main:	locals 0 1
	push_int 12
	store_var 0 1		# a = 12
	push_var 0 1
	put
	put_str "! = "
	push_var 0 1
	set_arg 1
	call -1 fact		# f(a)
	put
	put_nl
	ret

fact:	locals 1 0
	push_arg 0 1
	set_arg 1
	push_int 1
	set_arg 2
	call -1 fact_tail	# fact_tail(n, 1)
	ret
fact_tail:
	locals 2 0
	push_arg 0 1
	push_int 0
	jeq L1			# n == 0
	jump L2
L1:	push_arg 0 2
	ret
L2:	push_arg 0 1
	push_int 1
	sub			# n - 1
	push_arg 0 1
	push_arg 0 2
	mult			# n * f
	store_arg 0 2
	store_arg 0 1
	jump fact_tail		# fact_tail(n - 1, n * f)