Replace ldaxidx by inline code.

[cc65] / src / cc65 / coptptrload.c

diff --git a/src/cc65/coptptrload.c b/src/cc65/coptptrload.c
index 4ecfa99267ecb7349719ca5ee7139f0737281e13..556e4e209a3682175e713d127c1f2087572d525f 100644 (file)
--- a/src/cc65/coptptrload.c
+++ b/src/cc65/coptptrload.c
@@ -929,7 +929,7 @@ unsigned OptPtrLoad10 (CodeSeg* S)
  *
  *      stx     ptr1+1
  *      sta     ptr1
- *      ldy     ...                  
+ *      ldy     ...
  *      ldx     #$00
  *      lda     (ptr1),y
  *
@@ -988,3 +988,87 @@ unsigned OptPtrLoad10 (CodeSeg* S)
 
 
 
+unsigned OptPtrLoad11 (CodeSeg* S)
+/* Search for the sequence
+ *
+ *      ldy     ...
+ *      jsr     ldaxidx
+ *
+ * and replace it by:
+ *
+ *      ldy     ...
+ *      sta     ptr1
+ *      stx     ptr1+1
+ *      lda     (ptr1),y
+ *      tax
+ *      dey
+ *      lda     (ptr1),y
+ *
+ * This step must be executed *after* OptPtrLoad9! While code size increases
+ * by more than 200%, inlining will greatly improve visibility for the
+ * optimizer, so often part of the code gets improved later. So we will mark
+ * the step with less than 200% so it gets executed when -Oi is in effect.
+ */
+{
+    unsigned Changes = 0;
+
+    /* Walk over the entries */
+    unsigned I = 0;
+    while (I < CS_GetEntryCount (S)) {
+
+       CodeEntry* L[2];
+
+       /* Get next entry */
+               L[0] = CS_GetEntry (S, I);
+
+       /* Check for the sequence */
+               if (L[0]->OPC == OP65_LDY               &&
+                   CS_GetEntries (S, L+1, I+1, 1)      &&
+                   CE_IsCallTo (L[1], "ldaxidx")       &&
+           !CE_HasLabel (L[1])) {
+
+           CodeEntry* X;
+
+                   /* Store the high byte */
+                   X = NewCodeEntry (OP65_STA, AM65_ZP, "ptr1", 0, L[0]->LI);
+           CS_InsertEntry (S, X, I+1);
+
+           /* Store the low byte */
+           X = NewCodeEntry (OP65_STX, AM65_ZP, "ptr1+1", 0, L[0]->LI);
+           CS_InsertEntry (S, X, I+2);
+
+            /* lda (ptr1),y */
+            X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "ptr1", 0, L[1]->LI);
+            CS_InsertEntry (S, X, I+3);
+
+            /* tax */
+            X = NewCodeEntry (OP65_TAX, AM65_IMP, 0, 0, L[1]->LI);
+            CS_InsertEntry (S, X, I+4);
+
+            /* dey */
+            X = NewCodeEntry (OP65_DEY, AM65_IMP, 0, 0, L[1]->LI);
+            CS_InsertEntry (S, X, I+5);
+
+            /* lda (ptr1),y */
+            X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, "ptr1", 0, L[1]->LI);
+            CS_InsertEntry (S, X, I+6);
+
+           /* Delete the call to ldaxidx */
+           CS_DelEntry (S, I+7);
+
+           /* Remember, we had changes */
+           ++Changes;
+
+       }
+
+       /* Next entry */
+       ++I;
+
+    }
+
+    /* Return the number of changes made */
+    return Changes;
+}
+
+
+