unsigned OptBNegAX3 (CodeSeg* S)
/* Search for the sequence:
*
* lda xx
* ldx yy
* jsr bnegax
* jne/jeq ...
*
* and replace it by
*
* lda xx
* ora xx+1
* jeq/jne ...
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_LDA &&
CS_GetEntries (S, L, I+1, 3) &&
L[0]->OPC == OP65_LDX &&
!CE_HasLabel (L[0]) &&
CE_IsCallTo (L[1], "bnegax") &&
!CE_HasLabel (L[1]) &&
(L[2]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[2])) {
/* ldx --> ora */
CE_ReplaceOPC (L[0], OP65_ORA);
/* Invert the branch */
CE_ReplaceOPC (L[2], GetInverseBranch (L[2]->OPC));
/* Delete the subroutine call */
CS_DelEntry (S, I+2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegA2 (CodeSeg* S)
/* Check for
*
* lda ..
* jsr bnega
* jeq/jne ..
*
* Adjust the conditional branch and remove the call to the subroutine.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if ((E->OPC == OP65_ADC ||
E->OPC == OP65_AND ||
E->OPC == OP65_DEA ||
E->OPC == OP65_EOR ||
E->OPC == OP65_INA ||
E->OPC == OP65_LDA ||
E->OPC == OP65_ORA ||
E->OPC == OP65_PLA ||
E->OPC == OP65_SBC ||
E->OPC == OP65_TXA ||
E->OPC == OP65_TYA) &&
CS_GetEntries (S, L, I+1, 2) &&
CE_IsCallTo (L[0], "bnega") &&
!CE_HasLabel (L[0]) &&
(L[1]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[1])) {
/* Invert the branch */
CE_ReplaceOPC (L[1], GetInverseBranch (L[1]->OPC));
/* Delete the subroutine call */
CS_DelEntry (S, I+1);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
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
*/
{
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_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 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);
/* 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;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptCmp9 (CodeSeg* S)
/* Search for the sequence
*
* sbc xx
* bvs/bvc L
* eor #$80
* L: asl a
* bcc/bcs somewhere
*
* If A is not used later (which should be the case), we can branch on the N
* flag instead of the carry flag and remove the asl.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[5];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_SBC &&
CS_GetEntries (S, L+1, I+1, 4) &&
(L[1]->OPC == OP65_BVC ||
L[1]->OPC == OP65_BVS) &&
L[1]->JumpTo != 0 &&
L[1]->JumpTo->Owner == L[3] &&
L[2]->OPC == OP65_EOR &&
CE_IsKnownImm (L[2], 0x80) &&
L[3]->OPC == OP65_ASL &&
L[3]->AM == AM65_ACC &&
(L[4]->OPC == OP65_BCC ||
L[4]->OPC == OP65_BCS ||
L[4]->OPC == OP65_JCC ||
L[4]->OPC == OP65_JCS) &&
!CE_HasLabel (L[4]) &&
!RegAUsed (S, I+4)) {
/* Replace the branch condition */
switch (GetBranchCond (L[4]->OPC)) {
case BC_CC: CE_ReplaceOPC (L[4], OP65_JPL); break;
case BC_CS: CE_ReplaceOPC (L[4], OP65_JMI); break;
default: Internal ("Unknown branch condition in OptCmp9");
}
/* Delete the asl insn */
CS_DelEntry (S, I+3);
/* Next sequence is somewhat ahead (if any) */
I += 3;
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static void ReplaceCmp (CodeSeg* S, unsigned I, cmp_t Cond)
/* Helper function for the replacement of routines that return a boolean
* followed by a conditional jump. Instead of the boolean value, the condition
* codes are evaluated directly.
* I is the index of the conditional branch, the sequence is already checked
* to be correct.
*/
{
CodeEntry* N;
CodeLabel* L;
/* Get the entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Replace the conditional branch */
switch (Cond) {
case CMP_EQ:
CE_ReplaceOPC (E, OP65_JEQ);
break;
case CMP_NE:
CE_ReplaceOPC (E, OP65_JNE);
break;
case CMP_GT:
/* Replace by
* beq @L
* jpl Target
* @L: ...
*/
if ((N = CS_GetNextEntry (S, I)) == 0) {
/* No such entry */
Internal ("Invalid program flow");
}
L = CS_GenLabel (S, N);
N = NewCodeEntry (OP65_BEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I);
CE_ReplaceOPC (E, OP65_JPL);
break;
case CMP_GE:
CE_ReplaceOPC (E, OP65_JPL);
break;
case CMP_LT:
CE_ReplaceOPC (E, OP65_JMI);
break;
case CMP_LE:
/* Replace by
* jmi Target
* jeq Target
*/
CE_ReplaceOPC (E, OP65_JMI);
L = E->JumpTo;
N = NewCodeEntry (OP65_JEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I+1);
break;
case CMP_UGT:
/* Replace by
* beq @L
* jcs Target
* @L: ...
*/
if ((N = CS_GetNextEntry (S, I)) == 0) {
/* No such entry */
Internal ("Invalid program flow");
}
L = CS_GenLabel (S, N);
N = NewCodeEntry (OP65_BEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I);
CE_ReplaceOPC (E, OP65_JCS);
break;
case CMP_UGE:
CE_ReplaceOPC (E, OP65_JCS);
break;
case CMP_ULT:
CE_ReplaceOPC (E, OP65_JCC);
break;
case CMP_ULE:
/* Replace by
* jcc Target
* jeq Target
*/
CE_ReplaceOPC (E, OP65_JCC);
L = E->JumpTo;
N = NewCodeEntry (OP65_JEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I+1);
break;
default:
Internal ("Unknown jump condition: %d", Cond);
}
}
unsigned OptCmp4 (CodeSeg* S)
/* Search for
*
* lda x
* ldx y
* cpx #a
* bne L1
* cmp #b
* L1: jne/jeq L2
*
* If a is zero, we may remove the compare. If a and b are both zero, we may
* replace it by the sequence
*
* lda x
* ora x+1
* jne/jeq ...
*
* L1 may be either the label at the branch instruction, or the target label
* of this instruction.
*/
{
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_LDA &&
CS_GetEntries (S, L, I+1, 5) &&
L[0]->OPC == OP65_LDX &&
!CE_HasLabel (L[0]) &&
IsImmCmp16 (L+1) &&
!RegAXUsed (S, I+6)) {
if ((L[4]->Info & OF_FBRA) != 0 && L[1]->Num == 0 && L[3]->Num == 0) {
/* The value is zero, we may use the simple code version. */
CE_ReplaceOPC (L[0], OP65_ORA);
CS_DelEntries (S, I+2, 3);
} else {
/* Move the lda instruction after the first branch. This will
* improve speed, since the load is delayed after the first
* test.
*/
CS_MoveEntry (S, I, I+4);
/* We will replace the ldx/cpx by lda/cmp */
CE_ReplaceOPC (L[0], OP65_LDA);
CE_ReplaceOPC (L[1], OP65_CMP);
/* Beware: If the first LDA instruction had a label, we have
* to move this label to the top of the sequence again.
*/
if (CE_HasLabel (E)) {
CS_MoveLabels (S, E, L[0]);
}
}
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX4 (CodeSeg* S)
/* Search for the sequence:
*
* jsr xxx
* jsr bnega(x)
* jeq/jne ...
*
* and replace it by:
*
* jsr xxx
* <boolean test>
* jne/jeq ...
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
CS_GetEntries (S, L, I+1, 2) &&
L[0]->OPC == OP65_JSR &&
strncmp (L[0]->Arg,"bnega",5) == 0 &&
!CE_HasLabel (L[0]) &&
(L[1]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[1])) {
CodeEntry* X;
/* Check if we're calling bnega or bnegax */
int ByteSized = (strcmp (L[0]->Arg, "bnega") == 0);
/* Insert apropriate test code */
if (ByteSized) {
/* Test bytes */
X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
} else {
/* Test words */
X = NewCodeEntry (OP65_STX, AM65_ZP, "tmp1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_ORA, AM65_ZP, "tmp1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
}
/* Delete the subroutine call */
CS_DelEntry (S, I+1);
/* Invert the branch */
CE_ReplaceOPC (L[1], GetInverseBranch (L[1]->OPC));
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX2 (CodeSeg* S)
/* Search for the sequence:
*
* ldy #xx
* jsr ldaxysp
* jsr bnegax
* jne/jeq ...
*
* and replace it by
*
* ldy #xx
* lda (sp),y
* dey
* ora (sp),y
* jeq/jne ...
*/
{
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") &&
CE_IsCallTo (L[2], "bnegax") &&
(L[3]->Info & OF_ZBRA) != 0) {
CodeEntry* X;
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+1);
/* dey */
X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, X, I+2);
/* ora (sp),y */
X = NewCodeEntry (OP65_ORA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* Invert the branch */
CE_ReplaceOPC (L[3], GetInverseBranch (L[3]->OPC));
/* Delete the entries no longer needed. */
CS_DelEntries (S, I+4, 2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
