unsigned OptTest2 (CodeSeg* S)
/* Search for an inc/dec operation followed by a load and a conditional
* branch based on the flags from the load. Remove the load if the insn
* isn't used later.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check if it's the sequence we're searching for */
if ((L[0]->OPC == OP65_INC || L[0]->OPC == OP65_DEC) &&
CS_GetEntries (S, L+1, I+1, 2) &&
!CE_HasLabel (L[1]) &&
(L[1]->Info & OF_LOAD) != 0 &&
(L[2]->Info & OF_FBRA) != 0 &&
L[1]->AM == L[0]->AM &&
strcmp (L[0]->Arg, L[1]->Arg) == 0 &&
(GetRegInfo (S, I+2, L[1]->Chg) & L[1]->Chg) == 0) {
/* Remove the load */
CS_DelEntry (S, I+1);
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
int RegEAXUsed (struct CodeSeg* S, unsigned Index)
/* Check if any of the four bytes in EAX are used. */
{
return (GetRegInfo (S, Index, REG_EAX) & REG_EAX) != 0;
}
int RegAXUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in A or(!) the value in X are used. */
{
return (GetRegInfo (S, Index, REG_AX) & REG_AX) != 0;
}
int RegYUsed (struct CodeSeg* S, unsigned Index)
/* Check if the value in Y is used. */
{
return (GetRegInfo (S, Index, REG_Y) & REG_Y) != 0;
}
unsigned OptAdd2 (CodeSeg* S)
/* Search for the sequence
*
* ldy #xx
* jsr ldaxysp
* ldy #yy
* jsr addeqysp
*
* and replace it by:
*
* ldy #xx-1
* lda (sp),y
* ldy #yy
* clc
* adc (sp),y
* sta (sp),y
* ldy #xx
* lda (sp),y
* ldy #yy+1
* adc (sp),y
* sta (sp),y
*
* provided that a/x is not used later.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[4];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_LDY &&
CE_IsConstImm (L[0]) &&
!CS_RangeHasLabel (S, I+1, 3) &&
CS_GetEntries (S, L+1, I+1, 3) &&
CE_IsCallTo (L[1], "ldaxysp") &&
L[2]->OPC == OP65_LDY &&
CE_IsConstImm (L[2]) &&
CE_IsCallTo (L[3], "addeqysp") &&
(GetRegInfo (S, I+4, REG_AX) & REG_AX) == 0) {
/* Insert new code behind the addeqysp */
const char* Arg;
CodeEntry* X;
/* ldy #xx-1 */
Arg = MakeHexArg (L[0]->Num-1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+4);
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+5);
/* ldy #yy */
X = NewCodeEntry (OP65_LDY, AM65_IMM, L[2]->Arg, 0, L[2]->LI);
CS_InsertEntry (S, X, I+6);
/* clc */
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, L[3]->LI);
CS_InsertEntry (S, X, I+7);
/* adc (sp),y */
X = NewCodeEntry (OP65_ADC, AM65_ZP_INDY, "sp", 0, L[3]->LI);
CS_InsertEntry (S, X, I+8);
/* sta (sp),y */
X = NewCodeEntry (OP65_STA, AM65_ZP_INDY, "sp", 0, L[3]->LI);
CS_InsertEntry (S, X, I+9);
/* ldy #xx */
X = NewCodeEntry (OP65_LDY, AM65_IMM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+10);
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+11);
/* ldy #yy+1 */
Arg = MakeHexArg (L[2]->Num+1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[2]->LI);
CS_InsertEntry (S, X, I+12);
/* adc (sp),y */
X = NewCodeEntry (OP65_ADC, AM65_ZP_INDY, "sp", 0, L[3]->LI);
CS_InsertEntry (S, X, I+13);
/* sta (sp),y */
X = NewCodeEntry (OP65_STA, AM65_ZP_INDY, "sp", 0, L[3]->LI);
CS_InsertEntry (S, X, I+14);
/* Delete the old code */
CS_DelEntries (S, I, 4);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
