; test read/write on actoive register (which is 16bit read/write)
tstadr	= 160000

	.asect
	.=1000
start:
	mov	#testadr,r3
	inc	r3
	mov	r3,r2
	; r2 = 160000, r3 = 160001
	clr	(r2)		; 0x0000
	movb	#377,(r2)       ; 0x0000 -> 0x00ff
	movb	#377,(r3)       ; 0x00ff -> 0xffff 177777
	movb	#0,(r2)		; 0xffff -> 0xff00 177400
	movb	#0,(r3)		; 0xff00 -> 0x0000
	halt
	; see logic analyzer trace