2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
6 Stockfish is free software: you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation, either version 3 of the License, or
9 (at your option) any later version.
11 Stockfish is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #if !defined(PAWNS_H_INCLUDED)
21 #define PAWNS_H_INCLUDED
27 const int PawnTableSize = 16384;
29 /// PawnEntry is a class which contains various information about a pawn
30 /// structure. Currently, it only includes a middle game and an end game
31 /// pawn structure evaluation, and a bitboard of passed pawns. We may want
32 /// to add further information in the future. A lookup to the pawn hash
33 /// table (performed by calling the probe method in a PawnTable object)
34 /// returns a pointer to a PawnEntry object.
38 friend struct PawnTable;
41 Score pawns_value() const;
42 Bitboard pawn_attacks(Color c) const;
43 Bitboard passed_pawns(Color c) const;
44 int file_is_half_open(Color c, File f) const;
45 int has_open_file_to_left(Color c, File f) const;
46 int has_open_file_to_right(Color c, File f) const;
49 Score king_safety(const Position& pos, Square ksq);
53 Score update_safety(const Position& pos, Square ksq);
56 Value shelter_storm(const Position& pos, Square ksq);
59 Bitboard passedPawns[COLOR_NB];
60 Bitboard pawnAttacks[COLOR_NB];
61 Square kingSquares[COLOR_NB];
62 int minKPdistance[COLOR_NB];
63 int castleRights[COLOR_NB];
65 int halfOpenFiles[COLOR_NB];
66 Score kingSafety[COLOR_NB];
70 /// The PawnTable class represents a pawn hash table. The most important
71 /// method is probe, which returns a pointer to a PawnEntry object.
75 PawnEntry* probe(const Position& pos);
78 static Score evaluate_pawns(const Position& pos, Bitboard ourPawns,
79 Bitboard theirPawns, PawnEntry* e);
81 HashTable<PawnEntry, PawnTableSize> entries;
85 inline Score PawnEntry::pawns_value() const {
89 inline Bitboard PawnEntry::pawn_attacks(Color c) const {
90 return pawnAttacks[c];
93 inline Bitboard PawnEntry::passed_pawns(Color c) const {
94 return passedPawns[c];
97 inline int PawnEntry::file_is_half_open(Color c, File f) const {
98 return halfOpenFiles[c] & (1 << int(f));
101 inline int PawnEntry::has_open_file_to_left(Color c, File f) const {
102 return halfOpenFiles[c] & ((1 << int(f)) - 1);
105 inline int PawnEntry::has_open_file_to_right(Color c, File f) const {
106 return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
110 inline Score PawnEntry::king_safety(const Position& pos, Square ksq) {
111 return kingSquares[Us] == ksq && castleRights[Us] == pos.can_castle(Us)
112 ? kingSafety[Us] : update_safety<Us>(pos, ksq);
115 #endif // !defined(PAWNS_H_INCLUDED)