INT 16,1 - Get Keyboard Status

	AH = 01


	on return:
	ZF = 0 if a key pressed (even Ctrl-Break)
	AX = 0 if no scan code is available
	AH = scan code
	AL = ASCII character or zero if special function key


	- data code is not removed from buffer
	- Ctrl-Break places a zero word in the keyboard buffer but does
	  register a keypress.