1 /*****************************************************************************/
5 /* Optimize push sequences */
9 /* (C) 2001-2012, Ullrich von Bassewitz */
10 /* Roemerstrasse 52 */
11 /* D-70794 Filderstadt */
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 /*****************************************************************************/
43 /*****************************************************************************/
45 /*****************************************************************************/
49 unsigned OptPush1 (CodeSeg* S)
55 ** If a/x are not used later, and Y is known, replace that by
60 ** saving 3 bytes and several cycles.
66 /* Walk over the entries */
68 while (I < CS_GetEntryCount (S)) {
73 L[0] = CS_GetEntry (S, I);
75 /* Check for the sequence */
76 if (CE_IsCallTo (L[0], "ldaxysp") &&
77 RegValIsKnown (L[0]->RI->In.RegY) &&
78 L[0]->RI->In.RegY < 0xFE &&
79 (L[1] = CS_GetNextEntry (S, I)) != 0 &&
80 !CE_HasLabel (L[1]) &&
81 CE_IsCallTo (L[1], "pushax") &&
82 !RegAXUsed (S, I+2)) {
84 /* Insert new code behind the pushax */
89 Arg = MakeHexArg (L[0]->RI->In.RegY+2);
90 X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[0]->LI);
91 CS_InsertEntry (S, X, I+2);
94 X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwysp", 0, L[1]->LI);
95 CS_InsertEntry (S, X, I+3);
97 /* Delete the old code */
98 CS_DelEntries (S, I, 2);
100 /* Remember, we had changes */
110 /* Return the number of changes made */
116 unsigned OptPush2 (CodeSeg* S)
122 ** may get replaced by
128 unsigned Changes = 0;
130 /* Walk over the entries */
132 while (I < CS_GetEntryCount (S)) {
137 L[0] = CS_GetEntry (S, I);
139 /* Check for the sequence */
140 if (CE_IsCallTo (L[0], "ldaxidx") &&
141 (L[1] = CS_GetNextEntry (S, I)) != 0 &&
142 !CE_HasLabel (L[1]) &&
143 CE_IsCallTo (L[1], "pushax")) {
145 /* Insert new code behind the pushax */
149 X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwidx", 0, L[1]->LI);
150 CS_InsertEntry (S, X, I+2);
152 /* Delete the old code */
153 CS_DelEntries (S, I, 2);
155 /* Remember, we had changes */
165 /* Return the number of changes made */