6502/cc65
1
0
Fork 0
mirror of https://github.com/cc65/cc65.git synced 2024-09-29 02:55:20 +00:00
Code Issues Projects Releases Wiki Activity

Another optimization for right shift of the sum of two bytes.

Browse Source 
git-svn-id: svn://svn.cc65.org/cc65/trunk@5710 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2012-06-10 22:15:00 +00:00
parent 878f469fc8
commit 8dc74f33da
1 changed files with 78 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
src/cc65/codeopt.c
View File

@ -234,6 +234,72 @@ static unsigned OptShift2(CodeSeg* S)
/* Remember, we had changes */
++Changes;
}
/* Next entry */
++I;
}
/* Free the register info */
CS_FreeRegInfo (S);
/* Return the number of changes made */
return Changes;
}
static unsigned OptShift3 (CodeSeg* S)
/* The sequence
*
* bcc L
* inx
* L: jsr shrax1
*
* may get replaced by
*
* ror a
*
* if X is zero on entry and unused later.
*/
{
unsigned Changes = 0;
unsigned I;
/* Generate register info */
CS_GenRegInfo (S);
/* Walk over the entries */
I = 0;
while (I < CS_GetEntryCount (S)) {
CodeEntry* L[3];
/* Get next entry */
L[0] = CS_GetEntry (S, I);
/* Check for the sequence */
if ((L[0]->OPC == OP65_BCC || L[0]->OPC == OP65_JCC) &&
L[0]->JumpTo != 0 &&
L[0]->RI->In.RegX == 0 &&
CS_GetEntries (S, L+1, I+1, 2) &&
L[1]->OPC == OP65_INX &&
L[0]->JumpTo->Owner == L[2] &&
!CS_RangeHasLabel (S, I, 2) &&
CE_IsCallTo (L[2], "shrax1") &&
!RegXUsed (S, I+3)) {
/* Add the replacement insn instead */
CodeEntry* X = NewCodeEntry (OP65_ROR, AM65_ACC, "a", 0, L[2]->LI);
CS_InsertEntry (S, X, I+3);
/* Remove the bcs/dex/jsr */
CS_DelEntries (S, I, 3);
/* Remember, we had changes */
++Changes;
}
/* Next entry */
@ -250,7 +316,7 @@ static unsigned OptShift2(CodeSeg* S)
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.
*/
@ -305,7 +371,7 @@ static unsigned OptShift3 (CodeSeg* S)
static unsigned GetShiftType (const char* Sub)
/* Helper function for OptShift3 */
/* Helper function for OptShift5 */
{
if (*Sub == 'a') {
if (strcmp (Sub+1, "slax1") == 0) {
@ -325,7 +391,7 @@ static unsigned GetShiftType (const char* Sub)
static unsigned OptShift4 (CodeSeg* S)
static unsigned OptShift5 (CodeSeg* S)
/* Search for the sequence
*
* lda xxx
@ -446,7 +512,7 @@ static unsigned OptShift4 (CodeSeg* S)
static unsigned OptShift5 (CodeSeg* S)
static unsigned OptShift6 (CodeSeg* S)
/* Inline the shift subroutines. */
{
unsigned Changes = 0;
@ -1131,9 +1197,10 @@ static OptFunc DOptPush2 = { OptPush2, "OptPush2", 50, 0,
static OptFunc DOptPushPop = { OptPushPop, "OptPushPop", 0, 0, 0, 0, 0, 0 };
static OptFunc DOptShift1 = { OptShift1, "OptShift1", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptShift2 = { OptShift2, "OptShift2", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptShift3 = { OptShift3, "OptShift3", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptShift4 = { OptShift4, "OptShift4", 110, 0, 0, 0, 0, 0 };
static OptFunc DOptShift5 = { OptShift5, "OptShift5", 200, 0, 0, 0, 0, 0 };
static OptFunc DOptShift3 = { OptShift3, "OptShift3", 17, 0, 0, 0, 0, 0 };
static OptFunc DOptShift4 = { OptShift4, "OptShift4", 100, 0, 0, 0, 0, 0 };
static OptFunc DOptShift5 = { OptShift5, "OptShift5", 110, 0, 0, 0, 0, 0 };
static OptFunc DOptShift6 = { OptShift6, "OptShift6", 200, 0, 0, 0, 0, 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 };
@ -1230,6 +1297,7 @@ static OptFunc* OptFuncs[] = {
&DOptShift3,
&DOptShift4,
&DOptShift5,
&DOptShift6,
&DOptSize1,
&DOptSize2,
&DOptStackOps,
@ -1523,8 +1591,9 @@ static unsigned RunOptGroup1 (CodeSeg* S)
Changes += RunOptFunc (S, &DOptStore5, 1);
Changes += RunOptFunc (S, &DOptShift1, 1);
Changes += RunOptFunc (S, &DOptShift2, 1);
Changes += RunOptFunc (S, &DOptShift3, 1);
Changes += RunOptFunc (S, &DOptShift4, 1);
Changes += RunOptFunc (S, &DOptShift5, 1);
Changes += RunOptFunc (S, &DOptShift6, 1);
Changes += RunOptFunc (S, &DOptStore1, 1);
Changes += RunOptFunc (S, &DOptStore2, 5);
Changes += RunOptFunc (S, &DOptStore3, 5);
@ -1624,6 +1693,7 @@ static unsigned RunOptGroup4 (CodeSeg* S)
unsigned Changes = 0;
/* Repeat some of the steps here */
Changes += RunOptFunc (S, &DOptShift3, 1);
Changes += RunOptFunc (S, &DOptPush1, 1);
Changes += RunOptFunc (S, &DOptPush2, 1);
Changes += RunOptFunc (S, &DOptUnusedLoads, 1);