Bitfields for keyboard shift flags:
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: #00587,#03743,MEM 0040h:0017h,#M0010