count	EQU	$1004	; Put count in port B
dir	EQU	$1003	; Put dir in port C

start:	CLRA		; Set the current state to S0.
output:	STAA	count	; Output current state # as count.
	JSR	delay	; Delay so we can see what's happening
loop:	TST	dir	; Test the "dir" input
	BEQ	down	; Go down if dir=0
up:	CMPA	#5	; Already 5?
	BEQ	loop	; If so, no change.
	INCA		; Increment state number.
	BRA	output	; Update output and repeat.
down:	TST	count	; Check current count
	BEQ	loop	; If count=0, keep it.
	DECA		; Decrement state number.
	BRA	output	; Update output and repeat.

delay:	LDX	#1000
dloop:	DEX
	BNE	dloop
	RTS