+++ /dev/null
-/*
- Stockfish, a UCI chess playing engine derived from Glaurung 2.1
- Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
- Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
-
- Stockfish is free software: you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation, either version 3 of the License, or
- (at your option) any later version.
-
- Stockfish is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
-
-
-#if !defined(PAWNS_H_INCLUDED)
-#define PAWNS_H_INCLUDED
-
-////
-//// Includes
-////
-
-#include "bitboard.h"
-#include "position.h"
-#include "value.h"
-
-////
-//// Types
-////
-
-const int PawnTableSize = 16384;
-
-/// PawnInfo is a class which contains various information about a pawn
-/// structure. Currently, it only includes a middle game and an end game
-/// 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 get_pawn_info method in a PawnInfoTable object)
-/// returns a pointer to a PawnInfo object.
-class PawnInfo {
-
- friend class PawnInfoTable;
-
-public:
- Score pawns_value() const;
- Bitboard pawn_attacks(Color c) const;
- Bitboard passed_pawns(Color c) const;
- int file_is_half_open(Color c, File f) const;
- int has_open_file_to_left(Color c, File f) const;
- int has_open_file_to_right(Color c, File f) const;
-
- template<Color Us>
- Score king_shelter(const Position& pos, Square ksq);
-
-private:
- template<Color Us>
- Score updateShelter(const Position& pos, Square ksq);
-
- Key key;
- Bitboard passedPawns[2];
- Bitboard pawnAttacks[2];
- Square kingSquares[2];
- Score value;
- int halfOpenFiles[2];
- Score kingShelters[2];
-};
-
-/// The PawnInfoTable class represents a pawn hash table. It is basically
-/// just an array of PawnInfo objects and a few methods for accessing these
-/// objects. The most important method is get_pawn_info, which looks up a
-/// position in the table and returns a pointer to a PawnInfo object.
-
-class PawnInfoTable {
-
- enum SideType { KingSide, QueenSide };
-
-public:
- PawnInfoTable();
- ~PawnInfoTable();
- PawnInfo* get_pawn_info(const Position& pos) const;
- void prefetch(Key key) const;
-
-private:
- template<Color Us>
- Score evaluate_pawns(const Position& pos, Bitboard ourPawns, Bitboard theirPawns, PawnInfo* pi) const;
-
- PawnInfo* entries;
-};
-
-
-////
-//// Inline functions
-////
-
-inline void PawnInfoTable::prefetch(Key key) const {
-
- unsigned index = unsigned(key & (PawnTableSize - 1));
- PawnInfo* pi = entries + index;
- ::prefetch((char*) pi);
-}
-
-inline Score PawnInfo::pawns_value() const {
- return value;
-}
-
-inline Bitboard PawnInfo::pawn_attacks(Color c) const {
- return pawnAttacks[c];
-}
-
-inline Bitboard PawnInfo::passed_pawns(Color c) const {
- return passedPawns[c];
-}
-
-inline int PawnInfo::file_is_half_open(Color c, File f) const {
- return (halfOpenFiles[c] & (1 << int(f)));
-}
-
-inline int PawnInfo::has_open_file_to_left(Color c, File f) const {
- return halfOpenFiles[c] & ((1 << int(f)) - 1);
-}
-
-inline int PawnInfo::has_open_file_to_right(Color c, File f) const {
- return halfOpenFiles[c] & ~((1 << int(f+1)) - 1);
-}
-
-/// PawnInfo::updateShelter() calculates and caches king shelter. It is called
-/// only when king square changes, about 20% of total king_shelter() calls.
-template<Color Us>
-Score PawnInfo::updateShelter(const Position& pos, Square ksq) {
-
- const int Shift = (Us == WHITE ? 8 : -8);
-
- Bitboard pawns;
- int r, shelter = 0;
-
- if (relative_rank(Us, ksq) <= RANK_4)
- {
- pawns = pos.pieces(PAWN, Us) & this_and_neighboring_files_bb(ksq);
- r = square_rank(ksq) * 8;
- for (int i = 1; i < 4; i++)
- {
- r += Shift;
- shelter += BitCount8Bit[(pawns >> r) & 0xFF] * (128 >> i);
- }
- }
- kingSquares[Us] = ksq;
- kingShelters[Us] = make_score(shelter, 0);
- return kingShelters[Us];
-}
-
-template<Color Us>
-inline Score PawnInfo::king_shelter(const Position& pos, Square ksq) {
- return kingSquares[Us] == ksq ? kingShelters[Us] : updateShelter<Us>(pos, ksq);
-}
-
-#endif // !defined(PAWNS_H_INCLUDED)