/* Walk over all entries minus the last one */
unsigned I = 0;
- while (I < GetCodeEntryCount (S)) {
+ while (I < CS_GetEntryCount (S)) {
/* Get the next entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's an unconditional branch to a local target */
if ((E->Info & OF_UBRA) != 0 &&
/* Insert an RTS instruction */
CodeEntry* X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, E->LI);
- InsertCodeEntry (S, X, I+1);
+ CS_InsertEntry (S, X, I+1);
/* Delete the jump */
- DelCodeEntry (S, I);
+ CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
unsigned I;
/* Get the number of entries, bail out if we have less than two entries */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
while (I < Count-1) {
/* Get the next entry */
- E = GetCodeEntry (S, I);
+ E = CS_GetEntry (S, I);
/* Check if it's a branch, if it has a local target, and if the target
* is the next instruction.
*/
- if (E->AM == AM65_BRA && E->JumpTo && E->JumpTo->Owner == GetCodeEntry (S, I+1)) {
+ if (E->AM == AM65_BRA && E->JumpTo && E->JumpTo->Owner == CS_GetEntry (S, I+1)) {
/* Delete the dead jump */
- DelCodeEntry (S, I);
+ CS_DelEntry (S, I);
/* Keep the number of entries updated */
--Count;
unsigned I;
/* Get the number of entries, bail out if we have less than two entries */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
CodeEntry* N;
/* Get this entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's an unconditional branch, and if the next entry has
* no labels attached
*/
- if ((E->Info & OF_DEAD) != 0 &&
- (N = GetNextCodeEntry (S, I)) != 0 &&
- !CodeEntryHasLabel (N)) {
+ if ((E->Info & OF_DEAD) != 0 &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ !CE_HasLabel (N)) {
/* Delete the next entry */
- DelCodeEntry (S, I+1);
+ CS_DelEntry (S, I+1);
/* Keep the number of entries updated */
--Count;
/* Walk over all entries */
unsigned I = 0;
- while (I < GetCodeEntryCount (S)) {
+ while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeLabel* OldLabel;
/* Get this entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a branch, if it has a jump label, if this jump
* label is not attached to the instruction itself, and if the
*/
if ((N->Info & OF_UBRA) != 0 ||
((E->Info & OF_CBRA) != 0 &&
- GetBranchCond (E->OPC) == GetBranchCond (N->OPC))) {
+ GetBranchCond (E->OPC) == GetBranchCond (N->OPC))) {
/* This is a jump cascade and we may jump to the final target.
- * Insert a new instruction, then remove the old one
+ * Insert a new instruction, then remove the old one
*/
- CodeEntry* X = NewCodeEntry (E->OPC, E->AM, N->Arg, N->JumpTo, E->LI);
+ CodeEntry* X = NewCodeEntry (E->OPC, E->AM, N->Arg, N->JumpTo, E->LI);
- /* Insert it behind E */
- InsertCodeEntry (S, X, I+1);
+ /* Insert it behind E */
+ CS_InsertEntry (S, X, I+1);
- /* Remove E */
- DelCodeEntry (S, I);
+ /* Remove E */
+ CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
*/
if ((E->Info & OF_CBRA) != 0 && (N->Info & OF_CBRA) != 0) {
- CodeEntry* X; /* Instruction behind N */
- CodeLabel* LX; /* Label attached to X */
+ CodeEntry* X; /* Instruction behind N */
+ CodeLabel* LX; /* Label attached to X */
- /* Get the branch conditions of both branches */
- bc_t BC1 = GetBranchCond (E->OPC);
- bc_t BC2 = GetBranchCond (N->OPC);
+ /* Get the branch conditions of both branches */
+ bc_t BC1 = GetBranchCond (E->OPC);
+ bc_t BC2 = GetBranchCond (N->OPC);
- /* Check the branch conditions */
- if (BC1 != GetInverseCond (BC2)) {
- /* Condition not met */
- goto NextEntry;
- }
+ /* Check the branch conditions */
+ if (BC1 != GetInverseCond (BC2)) {
+ /* Condition not met */
+ goto NextEntry;
+ }
- /* We may jump behind this conditional branch. Get the
- * pointer to the next instruction
- */
- if ((X = GetNextCodeEntry (S, GetCodeEntryIndex (S, N))) == 0) {
- /* N is the last entry, bail out */
- goto NextEntry;
- }
+ /* We may jump behind this conditional branch. Get the
+ * pointer to the next instruction
+ */
+ if ((X = CS_GetNextEntry (S, CS_GetEntryIndex (S, N))) == 0) {
+ /* N is the last entry, bail out */
+ goto NextEntry;
+ }
- /* Get the label attached to X, create a new one if needed */
- LX = GenCodeLabel (S, X);
+ /* Get the label attached to X, create a new one if needed */
+ LX = CS_GenLabel (S, X);
- /* Move the reference from E to the new label */
- MoveCodeLabelRef (S, E, LX);
+ /* Move the reference from E to the new label */
+ CS_MoveLabelRef (S, E, LX);
/* Remember, we had changes */
++Changes;
unsigned I;
/* Get the number of entries, bail out if we have less than 2 entries */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
CodeEntry* N;
/* Get this entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a subroutine call and if the following insn is RTS */
- if (E->OPC == OP65_JSR &&
- (N = GetNextCodeEntry (S, I)) != 0 &&
+ if (E->OPC == OP65_JSR &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
N->OPC == OP65_RTS) {
/* Change the jsr to a jmp and use the additional info for a jump */
E->AM = AM65_BRA;
- ReplaceOPC (E, OP65_JMP);
+ CE_ReplaceOPC (E, OP65_JMP);
/* Remember, we had changes */
++Changes;
unsigned I;
/* Get the number of entries, bail out if we have not enough */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
if (Count < 3) {
return 0;
}
while (I < Count-1) {
/* Get next entry */
- E2 = GetCodeEntry (S, I+1);
+ E2 = CS_GetEntry (S, I+1);
/* Check if we have a jump or branch, and a matching label */
if ((E2->Info & OF_UBRA) != 0 && E2->JumpTo) {
T2 = E2->JumpTo->Owner;
/* Get the entry preceeding this one (if possible) */
- TI = GetCodeEntryIndex (S, T2);
+ TI = CS_GetEntryIndex (S, T2);
if (TI == 0) {
/* There is no entry before this one */
goto NextEntry;
}
- T1 = GetCodeEntry (S, TI-1);
+ T1 = CS_GetEntry (S, TI-1);
/* Get the entry preceeding the jump */
- E1 = GetCodeEntry (S, I);
+ E1 = CS_GetEntry (S, I);
/* Check if both preceeding instructions are identical */
if (!CodeEntriesAreEqual (E1, T1)) {
* This routine will create a new label if the instruction does
* not already have one.
*/
- TL1 = GenCodeLabel (S, T1);
+ TL1 = CS_GenLabel (S, T1);
/* Change the jump target to point to this new label */
- MoveCodeLabelRef (S, E2, TL1);
+ CS_MoveLabelRef (S, E2, TL1);
/* If the instruction preceeding the jump has labels attached,
* move references to this label to the new label.
*/
- if (CodeEntryHasLabel (E1)) {
- MoveCodeLabels (S, E1, T1);
+ if (CE_HasLabel (E1)) {
+ CS_MoveLabels (S, E1, T1);
}
/* Remove the entry preceeding the jump */
- DelCodeEntry (S, I);
+ CS_DelEntry (S, I);
--Count;
/* Remember, we had changes */
/*****************************************************************************/
-/* Optimize conditional branches */
+/* Optimize conditional branches */
/*****************************************************************************/
unsigned I;
/* Get the number of entries, bail out if we have not enough */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
if (Count < 2) {
return 0;
}
CodeLabel* L;
/* Get next entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a register load */
- if ((E->Info & OF_LOAD) != 0 && /* It's a load instruction */
- E->AM == AM65_IMM && /* ..with immidiate addressing */
- (E->Flags & CEF_NUMARG) != 0 && /* ..and a numeric argument. */
- (N = GetNextCodeEntry (S, I)) != 0 && /* There is a following entry */
- (N->Info & OF_CBRA) != 0 && /* ..which is a conditional branch */
- !CodeEntryHasLabel (N)) { /* ..and does not have a label */
+ if ((E->Info & OF_LOAD) != 0 && /* It's a load instruction */
+ E->AM == AM65_IMM && /* ..with immidiate addressing */
+ (E->Flags & CEF_NUMARG) != 0 && /* ..and a numeric argument. */
+ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a following entry */
+ (N->Info & OF_CBRA) != 0 && /* ..which is a conditional branch */
+ !CE_HasLabel (N)) { /* ..and does not have a label */
/* Get the branch condition */
bc_t BC = GetBranchCond (N->OPC);
/* Check the argument against the branch condition */
- if ((BC == BC_EQ && E->Num != 0) ||
- (BC == BC_NE && E->Num == 0) ||
+ if ((BC == BC_EQ && E->Num != 0) ||
+ (BC == BC_NE && E->Num == 0) ||
(BC == BC_PL && (E->Num & 0x80) != 0) ||
(BC == BC_MI && (E->Num & 0x80) == 0)) {
/* Remove the conditional branch */
- DelCodeEntry (S, I+1);
+ CS_DelEntry (S, I+1);
--Count;
/* Remember, we had changes */
++Changes;
- } else if ((BC == BC_EQ && E->Num == 0) ||
- (BC == BC_NE && E->Num != 0) ||
+ } else if ((BC == BC_EQ && E->Num == 0) ||
+ (BC == BC_NE && E->Num != 0) ||
(BC == BC_PL && (E->Num & 0x80) == 0) ||
(BC == BC_MI && (E->Num & 0x80) != 0)) {
/* The branch is always taken, replace it by a jump */
- ReplaceOPC (N, OP65_JMP);
+ CE_ReplaceOPC (N, OP65_JMP);
/* Remember, we had changes */
++Changes;
}
- if ((E->Info & OF_CBRA) != 0 && /* It's a conditional branch */
- (L = E->JumpTo) != 0 && /* ..referencing a local label */
- (N = GetNextCodeEntry (S, I)) != 0 && /* There is a following entry */
- (N->Info & OF_UBRA) != 0 && /* ..which is an uncond branch, */
- !CodeEntryHasLabel (N) && /* ..has no label attached */
- L->Owner == GetNextCodeEntry (S, I+1)) {/* ..and jump target follows */
+ if ((E->Info & OF_CBRA) != 0 && /* It's a conditional branch */
+ (L = E->JumpTo) != 0 && /* ..referencing a local label */
+ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a following entry */
+ (N->Info & OF_UBRA) != 0 && /* ..which is an uncond branch, */
+ !CE_HasLabel (N) && /* ..has no label attached */
+ L->Owner == CS_GetNextEntry (S, I+1)) {/* ..and jump target follows */
/* Replace the jump by a conditional branch with the inverse branch
* condition than the branch around it.
*/
- ReplaceOPC (N, GetInverseBranch (E->OPC));
+ CE_ReplaceOPC (N, GetInverseBranch (E->OPC));
/* Remove the conditional branch */
- DelCodeEntry (S, I);
+ CS_DelEntry (S, I);
--Count;
/* Remember, we had changes */
/*****************************************************************************/
-/* Remove unused loads */
+/* Remove unused loads and stores */
/*****************************************************************************/
/* Walk over the entries */
unsigned I = 0;
- while (I < GetCodeEntryCount (S)) {
+ while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
/* Get next entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a register load or transfer insn */
- if ((E->Info & (OF_LOAD | OF_XFR)) != 0 &&
- (N = GetNextCodeEntry (S, I)) != 0 &&
+ if ((E->Info & (OF_LOAD | OF_XFR | OF_REG_INCDEC)) != 0 &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
(N->Info & OF_FBRA) == 0) {
/* Check which sort of load or transfer it is */
unsigned R;
switch (E->OPC) {
- case OP65_TXA:
- case OP65_TYA:
- case OP65_LDA: R = REG_A; break;
- case OP65_TAX:
- case OP65_LDX: R = REG_X; break;
- case OP65_TAY:
- case OP65_LDY: R = REG_Y; break;
- default: goto NextEntry; /* OOPS */
+ case OP65_DEA:
+ case OP65_INA:
+ case OP65_LDA:
+ case OP65_TXA:
+ case OP65_TYA: R = REG_A; break;
+ case OP65_DEX:
+ case OP65_INX:
+ case OP65_LDX:
+ case OP65_TAX: R = REG_X; break;
+ case OP65_DEY:
+ case OP65_INY:
+ case OP65_LDY:
+ case OP65_TAY: R = REG_Y; break;
+ default: goto NextEntry; /* OOPS */
}
/* Get register usage and check if the register value is used later */
- if ((GetRegInfo (S, I+1) & R) == 0) {
+ if ((GetRegInfo (S, I+1, R) & R) == 0) {
- /* Register value is not used, remove the load */
- DelCodeEntry (S, I);
+ /* Register value is not used, remove the load */
+ CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
}
+NextEntry:
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
+unsigned OptUnusedStores (CodeSeg* S)
+/* Remove stores into zero page registers that aren't used later */
+{
+ unsigned Changes = 0;
+
+ /* Walk over the entries */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if it's a register load or transfer insn */
+ if ((E->Info & OF_STORE) != 0 &&
+ E->AM == AM65_ZP &&
+ (E->Chg & REG_ZP) != 0) {
+
+ /* Check for the zero page location. We know that there cannot be
+ * more than one zero page location involved in the store.
+ */
+ unsigned R = E->Chg & REG_ZP;
+
+ /* Get register usage and check if the register value is used later */
+ if ((GetRegInfo (S, I+1, R) & R) == 0) {
+
+ /* Register value is not used, remove the load */
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ }
+ }
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
+unsigned OptDuplicateLoads (CodeSeg* S)
+/* Remove loads of registers where the value loaded is already in the register. */
+{
+ unsigned Changes = 0;
+ unsigned I;
+
+ /* Generate register info for this step */
+ CS_GenRegInfo (S);
+
+ /* Walk over the entries */
+ I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* N;
+
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Assume we won't delete the entry */
+ int Delete = 0;
+
+ /* Get a pointer to the input registers of the insn */
+ const RegContents* In = &E->RI->In;
+
+ /* Handle the different instructions */
+ switch (E->OPC) {
+
+ case OP65_LDA:
+ if (In->RegA >= 0 && /* Value of A is known */
+ CE_KnownImm (E) && /* Value to be loaded is known */
+ In->RegA == (long) E->Num && /* Both are equal */
+ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a next entry */
+ (N->Info & OF_FBRA) == 0) { /* Which is not a cond branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_LDX:
+ if (In->RegX >= 0 && /* Value of X is known */
+ CE_KnownImm (E) && /* Value to be loaded is known */
+ In->RegX == (long) E->Num && /* Both are equal */
+ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a next entry */
+ (N->Info & OF_FBRA) == 0) { /* Which is not a cond branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_LDY:
+ if (In->RegY >= 0 && /* Value of Y is known */
+ CE_KnownImm (E) && /* Value to be loaded is known */
+ In->RegY == (long) E->Num && /* Both are equal */
+ (N = CS_GetNextEntry (S, I)) != 0 && /* There is a next entry */
+ (N->Info & OF_FBRA) == 0) { /* Which is not a cond branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_STA:
+ /* If we store into a known zero page location, and this
+ * location does already contain the value to be stored,
+ * remove the store.
+ */
+ if (In->RegA >= 0 && /* Value of A is known */
+ E->AM == AM65_ZP && /* Store into zp */
+ (((E->Chg & REG_SREG_LO) != 0 && /* Store into sreg */
+ In->RegA == In->SRegLo) || /* Value identical */
+ ((E->Chg & REG_SREG_HI) != 0 && /* Store into sreg+1 */
+ In->RegA == In->SRegHi))) { /* Value identical */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_STX:
+ /* If we store into a known zero page location, and this
+ * location does already contain the value to be stored,
+ * remove the store.
+ */
+ if (In->RegX >= 0 && /* Value of A is known */
+ E->AM == AM65_ZP && /* Store into zp */
+ (((E->Chg & REG_SREG_LO) != 0 && /* Store into sreg */
+ In->RegX == In->SRegLo) || /* Value identical */
+ ((E->Chg & REG_SREG_HI) != 0 && /* Store into sreg+1 */
+ In->RegX == In->SRegHi))) { /* Value identical */
+ Delete = 1;
+
+ /* If the value in the X register is known and the same as
+ * that in the A register, replace the store by a STA. The
+ * optimizer will then remove the load instruction for X
+ * later. STX does support the zeropage,y addressing mode,
+ * so be sure to check for that.
+ */
+ } else if (In->RegX >= 0 &&
+ In->RegX == In->RegA &&
+ E->AM != AM65_ABSY &&
+ E->AM != AM65_ZPY) {
+ /* Use the A register instead */
+ CE_ReplaceOPC (E, OP65_STA);
+ }
+ break;
+
+ case OP65_STY:
+ /* If we store into a known zero page location, and this
+ * location does already contain the value to be stored,
+ * remove the store.
+ */
+ if (In->RegX >= 0 && /* Value of A is known */
+ E->AM == AM65_ZP && /* Store into zp */
+ (((E->Chg & REG_SREG_LO) != 0 && /* Store into sreg */
+ In->RegX == In->SRegLo) || /* Value identical */
+ ((E->Chg & REG_SREG_HI) != 0 && /* Store into sreg+1 */
+ In->RegX == In->SRegHi))) { /* Value identical */
+ Delete = 1;
+ /* If the value in the Y register is known and the same as
+ * that in the A register, replace the store by a STA. The
+ * optimizer will then remove the load instruction for Y
+ * later. If replacement by A is not possible try a
+ * replacement by X, but check for invalid addressing modes
+ * in this case.
+ */
+ } else if (In->RegY >= 0) {
+ if (In->RegY == In->RegA) {
+ CE_ReplaceOPC (E, OP65_STA);
+ } else if (In->RegY == In->RegX &&
+ E->AM != AM65_ABSX &&
+ E->AM != AM65_ZPX) {
+ CE_ReplaceOPC (E, OP65_STX);
+ }
+ }
+ break;
+
+ case OP65_TAX:
+ if (In->RegA >= 0 &&
+ In->RegA == In->RegX &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ (N->Info & OF_FBRA) == 0) {
+ /* Value is identical and not followed by a branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_TAY:
+ if (In->RegA >= 0 &&
+ In->RegA == In->RegY &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ (N->Info & OF_FBRA) == 0) {
+ /* Value is identical and not followed by a branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_TXA:
+ if (In->RegX >= 0 &&
+ In->RegX == In->RegA &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ (N->Info & OF_FBRA) == 0) {
+ /* Value is identical and not followed by a branch */
+ Delete = 1;
+ }
+ break;
+
+ case OP65_TYA:
+ if (In->RegY >= 0 &&
+ In->RegY == In->RegA &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ (N->Info & OF_FBRA) == 0) {
+ /* Value is identical and not followed by a branch */
+ Delete = 1;
+ }
+ break;
+
+ default:
+ break;
+
+ }
+
+ /* Delete the entry if requested */
+ if (Delete) {
+
+ /* Register value is not used, remove the load */
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ } else {
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ }
+
+ /* Free register info */
+ CS_FreeRegInfo (S);
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
+unsigned OptStoreLoad (CodeSeg* S)
+/* Remove a store followed by a load from the same location. */
+{
+ unsigned Changes = 0;
+
+ /* Walk over the entries */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* N;
+ CodeEntry* X;
+
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if it is a store instruction followed by a load from the
+ * same address which is itself not followed by a conditional branch.
+ */
+ if ((E->Info & OF_STORE) != 0 &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ !CE_HasLabel (N) &&
+ (N->Info & OF_LOAD) != 0 &&
+ strcmp (E->Arg, N->Arg) == 0 &&
+ (X = CS_GetNextEntry (S, I+1)) != 0 &&
+ (X->Info & OF_FBRA) == 0) {
+
+ /* Register value is not used, remove the load */
+ CS_DelEntry (S, I+1);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ }
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
+unsigned OptTransfers (CodeSeg* S)
+/* Remove transfers from one register to another and back */
+{
+ unsigned Changes = 0;
+
+ /* Walk over the entries */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* N;
+ CodeEntry* X;
+ CodeEntry* P;
+
+ /* Get next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if it is a store instruction followed by a load from the
+ * same address which is itself not followed by a conditional branch.
+ */
+ if ((E->Info & OF_XFR) != 0 &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ !CE_HasLabel (N) &&
+ (N->Info & OF_XFR) != 0) {
+
+ /* Check if it's a transfer and back */
+ if ((E->OPC == OP65_TAX && N->OPC == OP65_TXA && !RegXUsed (S, I+2)) ||
+ (E->OPC == OP65_TAY && N->OPC == OP65_TYA && !RegYUsed (S, I+2)) ||
+ (E->OPC == OP65_TXA && N->OPC == OP65_TAX && !RegAUsed (S, I+2)) ||
+ (E->OPC == OP65_TYA && N->OPC == OP65_TAY && !RegAUsed (S, I+1))) {
+
+ /* If the next insn is a conditional branch, check if the insn
+ * preceeding the first xfr will set the flags right, otherwise we
+ * may not remove the sequence.
+ */
+ if ((X = CS_GetNextEntry (S, I+1)) == 0) {
+ goto NextEntry;
+ }
+ if ((X->Info & OF_FBRA) != 0) {
+ if (I == 0) {
+ /* No preceeding entry */
+ goto NextEntry;
+ }
+ P = CS_GetEntry (S, I-1);
+ if ((P->Info & OF_SETF) == 0) {
+ /* Does not set the flags */
+ goto NextEntry;
+ }
+ }
+
+ /* Remove both transfers */
+ CS_DelEntry (S, I+1);
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+ }
+ }
+
NextEntry:
/* Next entry */
++I;
/*****************************************************************************/
-/* Optimize branch types */
+/* Optimize branch types */
/*****************************************************************************/
unsigned I;
/* Get the number of entries, bail out if we have not enough */
- unsigned Count = GetCodeEntryCount (S);
+ unsigned Count = CS_GetEntryCount (S);
/* Walk over the entries */
I = 0;
while (I < Count) {
/* Get next entry */
- CodeEntry* E = GetCodeEntry (S, I);
+ CodeEntry* E = CS_GetEntry (S, I);
/* Check if it's a conditional branch to a local label. */
if ((E->Info & OF_CBRA) != 0) {
if (E->JumpTo != 0) {
/* Get the index of the branch target */
- unsigned TI = GetCodeEntryIndex (S, E->JumpTo->Owner);
+ unsigned TI = CS_GetEntryIndex (S, E->JumpTo->Owner);
/* Determine the branch distance */
int Distance = 0;
/* Forward branch */
unsigned J = I;
while (J < TI) {
- CodeEntry* N = GetCodeEntry (S, J++);
- Distance += N->Size;
+ CodeEntry* N = CS_GetEntry (S, J++);
+ Distance += N->Size;
}
} else {
/* Backward branch */
unsigned J = TI;
while (J < I) {
- CodeEntry* N = GetCodeEntry (S, J++);
+ CodeEntry* N = CS_GetEntry (S, J++);
Distance += N->Size;
}
}
/* Make the branch short/long according to distance */
if ((E->Info & OF_LBRA) == 0 && Distance > 120) {
/* Short branch but long distance */
- ReplaceOPC (E, MakeLongBranch (E->OPC));
+ CE_ReplaceOPC (E, MakeLongBranch (E->OPC));
++Changes;
} else if ((E->Info & OF_LBRA) != 0 && Distance < 120) {
/* Long branch but short distance */
- ReplaceOPC (E, MakeShortBranch (E->OPC));
+ CE_ReplaceOPC (E, MakeShortBranch (E->OPC));
++Changes;
}
} else if ((E->Info & OF_LBRA) == 0) {
/* Short branch to external symbol - make it long */
- ReplaceOPC (E, MakeLongBranch (E->OPC));
+ CE_ReplaceOPC (E, MakeLongBranch (E->OPC));
++Changes;
}
-
-
-
-
projects / cc65 / blobdiff