code segment
  assume cs:code
start: 
     mov dx,0c418h
     out dx,al																
delay:
     in al,dx

     mov bl,al 
     mov cl,4
     shr bl,cl
     
      mov dl,bl          ;顯示高四位 
      cmp dl,09h
      jbe show1
      add dl,07h
show1:add dl,30h                
      mov ah,02h
      int 21h
     
      mov bl,al 
      and bl,0fh
      mov dl,bl  
      cmp dl,09h         ;顯示低四位
      jbe show2
      add dl,07h
show2:add dl,30h                
      mov ah,02h
      int 21h
              
     mov ah,02h
     int 21h  

     mov dl,0ffh
     mov ah,6
     int 21h
     jz start

     mov ah,4ch
     int 21h
code ends
    end start