-extern Bitboard SquareBB[64];
-extern Bitboard FileBB[8];
-extern Bitboard RankBB[8];
-extern Bitboard AdjacentFilesBB[8];
-extern Bitboard ThisAndAdjacentFilesBB[8];
-extern Bitboard InFrontBB[2][8];
-extern Bitboard StepAttacksBB[16][64];
-extern Bitboard BetweenBB[64][64];
-extern Bitboard ForwardBB[2][64];
-extern Bitboard PassedPawnMask[2][64];
-extern Bitboard AttackSpanMask[2][64];
-extern Bitboard PseudoAttacks[6][64];
+const Bitboard DarkSquares = 0xAA55AA55AA55AA55ULL;
+
+const Bitboard FileABB = 0x0101010101010101ULL;
+const Bitboard FileBBB = FileABB << 1;
+const Bitboard FileCBB = FileABB << 2;
+const Bitboard FileDBB = FileABB << 3;
+const Bitboard FileEBB = FileABB << 4;
+const Bitboard FileFBB = FileABB << 5;
+const Bitboard FileGBB = FileABB << 6;
+const Bitboard FileHBB = FileABB << 7;
+
+const Bitboard Rank1BB = 0xFF;
+const Bitboard Rank2BB = Rank1BB << (8 * 1);
+const Bitboard Rank3BB = Rank1BB << (8 * 2);
+const Bitboard Rank4BB = Rank1BB << (8 * 3);
+const Bitboard Rank5BB = Rank1BB << (8 * 4);
+const Bitboard Rank6BB = Rank1BB << (8 * 5);
+const Bitboard Rank7BB = Rank1BB << (8 * 6);
+const Bitboard Rank8BB = Rank1BB << (8 * 7);
+
+extern int SquareDistance[SQUARE_NB][SQUARE_NB];
+
+extern Bitboard RookMasks [SQUARE_NB];
+extern Bitboard RookMagics [SQUARE_NB];
+extern Bitboard* RookAttacks[SQUARE_NB];
+extern unsigned RookShifts [SQUARE_NB];
+
+extern Bitboard BishopMasks [SQUARE_NB];
+extern Bitboard BishopMagics [SQUARE_NB];
+extern Bitboard* BishopAttacks[SQUARE_NB];
+extern unsigned BishopShifts [SQUARE_NB];
+
+extern Bitboard SquareBB[SQUARE_NB];
+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 LineBB[SQUARE_NB][SQUARE_NB];
+extern Bitboard DistanceRingBB[SQUARE_NB][8];
+extern Bitboard ForwardBB[COLOR_NB][SQUARE_NB];
+extern Bitboard PassedPawnMask[COLOR_NB][SQUARE_NB];
+extern Bitboard PawnAttackSpan[COLOR_NB][SQUARE_NB];
+extern Bitboard PseudoAttacks[PIECE_TYPE_NB][SQUARE_NB];