fact:
    ld [fp+12] -> %r0          / do the if statement
    cmp %r0, %g0
    bne l1
    mov %g1 -> %r0
    ret

l1:
    ld [fp+12] -> %r0          / push i-1 on the stack
    add %r0, %gm1 -> %r0
    st %r0 -> [sp]--
    jsr fact                   / recursive call to fact
    pop #4                     / pop the argument off the stack

    ld [fp+12] -> %r1          / multiply fact(i-1)*i
    mul %r0, %r1 -> %r0
    ret

main: 
    push #4
    mov #4 -> %r0
    st %r0 -> [sp]--
    jsr fact
    pop #4
    st %r0 -> [fp]
    ret