.text
; input R16/17/18/19, stack
; output R16/17/18/19

; lsr(int l, int cnt)
lsr32::
	push R0
	ld R0,y+
loop:
	tst R0
	breq done
	lsr R19
	ror R18
	ror R17
	ror R16
	dec R0
	rjmp loop
done:
	pop R0
	ret