tosdiva0" },
93 { "toseqax", -1, 0, -1, "toseqa0" },
94 { "tosgeax", -1, 0, -1, "tosgea0" },
95 { "tosgtax", -1, 0, -1, "tosgta0" },
96 { "tosleax", -1, 0, -1, "toslea0" },
97 { "tosorax", -1, 0, -1, "tosora0" },
98 { "lsubeqysp", -1, -1, 0, "lsubeq0sp" },
99 { "steaxysp", -1, -1, 0, "steax0sp" },
100 { "subeqysp", -1, -1, 0, "subeq0sp" },
101 { "tosaslax", -1, 0, -1, "tosasla0" },
102 { "tosasrax", -1, 0, -1, "tosasra0" },
103 { "tosltax", -1, 0, -1, "toslta0" },
104 { "tosmodax", -1, 0, -1, "tosmoda0" },
105 { "tosmulax", -1, 0, -1, "tosmula0" },
106 { "tosneax", -1, 0, -1, "tosnea0" },
107 { "tosrsubax", -1, 0, -1, "tosrsuba0" },
108 { "tosshlax", -1, 0, -1, "tosshla0" },
109 { "tosshrax", -1, 0, -1, "tosshra0" },
110 { "tossubax", -1, 0, -1, "tossuba0" },
111 { "tosudivax", -1, 0, -1, "tosudiva0" },
112 { "tosugeax", -1, 0, -1, "tosugea0" },
113 { "tosugtax", -1, 0, -1, "tosugta0" },
114 { "tosuleax", -1, 0, -1, "tosulea0" },
115 { "tosultax", -1, 0, -1, "tosulta0" },
116 { "tosumodax", -1, 0, -1, "tosumoda0" },
117 { "tosumulax", -1, 0, -1, "tosumula0" },
118 { "tosxorax", -1, 0, -1, "tosxora0" },
121 "tosadd0ax", /* tosaddeax, sreg = 0 */
122 "laddeqa", /* laddeq, sreg = 0, x = 0 */
123 "laddeq1", /* laddeq, sreg = 0, x = 0, a = 1 */
124 "tosand0ax", /* tosandeax, sreg = 0 */
125 "tosdiv0ax", /* tosdiveax, sreg = 0 */
126 "tosmod0ax", /* tosmodeax, sreg = 0 */
127 "tosmul0ax", /* tosmuleax, sreg = 0 */
128 "tosumul0ax", /* tosumuleax, sreg = 0 */
129 "tosor0ax", /* tosoreax, sreg = 0 */
130 "push0ax", /* pusheax, sreg = 0 */
131 "tosrsub0ax", /* tosrsubeax, sreg = 0 */
132 "tosshl0ax", /* tosshleax, sreg = 0 */
133 "tosasl0ax", /* tosasleax, sreg = 0 */
134 "tosshr0ax", /* tosshreax, sreg = 0 */
135 "tosasr0ax", /* tosasreax, sreg = 0 */
136 "tossub0ax", /* tossubeax, sreg = 0 */
137 "lsubeqa", /* lsubeq, sreg = 0, x = 0 */
138 "lsubeq1", /* lsubeq, sreg = 0, x = 0, a = 1 */
139 "tosudiv0ax", /* tosudiveax, sreg = 0 */
140 "tosumod0ax", /* tosumodeax, sreg = 0 */
141 "tosxor0ax", /* tosxoreax, sreg = 0 */
144 #define CALL_COUNT (sizeof(CallTable) / sizeof(CallTable[0]))
148 /*****************************************************************************/
150 /*****************************************************************************/
154 static const CallDesc* FindCall (const char* Name)
155 /* Find the function with the given name. Return a pointer to the table entry
156 * or NULL if the function was not found.
159 /* Do a binary search */
161 int Last = CALL_COUNT - 1;
164 while (First <= Last) {
166 /* Set current to mid of range */
167 int Current = (Last + First) / 2;
170 int Result = strcmp (CallTable[Current].LongFunc, Name);
176 /* Found. Repeat the procedure until the first of all entries
177 * with the same name is found.
184 /* Return the first entry if found, or NULL otherwise */
185 return Found? &CallTable[First] : 0;
190 /*****************************************************************************/
192 /*****************************************************************************/
196 unsigned OptSize1 (CodeSeg* S)
197 /* Do size optimization by calling special subroutines that preload registers.
198 * This routine does not work standalone, it needs a following register load
203 unsigned Changes = 0;
206 /* Generate register info for the following step */
209 /* Walk over the entries */
211 while (I < CS_GetEntryCount (S)) {
216 E = CS_GetEntry (S, I);
218 /* Check if it's a subroutine call */
219 if (E->OPC == OP65_JSR && (D = FindCall (E->Arg)) != 0) {
221 /* Check for any of the known functions. */
224 /* Check the registers */
225 if ((D->A < 0 || D->A == E->RI->In.RegA) &&
226 (D->X < 0 || D->X == E->RI->In.RegX) &&
227 (D->Y < 0 || D->Y == E->RI->In.RegY)) {
229 /* Ok, match for all registers */
231 X = NewCodeEntry (E->OPC, E->AM, D->ShortFunc, 0, E->LI);
232 CS_InsertEntry (S, X, I+1);
235 /* Remember that we had changes */
242 /* Next table entry, bail out if next entry not valid */
243 if (++D >= CallTable + CALL_COUNT ||
244 strcmp (D->LongFunc, E->Arg) != 0) {
245 /* End of table or entries reached */
256 /* Free register info */
259 /* Return the number of changes made */
265 unsigned OptSize2 (CodeSeg* S)
266 /* Do size optimization by using shorter code sequences, even if this
267 * introduces relations between instructions. This step must be one of the
268 * last steps, because it makes further work much more difficult.
271 unsigned Changes = 0;
274 /* Generate register info for the following step */
277 /* Walk over the entries */
279 while (I < CS_GetEntryCount (S)) {
282 CodeEntry* E = CS_GetEntry (S, I);
284 /* Get the input registers */
285 const RegContents* In = &E->RI->In;
287 /* Assume we have no replacement */
290 /* Check the instruction */
294 if (CE_KnownImm (E)) {
295 short Val = (short) E->Num;
296 if (Val == In->RegX) {
297 X = NewCodeEntry (OP65_TXA, AM65_IMP, 0, 0, E->LI);
298 } else if (Val == In->RegY) {
299 X = NewCodeEntry (OP65_TYA, AM65_IMP, 0, 0, E->LI);
300 } else if (RegValIsKnown (In->RegA) && CPU >= CPU_65C02) {
301 if (Val == ((In->RegA - 1) & 0xFF)) {
302 X = NewCodeEntry (OP65_DEA, AM65_IMP, 0, 0, E->LI);
303 } else if (Val == ((In->RegA + 1) & 0xFF)) {
304 X = NewCodeEntry (OP65_INA, AM65_IMP, 0, 0, E->LI);
311 if (CE_KnownImm (E)) {
312 short Val = (short) E->Num;
313 if (RegValIsKnown (In->RegX) && Val == ((In->RegX - 1) & 0xFF)) {
314 X = NewCodeEntry (OP65_DEX, AM65_IMP, 0, 0, E->LI);
315 } else if (RegValIsKnown (In->RegX) && Val == ((In->RegX + 1) & 0xFF)) {
316 X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, E->LI);
317 } else if (Val == In->RegA) {
318 X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, E->LI);
324 if (CE_KnownImm (E)) {
325 short Val = (short) E->Num;
326 if (RegValIsKnown (In->RegY) && Val == ((In->RegY - 1) & 0xFF)) {
327 X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, E->LI);
328 } else if (RegValIsKnown (In->RegY) && Val == ((In->RegY + 1) & 0xFF)) {
329 X = NewCodeEntry (OP65_INY, AM65_IMP, 0, 0, E->LI);
330 } else if (Val == In->RegA) {
331 X = NewCodeEntry (OP65_TAY, AM65_IMP, 0, 0, E->LI);
337 /* Avoid gcc warnings */
342 /* Insert the replacement if we have one */
344 CS_InsertEntry (S, X, I+1);
354 /* Free register info */
357 /* Return the number of changes made */