INT 16,11 - Extended Get Keyboard Status (AT+)

	AH = 11h

	on return:
	ZF = 0 if key pressed (data waiting)
	AX = 0 if no scan code is available
	AH = scan code
	AL = ASCII character or zero if special function key

	- available on AT and PS/2 machines with extended keyboard support
	- data is not removed from buffer
	- similar to INT 16,1