title "The first program"
.model small
.stack 100h
.data

msg1 db "Welcome",0dh,0ah,'$'
msg2 db 0dh,0ah,"Enter a number ",'$'
msg3 db 0dh,0ah,"The sum is ",'$'

.code

EXTERN SUM:near

mov ax,@data
mov ds,ax

mov ah,09
lea dx,msg1
int 21h

mov ah,09
lea dx,msg2
int 21h

mov ah,01
int 21h
sub al,30h
mov bl,al

mov ah,09
lea dx,msg2
int 21h

mov ah,01
int 21h
sub al,30h

call sum

mov ah,09
lea dx,msg3
int 21h

mov ah,02
mov dl,bl
add dl,30h
int 21h

mov ax,4c00h
int 21h

end