-#include <string.h>
-
/* cc65 */
#include "codeent.h"
#include "codeinfo.h"
#include "codeopt.h"
+#include "cpu.h"
#include "error.h"
#include "coptind.h"
/*****************************************************************************/
-/* Macros */
+/* Helper functions */
/*****************************************************************************/
-/* Macro to increment and decrement register contents if they're valid */
-#define INC(reg,val) if ((reg) >= 0) (reg) = ((reg) + val) & 0xFF
-#define DEC(reg,val) if ((reg) >= 0) (reg) = ((reg) - val) & 0xFF
+static int GetBranchDist (CodeSeg* S, unsigned From, CodeEntry* To)
+/* Get the branch distance between the two entries and return it. The distance
+ * will be negative for backward jumps and positive for forward jumps.
+ */
+{
+ /* Get the index of the branch target */
+ unsigned TI = CS_GetEntryIndex (S, To);
+
+ /* Determine the branch distance */
+ int Distance = 0;
+ if (TI >= From) {
+ /* Forward branch, do not count the current insn */
+ unsigned J = From+1;
+ while (J < TI) {
+ CodeEntry* N = CS_GetEntry (S, J++);
+ Distance += N->Size;
+ }
+ } else {
+ /* Backward branch */
+ unsigned J = TI;
+ while (J < From) {
+ CodeEntry* N = CS_GetEntry (S, J++);
+ Distance -= N->Size;
+ }
+ }
+
+ /* Return the calculated distance */
+ return Distance;
+}
+
+
+
+static int IsShortDist (int Distance)
+/* Return true if the given distance is a short branch distance */
+{
+ return (Distance >= -125 && Distance <= 125);
+}
/*****************************************************************************/
-/* Replace jumps to RTS by RTS */
+/* Replace jumps to RTS by RTS */
/*****************************************************************************/
-unsigned OptRTSJumps (CodeSeg* S)
+unsigned OptRTSJumps1 (CodeSeg* S)
/* Replace jumps to RTS by RTS */
{
unsigned Changes = 0;
+unsigned OptRTSJumps2 (CodeSeg* S)
+/* Replace long conditional jumps to RTS */
+{
+ unsigned Changes = 0;
+
+ /* Walk over all entries minus the last one */
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
+
+ CodeEntry* N;
+
+ /* Get the next entry */
+ CodeEntry* E = CS_GetEntry (S, I);
+
+ /* Check if it's an unconditional branch to a local target */
+ if ((E->Info & OF_CBRA) != 0 && /* Conditional branch */
+ (E->Info & OF_LBRA) != 0 && /* Long branch */
+ E->JumpTo != 0 && /* Local label */
+ E->JumpTo->Owner->OPC == OP65_RTS && /* Target is an RTS */
+ (N = CS_GetNextEntry (S, I)) != 0) { /* There is a next entry */
+
+ CodeEntry* X;
+ CodeLabel* LN;
+ opc_t NewBranch;
+
+ /* We will create a jump around an RTS instead of the long branch */
+ X = NewCodeEntry (OP65_RTS, AM65_IMP, 0, 0, E->JumpTo->Owner->LI);
+ CS_InsertEntry (S, X, I+1);
+
+ /* Get the new branch opcode */
+ NewBranch = MakeShortBranch (GetInverseBranch (E->OPC));
+
+ /* Get the label attached to N, create a new one if needed */
+ LN = CS_GenLabel (S, N);
+
+ /* Generate the branch */
+ X = NewCodeEntry (NewBranch, AM65_BRA, LN->Name, LN, E->LI);
+ CS_InsertEntry (S, X, I+1);
+
+ /* Delete the long branch */
+ CS_DelEntry (S, I);
+
+ /* Remember, we had changes */
+ ++Changes;
+
+ }
+
+ /* Next entry */
+ ++I;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
/*****************************************************************************/
/* Remove dead jumps */
/*****************************************************************************/
/* Remove dead jumps (jumps to the next instruction) */
{
unsigned Changes = 0;
- CodeEntry* E;
- unsigned I;
-
- /* Get the number of entries, bail out if we have less than two entries */
- unsigned Count = CS_GetEntryCount (S);
- if (Count < 2) {
- return 0;
- }
/* Walk over all entries minus the last one */
- I = 0;
- while (I < Count-1) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
/* Get the next entry */
- E = CS_GetEntry (S, I);
+ CodeEntry* 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 == CS_GetEntry (S, I+1)) {
+ if (E->AM == AM65_BRA &&
+ E->JumpTo &&
+ E->JumpTo->Owner == CS_GetNextEntry (S, I)) {
/* Delete the dead jump */
CS_DelEntry (S, I);
- /* Keep the number of entries updated */
- --Count;
-
/* Remember, we had changes */
++Changes;
*/
{
unsigned Changes = 0;
- unsigned I;
-
- /* Get the number of entries, bail out if we have less than two entries */
- unsigned Count = CS_GetEntryCount (S);
- if (Count < 2) {
- return 0;
- }
/* Walk over all entries */
- I = 0;
- while (I < Count) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
/* Delete the next entry */
CS_DelEntry (S, I+1);
- /* Keep the number of entries updated */
- --Count;
-
/* Remember, we had changes */
++Changes;
*/
{
unsigned Changes = 0;
- unsigned I;
-
- /* Get the number of entries, bail out if we have less than 2 entries */
- unsigned Count = CS_GetEntryCount (S);
- if (Count < 2) {
- return 0;
- }
/* Walk over all entries minus the last one */
- I = 0;
- while (I < Count-1) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeEntry* E1; /* Entry 1 */
CodeEntry* E2; /* Entry 2 */
CodeEntry* T1; /* Jump target entry 1 */
- CodeEntry* T2; /* Jump target entry 2 */
CodeLabel* TL1; /* Target label 1 */
- unsigned TI; /* Target index */
- unsigned I;
-
- /* Get the number of entries, bail out if we have not enough */
- unsigned Count = CS_GetEntryCount (S);
- if (Count < 3) {
- return 0;
- }
/* Walk over the entries */
- I = 0;
- while (I < Count-1) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
/* Get next entry */
- E2 = CS_GetEntry (S, I+1);
+ E2 = CS_GetNextEntry (S, I);
/* Check if we have a jump or branch, and a matching label */
- if ((E2->Info & OF_UBRA) != 0 && E2->JumpTo) {
-
- /* Get the target instruction for the label */
- T2 = E2->JumpTo->Owner;
+ if (E2 && (E2->Info & OF_UBRA) != 0 && E2->JumpTo) {
- /* Get the entry preceeding this one (if possible) */
- TI = CS_GetEntryIndex (S, T2);
- if (TI == 0) {
- /* There is no entry before this one */
+ /* Get the entry preceeding the branch target */
+ T1 = CS_GetPrevEntry (S, CS_GetEntryIndex (S, E2->JumpTo->Owner));
+ if (T1 == 0) {
+ /* There is no such entry */
goto NextEntry;
}
- T1 = CS_GetEntry (S, TI-1);
/* Get the entry preceeding the jump */
E1 = CS_GetEntry (S, I);
/* Remove the entry preceeding the jump */
CS_DelEntry (S, I);
- --Count;
/* Remember, we had changes */
++Changes;
*/
{
unsigned Changes = 0;
- unsigned I;
-
- /* Get the number of entries, bail out if we have not enough */
- unsigned Count = CS_GetEntryCount (S);
- if (Count < 2) {
- return 0;
- }
/* Walk over the entries */
- I = 0;
- while (I < Count-1) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeLabel* L;
/* Remove the conditional branch */
CS_DelEntry (S, I+1);
- --Count;
/* Remember, we had changes */
++Changes;
/* Remove the conditional branch */
CS_DelEntry (S, I);
- --Count;
/* Remember, we had changes */
++Changes;
/*****************************************************************************/
-/* Remove unused loads */
+/* Remove unused loads and stores */
/*****************************************************************************/
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 = CS_GetNextEntry (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_DEA:
+ case OP65_INA:
+ case OP65_LDA:
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;
+ 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 */
CS_DelEntry (S, I);
-unsigned OptDuplicateLoads (CodeSeg* S)
+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 OptDupLoads (CodeSeg* S)
/* Remove loads of registers where the value loaded is already in the register. */
{
unsigned Changes = 0;
/* 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 (E->RI->In.RegA >= 0 && /* Value of A is known */
+ if (In->RegA >= 0 && /* Value of A is known */
CE_KnownImm (E) && /* Value to be loaded is known */
- E->RI->In.RegA == E->Num && /* Both are equal */
+ 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 (E->RI->In.RegX >= 0 && /* Value of X is known */
+ if (In->RegX >= 0 && /* Value of X is known */
CE_KnownImm (E) && /* Value to be loaded is known */
- E->RI->In.RegX == E->Num && /* Both are equal */
+ 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 (E->RI->In.RegY >= 0 && /* Value of Y is known */
+ if (In->RegY >= 0 && /* Value of Y is known */
CE_KnownImm (E) && /* Value to be loaded is known */
- E->RI->In.RegY == E->Num && /* Both are equal */
+ 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 the value in the X register is known and the same as
+ /* 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.
*/
- if (E->RI->In.RegX >= 0 &&
- E->RI->In.RegX == E->RI->In.RegA &&
- E->AM != AM65_ABSY &&
- E->AM != AM65_ZPY) {
+ } 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
+ * replacement by X, but check for invalid addressing modes
* in this case.
*/
- if (E->RI->In.RegY >= 0) {
- if (E->RI->In.RegY == E->RI->In.RegA) {
+ } else if (In->RegY >= 0) {
+ if (In->RegY == In->RegA) {
CE_ReplaceOPC (E, OP65_STA);
- } else if (E->RI->In.RegY == E->RI->In.RegX &&
- E->AM != AM65_ABSX &&
+ } else if (In->RegY == In->RegX &&
+ E->AM != AM65_ABSX &&
E->AM != AM65_ZPX) {
CE_ReplaceOPC (E, OP65_STX);
}
break;
case OP65_TAX:
- if (E->RI->In.RegA >= 0 &&
- E->RI->In.RegA == E->RI->In.RegX &&
- (N = CS_GetNextEntry (S, I)) != 0 &&
+ 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 (E->RI->In.RegA >= 0 &&
- E->RI->In.RegA == E->RI->In.RegY &&
+ 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 */
break;
case OP65_TXA:
- if (E->RI->In.RegX >= 0 &&
- E->RI->In.RegX == E->RI->In.RegA &&
+ 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 */
break;
case OP65_TYA:
- if (E->RI->In.RegY >= 0 &&
- E->RI->In.RegY == E->RI->In.RegA &&
+ 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 */
/* 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 &&
+ if ((E->Info & OF_STORE) != 0 &&
+ (N = CS_GetNextEntry (S, I)) != 0 &&
+ !CE_HasLabel (N) &&
+ E->AM == N->AM &&
+ ((E->OPC == OP65_STA && N->OPC == OP65_LDA) ||
+ (E->OPC == OP65_STX && N->OPC == OP65_LDX) ||
+ (E->OPC == OP65_STY && N->OPC == OP65_LDY)) &&
+ 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 */
+ /* Register has already the correct value, remove the load */
CS_DelEntry (S, I+1);
/* Remember, we had 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;
+
+ }
+
+ /* Return the number of changes made */
+ return Changes;
+}
+
+
+
/*****************************************************************************/
/* Optimize branch types */
/*****************************************************************************/
/* Change branches for the distance needed. */
{
unsigned Changes = 0;
- unsigned I;
-
- /* Get the number of entries, bail out if we have not enough */
- unsigned Count = CS_GetEntryCount (S);
/* Walk over the entries */
- I = 0;
- while (I < Count) {
+ unsigned I = 0;
+ while (I < CS_GetEntryCount (S)) {
/* Get next entry */
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->Info & OF_CBRA) {
/* Is this a branch to a local symbol? */
if (E->JumpTo != 0) {
- /* Get the index of the branch target */
- unsigned TI = CS_GetEntryIndex (S, E->JumpTo->Owner);
-
- /* Determine the branch distance */
- int Distance = 0;
- if (TI >= I) {
- /* Forward branch */
- unsigned J = I;
- while (J < TI) {
- CodeEntry* N = CS_GetEntry (S, J++);
- Distance += N->Size;
- }
- } else {
- /* Backward branch */
- unsigned J = TI;
- while (J < I) {
- CodeEntry* N = CS_GetEntry (S, J++);
- Distance += N->Size;
- }
- }
+ /* Check if the branch distance is short */
+ int IsShort = IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner));
/* Make the branch short/long according to distance */
- if ((E->Info & OF_LBRA) == 0 && Distance > 120) {
+ if ((E->Info & OF_LBRA) == 0 && !IsShort) {
/* Short branch but long distance */
CE_ReplaceOPC (E, MakeLongBranch (E->OPC));
++Changes;
- } else if ((E->Info & OF_LBRA) != 0 && Distance < 120) {
+ } else if ((E->Info & OF_LBRA) != 0 && IsShort) {
/* Long branch but short distance */
CE_ReplaceOPC (E, MakeShortBranch (E->OPC));
++Changes;
++Changes;
}
+
+ } else if (CPU == CPU_65C02 &&
+ (E->Info & OF_UBRA) != 0 &&
+ E->JumpTo != 0 &&
+ IsShortDist (GetBranchDist (S, I, E->JumpTo->Owner))) {
+
+ /* The jump is short and may be replaced by a BRA on the 65C02 CPU */
+ CE_ReplaceOPC (E, OP65_BRA);
+ ++Changes;
}
/* Next entry */
projects / cc65 / blobdiff