8086 Assembly Langauge Program to add two numbers

data segment
num1 dw 10h
num2 dw 20h
res dw 1 dup(0)
data ends

code segment
assume cs:code, ds:data
start:

mov ax,data
mov ds,ax

mov ax,num1
add ax,num2
mov res,ax

mov ah,4ch
int 21h

code ends
end start