用汇编编写DOS下的内存驻留程序(5)：键盘输入扩充程序

; mov al,cs:[si]
  inc cs:current
  pop si
  cmp al,0    ;Is this end of string?
  je ReadChar   ;If so,then read a real char?
  ret
 KeyRead  endp
 Initialize:
  assume cs:cseg,ds:cseg
  mov bx,cs
  mov ds,bx
  mov al,16h
  mov ah,35h
  int 21h
  mov word ptr Old_Keyboard_IO,bx
  mov word ptr Old_Keyboard_IO,es
  mov dx,offset New_Keyboard_IO
  mov al,16h
  mov ah,25h
  int 21h
  mov dx,offset Initialize
  int 27h
 cseg ends
  end Start