PRINT macro
      mov ah,2
      int 21h
endm
CENTER macro
       mov bh,0
       mov dh,12
       mov dl,35
       mov ah,2
       int 10h
endm 
COLOR macro
      mov ah,6
      mov al,0
      mov bh,4h
      int 10h
endm
dseg segment
     help db 0
dseg ends 
sseg segment stack
     db 100h dup(0)
sseg ends
cseg segment
     assume cs:cseg,ds:dseg,ss:sseg
num1:mov help,al
     mov dl,help
     mov cl,4
     shr dl,cl
     and dl,0fh
     add dl,30h
     ret
num2:mov dl,help
     and dl,0fh
     add dl,30h         
     ret
start:mov ax,dseg
      mov ds,ax
now: mov ah,0bh   
     int 21h
     cmp al,0ffh
     je fin
;*********************************************
   COLOR
   CENTER
     mov al,4     
     out 70h,al
     in al,71h
   call num1
   PRINT    
   call num2
   PRINT
   mov dl,':'                     
   PRINT

;*****************************************
      mov al,2     
      out 70h,al
      in al,71h
  call num1
  PRINT
  call num2
  PRINT
  mov dl,':'                     
  PRINT
;****************************************** 
      mov al,0     
      out 70h,al
      in al,71h
  call num1
  PRINT
  call num2
  PRINT
;******************************************          
       mov cx,0ffffh
       mov si,0ffh
 rega:loop rega
      dec si
      jnz rega 
      jmp now
  fin:mov ax,4c00h
      int 21h
cseg ends
end start