SYS_EXIT  equ 1
    SYS_READ  equ 3
    SYS_WRITE equ 4
    STDIN     equ 0
    STDOUT    equ 1

segment .data

    msg db "Please enter a digit ", 0xA,0xD
    len equ $- msg

segment .bss

    number1 resb 2
    number2 resb 2
    result resb 1
    result2 resb 1


segment .text

    msg2 db "Please enter a second digit", 0xA,0xD
    len2 equ $- msg2

    msg3 db "The sum is: "
    len3 equ $- msg3

    msg4 db "The minus is: "
    len4 equ $- msg4

global _start

 _start:

    mov eax, SYS_WRITE   ; System write
    mov ebx, STDOUT      ; System output
    mov ecx, msg         ; What to write
    mov edx, len     ; Length to write
    int 0x80             ; Interupt Kernel

    mov eax, SYS_READ    ; System read
    mov ebx, STDIN       ;
    mov ecx, number1
    mov edx, 2
    int 0x80

    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, msg2
    mov edx, len2
    int 0x80

    mov eax, SYS_READ
    mov ebx, STDIN
    mov ecx, number2
    mov edx, 2
    int 0x80


    call add



add:
    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, msg3
    mov edx, len3
    int 0x80

    ;load number1 into eax and subtract '0' to convert from ASCII to decimal
    mov eax, [number1]
    sub eax, '0'
    ; do the same for number2
    mov ebx, [number2]
    sub ebx, '0'

    ; add eax and ebx, storing the result in eax
    add eax, ebx
    ; add '0' to eax to convert the digit from decimal to ASCII
    add eax, '0'

    ; store the result in result
    mov [result], eax

    ; print the result digit
    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, result
    mov edx, 1
    int 0x80

    ret

minus:

    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, msg4
    mov edx, len4
    int 0x80

    ;load number1 into eax and subtract '0' to convert from ASCII to decimal
    mov eax, [number1]
    sub eax, '0'
    ; do the same for number2
    mov ebx, [number2]
    sub ebx, '0'

    ; add eax and ebx, storing the result in eax
    sub eax, ebx
    ; add '0' to eax to convert the digit from decimal to ASCII
    add eax, '0'

    ; store the result in result
    mov [result2], eax

    ; print the result digit
    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, result
    mov edx, 1
    int 0x80

    ret

mul:

   ;load number1 into eax and subtract '0' to convert from ASCII to decimal
    mov al, [number1]
    sub al, '0'
    ; do the same for number2
    mov bl, [number2]
    sub bl, '0'

    ; add eax and ebx, storing the result in eax
    mul bl
    ; add '0' to eax to convert the digit from decimal to ASCII
    add al, '0'

    ; store the result in result
    mov [result], al

    ; print the result digit
    mov eax, SYS_WRITE
    mov ebx, STDOUT
    mov ecx, result
    mov edx, 1
    int 0x80

    ret


exit:
    mov eax, SYS_EXIT
    xor ebx, ebx
    int 0x80