INT 16 - HUNTER 16 - CONTROL SHIFT KEYS                                         
	AH = 21h
	AL = shift keys to control (see #00582)
	BL = shift state for disabled keys
Note:	If a bit in AL is set the key is disabled and set to the state of the
	  corresponding bit in BL
SeeAlso: AH=20h"HUNTER",AH=22h"HUNTER"