1’s Compliment

.model small

.data

  a db 04H

.code

            mov      ax, @data       

            mov      ds, ax

            mov      al, a                 

            mov      cx, 08              

up:        rcl        al, 1                 

            cmc                             

            loop     up                   

            rcl        al, 1                 

            add      al, 1                 

           

            mov      ah, 4cH

            int  3H

            end