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Added some code rewriting (may enable optimizations in a few cases).

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git-svn-id: svn://svn.cc65.org/cc65/trunk@3727 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
cuz 2006-04-15 20:31:43 +00:00
parent d82d94ecc1
commit c156b20738
3 changed files with 94 additions and 5 deletions
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4
src/cc65/codeopt.c
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@ -1865,6 +1865,7 @@ static OptFunc DOptStore1 = { OptStore1, "OptStore1", 70, 0,
static OptFunc DOptStore2 = { OptStore2, "OptStore2", 220, 0, 0, 0, 0, 0 };
static OptFunc DOptStore3 = { OptStore3, "OptStore3", 120, 0, 0, 0, 0, 0 };
static OptFunc DOptStore4 = { OptStore4, "OptStore4", 50, 0, 0, 0, 0, 0 };
static OptFunc DOptStore5 = { OptStore5, "OptStore5", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptStoreLoad = { OptStoreLoad, "OptStoreLoad", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptSub1 = { OptSub1, "OptSub1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptSub2 = { OptSub2, "OptSub2", 100, 0, 0, 0, 0, 0 };
@ -1939,6 +1940,7 @@ static OptFunc* OptFuncs[] = {
&DOptStore2,
&DOptStore3,
&DOptStore4,
&DOptStore5,
&DOptStoreLoad,
&DOptSub1,
&DOptSub2,
@ -2200,6 +2202,7 @@ static unsigned RunOptGroup1 (CodeSeg* S)
Changes += RunOptFunc (S, &DOptAdd2, 1);
Changes += RunOptFunc (S, &DOptAdd4, 1);
Changes += RunOptFunc (S, &DOptStore4, 1);
Changes += RunOptFunc (S, &DOptStore5, 1);
Changes += RunOptFunc (S, &DOptShift1, 1);
Changes += RunOptFunc (S, &DOptShift2, 1);
Changes += RunOptFunc (S, &DOptShift3, 1);
@ -2274,6 +2277,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
C += RunOptFunc (S, &DOptDupLoads, 1);
C += RunOptFunc (S, &DOptStoreLoad, 1);
C += RunOptFunc (S, &DOptTransfers1, 1);
C += RunOptFunc (S, &DOptStore5, 1);
C += RunOptFunc (S, &DOptPushPop, 1);
C += RunOptFunc (S, &DOptPrecalc, 1);

68
src/cc65/coptstore.c
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@ -6,7 +6,7 @@
/* */
/* */
/* */
/* (C) 2002-2005, Ullrich von Bassewitz */
/* (C) 2002-2006, Ullrich von Bassewitz */
/* Römerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
@ -386,3 +386,69 @@ unsigned OptStore4 (CodeSeg* S)
unsigned OptStore5 (CodeSeg* S)
/* Search for the sequence
*
* lda foo
* ldx bar
* sta something
* stx something-else
*
* and replace it by
*
* lda foo
* sta something
* lda bar
* sta something-else
*
* if X is not used later. This replacement doesn't save any cycles or bytes,
* but it keeps the value of X, which may be reused later.
*/
{
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_LDA &&
!CS_RangeHasLabel (S, I+1, 3) &&
CS_GetEntries (S, L+1, I+1, 3) &&
L[1]->OPC == OP65_LDX &&
L[2]->OPC == OP65_STA &&
L[3]->OPC == OP65_STX &&
!RegXUsed (S, I+4)) {
CodeEntry* X;
/* Insert the code after the sequence */
X = NewCodeEntry (OP65_LDA, L[1]->AM, L[1]->Arg, 0, L[1]->LI);
CS_InsertEntry (S, X, I+4);
X = NewCodeEntry (OP65_STA, L[3]->AM, L[3]->Arg, 0, L[3]->LI);
CS_InsertEntry (S, X, I+5);
/* Delete the old code */
CS_DelEntry (S, I+3);
CS_DelEntry (S, I+1);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Return the number of changes made */
return Changes;
}

27
src/cc65/coptstore.h
View File

@ -6,10 +6,10 @@
/* */
/* */
/* */
/* (C) 2002-2003 Ullrich von Bassewitz */
/* Römerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* (C) 2002-2006, Ullrich von Bassewitz */
/* Römerstrasse 52 */
/* D-70794 Filderstadt */
/* EMail: uz@cc65.org */
/* */
/* */
/* This software is provided 'as-is', without any expressed or implied */
@ -85,6 +85,25 @@ unsigned OptStore4 (CodeSeg* S);
* from the load.
*/
unsigned OptStore5 (CodeSeg* S);
/* Search for the sequence
*
* lda foo
* ldx bar
* sta something
* stx something-else
*
* and replace it by
*
* lda foo
* sta something
* lda bar
* sta something-else
*
* if X is not used later. This replacement doesn't save any cycles or bytes,
* but it keeps the value of X, which may be reused later.
*/
/* End of coptstore.h */