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Transform tosshlax and friends into a sequence that doesn't use the stack if

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possible.


git-svn-id: svn://svn.cc65.org/cc65/trunk@5764 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2012-07-06 20:01:46 +00:00
parent 5f0db62f58
commit e50649af2c
2 changed files with 126 additions and 4 deletions
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4
src/cc65/codeopt.c
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@ -1606,7 +1606,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptBNegA2, 1);
C += RunOptFunc (S, &DOptNegAX1, 1);
C += RunOptFunc (S, &DOptNegAX2, 1);
C += RunOptFunc (S, &DOptStackOps, 1);
C += RunOptFunc (S, &DOptStackOps, 3);
C += RunOptFunc (S, &DOptSub1, 1);
C += RunOptFunc (S, &DOptSub2, 1);
C += RunOptFunc (S, &DOptSub3, 1);
@ -1760,7 +1760,7 @@ static unsigned RunOptGroup7 (CodeSeg* S)
Changes += RunOptFunc (S, &DOptUnusedLoads, 1);
Changes += RunOptFunc (S, &DOptJumpTarget1, 5);
Changes += RunOptFunc (S, &DOptStore5, 1);
Changes += RunOptFunc (S, &DOptTransfers1, 1);
Changes += RunOptFunc (S, &DOptTransfers1, 1);
Changes += RunOptFunc (S, &DOptTransfers3, 1);
}

126
src/cc65/coptstop.c
View File

@ -716,7 +716,7 @@ static int IsRegVar (StackOpData* D)
/*****************************************************************************/
/* Actual optimization functions */
/* Actual optimization functions */
/*****************************************************************************/
@ -832,6 +832,71 @@ static unsigned Opt_toseqax_tosneax (StackOpData* D, const char* BoolTransformer
static unsigned Opt_tosshift (StackOpData* D, const char* Name)
/* Optimize shift sequences. */
{
CodeEntry* X;
/* Store the value into the zeropage instead of pushing it */
ReplacePushByStore (D);
/* Inline the compare */
D->IP = D->OpIndex+1;
/* tay */
X = NewCodeEntry (OP65_TAY, AM65_IMP, 0, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
/* If the lhs is direct (but not stack relative), we can just reload the
* data later.
*/
if ((D->Lhs.A.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT &&
(D->Lhs.X.Flags & (LI_DIRECT | LI_RELOAD_Y)) == LI_DIRECT) {
CodeEntry* LoadX = D->Lhs.X.LoadEntry;
CodeEntry* LoadA = D->Lhs.A.LoadEntry;
/* lda */
X = NewCodeEntry (OP65_LDA, LoadA->AM, LoadA->Arg, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
/* ldx */
X = NewCodeEntry (OP65_LDX, LoadX->AM, LoadX->Arg, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
/* Lhs load entries can be removed */
D->Lhs.X.Flags |= LI_REMOVE;
D->Lhs.A.Flags |= LI_REMOVE;
} else {
/* Save lhs into zeropage and reload later */
AddStoreX (D);
AddStoreA (D);
/* lda zp */
X = NewCodeEntry (OP65_LDA, AM65_ZP, D->ZPLo, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
/* ldx zp+1 */
X = NewCodeEntry (OP65_LDX, AM65_ZP, D->ZPHi, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
}
/* jsr shlaxy/aslaxy/whatever */
X = NewCodeEntry (OP65_JSR, AM65_ABS, Name, 0, D->OpEntry->LI);
InsertEntry (D, X, D->IP++);
/* Remove the push and the call to the tossubax function */
RemoveRemainders (D);
/* We changed the sequence */
return 1;
}
static unsigned Opt___bzero (StackOpData* D)
/* Optimize the __bzero sequence */
{
@ -1169,6 +1234,22 @@ static unsigned Opt_tosandax (StackOpData* D)
static unsigned Opt_tosaslax (StackOpData* D)
/* Optimize the tosaslax sequence */
{
return Opt_tosshift (D, "aslaxy");
}
static unsigned Opt_tosasrax (StackOpData* D)
/* Optimize the tosasrax sequence */
{
return Opt_tosshift (D, "asraxy");
}
static unsigned Opt_toseqax (StackOpData* D)
/* Optimize the toseqax sequence */
{
@ -1237,7 +1318,7 @@ static unsigned Opt_tosltax (StackOpData* D)
CodeLabel* L;
/* Inline the sbc */
/* Inline the compare */
D->IP = D->OpIndex+1;
/* Must be true because of OP_RHS_LOAD */
@ -1314,6 +1395,22 @@ static unsigned Opt_tosorax (StackOpData* D)
static unsigned Opt_tosshlax (StackOpData* D)
/* Optimize the tosshlax sequence */
{
return Opt_tosshift (D, "shlaxy");
}
static unsigned Opt_tosshrax (StackOpData* D)
/* Optimize the tosshrax sequence */
{
return Opt_tosshift (D, "shraxy");
}
static unsigned Opt_tossubax (StackOpData* D)
/* Optimize the tossubax sequence. Note: subtraction is not commutative! */
{
@ -1547,11 +1644,18 @@ static const OptFuncDesc FuncTable[] = {
{ "staxspidx", Opt_staxspidx, REG_AX, OP_NONE },
{ "tosaddax", Opt_tosaddax, REG_NONE, OP_NONE },
{ "tosandax", Opt_tosandax, REG_NONE, OP_NONE },
{ "tosaslax", Opt_tosaslax, REG_NONE, OP_NONE },
#if 0
/* Library routine missing */
{ "tosasrax", Opt_tosasrax, REG_NONE, OP_NONE },
#endif
{ "toseqax", Opt_toseqax, REG_NONE, OP_NONE },
{ "tosgeax", Opt_tosgeax, REG_NONE, OP_RHS_LOAD_DIRECT },
{ "tosltax", Opt_tosltax, REG_NONE, OP_RHS_LOAD_DIRECT },
{ "tosneax", Opt_tosneax, REG_NONE, OP_NONE },
{ "tosorax", Opt_tosorax, REG_NONE, OP_NONE },
{ "tosshlax", Opt_tosshlax, REG_NONE, OP_NONE },
{ "tosshrax", Opt_tosshrax, REG_NONE, OP_NONE },
{ "tossubax", Opt_tossubax, REG_NONE, OP_RHS_LOAD_DIRECT },
{ "tosugeax", Opt_tosugeax, REG_NONE, OP_RHS_LOAD_DIRECT },
{ "tosugtax", Opt_tosugtax, REG_NONE, OP_RHS_LOAD_DIRECT },
@ -1599,11 +1703,13 @@ static int HarmlessCall (const char* Name)
"aslax2",
"aslax3",
"aslax4",
"aslaxy",
"asrax1",
"asrax2",
"asrax3",
"asrax4",
"bnegax",
"complax",
"decax1",
"decax2",
"decax3",
@ -1629,6 +1735,7 @@ static int HarmlessCall (const char* Name)
"shlax2",
"shlax3",
"shlax4",
"shlaxy",
"shrax1",
"shrax2",
"shrax3",
@ -1744,6 +1851,9 @@ unsigned OptStackOps (CodeSeg* S)
StackOpData Data;
int I;
int OldEntryCount; /* Old number of entries */
unsigned UsedRegs; /* Registers used */
unsigned ChangedRegs; /* Registers changed */
enum {
Initialize,
@ -1782,6 +1892,7 @@ unsigned OptStackOps (CodeSeg* S)
case Initialize:
ResetStackOpData (&Data);
UsedRegs = ChangedRegs = REG_NONE;
State = Search;
/* FALLTHROUGH */
@ -1868,6 +1979,17 @@ unsigned OptStackOps (CodeSeg* S)
Data.UsedRegs |= (E->Use | E->Chg);
TrackLoads (&Data.Rhs, E, I);
}
/* If the registers from the push (A/X) are used before they're
* changed, we cannot change the sequence, because this would
* with a high probability change the register contents.
*/
UsedRegs |= E->Use;
if ((UsedRegs & ~ChangedRegs) & REG_AX) {
I = Data.PushIndex;
State = Initialize;
break;
}
ChangedRegs |= E->Chg;
break;
case FoundOp: