;; count with interrupt

.symbol
	stop 0
	cnt 20

.code 0
:main
	mv r1 #isr
	st r1 1000   ;; set up int vector
	mv r1 #0
	st r1 cnt    ;; cnt = 0
:loop
;; this is almost empty loop
	ld r1 cnt
	eq r2 r1 #10
	jf r2 loop
	trap stop

:isr
;; must not use r1 r2
	ld r3 cnt
	add r3 r3 #1
	st r3 cnt
	reti
.end