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Merge calls to decsp. The implemented routine is not perfect and will miss

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some pieces of code, but it's better than nothing.


git-svn-id: svn://svn.cc65.org/cc65/trunk@4339 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2009-10-07 15:28:35 +00:00
parent 2ae20c3b61
commit b208b7e3b1
1 changed files with 106 additions and 2 deletions
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104
src/cc65/codeopt.c
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@ -42,6 +42,7 @@
#include "cpu.h"
#include "print.h"
#include "xmalloc.h"
#include "xsprintf.h"
/* cc65 */
#include "asmlabel.h"
@ -1052,6 +1053,106 @@ static unsigned OptDecouple (CodeSeg* S)
/*****************************************************************************/
/* Optimize stack pointer ops */
/*****************************************************************************/
static unsigned IsDecSP (const CodeEntry* E)
/* Check if this is an insn that decrements the stack pointer. If so, return
* the decrement. If not, return zero.
* The function expects E to be a subroutine call.
*/
{
if (strncmp (E->Arg, "decsp", 5) == 0) {
if (E->Arg[5] >= '1' && E->Arg[5] <= '8') {
return (E->Arg[5] - '0');
}
} else if (strcmp (E->Arg, "subysp") == 0 && RegValIsKnown (E->RI->In.RegY)) {
return E->RI->In.RegY;
}
/* If we come here, it's not a decsp op */
return 0;
}
static unsigned OptStackPtrOps (CodeSeg* S)
/* Merge adjacent calls to decsp into one. NOTE: This function won't merge all
* known cases!
*/
{
unsigned Changes = 0;
unsigned I;
/* Generate register info for the following step */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
unsigned Dec1;
unsigned Dec2;
const CodeEntry* N;
/* Get the next entry */
const CodeEntry* E = CS_GetEntry (S, I);
/* Check for decspn or subysp */
if (E->OPC == OP65_JSR &&
(Dec1 = IsDecSP (E)) > 0 &&
(N = CS_GetNextEntry (S, I)) != 0 &&
(Dec2 = IsDecSP (N)) > 0 &&
(Dec1 += Dec2) <= 255 &&
!CE_HasLabel (N)) {
CodeEntry* X;
char Buf[20];
/* We can combine the two */
if (Dec1 <= 8) {
/* Insert a call to decsp */
xsprintf (Buf, sizeof (Buf), "decsp%u", Dec1);
X = NewCodeEntry (OP65_JSR, AM65_ABS, Buf, 0, N->LI);
CS_InsertEntry (S, X, I+2);
} else {
/* Insert a call to subysp */
const char* Arg = MakeHexArg (Dec1);
X = NewCodeEntry (OP65_LDY, AM65_IMM, Arg, 0, N->LI);
CS_InsertEntry (S, X, I+2);
X = NewCodeEntry (OP65_JSR, AM65_ABS, "subysp", 0, N->LI);
CS_InsertEntry (S, X, I+3);
}
/* Delete the old code */
CS_DelEntries (S, I, 2);
/* Regenerate register info */
CS_GenRegInfo (S);
/* Remember we had changes */
++Changes;
} else {
/* Next entry */
++I;
}
}
/* Free register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
/*****************************************************************************/
/* struct OptFunc */
/*****************************************************************************/
@ -1148,6 +1249,7 @@ static OptFunc DOptShift4 = { OptShift4, "OptShift4", 200, 0,
static OptFunc DOptSize1 = { OptSize1, "OptSize1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptSize2 = { OptSize2, "OptSize2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptStackOps = { OptStackOps, "OptStackOps", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptStackPtrOps = { OptStackPtrOps, "OptStackPtrOps", 50, 0, 0, 0, 0, 0 };
static OptFunc DOptStore1 = { OptStore1, "OptStore1", 70, 0, 0, 0, 0, 0 };
static OptFunc DOptStore2 = { OptStore2, "OptStore2", 220, 0, 0, 0, 0, 0 };
static OptFunc DOptStore3 = { OptStore3, "OptStore3", 120, 0, 0, 0, 0, 0 };
@ -1237,6 +1339,7 @@ static OptFunc* OptFuncs[] = {
&DOptSize1,
&DOptSize2,
&DOptStackOps,
&DOptStackPtrOps,
&DOptStore1,
&DOptStore2,
&DOptStore3,
@ -1486,6 +1589,7 @@ static unsigned RunOptGroup1 (CodeSeg* S)
{
unsigned Changes = 0;
Changes += RunOptFunc (S, &DOptStackPtrOps, 5);
Changes += RunOptFunc (S, &DOptPtrStore1, 1);
Changes += RunOptFunc (S, &DOptPtrStore2, 1);
Changes += RunOptFunc (S, &DOptAdd3, 1); /* Before OptPtrLoad5! */