-#include "codeopt.h"
-
-
-
-/*****************************************************************************/
-/* Data */
-/*****************************************************************************/
-
-
-
-/* Shift types */
-enum {
- SHIFT_NONE,
- SHIFT_ASR_1,
- SHIFT_ASL_1,
- SHIFT_LSR_1,
- SHIFT_LSL_1
-};
-
-
-
-/*****************************************************************************/
-/* Optimize shifts */
-/*****************************************************************************/
-
-
-
-static unsigned OptShift1 (CodeSeg* S)
-/* A call to the shlaxN routine may get replaced by one or more asl insns
- * if the value of X is not 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 for the sequence */
- if (E->OPC == OP65_JSR &&
- (strncmp (E->Arg, "shlax", 5) == 0 ||
- strncmp (E->Arg, "aslax", 5) == 0) &&
- strlen (E->Arg) == 6 &&
- IsDigit (E->Arg[5]) &&
- !RegXUsed (S, I+1)) {
-
- /* Insert shift insns */
- unsigned Count = E->Arg[5] - '0';
- while (Count--) {
- CodeEntry* X = NewCodeEntry (OP65_ASL, AM65_ACC, "a", 0, E->LI);
- CS_InsertEntry (S, X, I+1);
- }
-
- /* Delete the call to shlax */
- CS_DelEntry (S, I);
-
- /* Remember, we had changes */
- ++Changes;
-
- }
-
- /* Next entry */
- ++I;
-
- }
-
- /* Return the number of changes made */
- return Changes;
-}
-
-
-
-static unsigned OptShift2 (CodeSeg* S)
-/* A call to the shraxN routine may get replaced by one or more lsr insns
- * if the value of X is zero.
- */
-{
- unsigned Changes = 0;
- unsigned I;
-
- /* Generate register info */
- 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 the sequence */
- if (E->OPC == OP65_JSR &&
- strncmp (E->Arg, "shrax", 5) == 0 &&
- strlen (E->Arg) == 6 &&
- IsDigit (E->Arg[5]) &&
- E->RI->In.RegX == 0) {
-
- /* Insert shift insns */
- unsigned Count = E->Arg[5] - '0';
- while (Count--) {
- CodeEntry* X = NewCodeEntry (OP65_LSR, AM65_ACC, "a", 0, E->LI);
- CS_InsertEntry (S, X, I+1);
- }
-
- /* Delete the call to shlax */
- CS_DelEntry (S, I);
-
- /* Remember, we had changes */
- ++Changes;
-
- }
-
- /* Next entry */
- ++I;
-
- }
-
- /* Free the register info */
- CS_FreeRegInfo (S);
-
- /* Return the number of changes made */
- return Changes;
-}
-
-
-
-static unsigned GetShiftType (const char* Sub)
-/* Helper function for OptShift3 */
-{
- if (*Sub == 'a') {
- if (strcmp (Sub+1, "slax1") == 0) {
- return SHIFT_ASL_1;
- } else if (strcmp (Sub+1, "srax1") == 0) {
- return SHIFT_ASR_1;
- }
- } else if (*Sub == 's') {
- if (strcmp (Sub+1, "hlax1") == 0) {
- return SHIFT_LSL_1;
- } else if (strcmp (Sub+1, "hrax1") == 0) {
- return SHIFT_LSR_1;
- }
- }
- return SHIFT_NONE;
-}
-
-
-
-static unsigned OptShift3 (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 = GetShiftType (L[2]->Arg)) != SHIFT_NONE&&
- 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;
-}
-