-extern Bitboard FileBB[FILE_NB];
-extern Bitboard RankBB[RANK_NB];
-extern Bitboard AdjacentFilesBB[FILE_NB];
-extern Bitboard InFrontBB[COLOR_NB][RANK_NB];
-extern Bitboard StepAttacksBB[PIECE_NB][SQUARE_NB];
-extern Bitboard BetweenBB[SQUARE_NB][SQUARE_NB];
-extern Bitboard DistanceRingsBB[SQUARE_NB][8];
-extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
-extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
-extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];