INT 16 - KEYBOARD - GET ENHANCED KEYSTROKE (enhanced kbd support only)
        AH = 10h
Return: AH = BIOS scan code
        AL = ASCII character
Notes:  if no keystroke is available, this function waits until one is placed
          in the keyboard buffer
        the BIOS scan code is usually, but not always, the same as the hardware
          scan code processed by INT 09.  It is the same for ASCII keystrokes
          and most unshifted special keys (F-keys, arrow keys, etc.), but
          differs for shifted special keys.
        unlike AH=00h, this function does not discard extended keystrokes
SeeAlso: AH=11h,AH=20h