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git-svn-id: svn://svn.cc65.org/cc65/trunk@731 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2001-05-18 20:32:18 +00:00
parent 4e645d3ab8
commit 68c0d38dfa
1 changed files with 82 additions and 59 deletions
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141
src/cc65/codeopt.c
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@ -127,94 +127,118 @@ static unsigned OptBoolTransforms (CodeSeg* S)
*/
{
unsigned Changes = 0;
unsigned I;
/* Get the number of entries, bail out if we have not enough */
unsigned Count = GetCodeEntryCount (S);
if (Count < 2) {
return 0;
}
/* Walk over the entries */
I = 0;
while (I < Count-1) {
unsigned I = 0;
while (I < GetCodeEntryCount (S)) {
CodeEntry* N;
cmp_t Cond;
/* Get next entry */
CodeEntry* E = GetCodeEntry (S, I);
/* Check for a boolean transformer */
if (E->OPC == OPC_JSR && strncmp (E->Arg, "bool", 4) == 0) {
if (E->OPC == OPC_JSR &&
strncmp (E->Arg, "bool", 4) == 0 &&
(N = GetNextCodeEntry (S, I)) != 0 &&
(N->Info & OF_ZBRA) != 0 &&
(Cond = FindCmpCond (E->Arg+4)) != CMP_INV) {
cmp_t Cond;
/* Get the next entry */
CodeEntry* N = GetCodeEntry (S, I+1);
/* Check if this is a conditional branch */
if ((N->Info & OF_CBRA) == 0) {
/* No conditional branch, bail out */
goto NextEntry;
}
CodeEntry* X;
CodeLabel* L;
/* 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.
*/
Cond = FindCmpCond (E->Arg + 4);
if (Cond == CMP_INV) {
/* Unknown function */
goto NextEntry;
}
/* 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];
/* Jumps if condition false, invert condition */
Cond = CmpInvertTab [Cond];
}
/* Check if we can replace the code by something better */
switch (Cond) {
case CMP_EQ:
ReplaceOPC (N, OPC_JEQ);
break;
case CMP_EQ:
ReplaceOPC (N, OPC_JEQ);
break;
case CMP_NE:
ReplaceOPC (N, OPC_JNE);
break;
case CMP_NE:
ReplaceOPC (N, OPC_JNE);
break;
case CMP_GT:
/* Not now ### */
goto NextEntry;
/* Replace by
* beq @L
* jpl Target
* @L: ...
*/
if ((X = GetNextCodeEntry (S, I+1)) == 0) {
/* No such entry */
goto NextEntry;
}
L = GenCodeLabel (S, X);
X = NewCodeEntry (OPC_BEQ, AM_BRA, L->Name, L);
InsertCodeEntry (S, X, I+1);
ReplaceOPC (N, OPC_JPL);
break;
case CMP_GE:
ReplaceOPC (N, OPC_JPL);
break;
case CMP_GE:
ReplaceOPC (N, OPC_JPL);
break;
case CMP_LT:
case CMP_LT:
ReplaceOPC (N, OPC_JMI);
break;
case CMP_LE:
/* Replace by
* jmi Target
* jeq Target
*/
ReplaceOPC (N, OPC_JMI);
break;
L = N->JumpTo;
X = NewCodeEntry (OPC_JEQ, AM_BRA, L->Name, L);
InsertCodeEntry (S, X, I+2);
break;
case CMP_LE:
/* Not now ### */
goto NextEntry;
case CMP_UGT:
/* Not now ### */
goto NextEntry;
case CMP_UGE:
case CMP_UGT:
/* Replace by
* beq @L
* jcs Target
* @L: ...
*/
if ((X = GetNextCodeEntry (S, I+1)) == 0) {
/* No such entry */
goto NextEntry;
}
L = GenCodeLabel (S, X);
X = NewCodeEntry (OPC_BEQ, AM_BRA, L->Name, L);
InsertCodeEntry (S, X, I+1);
ReplaceOPC (N, OPC_JCS);
break;
break;
case CMP_ULT:
case CMP_UGE:
ReplaceOPC (N, OPC_JCS);
break;
case CMP_ULT:
ReplaceOPC (N, OPC_JCC);
break;
case CMP_ULE:
/* Replace by
* jcc Target
* jeq Target
*/
ReplaceOPC (N, OPC_JCC);
break;
case CMP_ULE:
/* Not now ### */
goto NextEntry;
L = N->JumpTo;
X = NewCodeEntry (OPC_JEQ, AM_BRA, L->Name, L);
InsertCodeEntry (S, X, I+2);
break;
default:
Internal ("Unknown jump condition: %d", Cond);
@ -223,7 +247,6 @@ static unsigned OptBoolTransforms (CodeSeg* S)
/* Remove the call to the bool transformer */
DelCodeEntry (S, I);
--Count;
/* Remember, we had changes */
++Changes;