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Move the optimization routines for shifts into a separate module.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@5766 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2012-07-07 15:21:12 +00:00
parent cd4f87b2cc
commit 4139c83abf
5 changed files with 695 additions and 521 deletions
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522
src/cc65/codeopt.c
View File

@ -57,6 +57,7 @@
#include "coptptrload.h" #include "coptptrload.h"
#include "coptptrstore.h" #include "coptptrstore.h"
#include "coptpush.h" #include "coptpush.h"
#include "coptshift.h"
#include "coptsize.h" #include "coptsize.h"
#include "coptstop.h" #include "coptstop.h"
#include "coptstore.h" #include "coptstore.h"
@ -68,527 +69,6 @@
/*****************************************************************************/
/* 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. If X is used later, but it is zero
* on entry and it's a shift by one, it may get replaced by:
*
* asl a
* bcc L1
* inx
* L1:
*
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeEntry* X;
CodeLabel* L;
/* 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])) {
if (!RegXUsed (S, I+1)) {
/* Insert shift insns */
unsigned Count = E->Arg[5] - '0';
while (Count--) {
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;
} else if (E->RI->In.RegX == 0 &&
E->Arg[5] == '1' &&
(N = CS_GetNextEntry (S, I)) != 0) {
/* asl a */
X = NewCodeEntry (OP65_ASL, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* bcc L1 */
L = CS_GenLabel (S, N);
X = NewCodeEntry (OP65_BCC, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, X, I+2);
/* inx */
X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* 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 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 Count;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
strncmp (E->Arg, "asrax", 5) == 0 &&
strlen (E->Arg) == 6 &&
IsDigit (E->Arg[5]) &&
(Count = (E->Arg[5] - '0')) >= 1 &&
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;
}
static unsigned OptShift3 (CodeSeg* S)
/* The sequence
*
* bcc L
* inx
* L: jsr shrax1
*
* may get replaced by
*
* ror a
*
* if X is zero on entry and unused later. 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)) {
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 &&
strlen (L[2]->Arg) == 6 &&
memcmp (L[2]->Arg, "shrax", 5) == 0 &&
IsDigit (L[2]->Arg[5]) &&
!RegXUsed (S, I+3)) {
unsigned ShiftCount = (L[2]->Arg[5] - '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 (--ShiftCount) {
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;
}
static 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)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(strncmp (E->Arg, "shrax", 5) == 0 ||
strncmp (E->Arg, "asrax", 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 shrax */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned GetShiftType (const char* Sub)
/* Helper function for OptShift5 */
{
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 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 = 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;
}
static unsigned OptShift6 (CodeSeg* S)
/* Inline the shift subroutines. */
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
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 &&
(strncmp (E->Arg, "shlax", 5) == 0 ||
strncmp (E->Arg, "aslax", 5) == 0) &&
strlen (E->Arg) == 6 &&
IsDigit (E->Arg[5])) {
/* Get number of shifts */
unsigned ShiftCount = (E->Arg[5] - '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 (ShiftCount > 1 || S->CodeSizeFactor > 200) {
unsigned Size = 4 + 3 * ShiftCount;
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 (ShiftCount--) {
/* 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;
}
/*****************************************************************************/ /*****************************************************************************/
/* Optimize loads */ /* Optimize loads */
/*****************************************************************************/ /*****************************************************************************/

566
src/cc65/coptshift.c Normal file
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@ -0,0 +1,566 @@
/*****************************************************************************/
/* */
/* coptshift.c */
/* */
/* Optimize shifts */
/* */
/* */
/* */
/* (C) 2001-2012, 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. */
/* */
/*****************************************************************************/
/* common */
#include "chartype.h"
/* cc65 */
#include "codeent.h"
#include "codeinfo.h"
#include "coptshift.h"
/*****************************************************************************/
/* Data */
/*****************************************************************************/
/* Shift types */
enum {
SHIFT_NONE,
SHIFT_ASR_1,
SHIFT_ASL_1,
SHIFT_LSR_1,
SHIFT_LSL_1
};
/*****************************************************************************/
/* Optimize shifts */
/*****************************************************************************/
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. If X is used later, but it is zero
* on entry and it's a shift by one, it may get replaced by:
*
* asl a
* bcc L1
* inx
* L1:
*
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
CodeEntry* X;
CodeLabel* L;
/* 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])) {
if (!RegXUsed (S, I+1)) {
/* Insert shift insns */
unsigned Count = E->Arg[5] - '0';
while (Count--) {
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;
} else if (E->RI->In.RegX == 0 &&
E->Arg[5] == '1' &&
(N = CS_GetNextEntry (S, I)) != 0) {
/* asl a */
X = NewCodeEntry (OP65_ASL, AM65_ACC, "a", 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* bcc L1 */
L = CS_GenLabel (S, N);
X = NewCodeEntry (OP65_BCC, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, X, I+2);
/* inx */
X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* 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;
}
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 Count;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
strncmp (E->Arg, "asrax", 5) == 0 &&
strlen (E->Arg) == 6 &&
IsDigit (E->Arg[5]) &&
(Count = (E->Arg[5] - '0')) >= 1 &&
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 OptShift3 (CodeSeg* S)
/* The sequence
*
* bcc L
* inx
* L: jsr shrax1
*
* may get replaced by
*
* ror a
*
* if X is zero on entry and unused later. 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)) {
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 &&
strlen (L[2]->Arg) == 6 &&
memcmp (L[2]->Arg, "shrax", 5) == 0 &&
IsDigit (L[2]->Arg[5]) &&
!RegXUsed (S, I+3)) {
unsigned ShiftCount = (L[2]->Arg[5] - '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 (--ShiftCount) {
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 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)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(strncmp (E->Arg, "shrax", 5) == 0 ||
strncmp (E->Arg, "asrax", 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 shrax */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
static unsigned GetShiftType (const char* Sub)
/* Helper function for OptShift5 */
{
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;
}
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 = 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;
}
unsigned OptShift6 (CodeSeg* S)
/* Inline the shift subroutines. */
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
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 &&
(strncmp (E->Arg, "shlax", 5) == 0 ||
strncmp (E->Arg, "aslax", 5) == 0) &&
strlen (E->Arg) == 6 &&
IsDigit (E->Arg[5])) {
/* Get number of shifts */
unsigned ShiftCount = (E->Arg[5] - '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 (ShiftCount > 1 || S->CodeSizeFactor > 200) {
unsigned Size = 4 + 3 * ShiftCount;
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 (ShiftCount--) {
/* 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;
}

126
src/cc65/coptshift.h Normal file
View File

@ -0,0 +1,126 @@
/*****************************************************************************/
/* */
/* coptshift.h */
/* */
/* Optimize shifts */
/* */
/* */
/* */
/* (C) 2001-2012, 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. */
/* */
/*****************************************************************************/
#ifndef COPTSHIFT_H
#define COPTSHIFT_H
/* cc65 */
#include "codeseg.h"
/*****************************************************************************/
/* Optimize shifts */
/*****************************************************************************/
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. If X is used later, but it is zero
* on entry and it's a shift by one, it may get replaced by:
*
* asl a
* bcc L1
* inx
* L1:
*
*/
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 OptShift3 (CodeSeg* S);
/* The sequence
*
* bcc L
* inx
* L: jsr shrax1
*
* may get replaced by
*
* ror a
*
* if X is zero on entry and unused later. For shift counts > 1, more
*
* shr a
*
* must be added.
*/
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 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 OptShift6 (CodeSeg* S);
/* Inline the shift subroutines. */
/* End of coptshift.h */
#endif

1
src/cc65/make/gcc.mak
View File

@ -62,6 +62,7 @@ OBJS = anonname.o \
coptptrload.o \ coptptrload.o \
coptptrstore.o \ coptptrstore.o \
coptpush.o \ coptpush.o \
coptshift.o \
coptsize.o \ coptsize.o \
coptstop.o \ coptstop.o \
coptstore.o \ coptstore.o \

1
src/cc65/make/watcom.mak
View File

@ -94,6 +94,7 @@ OBJS = anonname.obj \
coptptrload.obj \ coptptrload.obj \
coptptrstore.obj\ coptptrstore.obj\
coptpush.obj \ coptpush.obj \
coptshift.obj \
coptsize.obj \ coptsize.obj \
coptstop.obj \ coptstop.obj \
coptstore.obj \ coptstore.obj \