Int 16 Fn 11  - Keyboard - Check For Enhanced Keystroke (enh Kbd Support   [B]

   AH = 11h

Return: ZF set if no keystroke available
   ZF clear if keystroke available
       AH = BIOS scan code
       AL = ASCII character

Notes: if a keystroke is available, it is not removed from the keyboard buffer
   unlike AH=01h, this function does not discard extended keystrokes
   some versions of the IBM BIOS Technical Reference erroneously report
     that CF is returned instead of ZF
   INT 16/AH=09h can be used to determine whether this function is
     supported, but only on later model PS/2s

See Also: AH=01h,AH=09h,AH=10h,AH=21h