Bitfields for keyboard shift flags 1:
Bit(s)	Description	)
 7	Insert active
 6	CapsLock active
 5	NumLock active
 4	ScrollLock active
 3	Alt key pressed (either Alt on 101/102-key keyboards)
 2	Ctrl key pressed (either Ctrl on 101/102-key keyboards)
 1	left shift key pressed
 0	right shift key pressed
SeeAlso: #00582,#00588,MEM 0040h:0017h,#M0010