cc65/src/cc65/coptbool.c

943 lines
26 KiB
C

/*****************************************************************************/
/* */
/* coptbool.c */
/* */
/* Optimize boolean sequences */
/* */
/* */
/* */
/* (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. */
/* */
/*****************************************************************************/
/* cc65 */
#include "codeent.h"
#include "codeinfo.h"
#include "error.h"
#include "coptbool.h"
/*****************************************************************************/
/* Data */
/*****************************************************************************/
/* Table used to invert a condition, indexed by condition */
static const unsigned char CmpInvertTab[] = {
CMP_NE, CMP_EQ,
CMP_LE, CMP_LT, CMP_GE, CMP_GT,
CMP_ULE, CMP_ULT, CMP_UGE, CMP_UGT
};
/*****************************************************************************/
/* Helper functions */
/*****************************************************************************/
static void ReplaceBranchCond (CodeSeg* S, unsigned I, cmp_t Cond)
/* Helper function for the replacement of routines that return a boolean
** followed by a conditional jump. Instead of the boolean value, the condition
** codes are evaluated directly.
** I is the index of the conditional branch, the sequence is already checked
** to be correct.
*/
{
CodeEntry* N;
CodeLabel* L;
/* Get the entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Replace the conditional branch */
switch (Cond) {
case CMP_EQ:
CE_ReplaceOPC (E, OP65_JEQ);
break;
case CMP_NE:
CE_ReplaceOPC (E, OP65_JNE);
break;
case CMP_GT:
/* Replace by
** beq @L
** jpl Target
** @L: ...
*/
if ((N = CS_GetNextEntry (S, I)) == 0) {
/* No such entry */
Internal ("Invalid program flow");
}
L = CS_GenLabel (S, N);
N = NewCodeEntry (OP65_BEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I);
CE_ReplaceOPC (E, OP65_JPL);
break;
case CMP_GE:
CE_ReplaceOPC (E, OP65_JPL);
break;
case CMP_LT:
CE_ReplaceOPC (E, OP65_JMI);
break;
case CMP_LE:
/* Replace by
** jmi Target
** jeq Target
*/
CE_ReplaceOPC (E, OP65_JMI);
L = E->JumpTo;
N = NewCodeEntry (OP65_JEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I+1);
break;
case CMP_UGT:
/* Replace by
** beq @L
** jcs Target
** @L: ...
*/
if ((N = CS_GetNextEntry (S, I)) == 0) {
/* No such entry */
Internal ("Invalid program flow");
}
L = CS_GenLabel (S, N);
N = NewCodeEntry (OP65_BEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I);
CE_ReplaceOPC (E, OP65_JCS);
break;
case CMP_UGE:
CE_ReplaceOPC (E, OP65_JCS);
break;
case CMP_ULT:
CE_ReplaceOPC (E, OP65_JCC);
break;
case CMP_ULE:
/* Replace by
** jcc Target
** jeq Target
*/
CE_ReplaceOPC (E, OP65_JCC);
L = E->JumpTo;
N = NewCodeEntry (OP65_JEQ, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, N, I+1);
break;
default:
Internal ("Unknown jump condition: %d", Cond);
}
}
/*****************************************************************************/
/* Optimize bool comparison and transformer subroutines with branches */
/*****************************************************************************/
unsigned OptBoolCmp (CodeSeg* S)
/* Search for calls to compare subroutines followed by a conditional branch
** and replace them by cheaper versions, since the branch means that the
** boolean value returned by these routines is not needed (we may also check
** that explicitly, but for the current code generator it is always true).
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
cmp_t Cond;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
(Cond = FindTosCmpCond (E->Arg)) != CMP_INV &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(N->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (N)) {
/* The tos... functions will return a boolean value in a/x and
** the Z flag says if this value is zero or not. We will call
** a cheaper subroutine instead, one that does not return a
** boolean value but only valid flags. Note: jeq jumps if
** the condition is not met, jne jumps if the condition is met.
** Invert the code if we jump on condition not met.
*/
if (GetBranchCond (N->OPC) == BC_EQ) {
/* Jumps if condition false, invert condition */
Cond = CmpInvertTab [Cond];
}
/* Replace the subroutine call. */
E = NewCodeEntry (OP65_JSR, AM65_ABS, "tosicmp", 0, E->LI);
CS_InsertEntry (S, E, I+1);
CS_DelEntry (S, I);
/* Replace the conditional branch */
ReplaceBranchCond (S, I+1, Cond);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBoolTrans (CodeSeg* S)
/* Try to remove the call to boolean transformer routines where the call is
** not really needed and change following branch condition accordingly.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
cmp_t Cond;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a boolean transformer */
if (E->OPC == OP65_JSR &&
(Cond = FindBoolCmpCond (E->Arg)) != CMP_INV &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(N->Info & OF_ZBRA) != 0 &&
(GetRegInfo (S, I + 2, PSTATE_Z) & PSTATE_Z) == 0) {
/* Make the boolean transformer unnecessary by changing the
** the conditional jump to evaluate the condition flags that
** are set after the compare directly. Note: jeq jumps if
** the condition is not met, jne jumps if the condition is met.
** Invert the code if we jump on condition not met.
*/
if (GetBranchCond (N->OPC) == BC_EQ) {
/* Jumps if condition false, invert condition */
Cond = CmpInvertTab [Cond];
}
/* Check if we can replace the code by something better */
ReplaceBranchCond (S, I+1, Cond);
/* Remove the call to the bool transformer */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBoolUnary (CodeSeg* S)
/* Try to remove the call to a bcastax/bnegax routines where the call is
** not really needed and change following branch condition accordingly.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* N;
cmp_t Cond;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a boolean transformer */
if (E->OPC == OP65_JSR &&
(Cond = FindBoolCmpCond (E->Arg)) != CMP_INV &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(N->Info & OF_ZBRA) != 0) {
/* Make the boolean transformer unnecessary by changing the
** the conditional jump to evaluate the condition flags that
** are set after the compare directly. Note: jeq jumps if
** the condition is not met, jne jumps if the condition is met.
** Invert the code if we jump on condition not met.
*/
if (GetBranchCond (N->OPC) == BC_EQ) {
/* Jumps if condition false, invert condition */
Cond = CmpInvertTab [Cond];
}
/* Check if we can replace the code by something better */
ReplaceBranchCond (S, I+1, Cond);
/* Remove the call to the bool transformer */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* Remove calls to the boolean cast/negation subroutines */
/*****************************************************************************/
unsigned OptBoolUnary1 (CodeSeg* S)
/* Search for and remove cmp #0/bcastax/boolne following a bcastax/bnegax.
** Or search for and remove cmp #1/bnegax/booleq following a bcastax/bnegax
** and invert the bcastax/bnegax.
*/
{
unsigned Changes = 0;
int Neg = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence.
** We allow the first entry to have labels.
*/
if (L[0]->OPC == OP65_JSR &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
!CE_HasLabel (L[1])) {
if (strcmp (L[0]->Arg, "bnegax") == 0) {
Neg = 1;
} else if (strcmp (L[0]->Arg, "bcastax") == 0) {
Neg = 0;
} else {
/* Next entry */
++I;
continue;
}
if ((L[1]->OPC == OP65_CMP && CE_IsKnownImm (L[1], 0x0)) ||
CE_IsCallTo (L[1], "boolne") ||
CE_IsCallTo (L[1], "bcastax")) {
/* Delete the entry no longer needed. */
CS_DelEntry (S, I + 1);
/* Remember, we had changes */
++Changes;
/* We are still at this index */
continue;
} else if ((L[1]->OPC == OP65_CMP && CE_IsKnownImm (L[1], 0x1)) ||
CE_IsCallTo (L[1], "booleq") ||
CE_IsCallTo (L[1], "bnegax")) {
/* Invert the previous bool conversion */
CE_SetArg (L[0], Neg ? "bcastax" : "bnegax");
/* Delete the entry no longer needed */
CS_DelEntry (S, I + 1);
/* Remember, we had changes */
++Changes;
/* We are still at this index */
continue;
}
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBoolUnary2 (CodeSeg* S)
/* Search for and remove cmp #0/bcastax/boolne following a boolean transformer.
** Or search for and remove cmp #1/bnegax/booleq following a boolean transformer
** and invert the boolean transformer.
*/
{
unsigned Changes = 0;
cmp_t Cond;
char Buf[16];
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence.
** We allow the first entry to have labels.
*/
if (L[0]->OPC == OP65_JSR &&
(L[1] = CS_GetNextEntry (S, I)) != 0 &&
!CE_HasLabel (L[1]) &&
(Cond = FindBoolCmpCond (L[0]->Arg)) != CMP_INV) {
if ((L[1]->OPC == OP65_CMP && CE_IsKnownImm (L[1], 0x0)) ||
CE_IsCallTo (L[1], "boolne") ||
CE_IsCallTo (L[1], "bcastax")) {
/* Delete the entry no longer needed */
CS_DelEntry (S, I + 1);
/* Remember, we had changes */
++Changes;
/* We are still at this index */
continue;
} else if ((L[1]->OPC == OP65_CMP && CE_IsKnownImm (L[1], 0x1)) ||
CE_IsCallTo (L[1], "booleq") ||
CE_IsCallTo (L[1], "bnegax")) {
/* Invert the bool conversion */
if (GetBoolCmpSuffix (Buf, GetNegatedCond (Cond)) == 0) {
Internal ("No inverted boolean transformer for: %s", L[0]->Arg);
}
CE_SetArg (L[0], Buf);
/* Delete the entry no longer needed */
CS_DelEntry (S, I + 1);
/* Remember, we had changes */
++Changes;
/* We are still at this index */
continue;
}
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBoolUnary3 (CodeSeg* S)
/* If A == 0, replace bcastax/bnegax with
**
** cpx #0
** jsr boolne/booleq
**
** Or if X == 0, replace bcastax/bnegax with
**
** cmp #0
** jsr boolne/booleq
**
*/
{
unsigned Changes = 0;
opc_t Op = OP65_COUNT;
const char* Sub = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* E;
CodeEntry* X;
/* Get next entry */
E = CS_GetEntry (S, I);
/* Check for the sequence */
if (!CE_HasLabel (E)) {
/* Choose the right subroutine */
if (CE_IsCallTo (E, "bnegax")) {
Sub = "booleq";
} else if (CE_IsCallTo (E, "bcastax")) {
Sub = "boolne";
}
/* Choose the right opcode */
if (RegValIsKnown (E->RI->In.RegA) && E->RI->In.RegA == 0) {
Op = OP65_CPX;
} else if (RegValIsKnown (E->RI->In.RegX) && E->RI->In.RegX == 0) {
Op = OP65_CMP;
}
/* Replace the sequence if all requirements are met*/
if (Op != OP65_COUNT && Sub != 0) {
/* Replace bcastax/bnegax with boolne/booleq */
CE_SetArg (E, Sub);
/* Insert the compare */
X = NewCodeEntry (Op, AM65_IMM, "$00", 0, E->LI);
CS_InsertEntry (S, X, I);
/* Remember, we had changes */
++Changes;
/* Correct the index */
++I;
}
/* Reset the choices */
Op = OP65_COUNT;
Sub = 0;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* bnega optimizations */
/*****************************************************************************/
unsigned OptBNegA1 (CodeSeg* S)
/* Check for
**
** ldx #$00
** lda ..
** jsr bnega
**
** Remove the ldx if the lda does not use it.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for a ldx */
if (E->OPC == OP65_LDX &&
E->AM == AM65_IMM &&
CE_HasNumArg (E) &&
E->Num == 0 &&
CS_GetEntries (S, L, I+1, 2) &&
L[0]->OPC == OP65_LDA &&
(L[0]->Use & REG_X) == 0 &&
!CE_HasLabel (L[0]) &&
CE_IsCallTo (L[1], "bnega") &&
!CE_HasLabel (L[1])) {
/* Remove the ldx instruction */
CS_DelEntry (S, I);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegA2 (CodeSeg* S)
/* Check for
**
** lda ..
** jsr bnega
** jeq/jne ..
**
** Adjust the conditional branch and remove the call to the subroutine.
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if ((E->OPC == OP65_ADC ||
E->OPC == OP65_AND ||
E->OPC == OP65_DEA ||
E->OPC == OP65_EOR ||
E->OPC == OP65_INA ||
E->OPC == OP65_LDA ||
E->OPC == OP65_ORA ||
E->OPC == OP65_PLA ||
E->OPC == OP65_SBC ||
E->OPC == OP65_TXA ||
E->OPC == OP65_TYA) &&
CS_GetEntries (S, L, I+1, 2) &&
CE_IsCallTo (L[0], "bnega") &&
!CE_HasLabel (L[0]) &&
(L[1]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[1]) &&
(GetRegInfo (S, I + 3, PSTATE_Z) & PSTATE_Z) == 0) {
/* Invert the branch */
CE_ReplaceOPC (L[1], GetInverseBranch (L[1]->OPC));
/* Delete the subroutine call */
CS_DelEntry (S, I+1);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* bnegax optimizations */
/*****************************************************************************/
unsigned OptBNegAX1 (CodeSeg* S)
/* On a call to bnegax, if X is zero, the result depends only on the value in
** A, so change the call to a call to bnega. This will get further optimized
** later if possible.
*/
{
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 if this is a call to bnegax, and if X is known and zero */
if (E->RI->In.RegX == 0 && CE_IsCallTo (E, "bnegax")) {
CodeEntry* X = NewCodeEntry (OP65_JSR, AM65_ABS, "bnega", 0, E->LI);
CS_InsertEntry (S, X, I+1);
CS_DelEntry (S, I);
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX2 (CodeSeg* S)
/* Search for the sequence:
**
** ldy #xx
** jsr ldaxysp
** jsr bnegax
** jne/jeq ...
**
** and replace it by
**
** ldy #xx
** lda (sp),y
** dey
** ora (sp),y
** jeq/jne ...
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[4];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_LDY &&
CE_IsConstImm (L[0]) &&
!CS_RangeHasLabel (S, I+1, 3) &&
CS_GetEntries (S, L+1, I+1, 3) &&
CE_IsCallTo (L[1], "ldaxysp") &&
CE_IsCallTo (L[2], "bnegax") &&
(L[3]->Info & OF_ZBRA) != 0 &&
(GetRegInfo (S, I + 4, PSTATE_Z) & PSTATE_Z) == 0) {
CodeEntry* X;
/* lda (sp),y */
X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+1);
/* dey */
X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, L[1]->LI);
CS_InsertEntry (S, X, I+2);
/* ora (sp),y */
X = NewCodeEntry (OP65_ORA, AM65_ZP_INDY, "sp", 0, L[1]->LI);
CS_InsertEntry (S, X, I+3);
/* Invert the branch */
CE_ReplaceOPC (L[3], GetInverseBranch (L[3]->OPC));
/* Delete the entries no longer needed. */
CS_DelEntries (S, I+4, 2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX3 (CodeSeg* S)
/* Search for the sequence:
**
** lda xx
** ldx yy
** jsr bnegax
** jne/jeq ...
**
** and replace it by
**
** lda xx
** ora xx+1
** jeq/jne ...
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_LDA &&
CS_GetEntries (S, L, I+1, 3) &&
L[0]->OPC == OP65_LDX &&
!CE_HasLabel (L[0]) &&
CE_IsCallTo (L[1], "bnegax") &&
!CE_HasLabel (L[1]) &&
(L[2]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[2]) &&
(GetRegInfo (S, I + 4, PSTATE_Z) & PSTATE_Z) == 0) {
/* ldx --> ora */
CE_ReplaceOPC (L[0], OP65_ORA);
/* Invert the branch */
CE_ReplaceOPC (L[2], GetInverseBranch (L[2]->OPC));
/* Delete the subroutine call */
CS_DelEntry (S, I+2);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}
unsigned OptBNegAX4 (CodeSeg* S)
/* Search for the sequence:
**
** jsr xxx
** jsr bnega(x)
** jeq/jne ...
**
** and replace it by:
**
** jsr xxx
** <boolean test>
** jne/jeq ...
*/
{
unsigned Changes = 0;
/* Walk over the entries */
unsigned I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[2];
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
CS_GetEntries (S, L, I+1, 2) &&
L[0]->OPC == OP65_JSR &&
strncmp (L[0]->Arg,"bnega",5) == 0 &&
!CE_HasLabel (L[0]) &&
(L[1]->Info & OF_ZBRA) != 0 &&
!CE_HasLabel (L[1]) &&
(GetRegInfo (S, I + 3, PSTATE_Z) & PSTATE_Z) == 0) {
CodeEntry* X;
/* Check if we're calling bnega or bnegax */
int ByteSized = (strcmp (L[0]->Arg, "bnega") == 0);
/* Insert apropriate test code */
if (ByteSized) {
/* Test bytes */
X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
} else {
/* Test words */
X = NewCodeEntry (OP65_STX, AM65_ZP, "tmp1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_ORA, AM65_ZP, "tmp1", 0, L[0]->LI);
CS_InsertEntry (S, X, I+3);
}
/* Delete the subroutine call */
CS_DelEntry (S, I+1);
/* Invert the branch */
CE_ReplaceOPC (L[1], GetInverseBranch (L[1]->OPC));
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}