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Added two replacements for negax. Shift right for signed values can be treated

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like unsigned if X is known to be zero.


git-svn-id: svn://svn.cc65.org/cc65/trunk@5732 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2012-06-23 16:58:05 +00:00
parent 4333c76710
commit d5810a818c
3 changed files with 215 additions and 18 deletions
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43
src/cc65/codeopt.c
View file

@ -330,8 +330,8 @@ static unsigned OptShift3 (CodeSeg* S)
static unsigned OptShift4 (CodeSeg* S)
/* A call to the shraxN routine may get replaced by one or more lsr insns
* if the value of X is zero.
/* 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;
@ -348,10 +348,11 @@ static unsigned OptShift4 (CodeSeg* S)
CodeEntry* E = CS_GetEntry (S, I);
/* Check for the sequence */
if (E->OPC == OP65_JSR &&
strncmp (E->Arg, "shrax", 5) == 0 &&
strlen (E->Arg) == 6 &&
IsDigit (E->Arg[5]) &&
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 */
@ -1151,6 +1152,12 @@ static OptFunc DOptAdd3 = { OptAdd3, "OptAdd3", 65, 0,
static OptFunc DOptAdd4 = { OptAdd4, "OptAdd4", 90, 0, 0, 0, 0, 0 };
static OptFunc DOptAdd5 = { OptAdd5, "OptAdd5", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptAdd6 = { OptAdd6, "OptAdd6", 40, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegA1 = { OptBNegA1, "OptBNegA1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegA2 = { OptBNegA2, "OptBNegA2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX1 = { OptBNegAX1, "OptBNegAX1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX2 = { OptBNegAX2, "OptBNegAX2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX3 = { OptBNegAX3, "OptBNegAX3", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX4 = { OptBNegAX4, "OptBNegAX4", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBoolTrans = { OptBoolTrans, "OptBoolTrans", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBranchDist = { OptBranchDist, "OptBranchDist", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptCmp1 = { OptCmp1, "OptCmp1", 42, 0, 0, 0, 0, 0 };
@ -1176,15 +1183,11 @@ static OptFunc DOptJumpTarget2 = { OptJumpTarget2, "OptJumpTarget2", 100, 0,
static OptFunc DOptJumpTarget3 = { OptJumpTarget3, "OptJumpTarget3", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptLoad1 = { OptLoad1, "OptLoad1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptLoad2 = { OptLoad2, "OptLoad2", 200, 0, 0, 0, 0, 0 };
static OptFunc DOptNegAX1 = { OptNegAX1, "OptNegAX1", 165, 0, 0, 0, 0, 0 };
static OptFunc DOptNegAX2 = { OptNegAX2, "OptNegAX2", 200, 0, 0, 0, 0, 0 };
static OptFunc DOptRTS = { OptRTS, "OptRTS", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptRTSJumps1 = { OptRTSJumps1, "OptRTSJumps1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptRTSJumps2 = { OptRTSJumps2, "OptRTSJumps2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegA1 = { OptBNegA1, "OptBNegA1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegA2 = { OptBNegA2, "OptBNegA2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX1 = { OptBNegAX1, "OptBNegAX1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX2 = { OptBNegAX2, "OptBNegAX2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX3 = { OptBNegAX3, "OptBNegAX3", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptBNegAX4 = { OptBNegAX4, "OptBNegAX4", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptPrecalc = { OptPrecalc, "OptPrecalc", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptPtrLoad1 = { OptPtrLoad1, "OptPtrLoad1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptPtrLoad2 = { OptPtrLoad2, "OptPtrLoad2", 100, 0, 0, 0, 0, 0 };
@ -1246,6 +1249,12 @@ static OptFunc* OptFuncs[] = {
&DOptAdd4,
&DOptAdd5,
&DOptAdd6,
&DOptBNegA1,
&DOptBNegA2,
&DOptBNegAX1,
&DOptBNegAX2,
&DOptBNegAX3,
&DOptBNegAX4,
&DOptBoolTrans,
&DOptBranchDist,
&DOptCmp1,
@ -1271,12 +1280,8 @@ static OptFunc* OptFuncs[] = {
&DOptJumpTarget3,
&DOptLoad1,
&DOptLoad2,
&DOptBNegA1,
&DOptBNegA2,
&DOptBNegAX1,
&DOptBNegAX2,
&DOptBNegAX3,
&DOptBNegAX4,
&DOptNegAX1,
&DOptNegAX2,
&DOptPrecalc,
&DOptPtrLoad1,
&DOptPtrLoad11,
@ -1642,6 +1647,8 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptBNegA1, 1);
C += RunOptFunc (S, &DOptBNegA2, 1);
C += RunOptFunc (S, &DOptNegAX1, 1);
C += RunOptFunc (S, &DOptNegAX2, 1);
C += RunOptFunc (S, &DOptStackOps, 1);
C += RunOptFunc (S, &DOptSub1, 1);
C += RunOptFunc (S, &DOptSub2, 1);

158
src/cc65/coptneg.c
View file

@ -417,3 +417,161 @@ unsigned OptBNegAX4 (CodeSeg* S)
/*****************************************************************************/
/* negax optimizations */
/*****************************************************************************/
unsigned OptNegAX1 (CodeSeg* S)
/* Search for a call to negax and replace it by
*
* eor #$FF
* clc
* adc #$01
*
* if X isn't used later.
*/
{
unsigned Changes = 0;
unsigned I;
/* Generate register info for this step */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a call to negax, and if X isn't used later */
if (CE_IsCallTo (E, "negax") && !RegXUsed (S, I+1)) {
CodeEntry* X;
/* Add replacement code behind */
X = NewCodeEntry (OP65_EOR, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+1);
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_ADC, AM65_IMM, "$01", 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* Delete the call to negax */
CS_DelEntry (S, I);
/* Skip the generated code */
I += 2;
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
unsigned OptNegAX2 (CodeSeg* S)
/* Search for a call to negax and replace it by
*
* ldx #$FF
* eor #$FF
* clc
* adc #$01
* bne L1
* inx
* L1:
*
* if X is known and zero on entry.
*/
{
unsigned Changes = 0;
unsigned I;
/* Generate register info for this step */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* P;
/* Get next entry */
CodeEntry* E = CS_GetEntry (S, I);
/* Check if this is a call to negax, and if X is known and zero */
if (E->RI->In.RegX == 0 &&
CE_IsCallTo (E, "negax") &&
(P = CS_GetNextEntry (S, I)) != 0) {
CodeEntry* X;
CodeLabel* L;
/* Add replacement code behind */
/* ldx #$FF */
X = NewCodeEntry (OP65_LDX, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+1);
/* eor #$FF */
X = NewCodeEntry (OP65_EOR, AM65_IMM, "$FF", 0, E->LI);
CS_InsertEntry (S, X, I+2);
/* clc */
X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+3);
/* adc #$01 */
X = NewCodeEntry (OP65_ADC, AM65_IMM, "$01", 0, E->LI);
CS_InsertEntry (S, X, I+4);
/* Get the label attached to the insn following the call */
L = CS_GenLabel (S, P);
/* bne L */
X = NewCodeEntry (OP65_BNE, AM65_BRA, L->Name, L, E->LI);
CS_InsertEntry (S, X, I+5);
/* inx */
X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, E->LI);
CS_InsertEntry (S, X, I+6);
/* Delete the call to negax */
CS_DelEntry (S, I);
/* Skip the generated code */
I += 5;
/* We had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}

32
src/cc65/coptneg.h
View file

@ -132,6 +132,38 @@ unsigned OptBNegAX4 (CodeSeg* S);
/*****************************************************************************/
/* negax optimizations */
/*****************************************************************************/
unsigned OptNegAX1 (CodeSeg* S);
/* Search for a call to negax and replace it by
*
* eor #$FF
* clc
* adc #$01
*
* if X isn't used later.
*/
unsigned OptNegAX2 (CodeSeg* S);
/* Search for a call to negax and replace it by
*
* ldx #$FF
* eor #$FF
* clc
* adc #$01
* bne L1
* inx
* L1:
*
* if X is known and zero on entry.
*/
/* End of coptneg.h */
#endif