d_seg   segment
table   db 0dh,0ah, 'Please input Beep number(1-9,[0] or [Enter] to exit):','$'
d_seg   ends
c_seg   segment
        assume cs:c_seg,ds:d_seg
main    proc   far
start:
        mov ax,d_seg
        mov ds,ax
loop1:
        lea dx,table
        mov ah,9h
        int 21h
        mov ah,01
        int 21h
        cmp al,0dh      ;if key=return then exit
        jz exit
        mov ch,0
        sub al,30h
        jz exit
        cmp al,0ah
        jb loop2
        mov al,9
loop2:
        mov cl,al
beep:
        mov dl,07
        mov ah,02
        int 21h
        nop
        nop
        loop beep
        jmp loop1
exit:
        mov ax,4c00h
        int 21h
main    endp
c_seg     ends
.8086
c1_seg  segment
        
        xchg ax,bx
        mov ax,d_seg
        mov ds,ax
c1_seg  ends
          end start