- for (unsigned i = 0; i < (1 << 16); ++i)
- PopCnt16[i] = std::bitset<16>(i).count();
-
- for (Square s = SQ_A1; s <= SQ_H8; ++s)
- SquareBB[s] = (1ULL << s);
-
- for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
- for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
- SquareDistance[s1][s2] = std::max(distance<File>(s1, s2), distance<Rank>(s1, s2));
-
- for (Square s = SQ_A1; s <= SQ_H8; ++s)
- {
- PawnAttacks[WHITE][s] = pawn_attacks_bb<WHITE>(square_bb(s));
- PawnAttacks[BLACK][s] = pawn_attacks_bb<BLACK>(square_bb(s));
- }
-
- // Helper returning the target bitboard of a step from a square
- auto landing_square_bb = [&](Square s, int step)
- {
- Square to = Square(s + step);
- return is_ok(to) && distance(s, to) <= 2 ? square_bb(to) : Bitboard(0);
- };
-
- for (Square s = SQ_A1; s <= SQ_H8; ++s)
- {
- for (int step : {-9, -8, -7, -1, 1, 7, 8, 9} )
- PseudoAttacks[KING][s] |= landing_square_bb(s, step);
-
- for (int step : {-17, -15, -10, -6, 6, 10, 15, 17} )
- PseudoAttacks[KNIGHT][s] |= landing_square_bb(s, step);
- }
-
- Direction RookDirections[] = { NORTH, EAST, SOUTH, WEST };
- Direction BishopDirections[] = { NORTH_EAST, SOUTH_EAST, SOUTH_WEST, NORTH_WEST };
-
- init_magics(RookTable, RookMagics, RookDirections);
- init_magics(BishopTable, BishopMagics, BishopDirections);
-
- for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1)
- {
- PseudoAttacks[QUEEN][s1] = PseudoAttacks[BISHOP][s1] = attacks_bb<BISHOP>(s1, 0);
- PseudoAttacks[QUEEN][s1] |= PseudoAttacks[ ROOK][s1] = attacks_bb< ROOK>(s1, 0);
-
- for (PieceType pt : { BISHOP, ROOK })
- for (Square s2 = SQ_A1; s2 <= SQ_H8; ++s2)
- if (PseudoAttacks[pt][s1] & s2)
- LineBB[s1][s2] = (attacks_bb(pt, s1, 0) & attacks_bb(pt, s2, 0)) | s1 | s2;
- }
-}