INT 16 O - K3 v1.5x, K3PLUS v5.xx - GET EXTENDED BUFFER STATE                   
	AH = 20h
Return: AX = K3 version
	ES:BX -> extended keyboard buffer start
	ES:DX -> extended keyboard buffer end
	ES:SI -> next keystroke
	ES:DI -> last keystroke in buffer
	CX = number of keystrokes in buffer
Program: K3PLUS is an extended keyboard driver by Matthias Paul and Axel C.
	  Frinke, originally based on the K3 extended German keyboard driver
	  by Martin Gerdes published in c't magazine in 1988
Note:	this function was normally unsupported under K3PLUS v6.00-v6.22 and
	  is no longer supported by v6.30+; use AX=AF20h instead
SeeAlso: AH=25h"K3",AX=AF20h,INT 2F/AX=D44Fh/BX=0000h,INT 2F/AX=ED58h