jiecheng  proc  near
      push ax
      push bx
      push cx
      push dx



       xor ah,ah
       mov al,8
       mov bl,7
loop1:
       mul,bl
       dec bl
       cmp bl,0
       jne loop1
       mov dl,al
       mov ah,02h
       int 21h

       pop dx
       pop cx
       pop bx
       pop ax
       ret
jiecheng endp

第一个，8可以用其他数字换

nextcharacter  proc  near
      push ax
      push bx
      push cx
      push dx



        MOV    AH,01H       
        INT    16H
        mov dl,al
        inc dl
        mov ah,02h
        int 21h
       

       pop dx
       pop cx
       pop bx
       pop ax
       ret
nextcharacter endp