collapseos/blk/569

: (key)
    0 ( gid ) 0 ( dummy )
    BEGIN ( loop until a digit is pressed )
        DROP
        1+ DUP 7 = IF DROP 0 THEN ( inc gid )
        1 OVER LSHIFT 0xff -^ ( group dmask ) _get
    DUP 0xff = NOT UNTIL
    ( gid dmask )
    0xff XOR ( dpos ) 0 ( dindex )
    BEGIN 1+ 2DUP RSHIFT NOT UNTIL 1-
    ( gid dpos dindex ) SWAP DROP
    ( gid dindex ) SWAP 8 * + _dtbl + C@ _wait
;