/*****************************************************************************/
/* */
-/* coptsub.c */
+/* coptsub.c */
/* */
-/* Optimize subtraction sequences */
+/* Optimize subtraction sequences */
/* */
/* */
/* */
-/* (C) 2001 Ullrich von Bassewitz */
-/* Wacholderweg 14 */
-/* D-70597 Stuttgart */
-/* EMail: uz@cc65.org */
+/* (C) 2001-2006, Ullrich von Bassewitz */
+/* Römerstrasse 52 */
+/* D-70794 Filderstadt */
+/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
+/* common */
+#include "chartype.h"
+
/* cc65 */
#include "codeent.h"
#include "codeinfo.h"
/*****************************************************************************/
-/* Optimize subtractions */
+/* Optimize subtractions */
/*****************************************************************************/
unsigned OptSub1 (CodeSeg* S)
/* Search for the sequence
- *
- * sbc ...
- * bcs L
- * dex
- * L:
- *
- * and remove the handling of the high byte if X is not used later.
- */
+**
+** sbc ...
+** bcs L
+** dex
+** L:
+**
+** and remove the handling of the high byte if X is not used later.
+*/
{
unsigned Changes = 0;
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
- CodeEntry* L[3];
+ CodeEntry* L[3];
- /* Get next entry */
- CodeEntry* E = CS_GetEntry (S, I);
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
- /* Check for the sequence */
- if (E->OPC == OP65_SBC &&
- CS_GetEntries (S, L, I+1, 3) &&
- (L[0]->OPC == OP65_BCS || L[0]->OPC == OP65_JCS) &&
- L[0]->JumpTo != 0 &&
- !CE_HasLabel (L[0]) &&
- L[1]->OPC == OP65_DEX &&
- !CE_HasLabel (L[1]) &&
- L[0]->JumpTo->Owner == L[2] &&
- !RegXUsed (S, I+3)) {
+ /* Check for the sequence */
+ if (E->OPC == OP65_SBC &&
+ CS_GetEntries (S, L, I+1, 3) &&
+ (L[0]->OPC == OP65_BCS || L[0]->OPC == OP65_JCS) &&
+ L[0]->JumpTo != 0 &&
+ !CE_HasLabel (L[0]) &&
+ L[1]->OPC == OP65_DEX &&
+ !CE_HasLabel (L[1]) &&
+ L[0]->JumpTo->Owner == L[2] &&
+ !RegXUsed (S, I+3)) {
- /* Remove the bcs/dex */
- CS_DelEntries (S, I+1, 2);
+ /* Remove the bcs/dex */
+ CS_DelEntries (S, I+1, 2);
- /* Remember, we had changes */
- ++Changes;
+ /* Remember, we had changes */
+ ++Changes;
- }
+ }
- /* Next entry */
- ++I;
+ /* Next entry */
+ ++I;
}
unsigned OptSub2 (CodeSeg* S)
/* Search for the sequence
- *
- * lda xx
- * sec
- * sta tmp1
- * lda yy
- * sbc tmp1
- * sta yy
- *
- * and replace it by
- *
- * sec
- * lda yy
- * sbc xx
- * sta yy
- */
+**
+** lda xx
+** sec
+** sta tmp1
+** lda yy
+** sbc tmp1
+** sta yy
+**
+** and replace it by
+**
+** sec
+** lda yy
+** sbc xx
+** sta yy
+*/
{
unsigned Changes = 0;
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
- CodeEntry* L[5];
+ CodeEntry* L[5];
- /* Get next entry */
- CodeEntry* E = CS_GetEntry (S, I);
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
- /* Check for the sequence */
- if (E->OPC == OP65_LDA &&
- !CS_RangeHasLabel (S, I+1, 5) &&
- CS_GetEntries (S, L, I+1, 5) &&
- L[0]->OPC == OP65_SEC &&
- L[1]->OPC == OP65_STA &&
- strcmp (L[1]->Arg, "tmp1") == 0 &&
- L[2]->OPC == OP65_LDA &&
- L[3]->OPC == OP65_SBC &&
- strcmp (L[3]->Arg, "tmp1") == 0 &&
- L[4]->OPC == OP65_STA &&
- strcmp (L[4]->Arg, L[2]->Arg) == 0) {
+ /* Check for the sequence */
+ if (E->OPC == OP65_LDA &&
+ !CS_RangeHasLabel (S, I+1, 5) &&
+ CS_GetEntries (S, L, I+1, 5) &&
+ L[0]->OPC == OP65_SEC &&
+ L[1]->OPC == OP65_STA &&
+ strcmp (L[1]->Arg, "tmp1") == 0 &&
+ L[2]->OPC == OP65_LDA &&
+ L[3]->OPC == OP65_SBC &&
+ strcmp (L[3]->Arg, "tmp1") == 0 &&
+ L[4]->OPC == OP65_STA &&
+ strcmp (L[4]->Arg, L[2]->Arg) == 0) {
- /* Remove the store to tmp1 */
- CS_DelEntry (S, I+2);
+ /* Remove the store to tmp1 */
+ CS_DelEntry (S, I+2);
- /* Remove the subtraction */
- CS_DelEntry (S, I+3);
+ /* Remove the subtraction */
+ CS_DelEntry (S, I+3);
- /* Move the lda to the position of the subtraction and change the
- * op to SBC.
- */
- CS_MoveEntry (S, I, I+3);
- CE_ReplaceOPC (E, OP65_SBC);
+ /* Move the lda to the position of the subtraction and change the
+ ** op to SBC.
+ */
+ CS_MoveEntry (S, I, I+3);
+ CE_ReplaceOPC (E, OP65_SBC);
- /* If the sequence head had a label, move this label back to the
- * head.
- */
- if (CE_HasLabel (E)) {
- CS_MoveLabels (S, E, L[0]);
- }
+ /* If the sequence head had a label, move this label back to the
+ ** head.
+ */
+ if (CE_HasLabel (E)) {
+ CS_MoveLabels (S, E, L[0]);
+ }
- /* Remember, we had changes */
- ++Changes;
+ /* Remember, we had changes */
+ ++Changes;
- }
+ }
- /* Next entry */
- ++I;
+ /* Next entry */
+ ++I;
}
+unsigned OptSub3 (CodeSeg* S)
+/* Search for a call to decaxn and replace it by an 8 bit sub if the X register
+** is not used later.
+*/
+{
+ unsigned Changes = 0;
+
+ /* Walk over the entries */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* E;
+
+ /* Get next entry */
+ E = CS_GetEntry (S, I);
+
+ /* Check for the sequence */
+ if (E->OPC == OP65_JSR &&
+ strncmp (E->Arg, "decax", 5) == 0 &&
+ IsDigit (E->Arg[5]) &&
+ E->Arg[6] == '\0' &&
+ !RegXUsed (S, I+1)) {
+
+ CodeEntry* X;
+ const char* Arg;
+ /* Insert new code behind the sequence */
+ X = NewCodeEntry (OP65_SEC, AM65_IMP, 0, 0, E->LI);
+ CS_InsertEntry (S, X, I+1);
+
+ Arg = MakeHexArg (E->Arg[5] - '0');
+ X = NewCodeEntry (OP65_SBC, AM65_IMM, Arg, 0, E->LI);
+ CS_InsertEntry (S, X, I+2);
+
+ /* Delete the old code */
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ }
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
projects / cc65 / blobdiff