More optimizations

git-svn-id: svn://svn.cc65.org/cc65/trunk@837 b7a2c559-68d2-44c3-8de9-860c34a00d81

diff --git a/src/cc65/codeopt.c b/src/cc65/codeopt.c
index e8a40cc915390009711cf289d23b0584838a79b6..6be5b91e3445d6516b90e0909bdee6a983ffe1a0 100644 (file)
--- a/src/cc65/codeopt.c
+++ b/src/cc65/codeopt.c
@@ -540,6 +540,98 @@ static unsigned OptSub2 (CodeSeg* S)
 
 
 static unsigned OptAdd1 (CodeSeg* S)
+/* Search for the sequence
+ *
+ *             jsr     pushax
+ *      ldy     xxx
+ *     ldx     #$00
+ *      lda     (sp),y
+ *      jsr     tosaddax
+ *
+ * and replace it by:
+ *
+ *      ldy     xxx
+ *      clc
+ *      adc     (sp),y
+ *      bcc     L
+ *      inx
+ * L:
+ */
+{
+    unsigned Changes = 0;
+
+    /* Walk over the entries */
+    unsigned I = 0;
+    while (I < CS_GetEntryCount (S)) {
+
+       CodeEntry* L[5];
+
+       /* Get next entry */
+               CodeEntry* E = CS_GetEntry (S, I);
+
+       /* Check for the sequence */
+       if (E->OPC == OP65_JSR                               &&
+           strcmp (E->Arg, "pushax") == 0                   &&
+                   CS_GetEntries (S, L, I+1, 5)                     &&
+                   L[0]->OPC == OP65_LDY                            &&
+           !CE_HasLabel (L[0])                              &&
+           L[1]->OPC == OP65_LDX                            &&
+           CE_KnownImm (L[1])                               &&
+           L[1]->Num == 0                                   &&
+           !CE_HasLabel (L[1])                              &&
+           L[2]->OPC == OP65_LDA                            &&
+           !CE_HasLabel (L[2])                              &&
+           L[3]->OPC == OP65_JSR                            &&
+           strcmp (L[3]->Arg, "tosaddax") == 0              &&
+           !CE_HasLabel (L[3])) {
+
+           CodeEntry* X;
+           CodeLabel* Label;
+
+           /* Remove the call to pushax */
+           CS_DelEntry (S, I);
+
+           /* Add the clc . */
+           X = NewCodeEntry (OP65_CLC, AM65_IMP, 0, 0, L[3]->LI);
+           CS_InsertEntry (S, X, I+1);
+
+           /* Remove the load */
+           CS_DelEntry (S, I+3);      /* lda */
+           CS_DelEntry (S, I+2);      /* ldx */
+
+           /* Add the adc */
+           X = NewCodeEntry (OP65_ADC, AM65_ZP_INDY, "sp", 0, L[3]->LI);
+           CS_InsertEntry (S, X, I+2);
+
+           /* Generate the branch label and the branch */
+           Label = CS_GenLabel (S, L[4]);
+           X = NewCodeEntry (OP65_BCC, AM65_BRA, Label->Name, Label, L[3]->LI);
+           CS_InsertEntry (S, X, I+3);
+
+           /* Generate the increment of the high byte */
+           X = NewCodeEntry (OP65_INX, AM65_IMP, 0, 0, L[3]->LI);
+           CS_InsertEntry (S, X, I+4);
+
+           /* Delete the call to tosaddax */
+           CS_DelEntry (S, I+5);
+
+           /* Remember, we had changes */
+           ++Changes;
+
+       }
+
+       /* Next entry */
+       ++I;
+
+    }
+
+    /* Return the number of changes made */
+    return Changes;
+}
+
+
+
+static unsigned OptAdd2 (CodeSeg* S)
 /* Search for the sequence
  *
  *     adc     ...
@@ -1844,7 +1936,8 @@ static OptFunc OptFuncs [] = {
     OptEntry (OptSub1, optMain),
     OptEntry (OptSub2, optMain),
     /* Optimize additions */
-    OptEntry (OptAdd1, optMain),
+    OptEntry (OptAdd1, optPre),
+    OptEntry (OptAdd2, optMain),
     /* Optimize jump cascades */
     OptEntry (OptJumpCascades, optMain),
     /* Remove dead jumps */