From 2de4a26251099ddb9958bee56688f1fd28993797 Mon Sep 17 00:00:00 2001
From: cuz <cuz@b7a2c559-68d2-44c3-8de9-860c34a00d81>
Date: Sat, 17 Nov 2001 11:31:57 +0000
Subject: [PATCH] Added SBC optimizations suggested by Piotr Fusik

git-svn-id: svn://svn.cc65.org/cc65/trunk@1123 b7a2c559-68d2-44c3-8de9-860c34a00d81
---
 src/cc65/codegen.c | 35 ++++++++++++++++-------------------
 1 file changed, 16 insertions(+), 19 deletions(-)

diff --git a/src/cc65/codegen.c b/src/cc65/codegen.c
index c3e06fd32..01bb11507 100644
--- a/src/cc65/codegen.c
+++ b/src/cc65/codegen.c
@@ -1748,11 +1748,10 @@ void g_subeqstatic (unsigned flags, unsigned long label, long offs,
        		     	AddCodeLine ("sbc #$%02X", (int)(val & 0xFF));
        		     	AddCodeLine ("sta %s", lbuf);
        		    }
-       	  	} else {
+       	  	} else {	      
+		    AddCodeLine ("eor #$FF");
        		    AddCodeLine ("sec");
-       		    AddCodeLine ("sta tmp1");
-       	  	    AddCodeLine ("lda %s", lbuf);
-       	       	    AddCodeLine ("sbc tmp1");
+       	       	    AddCodeLine ("adc %s", lbuf);
        		    AddCodeLine ("sta %s", lbuf);
        	  	}
        		if ((flags & CF_UNSIGNED) == 0) {
@@ -1784,14 +1783,13 @@ void g_subeqstatic (unsigned flags, unsigned long label, long offs,
 		    AddCodeLine ("tax");
 		    AddCodeLine ("lda %s", lbuf);
 		}
-	    } else {
-		AddCodeLine ("sta tmp1");
-		AddCodeLine ("lda %s", lbuf);
-	        AddCodeLine ("sbc tmp1");
+	    } else {	      
+		AddCodeLine ("eor #$FF");
+       	       	AddCodeLine ("adc %s", lbuf);
 		AddCodeLine ("sta %s", lbuf);
-       	       	AddCodeLine ("stx tmp1");
-		AddCodeLine ("lda %s+1", lbuf);
-		AddCodeLine ("sbc tmp1");
+		AddCodeLine ("txa");
+		AddCodeLine ("eor #$FF");
+       	       	AddCodeLine ("adc %s+1", lbuf);
 		AddCodeLine ("sta %s+1", lbuf);
 		AddCodeLine ("tax");
 		AddCodeLine ("lda %s", lbuf);
@@ -1845,18 +1843,17 @@ void g_subeqlocal (unsigned flags, int offs, unsigned long val)
 		    AddCodeLine ("lda (sp),y");
 		    AddCodeLine ("sbc #$%02X", (unsigned char)val);
 		} else {
-		    AddCodeLine ("sta tmp1");
-	     	    AddCodeLine ("lda (sp),y");
-		    AddCodeLine ("sbc tmp1");
+		    AddCodeLine ("eor #$FF");
+	     	    AddCodeLine ("adc (sp),y");
 		}
        	 	AddCodeLine ("sta (sp),y");
 		if ((flags & CF_UNSIGNED) == 0) {
-		    unsigned L = GetLocalLabel();
+	    	    unsigned L = GetLocalLabel();
 	       	    AddCodeLine ("bpl %s", LocalLabelName (L));
-		    AddCodeLine ("dex");
-		    g_defcodelabel (L);
-		}
-       	 	break;
+	    	    AddCodeLine ("dex");
+	    	    g_defcodelabel (L);
+	    	}
+       	    	break;
        	    }
        	    /* FALLTHROUGH */
 
-- 
2.39.5