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Fixed OptPush1 in case later code would rely on that pushax zeroes register Y.

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This commit is contained in:
acqn 2020-08-31 01:56:57 +08:00 committed by Oliver Schmidt
parent 2a3d996077
commit f45d2515eb
2 changed files with 20 additions and 5 deletions
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19
src/cc65/coptpush.c
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@ -56,12 +56,14 @@ unsigned OptPush1 (CodeSeg* S)
**
** ldy #xx+2
** jsr pushwysp
** ldy #$00 ; present if later code expects Y = 0
**
** saving 3 bytes and several cycles.
** saving several cycles.
*/
{
unsigned I;
unsigned Changes = 0;
unsigned R;
/* Walk over the entries */
I = 0;
@ -79,7 +81,7 @@ unsigned OptPush1 (CodeSeg* S)
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
!CE_HasLabel (L[1]) &&
CE_IsCallTo (L[1], "pushax") &&
!RegAXUsed (S, I+2)) {
((R = (GetRegInfo (S, I+2, REG_AXY))) & REG_AX) == 0) {
/* Insert new code behind the pushax */
const char* Arg;
@ -94,12 +96,25 @@ unsigned OptPush1 (CodeSeg* S)
X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwysp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* pushax sets Y = 0 and following code might rely on this */
if ((R & REG_Y) != 0) {
/* ldy #0 */
X = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (0), 0, L[1]->LI);
CS_InsertEntry (S, X, I+4);
}
/* Delete the old code */
CS_DelEntries (S, I, 2);
/* Remember, we had changes */
++Changes;
/* Skip the handled lines */
if ((R & REG_Y) == 0) {
++I;
} else {
I += 2;
}
}
/* Next entry */

6
src/cc65/coptpush.h
View File

@ -52,16 +52,16 @@
unsigned OptPush1 (CodeSeg* S);
/* Given a sequence
**
** ldy #xx
** jsr ldaxysp
** jsr pushax
**
** If a/x are not used later, replace that by
** If a/x are not used later, and Y is known, replace that by
**
** ldy #xx+2
** jsr pushwysp
** ldy #$00 ; present if later code expects Y = 0
**
** saving 3 bytes and several cycles.
** saving several cycles.
*/
unsigned OptPush2 (CodeSeg* S);