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Stack adjustment code optimizations.

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This commit is contained in:
laubzega
2018-10-13 00:05:33 -07:00
committed by Oliver Schmidt
parent 249248ccc8
commit d3665b263e
5 changed files with 116 additions and 5 deletions
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85
src/cc65/codeopt.c
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@@ -69,7 +69,7 @@
#include "error.h"
#include "global.h"
#include "output.h"
#include "symtab.h"
/*****************************************************************************/
@@ -613,7 +613,86 @@ static unsigned OptStackPtrOps (CodeSeg* S)
return Changes;
}
static unsigned OptGotoSPAdj (CodeSeg* S)
/* Remove unnecessary SP adjustment while gotoing
*/
{
unsigned Changes = 0;
unsigned I;
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[10], *X;
unsigned short adjustment;
const char* Arg;
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if (L[0]->OPC == OP65_PHA &&
CS_GetEntries (S, L+1, I+1, 9) &&
L[1]->OPC == OP65_LDA &&
L[1]->AM == AM65_ABS &&
L[2]->OPC == OP65_CLC &&
L[3]->OPC == OP65_ADC &&
strcmp (L[3]->Arg, "sp") == 0 &&
L[6]->OPC == OP65_ADC &&
strcmp (L[6]->Arg, "sp+1") == 0 &&
L[9]->OPC == OP65_JMP
) {
printf("Goto SP adjustment found. Jump to: %s, data Label: %s\n", L[9]->Arg, L[1]->Arg);
adjustment = FindSPAdjustment(L[1]->Arg);
if (adjustment == 0) {
CS_DelEntries (S, I, 9);
}
else if (adjustment > 255) {
Arg = MakeHexArg (adjustment & 0xff);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, L[1]->LI);
CS_InsertEntry(S, X, I + 1);
Arg = MakeHexArg (adjustment >> 8);
X = NewCodeEntry (OP65_LDA, AM65_IMM, Arg, 0, L[5]->LI);
CS_InsertEntry(S, X, I + 6);
CS_DelEntry(S, I + 2);
CS_DelEntry(S, I + 6);
}
else if (adjustment > 8) {
Arg = MakeHexArg (adjustment & 0xff);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I);
X = NewCodeEntry (OP65_JSR, AM65_ABS, "addysp", 0, L[1]->LI);
CS_InsertEntry (S, X, I + 1);
CS_DelEntries(S, I + 2, 9);
}
else {
char Buf[20];
xsprintf (Buf, sizeof (Buf), "incsp%u", adjustment);
X = NewCodeEntry (OP65_JSR, AM65_ABS, Buf, 0, L[1]->LI);
CS_InsertEntry (S, X, I);
CS_DelEntries(S, I + 1, 9);
}
/* Regenerate register info */
CS_GenRegInfo (S);
/* Remember we had changes */
Changes++;
} else {
/* Next entry */
++I;
}
}
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* struct OptFunc */
@@ -675,6 +754,7 @@ static OptFunc DOptDeadCode = { OptDeadCode, "OptDeadCode", 100, 0,
static OptFunc DOptDeadJumps = { OptDeadJumps, "OptDeadJumps", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptDecouple = { OptDecouple, "OptDecouple", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptDupLoads = { OptDupLoads, "OptDupLoads", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptGotoSPAdj = { OptGotoSPAdj, "OptGotoSPAdj", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptIndLoads1 = { OptIndLoads1, "OptIndLoads1", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptIndLoads2 = { OptIndLoads2, "OptIndLoads2", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptJumpCascades = { OptJumpCascades, "OptJumpCascades", 100, 0, 0, 0, 0, 0 };
@@ -774,6 +854,7 @@ static OptFunc* OptFuncs[] = {
&DOptDeadJumps,
&DOptDecouple,
&DOptDupLoads,
&DOptGotoSPAdj,
&DOptIndLoads1,
&DOptIndLoads2,
&DOptJumpCascades,
@@ -1122,6 +1203,7 @@ static unsigned RunOptGroup1 (CodeSeg* S)
{
unsigned Changes = 0;
Changes += RunOptFunc (S, &DOptGotoSPAdj, 1);
Changes += RunOptFunc (S, &DOptStackPtrOps, 5);
Changes += RunOptFunc (S, &DOptPtrStore1, 1);
Changes += RunOptFunc (S, &DOptPtrStore2, 1);
@@ -1229,6 +1311,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptCmp6, 1);
C += RunOptFunc (S, &DOptCmp7, 1);
C += RunOptFunc (S, &DOptCmp9, 1);
C += RunOptFunc (S, &DOptTest1, 1);
C += RunOptFunc (S, &DOptLoad1, 1);
C += RunOptFunc (S, &DOptJumpTarget3, 1); /* After OptCondBranches2 */