data segment
buf1 db 'current time is: $'
buf2 db 10
     db 10 dup(?)
data ends
stack segment stack
      db 100 dup(?)
stack ends
code  segment
assume cs:code, ds:data
assume ss:stack
cursor macro row,clm
       mov ah,2
       mov bh,0
       mov dh,row
       mov dl,clm
       int 10h
       endm
win   macro rowl,clml,rowr,clmr,color
      mov ah,6
      mov al,0
      mov ch,rowl
      mov cl,clml
      mov dh,rowr
      mov dl,clmr
      mov bh,color
      int 10h
      endm
ascbcd macro reg
       inc bx
       inc bx
       mov reg,[bx]
       mov cl,4
       shl reg,cl
       inc bx
       mov al,[bx]
       and al,0fh
       or reg,al
       endm
bcdasc macro reg   
       inc bx
       inc bx
       mov al,reg
       mov cl,4
       shr al,cl
       or al,30h
       mov [bx],al
       inc bx
       mov al,reg
       and al,0fh
       or al,30h
       mov [bx],al
       endm
incbcd macro reg,count
       mov al,reg
       inc al
       daa
       mov reg,al
       cmp al,count
       jnz dispy
       mov reg,0
       endm
strdspy macro adrs
        lea dx,adrs
        mov ah,9
        int 21h
        endm
clock  proc far
start: push ds
       mov ax,0 
       push ax
       mov ax,data
       mov ds,ax
       win 0,0,24,79,7;
       win 9,28,15,52,01010111b
       cursor 11,32
       strdspy buf1
       cursor 13,36
       lea dx,buf2
       mov ah,0ah
       int 21h
       lea bx,buf2
       ascbcd ch
       ascbcd dh
       ascbcd dl
timer: call dely 
       incbcd bl,60h
       incbcd dh,60h
       incbcd ch,24h
dispy: lea bx,buf2
       bcdasc ch
       bcdasc dh
       bcdasc dl
       inc bx
       mov al,'$'
       mov [bx],al
       push dx
       cursor 13,36
       strdspy buf2
       pop dx
       jmp timer
dely proc
     push cx
     push ax
     mov ax,3fffh
x1:  mov cx,0ffffh
x2:  dec cx
     jne x2
     dec ax
     jne x1
     pop ax
     pop cx
     ret
dely endp
clock endp
code ends
     end start