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.