2 Stockfish, a UCI chess playing engine derived from Glaurung 2.1
3 Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
4 Copyright (C) 2008-2010 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/>.
21 #if !defined(PAWNS_H_INCLUDED)
22 #define PAWNS_H_INCLUDED
36 /// PawnInfo is a class which contains various information about a pawn
37 /// structure. Currently, it only includes a middle game and an end game
38 /// pawn structure evaluation, and a bitboard of passed pawns. We may want
39 /// to add further information in the future. A lookup to the pawn hash table
40 /// (performed by calling the get_pawn_info method in a PawnInfoTable object)
41 /// returns a pointer to a PawnInfo object.
46 friend class PawnInfoTable;
49 PawnInfo() { clear(); }
51 Score pawns_value() const;
52 Value kingside_storm_value(Color c) const;
53 Value queenside_storm_value(Color c) const;
54 Bitboard pawn_attacks(Color c) const;
55 Bitboard passed_pawns() const;
56 ScaleFactor scale_factor(Color c) const;
57 int file_is_half_open(Color c, File f) const;
58 int has_open_file_to_left(Color c, File f) const;
59 int has_open_file_to_right(Color c, File f) const;
60 int get_king_shelter(const Position& pos, Color c, Square ksq);
64 int updateShelter(const Position& pos, Color c, Square ksq);
68 Bitboard pawnAttacks[2];
69 Square kingSquares[2];
71 int16_t ksStormValue[2], qsStormValue[2];
72 uint8_t halfOpenFiles[2], kingShelters[2], factor[2];
75 /// The PawnInfoTable class represents a pawn hash table. It is basically
76 /// just an array of PawnInfo objects and a few methods for accessing these
77 /// objects. The most important method is get_pawn_info, which looks up a
78 /// position in the table and returns a pointer to a PawnInfo object.
83 PawnInfoTable(unsigned numOfEntries);
85 PawnInfo* get_pawn_info(const Position& pos);
89 Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi);
100 inline Score PawnInfo::pawns_value() const {
104 inline Bitboard PawnInfo::passed_pawns() const {
108 inline Bitboard PawnInfo::pawn_attacks(Color c) const {
109 return pawnAttacks[c];
112 inline Value PawnInfo::kingside_storm_value(Color c) const {
113 return Value(ksStormValue[c]);
116 inline Value PawnInfo::queenside_storm_value(Color c) const {
117 return Value(qsStormValue[c]);
120 inline ScaleFactor PawnInfo::scale_factor(Color c) const {
121 return ScaleFactor(factor[c]);
124 inline int PawnInfo::file_is_half_open(Color c, File f) const {
125 return (halfOpenFiles[c] & (1 << int(f)));
128 inline int PawnInfo::has_open_file_to_left(Color c, File f) const {
129 return halfOpenFiles[c] & ((1 << int(f)) - 1);
132 inline int PawnInfo::has_open_file_to_right(Color c, File f) const {
133 return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
136 inline int PawnInfo::get_king_shelter(const Position& pos, Color c, Square ksq) {
137 return (kingSquares[c] == ksq ? kingShelters[c] : updateShelter(pos, c, ksq));
140 #endif // !defined(PAWNS_H_INCLUDED)