X-Git-Url: https://git.sur5r.net/?a=blobdiff_plain;f=src%2Fcc65%2Fcoptsub.c;h=5449889f6228e5a9602dcc6ff6f5dbf317fcf7c0;hb=112ae0e3db511ddd92e769c11328646ebe2a6240;hp=cbd09caa0a9bcb9eab9e69151bdeca4b04d2e1ac;hpb=3c90e33414e5280501f5963150ffd8718fb77a7b;p=cc65

diff --git a/src/cc65/coptsub.c b/src/cc65/coptsub.c
index cbd09caa0..5449889f6 100644
--- a/src/cc65/coptsub.c
+++ b/src/cc65/coptsub.c
@@ -6,10 +6,10 @@
 /*                                                                           */
 /*                                                                           */
 /*                                                                           */
-/* (C) 2001      Ullrich von Bassewitz                                       */
-/*               Wacholderweg 14                                             */
-/*               D-70597 Stuttgart                                           */
-/* EMail:        uz@cc65.org                                                 */
+/* (C) 2001-2006, Ullrich von Bassewitz                                      */
+/*                Römerstrasse 52                                            */
+/*                D-70794 Filderstadt                                        */
+/* EMail:         uz@cc65.org                                                */
 /*                                                                           */
 /*                                                                           */
 /* This software is provided 'as-is', without any expressed or implied       */
@@ -33,6 +33,9 @@
 
 
 
+/* common */
+#include "chartype.h"
+
 /* cc65 */
 #include "codeent.h"
 #include "codeinfo.h"
@@ -175,4 +178,56 @@ unsigned OptSub2 (CodeSeg* S)
 
 
 
+unsigned OptSub3 (CodeSeg* S)
+/* Search for a call to decaxn and replace it by an 8 bit sub if the X register
+ * is not used later.
+ */
+{
+    unsigned Changes = 0;
+
+    /* Walk over the entries */
+    unsigned I = 0;
+    while (I < CS_GetEntryCount (S)) {
+
+	CodeEntry* E;
+
+      	/* Get next entry */
+       	E = CS_GetEntry (S, I);
+
+     	/* Check for the sequence */
+        if (E->OPC == OP65_JSR                          &&
+            strncmp (E->Arg, "decax", 5) == 0           &&
+            IsDigit (E->Arg[5])                         &&
+            E->Arg[6] == '\0'                           &&
+            !RegXUsed (S, I+1)) {
+
+            CodeEntry* X;
+            const char* Arg;
+
+            /* Insert new code behind the sequence */
+	    X = NewCodeEntry (OP65_SEC, AM65_IMP, 0, 0, E->LI);
+	    CS_InsertEntry (S, X, I+1);
+
+	    Arg = MakeHexArg (E->Arg[5] - '0');
+       	    X = NewCodeEntry (OP65_SBC, AM65_IMM, Arg, 0, E->LI);
+	    CS_InsertEntry (S, X, I+2);
+
+       	    /* Delete the old code */
+	    CS_DelEntry (S, I);
+
+	    /* Remember, we had changes */
+	    ++Changes;
+
+	}
+
+	/* Next entry */
+	++I;
+
+    }
+
+    /* Return the number of changes made */
+    return Changes;
+}
+
+