A few minor 65C02 optimizations.

git-svn-id: svn://svn.cc65.org/cc65/trunk@3944 b7a2c559-68d2-44c3-8de9-860c34a00d81
2009-02-22 15:39:19 +00:00
parent a0cd736adb
commit 3c168b4323
4 changed files with 40 additions and 16 deletions
--- a/libsrc/runtime/lsub.s
+++ b/libsrc/runtime/lsub.s
@@ -11,13 +11,20 @@
 	.import		addysp1
 	.importzp   	sp, sreg

+        .macpack        cpu
+
 tossubeax:
-      	ldy	#0
-       	sec
+      	sec
 	eor	#$FF
-       	adc	(sp),y		; byte 0
+.if (.cpu .bitand CPU_ISET_65SC02)
+     	adc	(sp)	       	; 65SC02 version - saves 2 cycles
+	ldy	#1
+.else
+      	ldy	#0
+      	adc	(sp),y	   	; lo byte
+      	iny
+.endif
       	pha			; Save low byte
-	iny
 	txa
 	eor	#$FF
 	adc	(sp),y		; byte 1