Several SBC optimizations suggested by Piotr Fusik

git-svn-id: svn://svn.cc65.org/cc65/trunk@1121 b7a2c559-68d2-44c3-8de9-860c34a00d81
2001-11-17 11:25:12 +00:00
parent 834eff684f
commit c413c5feeb
6 changed files with 53 additions and 58 deletions
--- a/libsrc/runtime/lsubeqsp.s
+++ b/libsrc/runtime/lsubeqsp.s
@@ -2,24 +2,23 @@
 ; Ullrich von Bassewitz, 08.10.1998
 ;
 ; CC65 runtime: -= operator for longs on the stack
-;			    
+;

       	.export	       	lsubeq0sp, lsubeqysp
-	.importzp   	sp, sreg, tmp1, tmp2
+	.importzp      	sp, sreg

 lsubeq0sp:
      	ldy	#0
 lsubeqysp:
    	sec
-	sta	tmp1
-	stx	tmp2
-       	lda	(sp),y
-	sbc	tmp1
+	eor	#$FF
+       	adc	(sp),y
 	sta	(sp),y
-	pha
+	pha	      		; Save low byte
 	iny
-       	lda	(sp),y
-	sbc	tmp2
+	txa
+	eor	#$FF
+       	adc	(sp),y
 	sta	(sp),y
 	tax
 	iny