/* */
/* */
/* */
-/* (C) 2001-2013, Ullrich von Bassewitz */
+/* (C) 2001-2019, Ullrich von Bassewitz */
/* Roemerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
const OptFuncDesc* OptFunc;
/* ZP register usage inside the sequence */
- unsigned UsedRegs;
+ unsigned ZPUsage;
/* Register load information for lhs and rhs */
LoadInfo Lhs;
static void AdjustLoadRegInfo (LoadRegInfo* RI, int Index, int Change)
/* Adjust a load register info struct after deleting or inserting an entry
- * with a given index
- */
+** with a given index
+*/
{
CHECK (abs (Change) == 1);
if (Change < 0) {
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.
- */
+ ** 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;
}
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.
- */
+ ** 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);
}
}
/* 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.
- */
+ ** 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;
}
} 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.
- */
+ ** 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;
}
static void InsertEntry (StackOpData* D, CodeEntry* E, int Index)
/* Insert a new entry. Depending on Index, D->PushIndex and D->OpIndex will
- * be adjusted by this function.
- */
+** be adjusted by this function.
+*/
{
/* Insert the entry into the code segment */
CS_InsertEntry (D->Code, E, Index);
static void DelEntry (StackOpData* D, int Index)
/* Delete an entry. Depending on Index, D->PushIndex and D->OpIndex will be
- * adjusted by this function, and PushEntry/OpEntry may get invalidated.
- */
+** adjusted by this function, and PushEntry/OpEntry may get invalidated.
+*/
{
/* Delete the entry from the code segment */
CS_DelEntry (D->Code, Index);
static void AdjustStackOffset (StackOpData* D, unsigned Offs)
/* Adjust the offset for all stack accesses in the range PushIndex to OpIndex.
- * OpIndex is adjusted according to the insertions.
- */
+** OpIndex is adjusted according to the insertions.
+*/
{
/* Walk over all entries */
int I = D->PushIndex + 1;
if (NeedCorrection) {
/* Get the code entry before this one. If it's a LDY, adjust the
- * value.
- */
+ ** value.
+ */
CodeEntry* P = CS_GetPrevEntry (D->Code, I);
if (P && P->OPC == OP65_LDY && CE_IsConstImm (P)) {
}
/* If we have rhs load insns that load from stack, we'll have to adjust
- * the offsets for these also.
- */
+ ** the offsets for these also.
+ */
if (D->Rhs.A.Flags & LI_RELOAD_Y) {
D->Rhs.A.Offs -= Offs;
}
static void ReplacePushByStore (StackOpData* D)
/* Replace the call to the push subroutine by a store into the zero page
- * location (actually, the push is not replaced, because we need it for
- * later, but the name is still ok since the push will get removed at the
- * end of each routine).
- */
+** location (actually, the push is not replaced, because we need it for
+** later, but the name is still ok since the push will get removed at the
+** end of each routine).
+*/
{
/* Store the value into the zeropage instead of pushing it. Check high
- * byte first so that the store is later in A/X order.
- */
+ ** byte first so that the store is later in A/X order.
+ */
if ((D->Lhs.X.Flags & LI_DIRECT) == 0) {
AddStoreX (D);
}
static void AddOpLow (StackOpData* D, opc_t OPC, LoadInfo* LI)
/* Add an op for the low byte of an operator. This function honours the
- * OP_DIRECT and OP_RELOAD_Y flags and generates the necessary instructions.
- * All code is inserted at the current insertion point.
- */
+** OP_DIRECT and OP_RELOAD_Y flags and generates the necessary instructions.
+** All code is inserted at the current insertion point.
+*/
{
CodeEntry* X;
if ((LI->A.Flags & LI_DIRECT) != 0) {
/* Op with a variable location. If the location is on the stack, we
- * need to reload the Y register.
- */
+ ** need to reload the Y register.
+ */
if ((LI->A.Flags & LI_RELOAD_Y) == 0) {
/* opc ... */
static void AddOpHigh (StackOpData* D, opc_t OPC, LoadInfo* LI, int KeepResult)
/* Add an op for the high byte of an operator. Special cases (constant values
- * or similar) have to be checked separately, the function covers only the
- * generic case. Code is inserted at the insertion point.
- */
+** or similar) have to be checked separately, the function covers only the
+** generic case. Code is inserted at the insertion point.
+*/
{
CodeEntry* X;
/* Remove register load insns */
{
/* Both registers may be loaded with one insn, but DelEntry will in this
- * case clear the other one.
- */
+ ** case clear the other one.
+ */
if ((LI->A.Flags & (LI_REMOVE | LI_DONT_REMOVE)) == LI_REMOVE) {
if (LI->A.LoadIndex >= 0) {
DelEntry (D, LI->A.LoadIndex);
static int IsRegVar (StackOpData* D)
/* If the value pushed is that of a zeropage variable, replace ZPLo and ZPHi
- * in the given StackOpData struct by the variable and return true. Otherwise
- * leave D untouched and return false.
- */
+** in the given StackOpData struct by the variable and return true. Otherwise
+** leave D untouched and return false.
+*/
{
CodeEntry* LoadA = D->Lhs.A.LoadEntry;
CodeEntry* LoadX = D->Lhs.X.LoadEntry;
CodeLabel* L;
/* Create a call to the boolean transformer function and a label for this
- * insn. This is needed for all variants. Other insns are inserted *before*
- * the call.
- */
+ ** insn. This is needed for all variants. Other insns are inserted *before*
+ ** the call.
+ */
X = NewCodeEntry (OP65_JSR, AM65_ABS, BoolTransformer, 0, D->OpEntry->LI);
InsertEntry (D, X, D->OpIndex + 1);
L = CS_GenLabel (D->Code, X);
/* If the lhs is direct (but not stack relative), encode compares with lhs
- * effectively reverting the order (which doesn't matter for ==).
- */
+ ** effectively reverting the order (which doesn't matter for ==).
+ */
if ((D->Lhs.A.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT &&
(D->Lhs.X.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT) {
ReplacePushByStore (D);
/* If the lhs is direct (but not stack relative), we can just reload the
- * data later.
- */
+ ** data later.
+ */
if ((D->Lhs.A.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT &&
(D->Lhs.X.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT) {
AddStoreA (D);
/* Be sure to setup IP after adding the stores, otherwise it will get
- * messed up.
- */
+ ** messed up.
+ */
D->IP = D->OpIndex+1;
/* tay */
}
/* If the return value of __bzero is used, we have to add code to reload
- * a/x from the pointer variable.
- */
+ ** a/x from the pointer variable.
+ */
if (RegAXUsed (D->Code, D->OpIndex+1)) {
X = NewCodeEntry (OP65_LDA, AM65_ZP, D->ZPLo, 0, D->OpEntry->LI);
InsertEntry (D, X, D->OpIndex+1);
}
/* X is always zero, A contains the size of the data area to zero.
- * Note: A may be zero, in which case the operation is null op.
- */
+ ** Note: A may be zero, in which case the operation is null op.
+ */
if (D->OpEntry->RI->In.RegA != 0) {
/* lda #$00 */
InsertEntry (D, X, D->OpIndex+4);
/* If we remove staxspidx, we must restore the Y register to what the
- * function would return.
- */
+ ** function would return.
+ */
X = NewCodeEntry (OP65_LDY, AM65_IMM, "$00", 0, D->OpEntry->LI);
InsertEntry (D, X, D->OpIndex+5);
CHECK (D->NextEntry != 0);
/* Check if the X register is known and zero when the add is done, and
- * if the add is followed by
- *
- * ldy #$00
- * jsr ldauidx ; or ldaidx
- *
- * If this is true, the addition does actually add an offset to a pointer
- * before it is dereferenced. Since both subroutines take an offset in Y,
- * we can pass the offset (instead of #$00) and remove the addition
- * alltogether.
- */
+ ** if the add is followed by
+ **
+ ** ldy #$00
+ ** jsr ldauidx ; or ldaidx
+ **
+ ** If this is true, the addition does actually add an offset to a pointer
+ ** before it is dereferenced. Since both subroutines take an offset in Y,
+ ** we can pass the offset (instead of #$00) and remove the addition
+ ** alltogether.
+ */
if (D->OpEntry->RI->In.RegX == 0 &&
D->NextEntry->OPC == OP65_LDY &&
CE_IsKnownImm (D->NextEntry, 0) &&
AddStoreA (D);
/* Replace the ldy by a tay. Be sure to create the new entry before
- * deleting the ldy, since we will reference the line info from this
- * insn.
- */
+ ** deleting the ldy, since we will reference the line info from this
+ ** insn.
+ */
X = NewCodeEntry (OP65_TAY, AM65_IMP, 0, 0, D->NextEntry->LI);
DelEntry (D, D->OpIndex + 1);
InsertEntry (D, X, D->OpIndex + 1);
/* Replace the call to ldaidx/ldauidx. Since X is already zero, and
- * the ptr is in the zero page location, we just need to load from
- * the pointer, and fix X in case of ldaidx.
- */
+ ** the ptr is in the zero page location, we just need to load from
+ ** the pointer, and fix X in case of ldaidx.
+ */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, D->ZPLo, 0, N->LI);
DelEntry (D, D->OpIndex + 2);
InsertEntry (D, X, D->OpIndex + 2);
X = NewCodeEntry (OP65_LDX, AM65_IMM, Arg, 0, D->OpEntry->LI);
} else {
/* Value of first op high byte is unknown. Load from ZP or
- * original storage.
- */
+ ** original storage.
+ */
if (D->Lhs.X.Flags & LI_DIRECT) {
CodeEntry* LoadX = D->Lhs.X.LoadEntry;
X = NewCodeEntry (OP65_LDX, LoadX->AM, LoadX->Arg, 0, D->OpEntry->LI);
static const OptFuncDesc* FindFunc (const char* Name)
/* Find the function with the given name. Return a pointer to the table entry
- * or NULL if the function was not found.
- */
+** or NULL if the function was not found.
+*/
{
return bsearch (Name, FuncTable, FUNC_COUNT, sizeof(OptFuncDesc), CmpFunc);
}
static int HarmlessCall (const char* Name)
/* Check if this is a call to a harmless subroutine that will not interrupt
- * the pushax/op sequence when encountered.
- */
+** the pushax/op sequence when encountered.
+*/
{
- static const char* Tab[] = {
+ static const char* const Tab[] = {
"aslax1",
"aslax2",
"aslax3",
/* Reset the given data structure */
{
Data->OptFunc = 0;
- Data->UsedRegs = REG_NONE;
+ Data->ZPUsage = REG_NONE;
ClearLoadInfo (&Data->Lhs);
ClearLoadInfo (&Data->Rhs);
static int PreCondOk (StackOpData* D)
/* Check if the preconditions for a call to the optimizer subfunction are
- * satisfied. As a side effect, this function will also choose the zero page
- * register to use.
- */
+** satisfied. As a side effect, this function will also choose the zero page
+** register to use.
+*/
{
/* Check the flags */
unsigned UnusedRegs = D->OptFunc->UnusedRegs;
return 0;
}
- /* Determine the zero page locations to use */
- if ((D->UsedRegs & REG_PTR1) == REG_NONE) {
+ /* Determine the zero page locations to use. We've tracked the used
+ ** ZP locations, so try to find some for us that are unused.
+ */
+ if ((D->ZPUsage & REG_PTR1) == REG_NONE) {
D->ZPLo = "ptr1";
D->ZPHi = "ptr1+1";
- } else if ((D->UsedRegs & REG_SREG) == REG_NONE) {
+ } else if ((D->ZPUsage & REG_SREG) == REG_NONE) {
D->ZPLo = "sreg";
D->ZPHi = "sreg+1";
- } else if ((D->UsedRegs & REG_PTR2) == REG_NONE) {
+ } else if ((D->ZPUsage & REG_PTR2) == REG_NONE) {
D->ZPLo = "ptr2";
D->ZPHi = "ptr2+1";
} else {
Data.Code = S;
/* Look for a call to pushax followed by a call to some other function
- * that takes it's first argument on the stack, and the second argument
- * in the primary register.
- * It depends on the code between the two if we can handle/transform the
- * sequence, so check this code for the following list of things:
- *
- * - the range must be a basic block (one entry, one exit)
- * - there may not be accesses to local variables with unknown
- * offsets (because we have to adjust these offsets).
- * - no subroutine calls
- * - no jump labels
- *
- * Since we need a zero page register later, do also check the
- * intermediate code for zero page use.
- */
+ ** that takes it's first argument on the stack, and the second argument
+ ** in the primary register.
+ ** It depends on the code between the two if we can handle/transform the
+ ** sequence, so check this code for the following list of things:
+ **
+ ** - the range must be a basic block (one entry, one exit)
+ ** - there may not be accesses to local variables with unknown
+ ** offsets (because we have to adjust these offsets).
+ ** - no subroutine calls
+ ** - no jump labels
+ **
+ ** Since we need a zero page register later, do also check the
+ ** intermediate code for zero page use.
+ */
I = 0;
while (I < (int)CS_GetEntryCount (S)) {
case Search:
/* While searching, track register load insns, so we can tell
- * what is in a register once pushax is encountered.
- */
+ ** what is in a register once pushax is encountered.
+ */
if (CE_HasLabel (E)) {
/* Currently we don't track across branches */
ClearLoadInfo (&Data.Lhs);
case FoundPush:
/* We' found a pushax before. Search for a stack op that may
- * follow and in the meantime, track zeropage usage and check
- * for code that will disable us from translating the sequence.
- */
+ ** 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,
- * we're going to replace.
- */
+ ** we're going to replace.
+ */
Data.OptFunc = FindFunc (E->Arg);
if (Data.OptFunc) {
/* Remember the op index and go on */
break;
} else if (!HarmlessCall (E->Arg)) {
/* A call to an unkown subroutine: We need to start
- * over after the last pushax. Note: This will also
- * happen if we encounter a call to pushax!
- */
+ ** over after the last pushax. Note: This will also
+ ** happen if we encounter a call to pushax!
+ */
I = Data.PushIndex;
State = Initialize;
break;
} else {
/* Track register usage */
- Data.UsedRegs |= (E->Use | E->Chg);
+ Data.ZPUsage |= (E->Use | E->Chg);
TrackLoads (&Data.Rhs, E, I);
}
} else if (E->Info & OF_STORE && (E->Chg & REG_ZP) == 0) {
/* Too dangerous - there may be a change of a variable
- * within the sequence.
- */
+ ** within the sequence.
+ */
I = Data.PushIndex;
State = Initialize;
break;
E->RI->In.RegY < 2)) {
/* If we are using the stack, and we don't have "indirect Y"
- * addressing mode, or the value of Y is unknown, or less
- * than two, we cannot cope with this piece of code. Having
- * an unknown value of Y means that we cannot correct the
- * stack offset, while having an offset less than two means
- * that the code works with the value on stack which is to
- * be removed.
- */
+ ** addressing mode, or the value of Y is unknown, or less
+ ** than two, we cannot cope with this piece of code. Having
+ ** an unknown value of Y means that we cannot correct the
+ ** stack offset, while having an offset less than two means
+ ** that the code works with the value on stack which is to
+ ** be removed.
+ */
I = Data.PushIndex;
State = Initialize;
break;
} else {
/* Other stuff: Track register usage */
- Data.UsedRegs |= (E->Use | E->Chg);
+ Data.ZPUsage |= (E->Use | E->Chg);
TrackLoads (&Data.Rhs, E, I);
}
/* If the registers from the push (A/X) are used before they're
- * changed, we cannot change the sequence, because this would
- * with a high probability change the register contents.
- */
+ ** changed, we cannot change the sequence, because this would
+ ** with a high probability change the register contents.
+ */
UsedRegs |= E->Use;
if ((UsedRegs & ~ChangedRegs) & REG_AX) {
I = Data.PushIndex;
case FoundOp:
/* Track zero page location usage beyond this point */
- Data.UsedRegs |= GetRegInfo (S, I, REG_SREG | REG_PTR1 | REG_PTR2);
+ Data.ZPUsage |= GetRegInfo (S, I, REG_SREG | REG_PTR1 | REG_PTR2);
/* Finalize the load info */
FinalizeLoadInfo (&Data.Lhs, S);
FinalizeLoadInfo (&Data.Rhs, S);
- /* If the Lhs loads do load from zeropage, we have to include
- * them into UsedRegs registers used. The Rhs loads have already
- * been tracked.
- */
+ /* Check if the lhs loads from zeropage. If this is true, these
+ ** zero page locations have to be added to ZPUsage, because
+ ** they cannot be used for intermediate storage. In addition,
+ ** if one of these zero page locations is destroyed between
+ ** pushing the lhs and the actual operation, we cannot use the
+ ** original zero page locations for the final op, but must
+ ** use another ZP location to save them.
+ */
+ ChangedRegs &= REG_ZP;
if (Data.Lhs.A.LoadEntry && Data.Lhs.A.LoadEntry->AM == AM65_ZP) {
- Data.UsedRegs |= Data.Lhs.A.LoadEntry->Use;
+ Data.ZPUsage |= Data.Lhs.A.LoadEntry->Use;
+ if ((Data.Lhs.A.LoadEntry->Use & ChangedRegs) != 0) {
+ Data.Lhs.A.Flags &= ~(LI_DIRECT | LI_RELOAD_Y);
+ }
}
if (Data.Lhs.X.LoadEntry && Data.Lhs.X.LoadEntry->AM == AM65_ZP) {
- Data.UsedRegs |= Data.Lhs.X.LoadEntry->Use;
+ Data.ZPUsage |= Data.Lhs.X.LoadEntry->Use;
+ if ((Data.Lhs.X.LoadEntry->Use & ChangedRegs) != 0) {
+ Data.Lhs.X.Flags &= ~(LI_DIRECT | LI_RELOAD_Y);
+ }
}
/* Check the preconditions. If they aren't ok, reset the insn
- * pointer to the pushax and start over. We will loose part of
- * load tracking but at least a/x has probably lost between
- * pushax and here and will be tracked again when restarting.
- */
+ ** pointer to the pushax and start over. We will loose part of
+ ** load tracking but at least a/x has probably lost between
+ ** pushax and here and will be tracked again when restarting.
+ */
if (!PreCondOk (&Data)) {
I = Data.PushIndex;
State = Initialize;
AdjustStackOffset (&Data, 2);
/* Regenerate register info, since AdjustStackOffset changed
- * the code
- */
+ ** the code
+ */
CS_GenRegInfo (S);
/* Call the optimizer function */
Changes += Data.OptFunc->Func (&Data);
/* Since the function may have added or deleted entries,
- * correct the index.
- */
+ ** correct the index.
+ */
I += CS_GetEntryCount (S) - OldEntryCount;
/* Regenerate register info */
/* Return the number of changes made */
return Changes;
}
-
-
-
projects / cc65 / blobdiff