[MASM] Ввод чисел и арифметические операции над ними

.586
.model flat,stdcall
option casemap:none
include windows.inc
include user32.inc
include kernel32.inc
include masm32.inc
includelib user32.lib
includelib masm32.lib
includelib kernel32.lib
 
.data
mestitle db " Вывод числа ",0 
mess db "Cумма  чисел =",0  ;13,10,0 - перевод строки
buffer db 128 dup (0)
 
format db "%s  %d",0
 
.code
start:
 
xor eax,eax
mov al,50
sub al,45
 
invoke wsprintf, addr buffer,addr format,addr mess,eax ; сообщение
invoke MessageBox,0,addr buffer,addr mestitle,MB_OK ; заголовок
invoke ExitProcess,0 
end start

mov al,50
sub al,45
 
invoke wsprintf, addr buffer,addr format,addr mess,eax ; сообщение
invoke MessageBox,0,addr buffer,addr mestitle,MB_OK ; заголовок
or al, 50
add 45
invoke wsprintf, addr buffer,addr format,addr mess,eax ; сообщение
invoke MessageBox,0,addr buffer,addr mestitle,MB_OK ; заголовок

invoke wsprintf, addr buffer,addr format,addr mess,eax ; ñîîáùåíèå
invoke MessageBox,0,addr buffer,addr mestitle,MB_OK ; çàãîëîâîê
 
invoke wsprintf, addr buffer,addr format,addr mess,eax ; ñîîáùåíèå
invoke MessageBox,0,addr buffer,addr mestitle,MB_OK ; çàãîëîâîê

 
format PE console 4.0
 
include 'win32a.inc'
    cinvoke crt_printf, entr,_1st
    cinvoke crt_scanf, itpt, buf
    cinvoke crt_printf, entr,_2nd
    cinvoke crt_scanf, itpt, bf2
    mov eax, [buf]
    mov ebx, eax
    mov ecx, [bf2]
    sub eax, ecx
    add ebx, ecx
    cinvoke crt_printf, res, ebx, eax
    invoke  crt_getch
        invoke  crt_exit,0
entr    db      'Enter %s number:',0
_1st    db  'first',0
_2nd    db  'second',0
res db  'result of: add %d.,sub %d.',0dh,0ah,'Press <Enter>',0
itpt    db  '%d',0
buf     dd      ?
bf2 dd  ?
; import data in the same section
 data import
 
 library msvcrt,'MSVCRT.DLL'
 
 import msvcrt,\
    crt_scanf,'scanf',\
    crt_printf,'printf',\
        crt_exit,'exit',\
    crt_getch, '_getch'
end data