define(n_r, i0)
define(j_r, l0)
define(prod_r, i0)
define(local_n_r, l1)

.global main

main:
    save    %sp, -96, %sp

    call    factorial
    mov     4, %o0

    b       skip
    mov     1, %g1


.global factorial

factorial:
    save    %sp, -64, %sp
    mov     %n_r, %local_n_r ! store int n in local variable

    mov     1, %prod_r  ! set product to 1

    b       fortest
    mov     1, %j_r ! set j to 1

for:
    call    .mul        ! n = n * j
    mov     %j_r, %o1

    mov     %o0, %prod_r   ! move the resulting answer into N
    inc     %j_r        ! j++

fortest:
    cmp     %j_r, %local_n_r ! check that j <= N
    ble,a   for
    mov     %prod_r, %o0 ! move n in o0 so that call to .mul can occur

    ret
    restore ! restore the window and return to calling instruction

skip:
    ta      0
~