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More optimizations

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git-svn-id: svn://svn.cc65.org/cc65/trunk@837 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2001-08-03 07:34:40 +00:00
parent 7cf676d40c
commit 59a94124a1
1 changed files with 94 additions and 1 deletions
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95
src/cc65/codeopt.c
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@ -540,6 +540,98 @@ static unsigned OptSub2 (CodeSeg* S)
static unsigned OptAdd1 (CodeSeg* S)
/* Search for the sequence
*
* jsr pushax
* ldy xxx
* ldx #$00
* lda (sp),y
* jsr tosaddax
*
* and replace it by:
*
* ldy xxx
* clc
* adc (sp),y
* bcc L
* inx
* L:
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[5];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
strcmp (E->Arg, "pushax") == 0 &&
CS_GetEntries (S, L, I+1, 5) &&
L[0]->OPC == OP65_LDY &&
!CE_HasLabel (L[0]) &&
L[1]->OPC == OP65_LDX &&
CE_KnownImm (L[1]) &&
L[1]->Num == 0 &&
!CE_HasLabel (L[1]) &&
L[2]->OPC == OP65_LDA &&
!CE_HasLabel (L[2]) &&
L[3]->OPC == OP65_JSR &&
strcmp (L[3]->Arg, "tosaddax") == 0 &&
!CE_HasLabel (L[3])) {
CodeEntry* X;
CodeLabel* Label;
/* Remove the call to pushax */
CS_DelEntry (S, I);
/* Add the clc . */
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, L[3]->LI);
CS_InsertEntry (S, X, I+1);
/* Remove the load */
CS_DelEntry (S, I+3); /* lda */
CS_DelEntry (S, I+2); /* ldx */
/* Add the adc */
X = NewCodeEntry (OP65_ADC, AM65_ZP_INDY, "sp", 0, L[3]->LI);
CS_InsertEntry (S, X, I+2);
/* Generate the branch label and the branch */
Label = CS_GenLabel (S, L[4]);
X = NewCodeEntry (OP65_BCC, AM65_BRA, Label->Name, Label, L[3]->LI);
CS_InsertEntry (S, X, I+3);
/* Generate the increment of the high byte */
X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, L[3]->LI);
CS_InsertEntry (S, X, I+4);
/* Delete the call to tosaddax */
CS_DelEntry (S, I+5);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned OptAdd2 (CodeSeg* S)
/* Search for the sequence
*
* adc ...
@ -1844,7 +1936,8 @@ static OptFunc OptFuncs [] = {
OptEntry (OptSub1, optMain),
OptEntry (OptSub2, optMain),
/* Optimize additions */
OptEntry (OptAdd1, optMain),
OptEntry (OptAdd1, optPre),
OptEntry (OptAdd2, optMain),
/* Optimize jump cascades */
OptEntry (OptJumpCascades, optMain),
/* Remove dead jumps */