Assembly language. NASM caculator

Question

The code compiles and runs. For some reason though it will only let me input one number my symbol to perform the calculation and then closes before I can put in another number. I'm trying to get the programs to output as the following

This is my NASM code so far:

segment .data
  num1: db 4
  num2: db 4
  button: db 2

        segment .bss


        segment .text
         global  asm_main

        asm_main:
    push    ebp
    mov     ebp, esp

----------- CODE STARTS HERE -----------------

  call read_int
    mov DWORD[num1], eax

    call read_char
    mov DWORD[button], edx

    call read_int
    mov DWORD[num2], eax

    cmp DWORD[button], '+'
    jne addition

    cmp DWORD[button], '-'
    je subtraction

    cmp DWORD[button], '*'
    je multiplication

    cmp DWORD[button], '/'
    je division

    cmp DWORD[button], '%'
    je modulus

    addition:
    mov eax, DWORD[num1]
    add eax, DWORD[num2]
    call print_int
    jmp end

    subtraction:
    jmp end
    multiplication:
    jmp end
    division:
    jmp end
    modulus:
    jmp end

   end:

You're not showing all the code, e.g. `read_char`. One problem is your use of DWORD with `button`, which you have declared as two bytes. — 500 - Internal Server Error, Jun 13 '18 at 16:37
Actually it's even worse, `db 2` does **not** define two bytes, it's just one byte with value `2`. You want `dd` for dwords. — Jester, Jun 13 '18 at 16:40
If you want to load and store dwords without overlapping into other storage, then yes. Or better, put them in `.bss` with `resd 1` because you don't care about the initial value. — Peter Cordes, Jun 14 '18 at 01:10

Assembly language. NASM caculator

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