unsigned OptShift2(CodeSeg* S)
/* A call to the asrax1 routines may get replaced by something simpler, if
* X is not used later:
*
* cmp #$80
* ror a
*
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Shift;
unsigned Count;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(Shift = GetShift (E->Arg)) != SHIFT_NONE &&
SHIFT_TYPE (Shift) == SHIFT_TYPE_ASR &&
(Count = SHIFT_COUNT (Shift)) > 0 &&
Count * 100 <= S->CodeSizeFactor &&
!RegXUsed (S, I+1)) {
CodeEntry* X;
unsigned J = I+1;
/* Generate the replacement sequence */
while (Count--) {
/* cmp #$80 */
X = NewCodeEntry (OP65_CMP, AM65_IMM, "$80", 0, E->LI);
CS_InsertEntry (S, X, J++);
/* ror a */
X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, J++);
}
/* Delete the call to asrax */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptNegAX1 (CodeSeg* S)
/* Search for a call to negax and replace it by
*
* eor #$FF
* clc
* adc #$01
*
* if X isn't used later.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a call to negax, and if X isn't used later */
if (CE_IsCallTo (E, "negax") && !RegXUsed (S, I+1)) {
CodeEntry* X;
/* Add replacement code behind */
X = NewCodeEntry (OP65_EOR, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+1);
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_ADC, AM65_IMM, "$01", 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* Delete the call to negax */
CS_DelEntry (S, I);
/* Skip the generated code */
I += 2;
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptSub3 (CodeSeg* S)
/* Search for a call to decaxn and replace it by an 8 bit sub if the X register
** is not used later.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* E;
/* Get next entry */
E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
strncmp (E->Arg, "decax", 5) == 0 &&
IsDigit (E->Arg[5]) &&
E->Arg[6] == '\0' &&
!RegXUsed (S, I+1)) {
CodeEntry* X;
const char* Arg;
/* Insert new code behind the sequence */
X = NewCodeEntry (OP65_SEC, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+1);
Arg = MakeHexArg (E->Arg[5] - '0');
X = NewCodeEntry (OP65_SBC, AM65_IMM, Arg, 0, E->LI);
CS_InsertEntry (S, X, I+2);
/* Delete the old code */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned OptLoad1 (CodeSeg* S)
/* Search for a call to ldaxysp where X is not used later and replace it by
** a load of just the A register.
*/
{
unsigned I;
unsigned Changes = 0;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* E;
/* Get next entry */
E = CS_GetEntry (S, I);
/* Check for the sequence */
if (CE_IsCallTo (E, "ldaxysp") &&
RegValIsKnown (E->RI->In.RegY) &&
!RegXUsed (S, I+1)) {
CodeEntry* X;
/* Reload the Y register */
const char* Arg = MakeHexArg (E->RI->In.RegY - 1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* Load from stack */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, E->LI);
CS_InsertEntry (S, X, I+2);
/* Now remove the call to the subroutine */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX1 (CodeSeg* S)
/* On a call to bnegax, if X is zero, the result depends only on the value in
* A, so change the call to a call to bnega. This will get further optimized
* later if possible.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a call to bnegax, and if X is known and zero */
if (E->RI->In.RegX == 0 && CE_IsCallTo (E, "bnegax")) {
CodeEntry* X = NewCodeEntry (OP65_JSR, AM65_ABS, "bnega", 0, E->LI);
CS_InsertEntry (S, X, I+1);
CS_DelEntry (S, I);
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptPush2 (CodeSeg* S)
/* A sequence
*
* jsr ldaxidx
* jsr pushax
*
* may get replaced by
*
* jsr pushwidx
*
*/
{
unsigned I;
unsigned Changes = 0;
/* Generate register info */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (CE_IsCallTo (L[0], "ldaxidx") &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
!CE_HasLabel (L[1]) &&
CE_IsCallTo (L[1], "pushax")) {
/* Insert new code behind the pushax */
CodeEntry* X;
/* jsr pushwidx */
X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwidx", 0, L[1]->LI);
CS_InsertEntry (S, X, I+2);
/* Delete the old code */
CS_DelEntries (S, I, 2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free the register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
unsigned OptCmp6 (CodeSeg* S)
/* Search for calls to compare subroutines followed by a conditional branch
* and replace them by cheaper versions, since the branch means that the
* boolean value returned by these routines is not needed (we may also check
* that explicitly, but for the current code generator it is always true).
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
cmp_t Cond;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(Cond = FindTosCmpCond (E->Arg)) != CMP_INV &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(N->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (N)) {
/* The tos... functions will return a boolean value in a/x and
* the Z flag says if this value is zero or not. We will call
* a cheaper subroutine instead, one that does not return a
* boolean value but only valid flags. Note: jeq jumps if
* the condition is not met, jne jumps if the condition is met.
* Invert the code if we jump on condition not met.
*/
if (GetBranchCond (N->OPC) == BC_EQ) {
/* Jumps if condition false, invert condition */
Cond = CmpInvertTab [Cond];
}
/* Replace the subroutine call. */
E = NewCodeEntry (OP65_JSR, AM65_ABS, "tosicmp", 0, E->LI);
CS_InsertEntry (S, E, I+1);
CS_DelEntry (S, I);
/* Replace the conditional branch */
ReplaceCmp (S, I+1, Cond);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptCmp1 (CodeSeg* S)
/* Search for the sequence
*
* ldx xx
* stx tmp1
* ora tmp1
*
* and replace it by
*
* ora xx
*/
{
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 for the sequence */
if (L[0]->OPC == OP65_LDX &&
!CS_RangeHasLabel (S, I+1, 2) &&
CS_GetEntries (S, L+1, I+1, 2) &&
L[1]->OPC == OP65_STX &&
strcmp (L[1]->Arg, "tmp1") == 0 &&
L[2]->OPC == OP65_ORA &&
strcmp (L[2]->Arg, "tmp1") == 0) {
CodeEntry* X;
/* Insert the ora instead */
X = NewCodeEntry (OP65_ORA, L[0]->AM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I);
/* Remove all other instructions */
CS_DelEntries (S, I+1, 3);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned Opt65C02Stores (CodeSeg* S)
/* Use STZ where possible */
{
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)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a store with a register value of zero and an addressing
* mode available with STZ.
*/
if (((E->OPC == OP65_STA && E->RI->In.RegA == 0) ||
(E->OPC == OP65_STX && E->RI->In.RegX == 0) ||
(E->OPC == OP65_STY && E->RI->In.RegY == 0)) &&
(E->AM == AM65_ZP || E->AM == AM65_ABS ||
E->AM == AM65_ZPX || E->AM == AM65_ABSX)) {
/* Replace by STZ */
CodeEntry* X = NewCodeEntry (OP65_STZ, E->AM, E->Arg, 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* Delete the old stuff */
CS_DelEntry (S, I);
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
unsigned Opt65C02Ind (CodeSeg* S)
/* Try to use the indirect addressing mode where possible */
{
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)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for addressing mode indirect indexed Y where Y is zero.
* Note: All opcodes that are available as (zp),y are also available
* as (zp), so we can ignore the actual opcode here.
*/
if (E->AM == AM65_ZP_INDY && E->RI->In.RegY == 0) {
/* Replace it by indirect addressing mode */
CodeEntry* X = NewCodeEntry (E->OPC, AM65_ZP_IND, E->Arg, 0, E->LI);
CS_InsertEntry (S, X, I+1);
CS_DelEntry (S, I);
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
unsigned Opt65C02BitOps (CodeSeg* S)
/* Use special bit op instructions of the C02 */
{
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* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_LDA &&
(L[0]->AM == AM65_ZP || L[0]->AM == AM65_ABS) &&
!CS_RangeHasLabel (S, I+1, 2) &&
CS_GetEntries (S, L+1, I+1, 2) &&
(L[1]->OPC == OP65_AND || L[1]->OPC == OP65_ORA) &&
CE_IsConstImm (L[1]) &&
L[2]->OPC == OP65_STA &&
L[2]->AM == L[0]->AM &&
strcmp (L[2]->Arg, L[0]->Arg) == 0 &&
!RegAUsed (S, I+3)) {
char Buf[32];
CodeEntry* X;
/* Use TRB for AND and TSB for ORA */
if (L[1]->OPC == OP65_AND) {
/* LDA #XX */
sprintf (Buf, "$%02X", (int) ((~L[1]->Num) & 0xFF));
X = NewCodeEntry (OP65_LDA, AM65_IMM, Buf, 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* TRB */
X = NewCodeEntry (OP65_TRB, L[0]->AM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+4);
} else {
/* LDA #XX */
sprintf (Buf, "$%02X", (int) L[1]->Num);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Buf, 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* TSB */
X = NewCodeEntry (OP65_TSB, L[0]->AM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+4);
}
/* Delete the old stuff */
CS_DelEntries (S, I, 3);
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
unsigned OptShift5 (CodeSeg* S)
/* Search for the sequence
*
* lda xxx
* ldx yyy
* jsr aslax1/asrax1/shlax1/shrax1
* sta aaa
* stx bbb
*
* and replace it by
*
* lda xxx
* asl a
* sta aaa
* lda yyy
* rol a
* sta bbb
*
* or similar, provided that a/x is not used later
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned ShiftType;
CodeEntry* L[5];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_LDA &&
(L[0]->AM == AM65_ABS || L[0]->AM == AM65_ZP) &&
CS_GetEntries (S, L+1, I+1, 4) &&
!CS_RangeHasLabel (S, I+1, 4) &&
L[1]->OPC == OP65_LDX &&
(L[1]->AM == AM65_ABS || L[1]->AM == AM65_ZP) &&
L[2]->OPC == OP65_JSR &&
(ShiftType = GetShift (L[2]->Arg)) != SHIFT_NONE &&
SHIFT_COUNT(ShiftType) == 1 &&
L[3]->OPC == OP65_STA &&
(L[3]->AM == AM65_ABS || L[3]->AM == AM65_ZP) &&
L[4]->OPC == OP65_STX &&
(L[4]->AM == AM65_ABS || L[4]->AM == AM65_ZP) &&
!RegAXUsed (S, I+5)) {
CodeEntry* X;
/* Handle the four shift types differently */
switch (ShiftType) {
case SHIFT_ASR_1:
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+5);
X = NewCodeEntry (OP65_CMP, AM65_IMM, "$80", 0, L[2]->LI);
CS_InsertEntry (S, X, I+6);
X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+7);
X = NewCodeEntry (OP65_STA, L[4]->AM, L[4]->Arg, 0, L[4]->LI);
CS_InsertEntry (S, X, I+8);
X = NewCodeEntry (OP65_LDA, L[0]->AM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+9);
X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+10);
X = NewCodeEntry (OP65_STA, L[3]->AM, L[3]->Arg, 0, L[3]->LI);
CS_InsertEntry (S, X, I+11);
CS_DelEntries (S, I, 5);
break;
case SHIFT_LSR_1:
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+5);
X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+6);
X = NewCodeEntry (OP65_STA, L[4]->AM, L[4]->Arg, 0, L[4]->LI);
CS_InsertEntry (S, X, I+7);
X = NewCodeEntry (OP65_LDA, L[0]->AM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+8);
X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+9);
X = NewCodeEntry (OP65_STA, L[3]->AM, L[3]->Arg, 0, L[3]->LI);
CS_InsertEntry (S, X, I+10);
CS_DelEntries (S, I, 5);
break;
case SHIFT_LSL_1:
case SHIFT_ASL_1:
/* These two are identical */
X = NewCodeEntry (OP65_ASL, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+1);
X = NewCodeEntry (OP65_STA, L[3]->AM, L[3]->Arg, 0, L[3]->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
X = NewCodeEntry (OP65_ROL, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+4);
X = NewCodeEntry (OP65_STA, L[4]->AM, L[4]->Arg, 0, L[4]->LI);
CS_InsertEntry (S, X, I+5);
CS_DelEntries (S, I+6, 4);
break;
}
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned OptStackPtrOps (CodeSeg* S)
/* Merge adjacent calls to decsp into one. NOTE: This function won't merge all
** known cases!
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Dec1;
unsigned Dec2;
const CodeEntry* N;
/* Get the next entry */
const CodeEntry* E = CS_GetEntry (S, I);
/* Check for decspn or subysp */
if (E->OPC == OP65_JSR &&
(Dec1 = IsDecSP (E)) > 0 &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(Dec2 = IsDecSP (N)) > 0 &&
(Dec1 += Dec2) <= 255 &&
!CE_HasLabel (N)) {
CodeEntry* X;
char Buf[20];
/* We can combine the two */
if (Dec1 <= 8) {
/* Insert a call to decsp */
xsprintf (Buf, sizeof (Buf), "decsp%u", Dec1);
X = NewCodeEntry (OP65_JSR, AM65_ABS, Buf, 0, N->LI);
CS_InsertEntry (S, X, I+2);
} else {
/* Insert a call to subysp */
const char* Arg = MakeHexArg (Dec1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, N->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_JSR, AM65_ABS, "subysp", 0, N->LI);
CS_InsertEntry (S, X, I+3);
}
/* Delete the old code */
CS_DelEntries (S, I, 2);
/* Regenerate register info */
CS_GenRegInfo (S);
/* Remember we had changes */
++Changes;
} else {
/* Next entry */
++I;
}
}
/* Return the number of changes made */
return Changes;
}
static unsigned OptDecouple (CodeSeg* S)
/* Decouple operations, that is, do the following replacements:
**
** dex -> ldx #imm
** inx -> ldx #imm
** dey -> ldy #imm
** iny -> ldy #imm
** tax -> ldx #imm
** txa -> lda #imm
** tay -> ldy #imm
** tya -> lda #imm
** lda zp -> lda #imm
** ldx zp -> ldx #imm
** ldy zp -> ldy #imm
**
** Provided that the register values are known of course.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
const char* Arg;
/* Get next entry and it's input register values */
CodeEntry* E = CS_GetEntry (S, I);
const RegContents* In = &E->RI->In;
/* Assume we have no replacement */
CodeEntry* X = 0;
/* Check the instruction */
switch (E->OPC) {
case OP65_DEA:
if (RegValIsKnown (In->RegA)) {
Arg = MakeHexArg ((In->RegA - 1) & 0xFF);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_DEX:
if (RegValIsKnown (In->RegX)) {
Arg = MakeHexArg ((In->RegX - 1) & 0xFF);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_DEY:
if (RegValIsKnown (In->RegY)) {
Arg = MakeHexArg ((In->RegY - 1) & 0xFF);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_INA:
if (RegValIsKnown (In->RegA)) {
Arg = MakeHexArg ((In->RegA + 1) & 0xFF);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_INX:
if (RegValIsKnown (In->RegX)) {
Arg = MakeHexArg ((In->RegX + 1) & 0xFF);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_INY:
if (RegValIsKnown (In->RegY)) {
Arg = MakeHexArg ((In->RegY + 1) & 0xFF);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_LDA:
if (E->AM == AM65_ZP) {
switch (GetKnownReg (E->Use & REG_ZP, In)) {
case REG_TMP1:
Arg = MakeHexArg (In->Tmp1);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_LO:
Arg = MakeHexArg (In->Ptr1Lo);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_HI:
Arg = MakeHexArg (In->Ptr1Hi);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_LO:
Arg = MakeHexArg (In->SRegLo);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_HI:
Arg = MakeHexArg (In->SRegHi);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
break;
}
}
break;
case OP65_LDX:
if (E->AM == AM65_ZP) {
switch (GetKnownReg (E->Use & REG_ZP, In)) {
case REG_TMP1:
Arg = MakeHexArg (In->Tmp1);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_LO:
Arg = MakeHexArg (In->Ptr1Lo);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_HI:
Arg = MakeHexArg (In->Ptr1Hi);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_LO:
Arg = MakeHexArg (In->SRegLo);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_HI:
Arg = MakeHexArg (In->SRegHi);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
break;
}
}
break;
case OP65_LDY:
if (E->AM == AM65_ZP) {
switch (GetKnownReg (E->Use, In)) {
case REG_TMP1:
Arg = MakeHexArg (In->Tmp1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_LO:
Arg = MakeHexArg (In->Ptr1Lo);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
break;
case REG_PTR1_HI:
Arg = MakeHexArg (In->Ptr1Hi);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_LO:
Arg = MakeHexArg (In->SRegLo);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
break;
case REG_SREG_HI:
Arg = MakeHexArg (In->SRegHi);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
break;
}
}
break;
case OP65_TAX:
if (E->RI->In.RegA >= 0) {
Arg = MakeHexArg (In->RegA);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_TAY:
if (E->RI->In.RegA >= 0) {
Arg = MakeHexArg (In->RegA);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_TXA:
if (E->RI->In.RegX >= 0) {
Arg = MakeHexArg (In->RegX);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
}
break;
case OP65_TYA:
if (E->RI->In.RegY >= 0) {
Arg = MakeHexArg (In->RegY);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, E->LI);
}
break;
default:
/* Avoid gcc warnings */
break;
}
/* Insert the replacement if we have one */
if (X) {
CS_InsertEntry (S, X, I+1);
CS_DelEntry (S, I);
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned OptLoad2 (CodeSeg* S)
/* Replace calls to ldaxysp by inline code */
{
unsigned I;
unsigned Changes = 0;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (CE_IsCallTo (L[0], "ldaxysp")) {
CodeEntry* X;
/* Followed by sta abs/stx abs? */
if (CS_GetEntries (S, L+1, I+1, 2) &&
L[1]->OPC == OP65_STA &&
L[2]->OPC == OP65_STX &&
(L[1]->Arg == 0 ||
L[2]->Arg == 0 ||
strcmp (L[1]->Arg, L[2]->Arg) != 0) &&
!CS_RangeHasLabel (S, I+1, 2) &&
!RegXUsed (S, I+3)) {
/* A/X are stored into memory somewhere and X is not used
** later
*/
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
/* sta abs */
X = NewCodeEntry (OP65_STA, L[2]->AM, L[2]->Arg, 0, L[2]->LI);
CS_InsertEntry (S, X, I+4);
/* dey */
X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, L[0]->LI);
CS_InsertEntry (S, X, I+5);
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[0]->LI);
CS_InsertEntry (S, X, I+6);
/* sta abs */
X = NewCodeEntry (OP65_STA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+7);
/* Now remove the call to the subroutine and the sta/stx */
CS_DelEntries (S, I, 3);
} else {
/* Standard replacement */
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[0]->LI);
CS_InsertEntry (S, X, I+1);
/* tax */
X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
/* dey */
X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[0]->LI);
CS_InsertEntry (S, X, I+4);
/* Now remove the call to the subroutine */
CS_DelEntry (S, I);
}
/* 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;
}
unsigned OptShift4 (CodeSeg* S)
/* Calls to the asraxN or shraxN routines may get replaced by one or more lsr
* insns if the value of X is zero.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Shift;
unsigned Count;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(Shift = GetShift (E->Arg)) != SHIFT_NONE &&
SHIFT_DIR (Shift) == SHIFT_DIR_RIGHT &&
E->RI->In.RegX == 0) {
CodeEntry* X;
/* Shift count may be in Y */
Count = SHIFT_COUNT (Shift);
if (Count == SHIFT_COUNT_Y) {
CodeLabel* L;
if (S->CodeSizeFactor < 200) {
/* Not acceptable */
goto NextEntry;
}
/* Generate:
*
* L1: lsr a
* dey
* bpl L1
* rol a
*
* A negative shift count or one that is greater or equal than
* the bit width of the left operand (which is promoted to
* integer before the operation) causes undefined behaviour, so
* above transformation is safe.
*/
/* lsr a */
X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, I+1);
L = CS_GenLabel (S, X);
/* dey */
X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+2);
/* bpl L1 */
X = NewCodeEntry (OP65_BPL, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, X, I+3);
/* rol a */
X = NewCodeEntry (OP65_ROL, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, I+4);
} else {
/* Insert shift insns */
while (Count--) {
X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, I+1);
}
}
/* Delete the call to shrax */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
NextEntry:
/* 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 OptShift3 (CodeSeg* S)
/* The sequence
*
* bcc L
* inx
* L: jsr shrax1
*
* may get replaced by
*
* ror a
*
* if X is zero on entry. For shift counts > 1, more
*
* shr a
*
* must be added.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Shift;
unsigned Count;
CodeEntry* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if ((L[0]->OPC == OP65_BCC || L[0]->OPC == OP65_JCC) &&
L[0]->JumpTo != 0 &&
L[0]->RI->In.RegX == 0 &&
CS_GetEntries (S, L+1, I+1, 2) &&
L[1]->OPC == OP65_INX &&
L[0]->JumpTo->Owner == L[2] &&
!CS_RangeHasLabel (S, I, 2) &&
L[2]->OPC == OP65_JSR &&
(Shift = GetShift (L[2]->Arg)) != SHIFT_NONE &&
SHIFT_DIR (Shift) == SHIFT_DIR_RIGHT &&
(Count = SHIFT_COUNT (Shift)) > 0) {
/* Add the replacement insn instead */
CodeEntry* X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+3);
while (--Count) {
X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+4);
}
/* Remove the bcs/dex/jsr */
CS_DelEntries (S, I, 3);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptStore5 (CodeSeg* S)
/* Search for the sequence
**
** lda foo
** ldx bar
** sta something
** stx something-else
**
** and replace it by
**
** lda foo
** sta something
** lda bar
** sta something-else
**
** if X is not used later. This replacement doesn't save any cycles or bytes,
** but it keeps the value of X, which may be reused 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_LDA &&
!CS_RangeHasLabel (S, I+1, 3) &&
CS_GetEntries (S, L+1, I+1, 3) &&
L[1]->OPC == OP65_LDX &&
L[2]->OPC == OP65_STA &&
L[3]->OPC == OP65_STX &&
!RegXUsed (S, I+4)) {
CodeEntry* X;
/* Insert the code after the sequence */
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+4);
X = NewCodeEntry (OP65_STA, L[3]->AM, L[3]->Arg, 0, L[3]->LI);
CS_InsertEntry (S, X, I+5);
/* Delete the old code */
CS_DelEntry (S, I+3);
CS_DelEntry (S, I+1);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptPush1 (CodeSeg* S)
/* Given a sequence
*
* jsr ldaxysp
* jsr pushax
*
* If a/x are not used later, and Y is known, replace that by
*
* ldy #xx+2
* jsr pushwysp
*
* saving 3 bytes and several cycles.
*/
{
unsigned I;
unsigned Changes = 0;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (CE_IsCallTo (L[0], "ldaxysp") &&
RegValIsKnown (L[0]->RI->In.RegY) &&
L[0]->RI->In.RegY < 0xFE &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
!CE_HasLabel (L[1]) &&
CE_IsCallTo (L[1], "pushax") &&
!RegAXUsed (S, I+2)) {
/* Insert new code behind the pushax */
const char* Arg;
CodeEntry* X;
/* ldy #xx+1 */
Arg = MakeHexArg (L[0]->RI->In.RegY+2);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
/* jsr pushwysp */
X = NewCodeEntry (OP65_JSR, AM65_ABS, "pushwysp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* Delete the old code */
CS_DelEntries (S, I, 2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptTest1 (CodeSeg* S)
/* Given a sequence
*
* stx xxx
* ora xxx
* beq/bne ...
*
* If X is zero, the sequence may be changed to
*
* cmp #$00
* beq/bne ...
*
* which may be optimized further by another step.
*
* If A is zero, the sequence may be changed to
*
* txa
* beq/bne ...
*
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
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_STX &&
CS_GetEntries (S, L+1, I+1, 2) &&
!CE_HasLabel (L[1]) &&
L[1]->OPC == OP65_ORA &&
strcmp (L[0]->Arg, L[1]->Arg) == 0 &&
!CE_HasLabel (L[2]) &&
(L[2]->Info & OF_ZBRA) != 0) {
/* Check if X is zero */
if (L[0]->RI->In.RegX == 0) {
/* Insert the compare */
CodeEntry* N = NewCodeEntry (OP65_CMP, AM65_IMM, "$00", 0, L[0]->LI);
CS_InsertEntry (S, N, I+2);
/* Remove the two other insns */
CS_DelEntry (S, I+1);
CS_DelEntry (S, I);
/* We had changes */
++Changes;
/* Check if A is zero */
} else if (L[1]->RI->In.RegA == 0) {
/* Insert the txa */
CodeEntry* N = NewCodeEntry (OP65_TXA, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, N, I+2);
/* Remove the two other insns */
CS_DelEntry (S, I+1);
CS_DelEntry (S, I);
/* We had changes */
++Changes;
}
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static CodeEntry* ParseInsn (CodeSeg* S, LineInfo* LI, const char* L)
/* Parse an instruction nnd generate a code entry from it. If the line contains
* errors, output an error message and return NULL.
* For simplicity, we don't accept the broad range of input a "real" assembler
* does. The instruction and the argument are expected to be separated by
* white space, for example.
*/
{
char Mnemo[IDENTSIZE+10];
const OPCDesc* OPC;
am_t AM = 0; /* Initialize to keep gcc silent */
char Arg[IDENTSIZE+10];
char Reg;
CodeEntry* E;
CodeLabel* Label;
/* Read the first token and skip white space after it */
L = SkipSpace (ReadToken (L, " \t:", Mnemo, sizeof (Mnemo)));
/* Check if we have a label */
if (*L == ':') {
/* Skip the colon and following white space */
L = SkipSpace (L+1);
/* Add the label */
CS_AddLabel (S, Mnemo);
/* If we have reached end of line, bail out, otherwise a mnemonic
* may follow.
*/
if (*L == '\0') {
return 0;
}
L = SkipSpace (ReadToken (L, " \t", Mnemo, sizeof (Mnemo)));
}
/* Try to find the opcode description for the mnemonic */
OPC = FindOP65 (Mnemo);
/* If we didn't find the opcode, print an error and bail out */
if (OPC == 0) {
Error ("ASM code error: %s is not a valid mnemonic", Mnemo);
return 0;
}
/* Get the addressing mode */
Arg[0] = '\0';
switch (*L) {
case '\0':
/* Implicit or accu */
if (OPC->Info & OF_NOIMP) {
AM = AM65_ACC;
} else {
AM = AM65_IMP;
}
break;
case '#':
/* Immidiate */
StrCopy (Arg, sizeof (Arg), L+1);
AM = AM65_IMM;
break;
case '(':
/* Indirect */
L = ReadToken (L+1, ",)", Arg, sizeof (Arg));
/* Check for errors */
if (*L == '\0') {
Error ("ASM code error: syntax error");
return 0;
}
/* Check the different indirect modes */
if (*L == ',') {
/* Expect zp x indirect */
L = SkipSpace (L+1);
if (toupper (*L) != 'X') {
Error ("ASM code error: `X' expected");
return 0;
}
L = SkipSpace (L+1);
if (*L != ')') {
Error ("ASM code error: `)' expected");
return 0;
}
L = SkipSpace (L+1);
if (*L != '\0') {
Error ("ASM code error: syntax error");
return 0;
}
AM = AM65_ZPX_IND;
} else if (*L == ')') {
/* zp indirect or zp indirect, y */
L = SkipSpace (L+1);
if (*L == ',') {
L = SkipSpace (L+1);
if (toupper (*L) != 'Y') {
Error ("ASM code error: `Y' expected");
return 0;
}
L = SkipSpace (L+1);
if (*L != '\0') {
Error ("ASM code error: syntax error");
return 0;
}
AM = AM65_ZP_INDY;
} else if (*L == '\0') {
AM = AM65_ZP_IND;
} else {
Error ("ASM code error: syntax error");
return 0;
}
}
break;
case 'a':
case 'A':
/* Accumulator? */
if (L[1] == '\0') {
AM = AM65_ACC;
break;
}
/* FALLTHROUGH */
default:
/* Absolute, maybe indexed */
L = ReadToken (L, ",", Arg, sizeof (Arg));
if (*L == '\0') {
/* Absolute, zeropage or branch */
if ((OPC->Info & OF_BRA) != 0) {
/* Branch */
AM = AM65_BRA;
} else if (GetZPInfo(Arg) != 0) {
AM = AM65_ZP;
} else {
/* Check for subroutine call to local label */
if ((OPC->Info & OF_CALL) && IsLocalLabelName (Arg)) {
Error ("ASM code error: "
"Cannot use local label `%s' in subroutine call",
Arg);
}
AM = AM65_ABS;
}
} else if (*L == ',') {
/* Indexed */
L = SkipSpace (L+1);
if (*L == '\0') {
Error ("ASM code error: syntax error");
return 0;
} else {
Reg = toupper (*L);
L = SkipSpace (L+1);
if (Reg == 'X') {
if (GetZPInfo(Arg) != 0) {
AM = AM65_ZPX;
} else {
AM = AM65_ABSX;
}
} else if (Reg == 'Y') {
AM = AM65_ABSY;
} else {
Error ("ASM code error: syntax error");
return 0;
}
if (*L != '\0') {
Error ("ASM code error: syntax error");
return 0;
}
}
}
break;
}
/* If the instruction is a branch, check for the label and generate it
* if it does not exist. This may lead to unused labels (if the label
* is actually an external one) which are removed by the CS_MergeLabels
* function later.
*/
Label = 0;
if (AM == AM65_BRA) {
/* Generate the hash over the label, then search for the label */
unsigned Hash = HashStr (Arg) % CS_LABEL_HASH_SIZE;
Label = CS_FindLabel (S, Arg, Hash);
/* If we don't have the label, it's a forward ref - create it */
if (Label == 0) {
/* Generate a new label */
Label = CS_NewCodeLabel (S, Arg, Hash);
}
}
/* We do now have the addressing mode in AM. Allocate a new CodeEntry
* structure and initialize it.
*/
E = NewCodeEntry (OPC->OPC, AM, Arg, Label, LI);
/* Return the new code entry */
return E;
}
unsigned OptNegAX2 (CodeSeg* S)
/* Search for a call to negax and replace it by
*
* ldx #$FF
* eor #$FF
* clc
* adc #$01
* bne L1
* inx
* L1:
*
* if X is known and zero on entry.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* P;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a call to negax, and if X is known and zero */
if (E->RI->In.RegX == 0 &&
CE_IsCallTo (E, "negax") &&
(P = CS_GetNextEntry (S, I)) != 0) {
CodeEntry* X;
CodeLabel* L;
/* Add replacement code behind */
/* ldx #$FF */
X = NewCodeEntry (OP65_LDX, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* eor #$FF */
X = NewCodeEntry (OP65_EOR, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+2);
/* clc */
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* adc #$01 */
X = NewCodeEntry (OP65_ADC, AM65_IMM, "$01", 0, E->LI);
CS_InsertEntry (S, X, I+4);
/* Get the label attached to the insn following the call */
L = CS_GenLabel (S, P);
/* bne L */
X = NewCodeEntry (OP65_BNE, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, X, I+5);
/* inx */
X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+6);
/* Delete the call to negax */
CS_DelEntry (S, I);
/* Skip the generated code */
I += 5;
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptShift6 (CodeSeg* S)
/* Inline the shift subroutines. */
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Shift;
unsigned Count;
CodeEntry* X;
unsigned IP;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a call to one of the shift routine */
if (E->OPC == OP65_JSR &&
(Shift = GetShift (E->Arg)) != SHIFT_NONE &&
SHIFT_DIR (Shift) == SHIFT_DIR_LEFT &&
(Count = SHIFT_COUNT (Shift)) > 0) {
/* Code is:
*
* stx tmp1
* asl a
* rol tmp1
* (repeat ShiftCount-1 times)
* ldx tmp1
*
* which makes 4 + 3 * ShiftCount bytes, compared to the original
* 3 bytes for the subroutine call. However, in most cases, the
* final load of the X register gets merged with some other insn
* and replaces a txa, so for a shift count of 1, we get a factor
* of 200, which matches nicely the CodeSizeFactor enabled with -Oi
*/
if (Count > 1 || S->CodeSizeFactor > 200) {
unsigned Size = 4 + 3 * Count;
if ((Size * 100 / 3) > S->CodeSizeFactor) {
/* Not acceptable */
goto NextEntry;
}
}
/* Inline the code. Insertion point is behind the subroutine call */
IP = (I + 1);
/* stx tmp1 */
X = NewCodeEntry (OP65_STX, AM65_ZP, "tmp1", 0, E->LI);
CS_InsertEntry (S, X, IP++);
while (Count--) {
/* asl a */
X = NewCodeEntry (OP65_ASL, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, IP++);
/* rol tmp1 */
X = NewCodeEntry (OP65_ROL, AM65_ZP, "tmp1", 0, E->LI);
CS_InsertEntry (S, X, IP++);
}
/* ldx tmp1 */
X = NewCodeEntry (OP65_LDX, AM65_ZP, "tmp1", 0, E->LI);
CS_InsertEntry (S, X, IP++);
/* Remove the subroutine call */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
NextEntry:
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptCmp8 (CodeSeg* S)
/* Check for register compares where the contents of the register and therefore
* the result of the compare is known.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
int RegVal;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a compare against an immediate value */
if ((E->Info & OF_CMP) != 0 &&
(RegVal = GetCmpRegVal (E)) >= 0 &&
CE_IsConstImm (E)) {
/* We are able to evaluate the compare at compile time. Check if
* one or more branches are ahead.
*/
unsigned JumpsChanged = 0;
CodeEntry* N;
while ((N = CS_GetNextEntry (S, I)) != 0 && /* Followed by something.. */
(N->Info & OF_CBRA) != 0 && /* ..that is a cond branch.. */
!CE_HasLabel (N)) { /* ..and has no label */
/* Evaluate the branch condition */
int Cond;
switch (GetBranchCond (N->OPC)) {
case BC_CC:
Cond = ((unsigned char)RegVal) < ((unsigned char)E->Num);
break;
case BC_CS:
Cond = ((unsigned char)RegVal) >= ((unsigned char)E->Num);
break;
case BC_EQ:
Cond = ((unsigned char)RegVal) == ((unsigned char)E->Num);
break;
case BC_MI:
Cond = ((signed char)RegVal) < ((signed char)E->Num);
break;
case BC_NE:
Cond = ((unsigned char)RegVal) != ((unsigned char)E->Num);
break;
case BC_PL:
Cond = ((signed char)RegVal) >= ((signed char)E->Num);
break;
case BC_VC:
case BC_VS:
/* Not set by the compare operation, bail out (Note:
* Just skipping anything here is rather stupid, but
* the sequence is never generated by the compiler,
* so it's quite safe to skip).
*/
goto NextEntry;
default:
Internal ("Unknown branch condition");
}
/* If the condition is false, we may remove the jump. Otherwise
* the branch will always be taken, so we may replace it by a
* jump (and bail out).
*/
if (!Cond) {
CS_DelEntry (S, I+1);
} else {
CodeLabel* L = N->JumpTo;
const char* LabelName = L? L->Name : N->Arg;
CodeEntry* X = NewCodeEntry (OP65_JMP, AM65_BRA, LabelName, L, N->LI);
CS_InsertEntry (S, X, I+2);
CS_DelEntry (S, I+1);
}
/* Remember, we had changes */
++JumpsChanged;
++Changes;
}
/* If we have made changes above, we may also remove the compare */
if (JumpsChanged) {
CS_DelEntry (S, I);
}
}
NextEntry:
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptStore3 (CodeSeg* S)
/* Search for a call to steaxysp. If the eax register is not used later, and
** the value is constant, just use the A register and store directly into the
** stack.
*/
{
unsigned I;
unsigned Changes = 0;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Get the input registers */
const RegInfo* RI = E->RI;
/* Check for the call */
if (CE_IsCallTo (E, "steaxysp") &&
RegValIsKnown (RI->In.RegA) &&
RegValIsKnown (RI->In.RegX) &&
RegValIsKnown (RI->In.RegY) &&
RegValIsKnown (RI->In.SRegLo) &&
RegValIsKnown (RI->In.SRegHi) &&
!RegEAXUsed (S, I+1)) {
/* Get the register values */
unsigned char A = (unsigned char) RI->In.RegA;
unsigned char X = (unsigned char) RI->In.RegX;
unsigned char Y = (unsigned char) RI->In.RegY;
unsigned char L = (unsigned char) RI->In.SRegLo;
unsigned char H = (unsigned char) RI->In.SRegHi;
/* Setup other variables */
unsigned Done = 0;
CodeEntry* N;
unsigned IP = I + 1; /* Insertion point */
/* Replace the store. We will not remove the loads, since this is
** too complex and will be done by other optimizer steps.
*/
N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (A), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x01;
/* Check if we can store one of the other bytes */
if (A == X && (Done & 0x02) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+1), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x02;
}
if (A == L && (Done & 0x04) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x04;
}
if (A == H && (Done & 0x08) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x08;
}
/* Store the second byte */
if ((Done & 0x02) == 0) {
N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (X), 0, E->LI);
CS_InsertEntry (S, N, IP++);
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+1), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x02;
}
/* Check if we can store one of the other bytes */
if (X == L && (Done & 0x04) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x04;
}
if (X == H && (Done & 0x08) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x08;
}
/* Store the third byte */
if ((Done & 0x04) == 0) {
N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (L), 0, E->LI);
CS_InsertEntry (S, N, IP++);
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+2), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x04;
}
/* Check if we can store one of the other bytes */
if (L == H && (Done & 0x08) == 0) {
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x08;
}
/* Store the fourth byte */
if ((Done & 0x08) == 0) {
N = NewCodeEntry (OP65_LDA, AM65_IMM, MakeHexArg (H), 0, E->LI);
CS_InsertEntry (S, N, IP++);
N = NewCodeEntry (OP65_LDY, AM65_IMM, MakeHexArg (Y+3), 0, E->LI);
CS_InsertEntry (S, N, IP++);
InsertStore (S, &IP, E->LI);
Done |= 0x08;
}
/* Remove the call */
CS_DelEntry (S, I);
/* Remember, we had changes */
++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;
}
static void InsertStore (CodeSeg* S, unsigned* IP, LineInfo* LI)
{
CodeEntry* X = NewCodeEntry (OP65_STA, AM65_ZP_INDY, "sp", 0, LI);
CS_InsertEntry (S, X, (*IP)++);
}
unsigned OptCmp5 (CodeSeg* S)
/* Optimize compares of local variables:
*
* ldy #o
* jsr ldaxysp
* cpx #a
* bne L1
* cmp #b
* jne/jeq L2
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[6];
/* Get the next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_LDY &&
CE_IsConstImm (L[0]) &&
CS_GetEntries (S, L+1, I+1, 5) &&
!CE_HasLabel (L[1]) &&
CE_IsCallTo (L[1], "ldaxysp") &&
IsImmCmp16 (L+2)) {
if ((L[5]->Info & OF_FBRA) != 0 && L[2]->Num == 0 && L[4]->Num == 0) {
CodeEntry* X;
char Buf[20];
/* The value is zero, we may use the simple code version:
* ldy #o-1
* lda (sp),y
* ldy #o
* ora (sp),y
* jne/jeq ...
*/
sprintf (Buf, "$%02X", (int)(L[0]->Num-1));
X = NewCodeEntry (OP65_LDY, AM65_IMM, Buf, 0, L[0]->LI);
CS_InsertEntry (S, X, I+1);
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_LDY, AM65_IMM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
X = NewCodeEntry (OP65_ORA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+4);
CS_DelEntries (S, I+5, 3); /* cpx/bne/cmp */
CS_DelEntry (S, I); /* ldy */
} else {
CodeEntry* X;
char Buf[20];
/* Change the code to just use the A register. Move the load
* of the low byte after the first branch if possible:
*
* ldy #o
* lda (sp),y
* cmp #a
* bne L1
* ldy #o-1
* lda (sp),y
* cmp #b
* jne/jeq ...
*/
X = NewCodeEntry (OP65_LDY, AM65_IMM, L[0]->Arg, 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+4);
X = NewCodeEntry (OP65_CMP, L[2]->AM, L[2]->Arg, 0, L[2]->LI);
CS_InsertEntry (S, X, I+5);
sprintf (Buf, "$%02X", (int)(L[0]->Num-1));
X = NewCodeEntry (OP65_LDY, AM65_IMM, Buf, 0, L[0]->LI);
CS_InsertEntry (S, X, I+7);
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+8);
CS_DelEntries (S, I, 3); /* ldy/jsr/cpx */
}
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
