mov a, 1002853
mov c, 2
call is_prime
end

is_prime:
cmp a, 2
jl exit
je exitPrime
inc c
call checkDividers
ret

checkDividers:
mov d, a
div d, c
mul d, c
cmp d, a
je exit
add c, 2
mov e, c
mul e, e
cmp e, a
jg exitPrime
call checkDividers

exitPrime:
msg 'number ', a, ' is prime!'
ret

exit:
msg 'number ', a, ' is not prime!'
ret

;)