}
// Give a bonus for a rook on a open or semi-open file
- if (ei.pi->semiopen(Us, file_of(s)))
- score += ei.pi->semiopen(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
+ if (ei.pi->semiopen_file(Us, file_of(s)))
+ score += ei.pi->semiopen_file(Them, file_of(s)) ? RookOpenFile : RookSemiopenFile;
- if (mob > 3 || ei.pi->semiopen(Us, file_of(s)))
+ if (mob > 3 || ei.pi->semiopen_file(Us, file_of(s)))
continue;
Square ksq = pos.king_square(Us);
// king has lost its castling capability.
if ( ((file_of(ksq) < FILE_E) == (file_of(s) < file_of(ksq)))
&& (rank_of(ksq) == rank_of(s) || relative_rank(Us, ksq) == RANK_1)
- && !ei.pi->semiopen_on_side(Us, file_of(ksq), file_of(ksq) < FILE_E))
- score -= (TrappedRook - make_score(mob * 8, 0)) * (pos.can_castle(Us) ? 1 : 2);
+ && !ei.pi->semiopen_side(Us, file_of(ksq), file_of(s) < file_of(ksq)))
+ score -= (TrappedRook - make_score(mob * 8, 0)) * (1 + !pos.can_castle(Us));
}
// An important Chess960 pattern: A cornered bishop blocked by a friendly
}
-/// Entry::update_safety() calculates and caches a bonus for king safety.
-/// It is called only when king square changes, which is about 20% of total
-/// king_safety() calls.
+/// Entry::do_king_safety() calculates a bonus for king safety. It is called only
+/// when king square changes, which is about 20% of total king_safety() calls.
template<Color Us>
-Score Entry::update_safety(const Position& pos, Square ksq) {
+Score Entry::do_king_safety(const Position& pos, Square ksq) {
kingSquares[Us] = ksq;
castlingRights[Us] = pos.can_castle(Us);
while (!(DistanceRingsBB[ksq][minKPdistance[Us]++] & pawns)) {}
if (relative_rank(Us, ksq) > RANK_4)
- return kingSafety[Us] = make_score(0, -16 * minKPdistance[Us]);
+ return make_score(0, -16 * minKPdistance[Us]);
Value bonus = shelter_storm<Us>(pos, ksq);
if (pos.can_castle(MakeCastling<Us, QUEEN_SIDE>::right))
bonus = std::max(bonus, shelter_storm<Us>(pos, relative_square(Us, SQ_C1)));
- return kingSafety[Us] = make_score(bonus, -16 * minKPdistance[Us]);
+ return make_score(bonus, -16 * minKPdistance[Us]);
}
// Explicit template instantiation
-template Score Entry::update_safety<WHITE>(const Position& pos, Square ksq);
-template Score Entry::update_safety<BLACK>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<WHITE>(const Position& pos, Square ksq);
+template Score Entry::do_king_safety<BLACK>(const Position& pos, Square ksq);
} // namespace Pawns
namespace Pawns {
-/// Pawns::Entry contains various information about a pawn structure. Currently,
-/// it only includes a middlegame and endgame pawn structure evaluation, and a
-/// bitboard of passed pawns. We may want to add further information in the future.
-/// A lookup to the pawn hash table (performed by calling the probe function)
-/// returns a pointer to an Entry object.
+/// Pawns::Entry contains various information about a pawn structure. A lookup
+/// to the pawn hash table (performed by calling the probe function) returns a
+/// pointer to an Entry object.
struct Entry {
Bitboard pawn_attacks(Color c) const { return pawnAttacks[c]; }
Bitboard passed_pawns(Color c) const { return passedPawns[c]; }
Bitboard candidate_pawns(Color c) const { return candidatePawns[c]; }
- int pawns_on_same_color_squares(Color c, Square s) const { return pawnsOnSquares[c][!!(DarkSquares & s)]; }
- int semiopen(Color c, File f) const { return semiopenFiles[c] & (1 << int(f)); }
- int semiopen_on_side(Color c, File f, bool left) const {
- return semiopenFiles[c] & (left ? ((1 << int(f)) - 1) : ~((1 << int(f+1)) - 1));
+ int semiopen_file(Color c, File f) const {
+ return semiopenFiles[c] & (1 << f);
+ }
+
+ int semiopen_side(Color c, File f, bool leftSide) const {
+ return semiopenFiles[c] & (leftSide ? (1 << f) - 1 : ~((1 << (f + 1)) - 1));
+ }
+
+ int pawns_on_same_color_squares(Color c, Square s) const {
+ return pawnsOnSquares[c][!!(DarkSquares & s)];
}
template<Color Us>
Score king_safety(const Position& pos, Square ksq) {
-
- return kingSquares[Us] == ksq && castlingRights[Us] == pos.can_castle(Us)
- ? kingSafety[Us] : update_safety<Us>(pos, ksq);
+ return kingSquares[Us] == ksq && castlingRights[Us] == pos.can_castle(Us)
+ ? kingSafety[Us] : (kingSafety[Us] = do_king_safety<Us>(pos, ksq));
}
template<Color Us>
- Score update_safety(const Position& pos, Square ksq);
+ Score do_king_safety(const Position& pos, Square ksq);
template<Color Us>
Value shelter_storm(const Position& pos, Square ksq);
Key key;
+ Score value;
Bitboard passedPawns[COLOR_NB];
Bitboard candidatePawns[COLOR_NB];
Bitboard pawnAttacks[COLOR_NB];
Square kingSquares[COLOR_NB];
+ Score kingSafety[COLOR_NB];
int minKPdistance[COLOR_NB];
int castlingRights[COLOR_NB];
- Score value;
int semiopenFiles[COLOR_NB];
- Score kingSafety[COLOR_NB];
- int pawnsOnSquares[COLOR_NB][COLOR_NB];
+ int pawnsOnSquares[COLOR_NB][COLOR_NB]; // [color][light/dark squares]
};
typedef HashTable<Entry, 16384> Table;
void init();
Entry* probe(const Position& pos, Table& entries);
-}
+} // namespace Pawns
#endif // #ifndef PAWNS_H_INCLUDED