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cc65/src/cc65/coptptrstore.c
Greg King 0390c34e88 Changed multi-line C comments into another style. 
The left side doesn't look unbalanced.
2014-06-30 16:51:07 -04:00

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/*****************************************************************************/
/* */
/* coptptrstore.c */
/* */
/* Optimize stores through pointers */
/* */
/* */
/* */
/* (C) 2012, Ullrich von Bassewitz */
/* Roemerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
/* warranty. In no event will the authors be held liable for any damages */
/* arising from the use of this software. */
/* */
/* Permission is granted to anyone to use this software for any purpose, */
/* including commercial applications, and to alter it and redistribute it */
/* freely, subject to the following restrictions: */
/* */
/* 1. The origin of this software must not be misrepresented; you must not */
/* claim that you wrote the original software. If you use this software */
/* in a product, an acknowledgment in the product documentation would be */
/* appreciated but is not required. */
/* 2. Altered source versions must be plainly marked as such, and must not */
/* be misrepresented as being the original software. */
/* 3. This notice may not be removed or altered from any source */
/* distribution. */
/* */
/*****************************************************************************/
#include <string.h>
/* common */
#include "chartype.h"
#include "strbuf.h"
#include "xmalloc.h"
#include "xsprintf.h"
/* cc65 */
#include "codeent.h"
#include "codeinfo.h"
#include "coptptrstore.h"
/*****************************************************************************/
/* Helper functions */
/*****************************************************************************/
static unsigned OptPtrStore1Sub (CodeSeg* S, unsigned I, CodeEntry** const L)
/* Check if this is one of the allowed suboperation for OptPtrStore1 */
{
/* Check for a label attached to the entry */
if (CE_HasLabel (L[0])) {
return 0;
}
/* Check for single insn sub ops */
if (L[0]->OPC == OP65_AND ||
L[0]->OPC == OP65_EOR ||
L[0]->OPC == OP65_ORA ||
(L[0]->OPC == OP65_JSR &&
(strncmp (L[0]->Arg, "shlax", 5) == 0 ||
strncmp (L[0]->Arg, "shrax", 5) == 0) &&
strlen (L[0]->Arg) == 6 &&
IsDigit (L[0]->Arg[5]))) {
/* One insn */
return 1;
} else if (L[0]->OPC == OP65_CLC &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
L[1]->OPC == OP65_ADC &&
!CE_HasLabel (L[1])) {
return 2;
} else if (L[0]->OPC == OP65_SEC &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
L[1]->OPC == OP65_SBC &&
!CE_HasLabel (L[1])) {
return 2;
}
/* Not found */
return 0;
}
static const char* LoadAXZP (CodeSeg* S, unsigned I)
/* If the two instructions preceeding S/I are a load of A/X from a two byte
** zero byte location, return the name of the zero page location. Otherwise
** return NULL.
*/
{
CodeEntry* L[2];
unsigned Len;
if (I >= 2 &&
CS_GetEntries (S, L, I-2, 2) &&
L[0]->OPC == OP65_LDA &&
L[0]->AM == AM65_ZP &&
L[1]->OPC == OP65_LDX &&
L[1]->AM == AM65_ZP &&
!CE_HasLabel (L[1]) &&
(Len = strlen (L[0]->Arg)) == strlen (L[1]->Arg) - 2 &&
memcmp (L[0]->Arg, L[1]->Arg, Len) == 0 &&
L[1]->Arg[Len] == '+' &&
L[1]->Arg[Len+1] == '1') {
/* Return the label */
return L[0]->Arg;
} else {
/* Not found */
return 0;
}
}
static const char* LoadAXImm (CodeSeg* S, unsigned I)
/* If the instructions preceeding S/I are a load of A/X of a constant value
** or a word sized address label, return the address of the location as a
** string.
** Beware: In case of a numeric value, the result is returned in static
** storage which is overwritten with each call.
*/
{
static StrBuf Buf = STATIC_STRBUF_INITIALIZER;
CodeEntry* L[2];
CodeEntry* ALoad;
CodeEntry* XLoad;
unsigned Len;
/* Fetch entry at I and check if A/X is known */
L[0] = CS_GetEntry (S, I);
if (L[0] != 0 &&
RegValIsKnown (L[0]->RI->In.RegA) &&
RegValIsKnown (L[0]->RI->In.RegX)) {
/* Numeric argument - get low and high byte */
unsigned Lo = (L[0]->RI->In.RegA & 0xFF);
unsigned Hi = (L[0]->RI->In.RegX & 0xFF);
/* Format into buffer */
SB_Printf (&Buf, "$%04X", Lo | (Hi << 8));
/* Return the address as a string */
return SB_GetConstBuf (&Buf);
}
/* Search back for the two instructions loading A and X. Abort
** the search if the registers are changed in any other way or
** if a label is reached while we don't have both loads.
*/
ALoad = 0;
XLoad = 0;
while (I-- > 0) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the loads of A and X */
if (ALoad == 0 && E->OPC == OP65_LDA && E->AM == AM65_IMM) {
ALoad = E;
} else if (E->Chg & REG_A) {
/* A is changed before we get the load */
return 0;
} else if (XLoad == 0 && E->OPC == OP65_LDX && E->AM == AM65_IMM) {
XLoad = E;
} else if (E->Chg & REG_X) {
/* X is changed before we get the load */
return 0;
}
if (ALoad != 0 && XLoad != 0) {
/* We have both */
break;
}
/* If we have a label, before both are found, bail out */
if (CE_HasLabel (E)) {
return 0;
}
}
/* Check for a load of a label address */
if ((Len = strlen (ALoad->Arg)) > 3 &&
ALoad->Arg[0] == '<' &&
ALoad->Arg[1] == '(' &&
strlen (XLoad->Arg) == Len &&
XLoad->Arg[0] == '>' &&
memcmp (ALoad->Arg+1, XLoad->Arg+1, Len-1) == 0) {
/* Load of an address label */
SB_CopyBuf (&Buf, ALoad->Arg + 2, Len - 3);
SB_Terminate (&Buf);
return SB_GetConstBuf (&Buf);
}
/* Not found */
return 0;
}
/*****************************************************************************/
/* Code */
/*****************************************************************************/
unsigned OptPtrStore1 (CodeSeg* S)
/* Search for the sequence:
**
** clc
** adc xxx
** bcc L
** inx
** L: jsr pushax
** ldx #$00
** lda yyy
** ldy #$00
** jsr staspidx
**
** and replace it by:
**
** sta ptr1
** stx ptr1+1
** ldy xxx
** ldx #$00
** lda yyy
** sta (ptr1),y
**
** or by
**
** ldy xxx
** ldx #$00
** lda yyy
** sta (zp),y
**
** or by
**
** ldy xxx
** ldx #$00
** lda yyy
** sta label,y
**
** or by
**
** ldy xxx
** ldx #$00
** lda yyy
** sta $xxxx,y
**
** depending on the code preceeding the sequence above.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[9];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_CLC &&
CS_GetEntries (S, L+1, I+1, 8) &&
L[1]->OPC == OP65_ADC &&
(L[1]->AM == AM65_ABS ||
L[1]->AM == AM65_ZP ||
L[1]->AM == AM65_IMM ||
(L[1]->AM == AM65_ZP_INDY &&
RegValIsKnown (L[1]->RI->In.RegY))) &&
(L[2]->OPC == OP65_BCC || L[2]->OPC == OP65_JCC) &&
L[2]->JumpTo != 0 &&
L[2]->JumpTo->Owner == L[4] &&
L[3]->OPC == OP65_INX &&
CE_IsCallTo (L[4], "pushax") &&
L[5]->OPC == OP65_LDX &&
L[6]->OPC == OP65_LDA &&
L[7]->OPC == OP65_LDY &&
CE_IsKnownImm (L[7], 0) &&
CE_IsCallTo (L[8], "staspidx") &&
!CS_RangeHasLabel (S, I+1, 3) &&
!CS_RangeHasLabel (S, I+5, 4)) {
CodeEntry* X;
const char* Loc;
am_t AM;
/* Track the insertion point */
unsigned IP = I + 9;
if ((Loc = LoadAXZP (S, I)) != 0) {
/* If the sequence is preceeded by a load of a ZP value,
** we can use this ZP value as a pointer using ZP
** indirect Y addressing.
*/
AM = AM65_ZP_INDY;
} else if ((Loc = LoadAXImm (S, I)) != 0) {
/* If the sequence is preceeded by a load of an immediate
** value, we can use this absolute value as an address
** using absolute indexed Y addressing.
*/
AM = AM65_ABSY;
}
/* If we don't have a store location, we use ptr1 with zp
** indirect Y addressing. We must store the value in A/X into
** ptr1 in this case.
*/
if (Loc == 0) {
/* Must use ptr1 */
Loc = "ptr1";
AM = AM65_ZP_INDY;
X = NewCodeEntry (OP65_STA, AM65_ZP, "ptr1", 0, L[8]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STX, AM65_ZP, "ptr1+1", 0, L[8]->LI);
CS_InsertEntry (S, X, IP++);
}
/* If the index is loaded from (zp),y, we cannot do that directly.
** Note: In this case, the Y register will contain the correct
** value after removing the old code, so we don't need to load
** it here.
*/
if (L[1]->AM == AM65_ZP_INDY) {
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_TAY, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
} else {
X = NewCodeEntry (OP65_LDY, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
}
X = NewCodeEntry (OP65_LDX, L[5]->AM, L[5]->Arg, 0, L[5]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDA, L[6]->AM, L[6]->Arg, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STA, AM, Loc, 0, L[8]->LI);
CS_InsertEntry (S, X, IP++);
/* Remove the old code */
CS_DelEntries (S, I, 9);
/* Skip most of the generated replacement code */
I += 3;
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptPtrStore2 (CodeSeg* S)
/* Search for the sequence:
**
** clc
** adc xxx
** bcc L
** inx
** L: jsr pushax
** ldy yyy
** ldx #$00
** lda (sp),y
** ldy #$00
** jsr staspidx
**
** and replace it by:
**
** sta ptr1
** stx ptr1+1
** ldy yyy-2
** ldx #$00
** lda (sp),y
** ldy xxx
** sta (ptr1),y
**
** or by
**
** ldy yyy-2
** ldx #$00
** lda (sp),y
** ldy xxx
** sta (zp),y
**
** or by
**
** ldy yyy-2
** ldx #$00
** lda (sp),y
** ldy xxx
** sta label,y
**
** or by
**
** ldy yyy-2
** ldx #$00
** lda (sp),y
** ldy xxx
** sta $xxxx,y
**
** depending on the code preceeding the sequence above.
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[10];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_CLC &&
CS_GetEntries (S, L+1, I+1, 9) &&
L[1]->OPC == OP65_ADC &&
(L[1]->AM == AM65_ABS ||
L[1]->AM == AM65_ZP ||
L[1]->AM == AM65_IMM ||
(L[1]->AM == AM65_ZP_INDY &&
RegValIsKnown (L[1]->RI->In.RegY))) &&
(L[2]->OPC == OP65_BCC || L[2]->OPC == OP65_JCC) &&
L[2]->JumpTo != 0 &&
L[2]->JumpTo->Owner == L[4] &&
L[3]->OPC == OP65_INX &&
CE_IsCallTo (L[4], "pushax") &&
L[5]->OPC == OP65_LDY &&
CE_IsConstImm (L[5]) &&
L[6]->OPC == OP65_LDX &&
L[7]->OPC == OP65_LDA &&
L[7]->AM == AM65_ZP_INDY &&
strcmp (L[7]->Arg, "sp") == 0 &&
L[8]->OPC == OP65_LDY &&
(L[8]->AM == AM65_ABS ||
L[8]->AM == AM65_ZP ||
L[8]->AM == AM65_IMM) &&
CE_IsCallTo (L[9], "staspidx") &&
!CS_RangeHasLabel (S, I+1, 3) &&
!CS_RangeHasLabel (S, I+5, 5)) {
CodeEntry* X;
const char* Arg;
const char* Loc;
am_t AM;
/* Track the insertion point */
unsigned IP = I + 10;
if ((Loc = LoadAXZP (S, I)) != 0) {
/* If the sequence is preceeded by a load of a ZP value,
** we can use this ZP value as a pointer using ZP
** indirect Y addressing.
*/
AM = AM65_ZP_INDY;
} else if ((Loc = LoadAXImm (S, I)) != 0) {
/* If the sequence is preceeded by a load of an immediate
** value, we can use this absolute value as an address
** using absolute indexed Y addressing.
*/
AM = AM65_ABSY;
}
/* If we don't have a store location, we use ptr1 with zp
** indirect Y addressing. We must store the value in A/X into
** ptr1 in this case.
*/
if (Loc == 0) {
/* Must use ptr1 */
Loc = "ptr1";
AM = AM65_ZP_INDY;
X = NewCodeEntry (OP65_STA, AM65_ZP, "ptr1", 0, L[8]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STX, AM65_ZP, "ptr1+1", 0, L[8]->LI);
CS_InsertEntry (S, X, IP++);
}
/* Generate four different replacements depending on the addressing
** mode of the store and from where the index is loaded:
**
** 1. If the index is not loaded ZP indirect Y, we can use Y for
** the store index.
**
** 2. If the index is loaded ZP indirect Y and we store absolute
** indexed, we need Y to load the index and will therefore
** use X as index for the store. The disadvantage is that we
** need to reload X later.
**
** 3. If the index is loaded ZP indirect Y and we store ZP indirect
** Y, we must use Y for load and store and must therefore save
** the A register when loading Y the second time.
*/
if (L[1]->AM != AM65_ZP_INDY) {
/* Case 1 */
Arg = MakeHexArg (L[5]->Num - 2);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[5]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDX, L[6]->AM, L[6]->Arg, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDA, L[7]->AM, L[7]->Arg, 0, L[7]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDY, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STA, AM, Loc, 0, L[9]->LI);
CS_InsertEntry (S, X, IP++);
} else if (AM == AM65_ABSY) {
/* Case 2 */
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
Arg = MakeHexArg (L[5]->Num - 2);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[5]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDA, L[7]->AM, L[7]->Arg, 0, L[7]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STA, AM65_ABSX, Loc, 0, L[9]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDX, L[6]->AM, L[6]->Arg, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
} else {
/* Case 3 */
Arg = MakeHexArg (L[5]->Num - 2);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[5]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDX, L[6]->AM, L[6]->Arg, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDA, L[7]->AM, L[7]->Arg, 0, L[7]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_PHA, AM65_IMP, 0, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
Arg = MakeHexArg (L[1]->RI->In.RegY);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_TAY, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_PLA, AM65_IMP, 0, 0, L[6]->LI);
CS_InsertEntry (S, X, IP++);
X = NewCodeEntry (OP65_STA, AM, Loc, 0, L[9]->LI);
CS_InsertEntry (S, X, IP++);
}
/* Remove the old code */
CS_DelEntries (S, I, 10);
/* Skip most of the generated replacement code */
I += 4;
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptPtrStore3 (CodeSeg* S)
/* Search for the sequence:
**
** jsr pushax
** ldy xxx
** jsr ldauidx
** subop
** ldy yyy
** jsr staspidx
**
** and replace it by:
**
** sta ptr1
** stx ptr1+1
** ldy xxx
** ldx #$00
** lda (ptr1),y
** subop
** ldy yyy
** sta (ptr1),y
**
** In case a/x is loaded from the register bank before the pushax, we can even
** use the register bank instead of ptr1.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned K;
CodeEntry* L[10];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (CE_IsCallTo (L[0], "pushax") &&
CS_GetEntries (S, L+1, I+1, 3) &&
L[1]->OPC == OP65_LDY &&
CE_IsConstImm (L[1]) &&
!CE_HasLabel (L[1]) &&
CE_IsCallTo (L[2], "ldauidx") &&
!CE_HasLabel (L[2]) &&
(K = OptPtrStore1Sub (S, I+3, L+3)) > 0 &&
CS_GetEntries (S, L+3+K, I+3+K, 2) &&
L[3+K]->OPC == OP65_LDY &&
CE_IsConstImm (L[3+K]) &&
!CE_HasLabel (L[3+K]) &&
CE_IsCallTo (L[4+K], "staspidx") &&
!CE_HasLabel (L[4+K])) {
const char* RegBank = 0;
const char* ZPLoc = "ptr1";
CodeEntry* X;
/* Get the preceeding two instructions and check them. We check
** for:
** lda regbank+n
** ldx regbank+n+1
*/
if (I > 1) {
CodeEntry* P[2];
P[0] = CS_GetEntry (S, I-2);
P[1] = CS_GetEntry (S, I-1);
if (P[0]->OPC == OP65_LDA &&
P[0]->AM == AM65_ZP &&
P[1]->OPC == OP65_LDX &&
P[1]->AM == AM65_ZP &&
!CE_HasLabel (P[1]) &&
strncmp (P[0]->Arg, "regbank+", 8) == 0) {
unsigned Len = strlen (P[0]->Arg);
if (strncmp (P[0]->Arg, P[1]->Arg, Len) == 0 &&
P[1]->Arg[Len+0] == '+' &&
P[1]->Arg[Len+1] == '1' &&
P[1]->Arg[Len+2] == '\0') {
/* Ok, found. Use the name of the register bank */
RegBank = ZPLoc = P[0]->Arg;
}
}
}
/* Insert the load via the zp pointer */
X = NewCodeEntry (OP65_LDX, AM65_IMM, "$00", 0, L[3]->LI);
CS_InsertEntry (S, X, I+3);
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, ZPLoc, 0, L[2]->LI);
CS_InsertEntry (S, X, I+4);
/* Insert the store through the zp pointer */
X = NewCodeEntry (OP65_STA, AM65_ZP_INDY, ZPLoc, 0, L[3]->LI);
CS_InsertEntry (S, X, I+6+K);
/* Delete the old code */
CS_DelEntry (S, I+7+K); /* jsr spaspidx */
CS_DelEntry (S, I+2); /* jsr ldauidx */
/* Create and insert the stores into the zp pointer if needed */
if (RegBank == 0) {
X = NewCodeEntry (OP65_STA, AM65_ZP, "ptr1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+1);
X = NewCodeEntry (OP65_STX, AM65_ZP, "ptr1+1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
}
/* Delete more old code. Do it here to keep a label attached to
** entry I in place.
*/
CS_DelEntry (S, I); /* jsr pushax */
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
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