From e81d5ec00a2ff1950d36d593a662ba24f5ae0ae0 Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sun, 16 Apr 2006 21:35:36 +0000
Subject: [PATCH] Added another optimization step

git-svn-id: svn://svn.cc65.org/cc65/trunk@3732 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 src/cc65/codeopt.c | 93 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 88 insertions(+), 5 deletions(-)

diff --git a/src/cc65/codeopt.c b/src/cc65/codeopt.c
index fa6ab9bfe..730c8db41 100644
--- a/src/cc65/codeopt.c
+++ b/src/cc65/codeopt.c
@@ -1395,6 +1395,86 @@ static unsigned OptPtrLoad7 (CodeSeg* S)
 
 
 static unsigned OptPtrLoad8 (CodeSeg* S)
+/* Search for the sequence:
+ *
+ *      lda     zp
+ *      ldx     zp+1
+ *      (anything that doesn't change a/x)
+ *      ldy     xx
+ *      jsr     ldauidx
+ *
+ * and replace it by:
+ *
+ *      lda     zp
+ *      ldx     zp+1
+ *      (anything that doesn't change a/x)
+ *      ldy     xx
+ *      ldx     #$00
+ *      lda     (zp),y
+ *
+ * Must execute before OptPtrLoad10!
+ */
+{
+    unsigned Changes = 0;
+
+    /* Generate register info */
+    CS_GenRegInfo (S);
+
+    /* Walk over the entries */
+    unsigned I = 0;
+    while (I < CS_GetEntryCount (S)) {
+
+	CodeEntry* L[5];
+	unsigned Len;
+
+      	/* Get next entry */
+       	L[0] = CS_GetEntry (S, I);
+
+     	/* Check for the sequence */
+       	if (L[0]->OPC == OP65_LDA && L[0]->AM == AM65_ZP        &&
+       	    CS_GetEntries (S, L+1, I+1, 4)     	                &&
+            !CS_RangeHasLabel (S, I+1, 4)                       &&
+       	    L[1]->OPC == OP65_LDX && L[1]->AM == AM65_ZP        &&
+            (Len = strlen (L[0]->Arg)) > 0                      &&
+            strncmp (L[0]->Arg, L[1]->Arg, Len) == 0            &&
+            strcmp (L[1]->Arg + Len, "+1") == 0                 &&
+            (L[2]->Chg & REG_AX) == 0                           &&
+       	    L[3]->OPC == OP65_LDY                               &&
+       	    CE_IsCallTo (L[4], "ldauidx")) {
+
+	    CodeEntry* X;
+
+	    /* ldx #$00 */
+	    X = NewCodeEntry (OP65_LDX, AM65_IMM, "$00", 0, L[3]->LI);
+	    CS_InsertEntry (S, X, I+5);
+
+	    /* lda (zp),y */
+	    X = NewCodeEntry (OP65_LDA, AM65_ZP_INDY, L[0]->Arg, 0, L[3]->LI);
+	    CS_InsertEntry (S, X, I+6);
+
+	    /* Remove the old code */
+	    CS_DelEntry (S, I+4);
+
+	    /* 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 OptPtrLoad9 (CodeSeg* S)
 /* Search for the sequence:
  *
  *      lda     zp
@@ -1472,7 +1552,7 @@ static unsigned OptPtrLoad8 (CodeSeg* S)
 
 
 
-static unsigned OptPtrLoad9 (CodeSeg* S)
+static unsigned OptPtrLoad10 (CodeSeg* S)
 /* Search for the sequence
  *
  *      ldy     ...
@@ -1848,8 +1928,9 @@ static OptFunc DOptPtrLoad4    	= { OptPtrLoad4,     "OptPtrLoad4",    	100, 0,
 static OptFunc DOptPtrLoad5    	= { OptPtrLoad5,     "OptPtrLoad5",    	 92, 0, 0, 0, 0, 0 };
 static OptFunc DOptPtrLoad6    	= { OptPtrLoad6,     "OptPtrLoad6",    	 50, 0, 0, 0, 0, 0 };
 static OptFunc DOptPtrLoad7    	= { OptPtrLoad7,     "OptPtrLoad7",    	 65, 0, 0, 0, 0, 0 };
-static OptFunc DOptPtrLoad8    	= { OptPtrLoad8,     "OptPtrLoad8",    	 86, 0, 0, 0, 0, 0 };
-static OptFunc DOptPtrLoad9    	= { OptPtrLoad9,     "OptPtrLoad9",    	100, 0, 0, 0, 0, 0 };
+static OptFunc DOptPtrLoad8    	= { OptPtrLoad8,     "OptPtrLoad8",    	108, 0, 0, 0, 0, 0 };
+static OptFunc DOptPtrLoad9    	= { OptPtrLoad9,     "OptPtrLoad9",    	 86, 0, 0, 0, 0, 0 };
+static OptFunc DOptPtrLoad10   	= { OptPtrLoad10,    "OptPtrLoad10",   	100, 0, 0, 0, 0, 0 };
 static OptFunc DOptPtrStore1   	= { OptPtrStore1,    "OptPtrStore1",    100, 0, 0, 0, 0, 0 };
 static OptFunc DOptPtrStore2   	= { OptPtrStore2,    "OptPtrStore2",     40, 0, 0, 0, 0, 0 };
 static OptFunc DOptPush1       	= { OptPush1,        "OptPush1",         65, 0, 0, 0, 0, 0 };
@@ -1914,6 +1995,7 @@ static OptFunc* OptFuncs[] = {
     &DOptNegAX4,
     &DOptPrecalc,
     &DOptPtrLoad1,
+    &DOptPtrLoad10,
     &DOptPtrLoad2,
     &DOptPtrLoad3,
     &DOptPtrLoad4,
@@ -2194,6 +2276,7 @@ static unsigned RunOptGroup1 (CodeSeg* S)
     Changes += RunOptFunc (S, &DOptPtrLoad6, 1);
     Changes += RunOptFunc (S, &DOptPtrLoad7, 1);
     Changes += RunOptFunc (S, &DOptPtrLoad8, 1);
+    Changes += RunOptFunc (S, &DOptPtrLoad9, 1);
     Changes += RunOptFunc (S, &DOptNegAX1, 1);
     Changes += RunOptFunc (S, &DOptNegAX2, 1);
     Changes += RunOptFunc (S, &DOptNegAX3, 1);
@@ -2245,7 +2328,7 @@ static unsigned RunOptGroup3 (CodeSeg* S)
     do {
        	C = 0;
 
-       	C += RunOptFunc (S, &DOptPtrLoad9, 1);
+       	C += RunOptFunc (S, &DOptPtrLoad10, 1);
        	C += RunOptFunc (S, &DOptNegA1, 1);
        	C += RunOptFunc (S, &DOptNegA2, 1);
        	C += RunOptFunc (S, &DOptSub1, 1);
@@ -2320,7 +2403,7 @@ static unsigned RunOptGroup5 (CodeSeg* S)
 /* Run another round of pattern replacements. These are done late, since there
  * may be better replacements before.
  */
-{                                      
+{
     unsigned Changes = 0;
 
     Changes += RunOptFunc (S, &DOptPush1, 1);
-- 
2.39.5