datarea  segment
         mess1  db 'personal_computer'
datarea  ends
extra    segment
         mess2     db  17 dup (?)
extra    ends
stack    segment stack
         db 100 dup(0)
stack    ends
code       segment
           assume  cs:code,ds:datarea,es:extra,ss:stack
start:     
      mov   ax,datarea
      mov   ds,ax
      mov   ch, 4
rotate: 
      mov   cl,  4
      rol   bx, cl
      mov   al,  bl
      and   al,  0fh
      add   al,  30h  ;¡¯0¡¯-¡¯9¡¯ ASCII 30H-39H
      cmp   al,  3ah
      jl    printit
      add   al,  7h   ;¡¯A¡¯-¡¯F¡¯ ASCII 41H-46H
printit: 
      mov   dl,  al
      mov   ah,  2
      int   21h
      dec   ch
      jnz   rotate                 
      mov   ah,4ch 
      int   21h 
code  ends 
      end   start