RosettaCodeData/Task/Ackermann-function/X86-Assembly/ackermann-function.x86

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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