操作后的NASM整数输入和打印整数

Question

我是nasm的新手，我正尝试在nasm中使用Mac osx执行以下操作。 不管那个事实，只是指导我如何从控制台读取整数

.data
_num word 0
_sum    word 0
_msg1   byte "Enter a number: ", 0
_msg2   byte "The sum is: ", 0

.code
main proc

mov edx, offset _msg1
call writestring
call readint
mov [_num], eax
call writestring
call readint

add eax, [_num]
mov [_sum], eax

call writestring
call readint

sub [_sum], eax
mov eax, [_sum]

call writeint

exit

main endp
end main