--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Examples/6502/a.s65	Thu Aug 30 14:57:44 2007 +0900
@@ -0,0 +1,46 @@
+;;
+;;   ackerman function
+
+;;   procedure name ACK
+;;      ACK(X,Y)
+;;	   == if X=0 then Y+1
+;;	      else if Y=0 then ACK(X-1,1)
+;;	      else ACK(X-1, ACK(X,Y-1))
+
+;;   calling sequence
+;;
+;;	X  on   x
+;;      Y  on   y
+;;		non compile 11.86 sec on Sun 140
+;;		    compile  7.54 sec on Sun 140
+
+start		cld
+		ldx	#1
+		ldy	#1
+		jsr	ack
+		brk
+
+ack		cpx	#0
+		bne	xneqzero	
+xeqzero		iny
+		tya
+		rts			
+
+xneqzero	cpy	#0
+		bne	yneqzero	
+		dex			;; x <- x-1
+yeqzero		ldy	#1
+		jmp	ack		 ;; tail recursion
+
+yneqzero	txa
+		pha
+		dey			;; y <- y-1
+		jsr	ack		;; ack x,y-1
+		tay
+		pla
+		tax
+		dex			;; x <- x-1
+		jmp	ack		;; tail recursion
+
+		end
+;;