#include "codeent.h"
#include "codeinfo.h"
#include "coptstop.h"
+#include "error.h"
LI_NONE = 0x00,
LI_DIRECT = 0x01, /* Direct op may be used */
LI_RELOAD_Y = 0x02, /* Reload index register Y */
- LI_TRANSFER = 0x04, /* Loaded value is transfered */
- LI_REMOVE = 0x08, /* Load may be removed */
+ LI_REMOVE = 0x04, /* Load may be removed */
+ LI_DUP_LOAD = 0x08, /* Duplicate load */
} LI_FLAGS;
/* Structure that tells us how to load the lhs values */
CodeEntry* LoadEntry; /* The actual entry, 0 if invalid */
int XferIndex; /* Index of transfer insn */
CodeEntry* XferEntry; /* The actual transfer entry */
- unsigned char Offs; /* Stack offset if data is on stack */
+ int Offs; /* Stack offset if data is on stack */
};
/* Now combined for both registers */
static void ClearLoadRegInfo (LoadRegInfo* RI)
/* Clear a LoadRegInfo struct */
{
- RI->LoadIndex = -1;
- RI->XferIndex = -1;
RI->Flags = LI_NONE;
-}
-
-
-
-static void InvalidateLoadRegInfo (LoadRegInfo* RI)
-/* Invalidate a LoadRegInfo struct */
-{
RI->LoadIndex = -1;
RI->XferIndex = -1;
+ RI->Offs = 0;
}
/* Track loads for a code entry */
{
if (E->Info & OF_LOAD) {
+
+ LoadRegInfo* RI = 0;
+
+ /* Determine, which register was loaded */
if (E->Chg & REG_A) {
- LI->A.LoadIndex = I;
- LI->A.XferIndex = -1;
+ RI = &LI->A;
+ } else if (E->Chg & REG_X) {
+ RI = &LI->X;
+ } else if (E->Chg & REG_Y) {
+ RI = &LI->Y;
}
- if (E->Chg & REG_X) {
- LI->X.LoadIndex = I;
- LI->X.XferIndex = -1;
+ CHECK (RI != 0);
+
+ /* If we had a load or xfer op before, this is a duplicate load which
+ * can cause problems if it encountered between the pushax and the op,
+ * so remember it.
+ */
+ if (RI->LoadIndex >= 0 || RI->XferIndex >= 0) {
+ RI->Flags |= LI_DUP_LOAD;
}
- if (E->Chg & REG_Y) {
- LI->Y.LoadIndex = I;
- LI->Y.XferIndex = -1;
+
+ /* Remember the load */
+ RI->LoadIndex = I;
+ RI->XferIndex = -1;
+
+ /* Set load flags */
+ RI->Flags &= ~(LI_DIRECT | LI_RELOAD_Y);
+ if (E->AM == AM65_IMM || E->AM == AM65_ZP || E->AM == AM65_ABS) {
+ /* These insns are all ok and replaceable */
+ RI->Flags |= LI_DIRECT;
+ } else if (E->AM == AM65_ZP_INDY &&
+ RegValIsKnown (E->RI->In.RegY) &&
+ strcmp (E->Arg, "sp") == 0) {
+ /* A load from the stack with known offset is also ok, but in this
+ * case we must reload the index register later. Please note that
+ * a load indirect via other zero page locations is not ok, since
+ * these locations may change between the push and the actual
+ * operation.
+ */
+ RI->Offs = (unsigned char) E->RI->In.RegY;
+ RI->Flags |= (LI_DIRECT | LI_RELOAD_Y);
}
+
+
} else if (E->Info & OF_XFR) {
+
+ /* Determine source and target of the transfer and handle the TSX insn */
+ LoadRegInfo* Src;
+ LoadRegInfo* Tgt;
switch (E->OPC) {
- case OP65_TAX:
- LI->X.LoadIndex = LI->A.LoadIndex;
- LI->X.XferIndex = I;
- break;
- case OP65_TAY:
- LI->Y.LoadIndex = LI->A.LoadIndex;
- LI->Y.XferIndex = I;
- break;
- case OP65_TXA:
- LI->A.LoadIndex = LI->X.LoadIndex;
- LI->A.XferIndex = I;
- break;
- case OP65_TYA:
- LI->A.LoadIndex = LI->Y.LoadIndex;
- LI->A.XferIndex = I;
- break;
- default:
- break;
+ case OP65_TAX: Src = &LI->A; Tgt = &LI->X; break;
+ case OP65_TAY: Src = &LI->A; Tgt = &LI->Y; break;
+ case OP65_TXA: Src = &LI->X; Tgt = &LI->A; break;
+ case OP65_TYA: Src = &LI->Y; Tgt = &LI->A; break;
+ case OP65_TSX: ClearLoadRegInfo (&LI->X); return;
+ case OP65_TXS: return;
+ default: Internal ("Unknown XFR insn in TrackLoads");
+ }
+
+ /* If we had a load or xfer op before, this is a duplicate load which
+ * can cause problems if it encountered between the pushax and the op,
+ * so remember it.
+ */
+ if (Tgt->LoadIndex >= 0 || Tgt->XferIndex >= 0) {
+ Tgt->Flags |= LI_DUP_LOAD;
+ }
+
+ /* Transfer the data */
+ Tgt->LoadIndex = Src->LoadIndex;
+ Tgt->XferIndex = I;
+ Tgt->Offs = Src->Offs;
+ Tgt->Flags &= ~(LI_DIRECT | LI_RELOAD_Y);
+ Tgt->Flags |= Src->Flags & (LI_DIRECT | LI_RELOAD_Y);
+
+ } else if (CE_IsCallTo (E, "ldaxysp") && RegValIsKnown (E->RI->In.RegY)) {
+
+ /* If we had a load or xfer op before, this is a duplicate load which
+ * can cause problems if it encountered between the pushax and the op,
+ * so remember it for both registers involved.
+ */
+ if (LI->A.LoadIndex >= 0 || LI->A.XferIndex >= 0) {
+ LI->A.Flags |= LI_DUP_LOAD;
+ }
+ if (LI->X.LoadIndex >= 0 || LI->X.XferIndex >= 0) {
+ LI->X.Flags |= LI_DUP_LOAD;
}
- } else if (CE_IsCallTo (E, "ldaxysp")) {
+
/* Both registers set, Y changed */
LI->A.LoadIndex = I;
LI->A.XferIndex = -1;
+ LI->A.Flags |= (LI_DIRECT | LI_RELOAD_Y);
+ LI->A.Offs = (unsigned char) E->RI->In.RegY - 1;
+
LI->X.LoadIndex = I;
LI->X.XferIndex = -1;
- InvalidateLoadRegInfo (&LI->Y);
+ LI->X.Flags |= (LI_DIRECT | LI_RELOAD_Y);
+ LI->X.Offs = (unsigned char) E->RI->In.RegY;
+
+ ClearLoadRegInfo (&LI->Y);
} else {
if (E->Chg & REG_A) {
- InvalidateLoadRegInfo (&LI->A);
+ ClearLoadRegInfo (&LI->A);
}
if (E->Chg & REG_X) {
- InvalidateLoadRegInfo (&LI->X);
+ ClearLoadRegInfo (&LI->X);
}
if (E->Chg & REG_Y) {
- InvalidateLoadRegInfo (&LI->Y);
+ ClearLoadRegInfo (&LI->Y);
}
}
}
/*****************************************************************************/
-/* Helpers */
+/* Helpers */
/*****************************************************************************/
-static void CheckOneDirectOp (LoadRegInfo* LI, unsigned char Offs)
-/* Check if the given entry is a lda instruction with an addressing mode
- * that allows us to replace it by another operation (like ora). If so, we may
- * use this location for the or and must not save the value in the zero
- * page location.
- */
-{
- /* Get the load entry */
- CodeEntry* E = LI->LoadEntry;
- if (E == 0) {
- /* No load insn */
- return;
- }
-
- /* Check the load entry */
- if (E) {
- /* Must check the call first since addressing mode is ABS, so second
- * "if" will catch otherwise.
- */
- if (CE_IsCallTo (E, "ldaxysp")) {
- /* Same as single loads from stack. Since we must distinguish
- * between A and X here, the necessary offset is passed to the
- * function as a parameter.
- */
- LI->Offs = (unsigned char) E->RI->In.RegY - Offs;
- LI->Flags |= (LI_DIRECT | LI_RELOAD_Y);
- } else if (E->AM == AM65_IMM || E->AM == AM65_ZP || E->AM == AM65_ABS) {
- /* These insns are all ok and replaceable */
- LI->Flags |= LI_DIRECT;
- } else if (E->AM == AM65_ZP_INDY &&
- RegValIsKnown (E->RI->In.RegY) &&
- strcmp (E->Arg, "sp") == 0) {
- /* A load from the stack with known offset is also ok, but in this
- * case we must reload the index register later. Please note that
- * a load indirect via other zero page locations is not ok, since
- * these locations may change between the push and the actual
- * operation.
- */
- LI->Offs = (unsigned char) E->RI->In.RegY;
- LI->Flags |= (LI_DIRECT | LI_RELOAD_Y);
- }
- }
-}
-
-
-
-static void CheckDirectOp (StackOpData* D)
-/* Check if the given entry is a lda instruction with an addressing mode
- * that allows us to replace it by another operation (like ora). If so, we may
- * use this location for the or and must not save the value in the zero
- * page location.
- */
-{
- /* Check flags for all load instructions */
- CheckOneDirectOp (&D->Lhs.A, 1);
- CheckOneDirectOp (&D->Lhs.X, 0);
- CheckOneDirectOp (&D->Rhs.A, 1);
- CheckOneDirectOp (&D->Rhs.X, 0);
-}
-
-
-
static void AddStoreA (StackOpData* D)
/* Add a store to zero page after the push insn */
{
}
}
}
+ if ((D->Rhs.A.Flags | D->Rhs.X.Flags) & LI_DUP_LOAD) {
+ /* Cannot optimize */
+ return 0;
+ }
/* Determine the zero page locations to use */
if ((D->UsedRegs & REG_PTR1) == REG_NONE) {
{
unsigned Changes = 0; /* Number of changes in one run */
StackOpData Data;
- unsigned I;
+ int I;
+ int OldEntryCount; /* Old number of entries */
enum {
Initialize,
* intermediate code for zero page use.
*/
I = 0;
- while (I < CS_GetEntryCount (S)) {
+ while (I < (int)CS_GetEntryCount (S)) {
/* Get the next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* While searching, track register load insns, so we can tell
* what is in a register once pushax is encountered.
*/
+ if (CE_HasLabel (E)) {
+ /* Currently we don't track across branches */
+ ClearLoadInfo (&Data.Lhs);
+ }
if (CE_IsCallTo (E, "pushax")) {
Data.PushIndex = I;
State = FoundPush;
* follow and in the meantime, track zeropage usage and check
* for code that will disable us from translating the sequence.
*/
+ if (CE_HasLabel (E)) {
+ /* Currently we don't track across branches */
+ ClearLoadInfo (&Data.Rhs);
+ }
if (E->OPC == OP65_JSR) {
/* Subroutine call: Check if this is one of the functions,
FinalizeLoadInfo (&Data.Lhs, S);
FinalizeLoadInfo (&Data.Rhs, S);
- /* Set flags for direct operations */
- CheckDirectOp (&Data);
-
/* If the Lhs loads do load from zeropage, we have to include
* them into UsedRegs registers used. The Rhs loads have already
* been tracked.
Data.OpEntry = CS_GetEntry (S, Data.OpIndex);
Data.NextEntry = CS_GetNextEntry (S, Data.OpIndex);
+ /* Remember the current number of code lines */
+ OldEntryCount = CS_GetEntryCount (S);
+
/* Adjust stack offsets to account for the upcoming removal */
AdjustStackOffset (&Data, 2);
/* Call the optimizer function */
Changes += Data.OptFunc->Func (&Data);
+ /* Since the function may have added or deleted entries,
+ * correct the index.
+ */
+ I += CS_GetEntryCount (S) - OldEntryCount;
+
/* Regenerate register info */
CS_GenRegInfo (S);
/* Done */
State = Initialize;
- break;
+ continue;
}
projects / cc65 / blobdiff