Program for exchange two numbers

.model small

.data

a db 09H

b db 08H

.code

            mov      ax, @data                   

            mov      ds, ax

            mov      ah, 0

            mov      al, a                             

            mov      bl, b                            

        mov  bh, 0

        xchg bl,al

       

        mov ah, 4cH

            int         3H

            end