section .text

global _main
_main:
    mov eax, 3 ;m
    mov ebx, 4 ;n
    call ack ;returns number in ebx
    ret

ack:
    cmp eax, 0
    je M0 ;if M == 0
    cmp ebx, 0
    je N0 ;if N == 0
    dec ebx ;else N-1
    push eax ;save M
    call ack1 ;ack(m,n) -> returned in ebx so no further instructions needed
    pop eax ;restore M
    dec eax ;M - 1
    call ack1 ;return ack(m-1,ack(m,n-1))
    ret
    M0:
        inc ebx ;return n + 1
        ret
    N0:
        dec eax
        inc ebx ;ebx always 0: inc -> ebx = 1
        call ack1 ;return ack(M-1,1)
        ret