386 model flat stdcall includelib kernel32 lib ExitProcess PROTO DWORD

.386 
.model flat, stdcall
includelib kernel32.lib
ExitProcess PROTO      ,:DWORD 
.data 
X dd 5
Y dd 7
Z dd 9

res dd ?
tmp dd ?

.code 
Winmain PROC
mov eax,X
xor edx,edx
mov ebx,Y
div ebx
mov tmp,eax

mov eax,Z
mov ebx,5
mul ebx

add eax,tmp 
mov res,eax
push 0
call ExitProcess
Winmain endp
end Winmain