/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ 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
- Glaurung is free software: you can redistribute it and/or modify
+ 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.
- Glaurung is distributed in the hope that it will be useful,
+ 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.
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
-
-////
-//// Includes
-////
-
#include <cassert>
-#include <iostream>
+#include <cstring>
#include <fstream>
+#include <map>
+#include <iostream>
+#include <sstream>
-#include "mersenne.h"
+#include "bitcount.h"
#include "movegen.h"
-#include "movepick.h"
#include "position.h"
#include "psqtab.h"
+#include "rkiss.h"
+#include "tt.h"
#include "ucioption.h"
-
-////
-//// Variables
-////
-
-int Position::castleRightsMask[64];
+using std::string;
+using std::cout;
+using std::endl;
Key Position::zobrist[2][8][64];
Key Position::zobEp[64];
Key Position::zobCastle[16];
-Key Position::zobMaterial[2][8][16];
Key Position::zobSideToMove;
+Key Position::zobExclusion;
+
+Score Position::PieceSquareTable[16][64];
+
+// Material values arrays, indexed by Piece
+const Value Position::PieceValueMidgame[17] = {
+ VALUE_ZERO,
+ PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame, VALUE_ZERO,
+ VALUE_ZERO, VALUE_ZERO,
+ PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame
+};
+
+const Value Position::PieceValueEndgame[17] = {
+ VALUE_ZERO,
+ PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
+ RookValueEndgame, QueenValueEndgame, VALUE_ZERO,
+ VALUE_ZERO, VALUE_ZERO,
+ PawnValueEndgame, KnightValueEndgame, BishopValueEndgame,
+ RookValueEndgame, QueenValueEndgame
+};
+
+// Material values array used by SEE, indexed by PieceType
+const Value Position::seeValues[] = {
+ VALUE_ZERO,
+ PawnValueMidgame, KnightValueMidgame, BishopValueMidgame,
+ RookValueMidgame, QueenValueMidgame, QueenValueMidgame*10
+};
+
+
+namespace {
+
+ // Bonus for having the side to move (modified by Joona Kiiski)
+ const Score TempoValue = make_score(48, 22);
+
+ struct PieceLetters : public std::map<char, Piece> {
+
+ PieceLetters() {
+
+ operator[]('K') = WK; operator[]('k') = BK;
+ operator[]('Q') = WQ; operator[]('q') = BQ;
+ operator[]('R') = WR; operator[]('r') = BR;
+ operator[]('B') = WB; operator[]('b') = BB;
+ operator[]('N') = WN; operator[]('n') = BN;
+ operator[]('P') = WP; operator[]('p') = BP;
+ operator[](' ') = PIECE_NONE;
+ operator[]('.') = PIECE_NONE_DARK_SQ;
+ }
+
+ char from_piece(Piece p) const {
+
+ std::map<char, Piece>::const_iterator it;
+ for (it = begin(); it != end(); ++it)
+ if (it->second == p)
+ return it->first;
+
+ assert(false);
+ return 0;
+ }
+ };
+
+ PieceLetters pieceLetters;
+}
-Value Position::MgPieceSquareTable[16][64];
-Value Position::EgPieceSquareTable[16][64];
+/// CheckInfo c'tor
-////
-//// Functions
-////
+CheckInfo::CheckInfo(const Position& pos) {
-/// Constructors
+ Color us = pos.side_to_move();
+ Color them = opposite_color(us);
-Position::Position() { } // Do we really need this one?
+ ksq = pos.king_square(them);
+ dcCandidates = pos.discovered_check_candidates(us);
-Position::Position(const Position &pos) {
- this->copy(pos);
+ checkSq[PAWN] = pos.attacks_from<PAWN>(ksq, them);
+ checkSq[KNIGHT] = pos.attacks_from<KNIGHT>(ksq);
+ checkSq[BISHOP] = pos.attacks_from<BISHOP>(ksq);
+ checkSq[ROOK] = pos.attacks_from<ROOK>(ksq);
+ checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK];
+ checkSq[KING] = EmptyBoardBB;
}
-Position::Position(const std::string &fen) {
- this->from_fen(fen);
+
+/// Position c'tors. Here we always create a copy of the original position
+/// or the FEN string, we want the new born Position object do not depend
+/// on any external data so we detach state pointer from the source one.
+
+Position::Position(const Position& pos, int th) {
+
+ memcpy(this, &pos, sizeof(Position));
+ detach(); // Always detach() in copy c'tor to avoid surprises
+ threadID = th;
+ nodes = 0;
+}
+
+Position::Position(const string& fen, bool isChess960, int th) {
+
+ from_fen(fen, isChess960);
+ threadID = th;
+}
+
+
+/// Position::detach() copies the content of the current state and castling
+/// masks inside the position itself. This is needed when the st pointee could
+/// become stale, as example because the caller is about to going out of scope.
+
+void Position::detach() {
+
+ startState = *st;
+ st = &startState;
+ st->previous = NULL; // as a safe guard
}
/// string. This function is not very robust - make sure that input FENs are
/// correct (this is assumed to be the responsibility of the GUI).
-void Position::from_fen(const std::string &fen) {
- File file;
- Rank rank;
- int i;
+void Position::from_fen(const string& fen, bool isChess960) {
+/*
+ A FEN string defines a particular position using only the ASCII character set.
- this->clear();
+ A FEN string contains six fields. The separator between fields is a space. The fields are:
- // Board
- rank = RANK_8;
- file = FILE_A;
- for(i = 0; fen[i] != ' '; i++) {
- if(isdigit(fen[i]))
- // Skip the given number of files
- file += (fen[i] - '1' + 1);
- else {
- Square square = make_square(file, rank);
- switch(fen[i]) {
- case 'K': this->put_piece(WK, square); file++; break;
- case 'Q': this->put_piece(WQ, square); file++; break;
- case 'R': this->put_piece(WR, square); file++; break;
- case 'B': this->put_piece(WB, square); file++; break;
- case 'N': this->put_piece(WN, square); file++; break;
- case 'P': this->put_piece(WP, square); file++; break;
- case 'k': this->put_piece(BK, square); file++; break;
- case 'q': this->put_piece(BQ, square); file++; break;
- case 'r': this->put_piece(BR, square); file++; break;
- case 'b': this->put_piece(BB, square); file++; break;
- case 'n': this->put_piece(BN, square); file++; break;
- case 'p': this->put_piece(BP, square); file++; break;
- case '/': file = FILE_A; rank--; break;
- case ' ': break;
- default:
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
+ 1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending
+ with rank 1; within each rank, the contents of each square are described from file A through file H.
+ Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken
+ from the standard English names. White pieces are designated using upper-case letters ("PNBRQK")
+ while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number
+ of blank squares), and "/" separate ranks.
+
+ 2) Active color. "w" means white moves next, "b" means black.
+
+ 3) Castling availability. If neither side can castle, this is "-". Otherwise, this has one or more
+ letters: "K" (White can castle kingside), "Q" (White can castle queenside), "k" (Black can castle
+ kingside), and/or "q" (Black can castle queenside).
+
+ 4) En passant target square in algebraic notation. If there's no en passant target square, this is "-".
+ If a pawn has just made a 2-square move, this is the position "behind" the pawn. This is recorded
+ regardless of whether there is a pawn in position to make an en passant capture.
+
+ 5) Halfmove clock: This is the number of halfmoves since the last pawn advance or capture. This is used
+ to determine if a draw can be claimed under the fifty-move rule.
+
+ 6) Fullmove number: The number of the full move. It starts at 1, and is incremented after Black's move.
+*/
+
+ char token;
+ int hmc, fmn;
+ std::istringstream ss(fen);
+ Square sq = SQ_A8;
+
+ clear();
+
+ // 1. Piece placement field
+ while (ss.get(token) && token != ' ')
+ {
+ if (pieceLetters.find(token) != pieceLetters.end())
+ {
+ put_piece(pieceLetters[token], sq);
+ sq++;
}
- }
+ else if (isdigit(token))
+ sq += Square(token - '0'); // Skip the given number of files
+ else if (token == '/')
+ sq -= SQ_A3; // Jump back of 2 rows
+ else
+ goto incorrect_fen;
}
- // Side to move
- i++;
- if(fen[i] == 'w')
- sideToMove = WHITE;
- else if(fen[i] == 'b')
- sideToMove = BLACK;
- else {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
+ // 2. Active color
+ if (!ss.get(token) || (token != 'w' && token != 'b'))
+ goto incorrect_fen;
- // Castling rights:
- i++;
- if(fen[i] != ' ') {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
+ sideToMove = (token == 'w' ? WHITE : BLACK);
- i++;
- while(strchr("KQkqabcdefghABCDEFGH-", fen[i])) {
- if(fen[i] == '-') {
- i++; break;
- }
- else if(fen[i] == 'K') this->allow_oo(WHITE);
- else if(fen[i] == 'Q') this->allow_ooo(WHITE);
- else if(fen[i] == 'k') this->allow_oo(BLACK);
- else if(fen[i] == 'q') this->allow_ooo(BLACK);
- else if(fen[i] >= 'A' && fen[i] <= 'H') {
- File rookFile, kingFile = FILE_NONE;
- for(Square square = SQ_B1; square <= SQ_G1; square++)
- if(this->piece_on(square) == WK)
- kingFile = square_file(square);
- if(kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'A') + FILE_A;
- if(rookFile < initialKFile) {
- this->allow_ooo(WHITE);
- initialQRFile = rookFile;
- }
- else {
- this->allow_oo(WHITE);
- initialKRFile = rookFile;
- }
- }
- else if(fen[i] >= 'a' && fen[i] <= 'h') {
- File rookFile, kingFile = FILE_NONE;
- for(Square square = SQ_B8; square <= SQ_G8; square++)
- if(this->piece_on(square) == BK)
- kingFile = square_file(square);
- if(kingFile == FILE_NONE) {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- initialKFile = kingFile;
- rookFile = File(fen[i] - 'a') + FILE_A;
- if(rookFile < initialKFile) {
- this->allow_ooo(BLACK);
- initialQRFile = rookFile;
- }
- else {
- this->allow_oo(BLACK);
- initialKRFile = rookFile;
- }
- }
- else {
- std::cout << "Error in FEN at character " << i << std::endl;
- return;
- }
- i++;
+ if (!ss.get(token) || token != ' ')
+ goto incorrect_fen;
+
+ // 3. Castling availability
+ while (ss.get(token) && token != ' ')
+ if (!set_castling_rights(token))
+ goto incorrect_fen;
+
+ // 4. En passant square
+ char col, row;
+ if ( (ss.get(col) && (col >= 'a' && col <= 'h'))
+ && (ss.get(row) && (row == '3' || row == '6')))
+ {
+ st->epSquare = make_square(file_from_char(col), rank_from_char(row));
+
+ // Ignore if no capture is possible
+ Color them = opposite_color(sideToMove);
+ if (!(attacks_from<PAWN>(st->epSquare, them) & pieces(PAWN, sideToMove)))
+ st->epSquare = SQ_NONE;
}
- while(fen[i] == ' ')
- i++;
+ // 5. Halfmove clock
+ if (ss >> hmc)
+ st->rule50 = hmc;
- // En passant square
- if(i < int(fen.length()) - 2)
- if(fen[i] >= 'a' && fen[i] <= 'h' && (fen[i+1] == '3' || fen[i+1] == '6'))
- epSquare = square_from_string(fen.substr(i, 2));
-
- // Various initialisation
-
- for(Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
- castleRightsMask[make_square(initialKFile, RANK_1)] ^=
- (WHITE_OO|WHITE_OOO);
- castleRightsMask[make_square(initialKFile, RANK_8)] ^=
- (BLACK_OO|BLACK_OOO);
+ // 6. Fullmove number
+ if (ss >> fmn)
+ startPosPlyCounter = (fmn - 1) * 2 + int(sideToMove == BLACK);
+
+ // Various initialisations
+ castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO;
+ castleRightsMask[make_square(initialKFile, RANK_8)] ^= BLACK_OO | BLACK_OOO;
castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
- this->find_checkers();
+ chess960 = isChess960;
+ find_checkers();
+
+ st->key = compute_key();
+ st->pawnKey = compute_pawn_key();
+ st->materialKey = compute_material_key();
+ st->value = compute_value();
+ st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
+ st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ return;
- key = this->compute_key();
- pawnKey = this->compute_pawn_key();
- materialKey = this->compute_material_key();
- mgValue = this->compute_mg_value();
- egValue = this->compute_eg_value();
- npMaterial[WHITE] = this->compute_non_pawn_material(WHITE);
- npMaterial[BLACK] = this->compute_non_pawn_material(BLACK);
+incorrect_fen:
+ cout << "Error in FEN string: " << fen << endl;
}
-/// Position::to_fen() converts the position object to a FEN string. This is
-/// probably only useful for debugging.
+/// Position::set_castling_rights() sets castling parameters castling avaiability.
+/// This function is compatible with 3 standards: Normal FEN standard, Shredder-FEN
+/// that uses the letters of the columns on which the rooks began the game instead
+/// of KQkq and also X-FEN standard that, in case of Chess960, if an inner Rook is
+/// associated with the castling right, the traditional castling tag will be replaced
+/// by the file letter of the involved rook as for the Shredder-FEN.
+
+bool Position::set_castling_rights(char token) {
+
+ Color c = token >= 'a' ? BLACK : WHITE;
+ Square sqA = (c == WHITE ? SQ_A1 : SQ_A8);
+ Square sqH = (c == WHITE ? SQ_H1 : SQ_H8);
+ Piece rook = (c == WHITE ? WR : BR);
+
+ initialKFile = square_file(king_square(c));
+ token = char(toupper(token));
+
+ if (token == 'K')
+ {
+ for (Square sq = sqH; sq >= sqA; sq--)
+ if (piece_on(sq) == rook)
+ {
+ do_allow_oo(c);
+ initialKRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (token == 'Q')
+ {
+ for (Square sq = sqA; sq <= sqH; sq++)
+ if (piece_on(sq) == rook)
+ {
+ do_allow_ooo(c);
+ initialQRFile = square_file(sq);
+ break;
+ }
+ }
+ else if (token >= 'A' && token <= 'H')
+ {
+ File rookFile = File(token - 'A') + FILE_A;
+ if (rookFile < initialKFile)
+ {
+ do_allow_ooo(c);
+ initialQRFile = rookFile;
+ }
+ else
+ {
+ do_allow_oo(c);
+ initialKRFile = rookFile;
+ }
+ }
+ else
+ return token == '-';
+
+ return true;
+}
+
+
+/// Position::to_fen() returns a FEN representation of the position. In case
+/// of Chess960 the Shredder-FEN notation is used. Mainly a debugging function.
+
+const string Position::to_fen() const {
+
+ string fen;
+ Square sq;
+ char emptyCnt = '0';
-const std::string Position::to_fen() const {
- char pieceLetters[] = " PNBRQK pnbrqk";
- std::string result;
- int skip;
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/')
+ {
+ for (File file = FILE_A; file <= FILE_H; file++)
+ {
+ sq = make_square(file, rank);
- for(Rank rank = RANK_8; rank >= RANK_1; rank--) {
- skip = 0;
- for(File file = FILE_A; file <= FILE_H; file++) {
- Square square = make_square(file, rank);
- if(this->square_is_occupied(square)) {
- if(skip > 0) result += (char)skip + '0';
- result += pieceLetters[this->piece_on(square)];
- skip = 0;
+ if (square_is_occupied(sq))
+ {
+ if (emptyCnt != '0')
+ {
+ fen += emptyCnt;
+ emptyCnt = '0';
+ }
+ fen += pieceLetters.from_piece(piece_on(sq));
+ } else
+ emptyCnt++;
}
- else skip++;
- }
- if(skip > 0) result += (char)skip + '0';
- result += (rank > RANK_1)? '/' : ' ';
- }
- result += (sideToMove == WHITE)? 'w' : 'b';
- result += ' ';
- if(castleRights == NO_CASTLES) result += '-';
- else {
- if(this->can_castle_kingside(WHITE)) result += 'K';
- if(this->can_castle_queenside(WHITE)) result += 'Q';
- if(this->can_castle_kingside(BLACK)) result += 'k';
- if(this->can_castle_queenside(BLACK)) result += 'q';
+ if (emptyCnt != '0')
+ {
+ fen += emptyCnt;
+ emptyCnt = '0';
+ }
}
- result += ' ';
- if(this->ep_square() == SQ_NONE) result += '-';
- else result += square_to_string(this->ep_square());
+ fen += (sideToMove == WHITE ? " w " : " b ");
- return result;
+ if (st->castleRights != CASTLES_NONE)
+ {
+ if (can_castle_kingside(WHITE))
+ fen += chess960 ? char(toupper(file_to_char(initialKRFile))) : 'K';
+
+ if (can_castle_queenside(WHITE))
+ fen += chess960 ? char(toupper(file_to_char(initialQRFile))) : 'Q';
+
+ if (can_castle_kingside(BLACK))
+ fen += chess960 ? file_to_char(initialKRFile) : 'k';
+
+ if (can_castle_queenside(BLACK))
+ fen += chess960 ? file_to_char(initialQRFile) : 'q';
+ } else
+ fen += '-';
+
+ fen += (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square()));
+ return fen;
}
/// Position::print() prints an ASCII representation of the position to
-/// the standard output.
-
-void Position::print() const {
- char pieceStrings[][8] =
- {"| ? ", "| P ", "| N ", "| B ", "| R ", "| Q ", "| K ", "| ? ",
- "| ? ", "|=P=", "|=N=", "|=B=", "|=R=", "|=Q=", "|=K="
- };
-
- for(Rank rank = RANK_8; rank >= RANK_1; rank--) {
- std::cout << "+---+---+---+---+---+---+---+---+\n";
- for(File file = FILE_A; file <= FILE_H; file++) {
- Square sq = make_square(file, rank);
- Piece piece = this->piece_on(sq);
- if(piece == EMPTY)
- std::cout << ((square_color(sq) == WHITE)? "| " : "| . ");
- else
- std::cout << pieceStrings[piece];
- }
- std::cout << "|\n";
+/// the standard output. If a move is given then also the san is printed.
+
+void Position::print(Move move) const {
+
+ const char* dottedLine = "\n+---+---+---+---+---+---+---+---+\n";
+
+ if (move)
+ {
+ Position p(*this, thread());
+ string dd = (color_of_piece_on(move_from(move)) == BLACK ? ".." : "");
+ cout << "\nMove is: " << dd << move_to_san(p, move);
}
- std::cout << "+---+---+---+---+---+---+---+---+\n";
- std::cout << this->to_fen() << std::endl;
- std::cout << key << std::endl;
+
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--)
+ {
+ cout << dottedLine << '|';
+ for (File file = FILE_A; file <= FILE_H; file++)
+ {
+ Square sq = make_square(file, rank);
+ Piece piece = piece_on(sq);
+
+ if (piece == PIECE_NONE && square_color(sq) == DARK)
+ piece = PIECE_NONE_DARK_SQ;
+
+ char c = (color_of_piece_on(sq) == BLACK ? '=' : ' ');
+ cout << c << pieceLetters.from_piece(piece) << c << '|';
+ }
+ }
+ cout << dottedLine << "Fen is: " << to_fen() << "\nKey is: " << st->key << endl;
}
-/// Position::copy() creates a copy of the input position.
+/// Position:hidden_checkers<>() returns a bitboard of all pinned (against the
+/// king) pieces for the given color and for the given pinner type. Or, when
+/// template parameter FindPinned is false, the pieces of the given color
+/// candidate for a discovery check against the enemy king.
+/// Bitboard checkersBB must be already updated when looking for pinners.
-void Position::copy(const Position &pos) {
- memcpy(this, &pos, sizeof(Position));
+template<bool FindPinned>
+Bitboard Position::hidden_checkers(Color c) const {
+
+ Bitboard result = EmptyBoardBB;
+ Bitboard pinners = pieces_of_color(FindPinned ? opposite_color(c) : c);
+
+ // Pinned pieces protect our king, dicovery checks attack
+ // the enemy king.
+ Square ksq = king_square(FindPinned ? c : opposite_color(c));
+
+ // Pinners are sliders, not checkers, that give check when candidate pinned is removed
+ pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]);
+
+ if (FindPinned && pinners)
+ pinners &= ~st->checkersBB;
+
+ while (pinners)
+ {
+ Square s = pop_1st_bit(&pinners);
+ Bitboard b = squares_between(s, ksq) & occupied_squares();
+
+ assert(b);
+
+ if ( !(b & (b - 1)) // Only one bit set?
+ && (b & pieces_of_color(c))) // Is an our piece?
+ result |= b;
+ }
+ return result;
}
/// Position:pinned_pieces() returns a bitboard of all pinned (against the
-/// king) pieces for the given color.
+/// king) pieces for the given color. Note that checkersBB bitboard must
+/// be already updated.
Bitboard Position::pinned_pieces(Color c) const {
- Bitboard b1, b2, pinned, pinners, sliders;
- Square ksq = this->king_square(c), s;
- Color them = opposite_color(c);
-
- pinned = EmptyBoardBB;
- b1 = this->occupied_squares();
-
- sliders = this->rooks_and_queens(them) & ~this->checkers();
- if(sliders & RookPseudoAttacks[ksq]) {
- b2 = this->rook_attacks(ksq) & this->pieces_of_color(c);
- pinners = rook_attacks_bb(ksq, b1 ^ b2) & sliders;
- while(pinners) {
- s = pop_1st_bit(&pinners);
- pinned |= (squares_between(s, ksq) & b2);
- }
- }
- sliders = this->bishops_and_queens(them) & ~this->checkers();
- if(sliders & BishopPseudoAttacks[ksq]) {
- b2 = this->bishop_attacks(ksq) & this->pieces_of_color(c);
- pinners = bishop_attacks_bb(ksq, b1 ^ b2) & sliders;
- while(pinners) {
- s = pop_1st_bit(&pinners);
- pinned |= (squares_between(s, ksq) & b2);
- }
- }
-
- return pinned;
+ return hidden_checkers<true>(c);
}
+
/// Position:discovered_check_candidates() returns a bitboard containing all
/// pieces for the given side which are candidates for giving a discovered
-/// check. The code is almost the same as the function for finding pinned
-/// pieces.
+/// check. Contrary to pinned_pieces() here there is no need of checkersBB
+/// to be already updated.
Bitboard Position::discovered_check_candidates(Color c) const {
- Bitboard b1, b2, dc, checkers, sliders;
- Square ksq = this->king_square(opposite_color(c)), s;
-
- dc = EmptyBoardBB;
- b1 = this->occupied_squares();
-
- sliders = this->rooks_and_queens(c);
- if(sliders & RookPseudoAttacks[ksq]) {
- b2 = this->rook_attacks(ksq) & this->pieces_of_color(c);
- checkers = rook_attacks_bb(ksq, b1 ^ b2) & sliders;
- while(checkers) {
- s = pop_1st_bit(&checkers);
- dc |= (squares_between(s, ksq) & b2);
- }
- }
-
- sliders = this->bishops_and_queens(c);
- if(sliders & BishopPseudoAttacks[ksq]) {
- b2 = this->bishop_attacks(ksq) & this->pieces_of_color(c);
- checkers = bishop_attacks_bb(ksq, b1 ^ b2) & sliders;
- while(checkers) {
- s = pop_1st_bit(&checkers);
- dc |= (squares_between(s, ksq) & b2);
- }
- }
- return dc;
+ return hidden_checkers<false>(c);
}
+/// Position::attackers_to() computes a bitboard containing all pieces which
+/// attacks a given square.
-/// Position::square_is_attacked() checks whether the given side attacks the
-/// given square.
+Bitboard Position::attackers_to(Square s) const {
-bool Position::square_is_attacked(Square s, Color c) const {
- return
- (this->pawn_attacks(opposite_color(c), s) & this->pawns(c)) ||
- (this->knight_attacks(s) & this->knights(c)) ||
- (this->king_attacks(s) & this->kings(c)) ||
- (this->rook_attacks(s) & this->rooks_and_queens(c)) ||
- (this->bishop_attacks(s) & this->bishops_and_queens(c));
+ return (attacks_from<PAWN>(s, BLACK) & pieces(PAWN, WHITE))
+ | (attacks_from<PAWN>(s, WHITE) & pieces(PAWN, BLACK))
+ | (attacks_from<KNIGHT>(s) & pieces(KNIGHT))
+ | (attacks_from<ROOK>(s) & pieces(ROOK, QUEEN))
+ | (attacks_from<BISHOP>(s) & pieces(BISHOP, QUEEN))
+ | (attacks_from<KING>(s) & pieces(KING));
}
+/// Position::attacks_from() computes a bitboard of all attacks
+/// of a given piece put in a given square.
-/// Position::attacks_to() computes a bitboard containing all pieces which
-/// attacks a given square. There are two versions of this function: One
-/// which finds attackers of both colors, and one which only finds the
-/// attackers for one side.
+Bitboard Position::attacks_from(Piece p, Square s) const {
+
+ assert(square_is_ok(s));
-Bitboard Position::attacks_to(Square s) const {
- return
- (this->black_pawn_attacks(s) & this->pawns(WHITE)) |
- (this->white_pawn_attacks(s) & this->pawns(BLACK)) |
- (this->knight_attacks(s) & this->pieces_of_type(KNIGHT)) |
- (this->rook_attacks(s) & this->rooks_and_queens()) |
- (this->bishop_attacks(s) & this->bishops_and_queens()) |
- (this->king_attacks(s) & this->pieces_of_type(KING));
+ switch (p)
+ {
+ case WB: case BB: return attacks_from<BISHOP>(s);
+ case WR: case BR: return attacks_from<ROOK>(s);
+ case WQ: case BQ: return attacks_from<QUEEN>(s);
+ default: return StepAttacksBB[p][s];
+ }
}
-Bitboard Position::attacks_to(Square s, Color c) const {
- return this->attacks_to(s) & this->pieces_of_color(c);
+Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) {
+
+ assert(square_is_ok(s));
+
+ switch (p)
+ {
+ case WB: case BB: return bishop_attacks_bb(s, occ);
+ case WR: case BR: return rook_attacks_bb(s, occ);
+ case WQ: case BQ: return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ);
+ default: return StepAttacksBB[p][s];
+ }
}
-/// Position::piece_attacks_square() tests whether the piece on square f
-/// attacks square t.
+/// Position::move_attacks_square() tests whether a move from the current
+/// position attacks a given square.
-bool Position::piece_attacks_square(Square f, Square t) const {
- assert(square_is_ok(f));
- assert(square_is_ok(t));
+bool Position::move_attacks_square(Move m, Square s) const {
- switch(this->piece_on(f)) {
- case WP: return this->white_pawn_attacks_square(f, t);
- case BP: return this->black_pawn_attacks_square(f, t);
- case WN: case BN: return this->knight_attacks_square(f, t);
- case WB: case BB: return this->bishop_attacks_square(f, t);
- case WR: case BR: return this->rook_attacks_square(f, t);
- case WQ: case BQ: return this->queen_attacks_square(f, t);
- case WK: case BK: return this->king_attacks_square(f, t);
- default: return false;
- }
+ assert(move_is_ok(m));
+ assert(square_is_ok(s));
- return false;
+ Bitboard occ, xray;
+ Square f = move_from(m), t = move_to(m);
+
+ assert(square_is_occupied(f));
+
+ if (bit_is_set(attacks_from(piece_on(f), t), s))
+ return true;
+
+ // Move the piece and scan for X-ray attacks behind it
+ occ = occupied_squares();
+ do_move_bb(&occ, make_move_bb(f, t));
+ xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN))
+ |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)))
+ & pieces_of_color(color_of_piece_on(f));
+
+ // If we have attacks we need to verify that are caused by our move
+ // and are not already existent ones.
+ return xray && (xray ^ (xray & attacks_from<QUEEN>(s)));
}
/// Position::find_checkers() computes the checkersBB bitboard, which
-/// contains a nonzero bit for each checking piece (0, 1 or 2). It
-/// currently works by calling Position::attacks_to, which is probably
-/// inefficient. Consider rewriting this function to use the last move
+/// contains a nonzero bit for each checking piece (0, 1 or 2). It
+/// currently works by calling Position::attackers_to, which is probably
+/// inefficient. Consider rewriting this function to use the last move
/// played, like in non-bitboard versions of Glaurung.
void Position::find_checkers() {
- checkersBB = attacks_to(this->king_square(this->side_to_move()),
- opposite_color(this->side_to_move()));
-}
-
-/// Position::move_is_legal() tests whether a pseudo-legal move is legal.
-/// There are two versions of this function: One which takes only a
-/// move as input, and one which takes a move and a bitboard of pinned
-/// pieces. The latter function is faster, and should always be preferred
-/// when a pinned piece bitboard has already been computed.
-
-bool Position::move_is_legal(Move m) const {
- return this->move_is_legal(m, this->pinned_pieces(this->side_to_move()));
+ Color us = side_to_move();
+ st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us));
}
-bool Position::move_is_legal(Move m, Bitboard pinned) const {
- Color us, them;
- Square ksq, from;
+/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
- assert(this->is_ok());
- assert(move_is_ok(m));
- assert(pinned == this->pinned_pieces(this->side_to_move()));
+bool Position::pl_move_is_legal(Move m, Bitboard pinned) const {
- // If we're in check, all pseudo-legal moves are legal, because our
- // check evasion generator only generates true legal moves.
- if(this->is_check()) return true;
+ assert(is_ok());
+ assert(move_is_ok(m));
+ assert(pinned == pinned_pieces(side_to_move()));
// Castling moves are checked for legality during move generation.
- if(move_is_castle(m)) return true;
+ if (move_is_castle(m))
+ return true;
- us = this->side_to_move();
- them = opposite_color(us);
+ // En passant captures are a tricky special case. Because they are
+ // rather uncommon, we do it simply by testing whether the king is attacked
+ // after the move is made
+ if (move_is_ep(m))
+ {
+ Color us = side_to_move();
+ Color them = opposite_color(us);
+ Square from = move_from(m);
+ Square to = move_to(m);
+ Square capsq = make_square(square_file(to), square_rank(from));
+ Square ksq = king_square(us);
+ Bitboard b = occupied_squares();
- from = move_from(m);
- ksq = this->king_square(us);
+ assert(to == ep_square());
+ assert(piece_on(from) == make_piece(us, PAWN));
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+ assert(piece_on(to) == PIECE_NONE);
- assert(this->color_of_piece_on(from) == us);
- assert(this->piece_on(ksq) == king_of_color(us));
+ clear_bit(&b, from);
+ clear_bit(&b, capsq);
+ set_bit(&b, to);
- // En passant captures are a tricky special case. Because they are
- // rather uncommon, we do it simply by testing whether the king is attacked
- // after the move is made:
- if(move_is_ep(m)) {
- Square to = move_to(m);
- Square capsq = make_square(square_file(to), square_rank(from));
- Bitboard b = this->occupied_squares();
-
- assert(to == this->ep_square());
- assert(this->piece_on(from) == pawn_of_color(us));
- assert(this->piece_on(capsq) == pawn_of_color(them));
- assert(this->piece_on(to) == EMPTY);
-
- clear_bit(&b, from); clear_bit(&b, capsq); set_bit(&b, to);
- return
- (!(rook_attacks_bb(ksq, b) & this->rooks_and_queens(them)) &&
- !(bishop_attacks_bb(ksq, b) & this->bishops_and_queens(them)));
+ return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them))
+ && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them));
}
+ Color us = side_to_move();
+ Square from = move_from(m);
+
+ assert(color_of_piece_on(from) == us);
+ assert(piece_on(king_square(us)) == make_piece(us, KING));
+
// If the moving piece is a king, check whether the destination
// square is attacked by the opponent.
- if(from == ksq) return !(this->square_is_attacked(move_to(m), them));
+ if (type_of_piece_on(from) == KING)
+ return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us)));
// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.
- if(!bit_is_set(pinned, from)) return true;
- if(direction_between_squares(from, ksq) ==
- direction_between_squares(move_to(m), ksq))
- return true;
+ return !pinned
+ || !bit_is_set(pinned, from)
+ || squares_aligned(from, move_to(m), king_square(us));
+}
+
+
+/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion
+
+bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const
+{
+ assert(is_check());
+
+ Color us = side_to_move();
+ Square from = move_from(m);
+ Square to = move_to(m);
+
+ // King moves and en-passant captures are verified in pl_move_is_legal()
+ if (type_of_piece_on(from) == KING || move_is_ep(m))
+ return pl_move_is_legal(m, pinned);
+
+ Bitboard target = checkers();
+ Square checksq = pop_1st_bit(&target);
+
+ if (target) // double check ?
+ return false;
+
+ // Our move must be a blocking evasion or a capture of the checking piece
+ target = squares_between(checksq, king_square(us)) | checkers();
+ return bit_is_set(target, to) && pl_move_is_legal(m, pinned);
+}
+
+/// Position::move_is_legal() takes a position and a (not necessarily pseudo-legal)
+/// move and tests whether the move is legal. This version is not very fast and
+/// should be used only in non time-critical paths.
+
+bool Position::move_is_legal(const Move m) const {
+
+ MoveStack mlist[MOVES_MAX];
+ MoveStack *cur, *last = generate<MV_PSEUDO_LEGAL>(*this, mlist);
+
+ for (cur = mlist; cur != last; cur++)
+ if (cur->move == m)
+ return pl_move_is_legal(m, pinned_pieces(sideToMove));
return false;
}
-/// Position::move_is_check() tests whether a pseudo-legal move is a check.
-/// There are two versions of this function: One which takes only a move as
-/// input, and one which takes a move and a bitboard of discovered check
-/// candidates. The latter function is faster, and should always be preferred
-/// when a discovered check candidates bitboard has already been computed.
+/// Fast version of Position::move_is_legal() that takes a position a move and
+/// a bitboard of pinned pieces as input, and tests whether the move is legal.
-bool Position::move_is_check(Move m) const {
- Bitboard dc = this->discovered_check_candidates(this->side_to_move());
- return this->move_is_check(m, dc);
+bool Position::move_is_legal(const Move m, Bitboard pinned) const {
+
+ assert(is_ok());
+ assert(pinned == pinned_pieces(sideToMove));
+
+ Color us = sideToMove;
+ Color them = opposite_color(sideToMove);
+ Square from = move_from(m);
+ Square to = move_to(m);
+ Piece pc = piece_on(from);
+
+ // Use a slower but simpler function for uncommon cases
+ if (move_is_special(m))
+ return move_is_legal(m);
+
+ // If the from square is not occupied by a piece belonging to the side to
+ // move, the move is obviously not legal.
+ if (color_of_piece(pc) != us)
+ return false;
+
+ // The destination square cannot be occupied by a friendly piece
+ if (color_of_piece_on(to) == us)
+ return false;
+
+ // Handle the special case of a pawn move
+ if (type_of_piece(pc) == PAWN)
+ {
+ // Move direction must be compatible with pawn color
+ int direction = to - from;
+ if ((us == WHITE) != (direction > 0))
+ return false;
+
+ // We have already handled promotion moves, so destination
+ // cannot be on the 8/1th rank.
+ if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1)
+ return false;
+
+ // Proceed according to the square delta between the origin and
+ // destination squares.
+ switch (direction)
+ {
+ case DELTA_NW:
+ case DELTA_NE:
+ case DELTA_SW:
+ case DELTA_SE:
+ // Capture. The destination square must be occupied by an enemy
+ // piece (en passant captures was handled earlier).
+ if (color_of_piece_on(to) != them)
+ return false;
+ break;
+
+ case DELTA_N:
+ case DELTA_S:
+ // Pawn push. The destination square must be empty.
+ if (!square_is_empty(to))
+ return false;
+ break;
+
+ case DELTA_NN:
+ // Double white pawn push. The destination square must be on the fourth
+ // rank, and both the destination square and the square between the
+ // source and destination squares must be empty.
+ if ( square_rank(to) != RANK_4
+ || !square_is_empty(to)
+ || !square_is_empty(from + DELTA_N))
+ return false;
+ break;
+
+ case DELTA_SS:
+ // Double black pawn push. The destination square must be on the fifth
+ // rank, and both the destination square and the square between the
+ // source and destination squares must be empty.
+ if ( square_rank(to) != RANK_5
+ || !square_is_empty(to)
+ || !square_is_empty(from + DELTA_S))
+ return false;
+ break;
+
+ default:
+ return false;
+ }
+ }
+ else if (!bit_is_set(attacks_from(pc, from), to))
+ return false;
+
+ // The move is pseudo-legal, check if it is also legal
+ return is_check() ? pl_move_is_evasion(m, pinned) : pl_move_is_legal(m, pinned);
}
-bool Position::move_is_check(Move m, Bitboard dcCandidates) const {
- Color us, them;
- Square ksq, from, to;
+/// Position::move_is_check() tests whether a pseudo-legal move is a check
+
+bool Position::move_is_check(Move m) const {
+
+ return move_is_check(m, CheckInfo(*this));
+}
+
+bool Position::move_is_check(Move m, const CheckInfo& ci) const {
- assert(this->is_ok());
+ assert(is_ok());
assert(move_is_ok(m));
- assert(dcCandidates ==
- this->discovered_check_candidates(this->side_to_move()));
-
- us = this->side_to_move();
- them = opposite_color(us);
-
- from = move_from(m);
- to = move_to(m);
- ksq = this->king_square(them);
- assert(this->color_of_piece_on(from) == us);
- assert(this->piece_on(ksq) == king_of_color(them));
-
- // Proceed according to the type of the moving piece:
- switch(this->type_of_piece_on(from)) {
- case PAWN:
- // Normal check?
- if(bit_is_set(this->pawn_attacks(them, ksq), to))
- return true;
- // Discovered check?
- else if(bit_is_set(dcCandidates, from) &&
- direction_between_squares(from, ksq) !=
- direction_between_squares(to, ksq))
+ assert(ci.dcCandidates == discovered_check_candidates(side_to_move()));
+ assert(color_of_piece_on(move_from(m)) == side_to_move());
+ assert(piece_on(ci.ksq) == make_piece(opposite_color(side_to_move()), KING));
+
+ Square from = move_from(m);
+ Square to = move_to(m);
+ PieceType pt = type_of_piece_on(from);
+
+ // Direct check ?
+ if (bit_is_set(ci.checkSq[pt], to))
return true;
- // Promotion with check?
- else if(move_promotion(m)) {
- Bitboard b = this->occupied_squares();
+
+ // Discovery check ?
+ if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
+ {
+ // For pawn and king moves we need to verify also direction
+ if ( (pt != PAWN && pt != KING)
+ || !squares_aligned(from, to, ci.ksq))
+ return true;
+ }
+
+ // Can we skip the ugly special cases ?
+ if (!move_is_special(m))
+ return false;
+
+ Color us = side_to_move();
+ Bitboard b = occupied_squares();
+
+ // Promotion with check ?
+ if (move_is_promotion(m))
+ {
clear_bit(&b, from);
- switch(move_promotion(m)) {
+ switch (move_promotion_piece(m))
+ {
case KNIGHT:
- return this->knight_attacks_square(to, ksq);
+ return bit_is_set(attacks_from<KNIGHT>(to), ci.ksq);
case BISHOP:
- return bit_is_set(bishop_attacks_bb(to, b), ksq);
+ return bit_is_set(bishop_attacks_bb(to, b), ci.ksq);
case ROOK:
- return bit_is_set(rook_attacks_bb(to, b), ksq);
+ return bit_is_set(rook_attacks_bb(to, b), ci.ksq);
case QUEEN:
- return bit_is_set(queen_attacks_bb(to, b), ksq);
+ return bit_is_set(queen_attacks_bb(to, b), ci.ksq);
default:
- assert(false);
+ assert(false);
}
- }
- // En passant capture with check? We have already handled the case
- // of direct checks and ordinary discovered check, the only case we
- // need to handle is the unusual case of a discovered check through the
- // captured pawn.
- else if(move_is_ep(m)) {
- Square capsq = make_square(square_file(to), square_rank(from));
- Bitboard b = this->occupied_squares();
-
- clear_bit(&b, from); clear_bit(&b, capsq); set_bit(&b, to);
- return
- ((rook_attacks_bb(ksq, b) & this->rooks_and_queens(us)) ||
- (bishop_attacks_bb(ksq, b) & this->bishops_and_queens(us)));
- }
- return false;
-
- case KNIGHT:
- // Discovered check?
- if(bit_is_set(dcCandidates, from))
- return true;
- // Normal check?
- else
- return bit_is_set(this->knight_attacks(ksq), to);
+ }
- case BISHOP:
- // Discovered check?
- if(bit_is_set(dcCandidates, from))
- return true;
- // Normal check?
- else
- return bit_is_set(this->bishop_attacks(ksq), to);
+ // En passant capture with check ? We have already handled the case
+ // of direct checks and ordinary discovered check, the only case we
+ // need to handle is the unusual case of a discovered check through
+ // the captured pawn.
+ if (move_is_ep(m))
+ {
+ Square capsq = make_square(square_file(to), square_rank(from));
+ clear_bit(&b, from);
+ clear_bit(&b, capsq);
+ set_bit(&b, to);
+ return (rook_attacks_bb(ci.ksq, b) & pieces(ROOK, QUEEN, us))
+ ||(bishop_attacks_bb(ci.ksq, b) & pieces(BISHOP, QUEEN, us));
+ }
- case ROOK:
- // Discovered check?
- if(bit_is_set(dcCandidates, from))
- return true;
- // Normal check?
- else
- return bit_is_set(this->rook_attacks(ksq), to);
-
- case QUEEN:
- // Discovered checks are impossible!
- assert(!bit_is_set(dcCandidates, from));
- // Normal check?
- return bit_is_set(this->queen_attacks(ksq), to);
-
- case KING:
- // Discovered check?
- if(bit_is_set(dcCandidates, from) &&
- direction_between_squares(from, ksq) !=
- direction_between_squares(to, ksq))
- return true;
- // Castling with check?
- if(move_is_castle(m)) {
+ // Castling with check ?
+ if (move_is_castle(m))
+ {
Square kfrom, kto, rfrom, rto;
- Bitboard b = this->occupied_squares();
-
kfrom = from;
rfrom = to;
- if(rfrom > kfrom) {
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- }
- else {
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
+
+ if (rfrom > kfrom)
+ {
+ kto = relative_square(us, SQ_G1);
+ rto = relative_square(us, SQ_F1);
+ } else {
+ kto = relative_square(us, SQ_C1);
+ rto = relative_square(us, SQ_D1);
}
+ clear_bit(&b, kfrom);
+ clear_bit(&b, rfrom);
+ set_bit(&b, rto);
+ set_bit(&b, kto);
+ return bit_is_set(rook_attacks_bb(rto, b), ci.ksq);
+ }
- clear_bit(&b, kfrom); clear_bit(&b, rfrom);
- set_bit(&b, rto); set_bit(&b, kto);
+ return false;
+}
- return bit_is_set(rook_attacks_bb(rto, b), ksq);
- }
- return false;
+/// Position::do_setup_move() makes a permanent move on the board.
+/// It should be used when setting up a position on board.
+/// You can't undo the move.
- default:
- assert(false);
- return false;
- }
+void Position::do_setup_move(Move m) {
- assert(false);
- return false;
-}
+ StateInfo newSt;
+
+ do_move(m, newSt);
+ // Reset "game ply" in case we made a non-reversible move.
+ // "game ply" is used for repetition detection.
+ if (st->rule50 == 0)
+ st->gamePly = 0;
-/// Position::move_is_capture() tests whether a move from the current
-/// position is a capture.
+ // Update the number of plies played from the starting position
+ startPosPlyCounter++;
-bool Position::move_is_capture(Move m) const {
- return
- this->color_of_piece_on(move_to(m)) == opposite_color(this->side_to_move())
- || move_is_ep(m);
+ // Our StateInfo newSt is about going out of scope so copy
+ // its content inside pos before it disappears.
+ detach();
}
+/// Position::do_move() makes a move, and saves all information necessary
+/// to a StateInfo object. The move is assumed to be legal.
+/// Pseudo-legal moves should be filtered out before this function is called.
-/// Position::move_attacks_square() tests whether a move from the current
-/// position attacks a given square. Only attacks by the moving piece are
-/// considered; the function does not handle X-ray attacks.
+void Position::do_move(Move m, StateInfo& newSt) {
-bool Position::move_attacks_square(Move m, Square s) const {
+ CheckInfo ci(*this);
+ do_move(m, newSt, ci, move_is_check(m, ci));
+}
+
+void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) {
+
+ assert(is_ok());
assert(move_is_ok(m));
- assert(square_is_ok(s));
+ assert(&newSt != st);
+
+ nodes++;
+ Key key = st->key;
+
+ // Copy some fields of old state to our new StateInfo object except the
+ // ones which are recalculated from scratch anyway, then switch our state
+ // pointer to point to the new, ready to be updated, state.
+ struct ReducedStateInfo {
+ Key pawnKey, materialKey;
+ int castleRights, rule50, gamePly, pliesFromNull;
+ Square epSquare;
+ Score value;
+ Value npMaterial[2];
+ };
- Square f = move_from(m), t = move_to(m);
+ memcpy(&newSt, st, sizeof(ReducedStateInfo));
+
+ newSt.previous = st;
+ st = &newSt;
+
+ // Save the current key to the history[] array, in order to be able to
+ // detect repetition draws.
+ history[st->gamePly++] = key;
+
+ // Update side to move
+ key ^= zobSideToMove;
+
+ // Increment the 50 moves rule draw counter. Resetting it to zero in the
+ // case of non-reversible moves is taken care of later.
+ st->rule50++;
+ st->pliesFromNull++;
- assert(this->square_is_occupied(f));
-
- switch(this->piece_on(f)) {
- case WP: return this->white_pawn_attacks_square(t, s);
- case BP: return this->black_pawn_attacks_square(t, s);
- case WN: case BN: return this->knight_attacks_square(t, s);
- case WB: case BB: return this->bishop_attacks_square(t, s);
- case WR: case BR: return this->rook_attacks_square(t, s);
- case WQ: case BQ: return this->queen_attacks_square(t, s);
- case WK: case BK: return this->king_attacks_square(t, s);
- default: assert(false);
+ if (move_is_castle(m))
+ {
+ st->key = key;
+ do_castle_move(m);
+ return;
}
- return false;
-}
+ Color us = side_to_move();
+ Color them = opposite_color(us);
+ Square from = move_from(m);
+ Square to = move_to(m);
+ bool ep = move_is_ep(m);
+ bool pm = move_is_promotion(m);
+
+ Piece piece = piece_on(from);
+ PieceType pt = type_of_piece(piece);
+ PieceType capture = ep ? PAWN : type_of_piece_on(to);
+
+ assert(color_of_piece_on(from) == us);
+ assert(color_of_piece_on(to) == them || square_is_empty(to));
+ assert(!(ep || pm) || piece == make_piece(us, PAWN));
+ assert(!pm || relative_rank(us, to) == RANK_8);
+
+ if (capture)
+ do_capture_move(key, capture, them, to, ep);
+
+ // Update hash key
+ key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to];
+
+ // Reset en passant square
+ if (st->epSquare != SQ_NONE)
+ {
+ key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
+ }
+ // Update castle rights, try to shortcut a common case
+ int cm = castleRightsMask[from] & castleRightsMask[to];
+ if (cm != ALL_CASTLES && ((cm & st->castleRights) != st->castleRights))
+ {
+ key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[from];
+ st->castleRights &= castleRightsMask[to];
+ key ^= zobCastle[st->castleRights];
+ }
+ // Prefetch TT access as soon as we know key is updated
+ prefetch((char*)TT.first_entry(key));
-/// Position::backup() is called when making a move. All information
-/// necessary to restore the position when the move is later unmade
-/// is saved to an UndoInfo object. The function Position::restore
-/// does the reverse operation: When one does a backup followed by
-/// a restore with the same UndoInfo object, the position is restored
-/// to the state before backup was called.
-
-void Position::backup(UndoInfo &u) const {
- u.castleRights = castleRights;
- u.epSquare = epSquare;
- u.checkersBB = checkersBB;
- u.key = key;
- u.pawnKey = pawnKey;
- u.materialKey = materialKey;
- u.rule50 = rule50;
- u.lastMove = lastMove;
- u.capture = NO_PIECE_TYPE;
- u.mgValue = mgValue;
- u.egValue = egValue;
-}
+ // Move the piece
+ Bitboard move_bb = make_move_bb(from, to);
+ do_move_bb(&(byColorBB[us]), move_bb);
+ do_move_bb(&(byTypeBB[pt]), move_bb);
+ do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
+ board[to] = board[from];
+ board[from] = PIECE_NONE;
-/// Position::restore() is called when unmaking a move. It copies back
-/// the information backed up during a previous call to Position::backup.
-
-void Position::restore(const UndoInfo &u) {
- castleRights = u.castleRights;
- epSquare = u.epSquare;
- checkersBB = u.checkersBB;
- key = u.key;
- pawnKey = u.pawnKey;
- materialKey = u.materialKey;
- rule50 = u.rule50;
- lastMove = u.lastMove;
- mgValue = u.mgValue;
- egValue = u.egValue;
-}
+ // Update piece lists, note that index[from] is not updated and
+ // becomes stale. This works as long as index[] is accessed just
+ // by known occupied squares.
+ index[to] = index[from];
+ pieceList[us][pt][index[to]] = to;
+
+ // If the moving piece was a pawn do some special extra work
+ if (pt == PAWN)
+ {
+ // Reset rule 50 draw counter
+ st->rule50 = 0;
+
+ // Update pawn hash key and prefetch in L1/L2 cache
+ st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+
+ // Set en passant square, only if moved pawn can be captured
+ if ((to ^ from) == 16)
+ {
+ if (attacks_from<PAWN>(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them))
+ {
+ st->epSquare = Square((int(from) + int(to)) / 2);
+ key ^= zobEp[st->epSquare];
+ }
+ }
+ if (pm) // promotion ?
+ {
+ PieceType promotion = move_promotion_piece(m);
-/// Position::do_move() makes a move, and backs up all information necessary
-/// to undo the move to an UndoInfo object. The move is assumed to be legal.
-/// Pseudo-legal moves should be filtered out before this function is called.
-/// There are two versions of this function, one which takes only the move and
-/// the UndoInfo as input, and one which takes a third parameter, a bitboard of
-/// discovered check candidates. The second version is faster, because knowing
-/// the discovered check candidates makes it easier to update the checkersBB
-/// member variable in the position object.
-
-void Position::do_move(Move m, UndoInfo &u) {
- this->do_move(m, u, this->discovered_check_candidates(this->side_to_move()));
-}
+ assert(promotion >= KNIGHT && promotion <= QUEEN);
-void Position::do_move(Move m, UndoInfo &u, Bitboard dcCandidates) {
- assert(this->is_ok());
- assert(move_is_ok(m));
+ // Insert promoted piece instead of pawn
+ clear_bit(&(byTypeBB[PAWN]), to);
+ set_bit(&(byTypeBB[promotion]), to);
+ board[to] = make_piece(us, promotion);
- // Back up the necessary information to our UndoInfo object (except the
- // captured piece, which is taken care of later:
- this->backup(u);
+ // Update piece counts
+ pieceCount[us][promotion]++;
+ pieceCount[us][PAWN]--;
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws:
- history[gamePly] = key;
+ // Update material key
+ st->materialKey ^= zobrist[us][PAWN][pieceCount[us][PAWN]];
+ st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]-1];
- // Increment the 50 moves rule draw counter. Resetting it to zero in the
- // case of non-reversible moves is taken care of later.
- rule50++;
+ // Update piece lists, move the last pawn at index[to] position
+ // and shrink the list. Add a new promotion piece to the list.
+ Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]];
+ index[lastPawnSquare] = index[to];
+ pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare;
+ pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE;
+ index[to] = pieceCount[us][promotion] - 1;
+ pieceList[us][promotion][index[to]] = to;
- if(move_is_castle(m))
- this->do_castle_move(m);
- else if(move_promotion(m))
- this->do_promotion_move(m, u);
- else if(move_is_ep(m))
- this->do_ep_move(m);
- else {
- Color us, them;
- Square from, to;
- PieceType piece, capture;
+ // Partially revert hash keys update
+ key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to];
+ st->pawnKey ^= zobrist[us][PAWN][to];
- us = this->side_to_move();
- them = opposite_color(us);
+ // Partially revert and update incremental scores
+ st->value -= pst(us, PAWN, to);
+ st->value += pst(us, promotion, to);
- from = move_from(m);
- to = move_to(m);
+ // Update material
+ st->npMaterial[us] += PieceValueMidgame[promotion];
+ }
+ }
- assert(this->color_of_piece_on(from) == us);
- assert(this->color_of_piece_on(to) == them || this->piece_on(to) == EMPTY);
+ // Prefetch pawn and material hash tables
+ prefetchTables(st->pawnKey, st->materialKey, threadID);
- piece = this->type_of_piece_on(from);
- capture = this->type_of_piece_on(to);
+ // Update incremental scores
+ st->value += pst_delta(piece, from, to);
- if(capture) {
- assert(capture != KING);
+ // Set capture piece
+ st->capturedType = capture;
- // Remove captured piece:
- clear_bit(&(byColorBB[them]), to);
- clear_bit(&(byTypeBB[capture]), to);
+ // Update the key with the final value
+ st->key = key;
- // Update hash key:
- key ^= zobrist[them][capture][to];
+ // Update checkers bitboard, piece must be already moved
+ st->checkersBB = EmptyBoardBB;
- // If the captured piece was a pawn, update pawn hash key:
- if(capture == PAWN)
- pawnKey ^= zobrist[them][PAWN][to];
+ if (moveIsCheck)
+ {
+ if (ep | pm)
+ st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
+ else
+ {
+ // Direct checks
+ if (bit_is_set(ci.checkSq[pt], to))
+ st->checkersBB = SetMaskBB[to];
+
+ // Discovery checks
+ if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from))
+ {
+ if (pt != ROOK)
+ st->checkersBB |= (attacks_from<ROOK>(ci.ksq) & pieces(ROOK, QUEEN, us));
+
+ if (pt != BISHOP)
+ st->checkersBB |= (attacks_from<BISHOP>(ci.ksq) & pieces(BISHOP, QUEEN, us));
+ }
+ }
+ }
- // Update incremental scores:
- mgValue -= this->mg_pst(them, capture, to);
- egValue -= this->eg_pst(them, capture, to);
+ // Finish
+ sideToMove = opposite_color(sideToMove);
+ st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- // Update material:
- if(capture != PAWN)
- npMaterial[them] -= piece_value_midgame(capture);
+ assert(is_ok());
+}
- // Update material hash key:
- materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
- // Update piece count:
- pieceCount[them][capture]--;
+/// Position::do_capture_move() is a private method used to update captured
+/// piece info. It is called from the main Position::do_move function.
- // Update piece list:
- pieceList[them][capture][index[to]] =
- pieceList[them][capture][pieceCount[them][capture]];
- index[pieceList[them][capture][index[to]]] = index[to];
+void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) {
- // Remember the captured piece, in order to be able to undo the move
- // correctly:
- u.capture = capture;
+ assert(capture != KING);
- // Reset rule 50 counter:
- rule50 = 0;
- }
+ Square capsq = to;
- // Move the piece:
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[piece]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[piece]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = board[from];
- board[from] = EMPTY;
-
- // Update hash key:
- key ^= zobrist[us][piece][from] ^ zobrist[us][piece][to];
-
- // Update incremental scores:
- mgValue -= this->mg_pst(us, piece, from);
- mgValue += this->mg_pst(us, piece, to);
- egValue -= this->eg_pst(us, piece, from);
- egValue += this->eg_pst(us, piece, to);
-
- // If the moving piece was a king, update the king square:
- if(piece == KING)
- kingSquare[us] = to;
-
- // If the move was a double pawn push, set the en passant square.
- // This code is a bit ugly right now, and should be cleaned up later.
- // FIXME
- if(epSquare != SQ_NONE) {
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
- }
- if(piece == PAWN) {
- if(abs(int(to) - int(from)) == 16) {
- if((us == WHITE && (this->white_pawn_attacks(from + DELTA_N) &
- this->pawns(BLACK))) ||
- (us == BLACK && (this->black_pawn_attacks(from + DELTA_S) &
- this->pawns(WHITE)))) {
- epSquare = Square((int(from) + int(to)) / 2);
- key ^= zobEp[epSquare];
+ // If the captured piece was a pawn, update pawn hash key,
+ // otherwise update non-pawn material.
+ if (capture == PAWN)
+ {
+ if (ep) // en passant ?
+ {
+ capsq = (them == BLACK)? (to - DELTA_N) : (to - DELTA_S);
+
+ assert(to == st->epSquare);
+ assert(relative_rank(opposite_color(them), to) == RANK_6);
+ assert(piece_on(to) == PIECE_NONE);
+ assert(piece_on(capsq) == make_piece(them, PAWN));
+
+ board[capsq] = PIECE_NONE;
}
- }
- // Reset rule 50 draw counter.
- rule50 = 0;
- // Update pawn hash key:
- pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
+ st->pawnKey ^= zobrist[them][PAWN][capsq];
}
+ else
+ st->npMaterial[them] -= PieceValueMidgame[capture];
- // Update piece lists:
- pieceList[us][piece][index[from]] = to;
- index[to] = index[from];
-
- // Update castle rights:
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[from];
- castleRights &= castleRightsMask[to];
- key ^= zobCastle[castleRights];
-
- // Update checkers bitboard:
- checkersBB = EmptyBoardBB;
- Square ksq = this->king_square(them);
-
- switch(piece) {
-
- case PAWN:
- if(bit_is_set(this->pawn_attacks(them, ksq), to))
- set_bit(&checkersBB, to);
- if(bit_is_set(dcCandidates, from))
- checkersBB |=
- ((this->rook_attacks(ksq) & this->rooks_and_queens(us)) |
- (this->bishop_attacks(ksq) & this->bishops_and_queens(us)));
- break;
-
- case KNIGHT:
- if(bit_is_set(this->knight_attacks(ksq), to))
- set_bit(&checkersBB, to);
- if(bit_is_set(dcCandidates, from))
- checkersBB |=
- ((this->rook_attacks(ksq) & this->rooks_and_queens(us)) |
- (this->bishop_attacks(ksq) & this->bishops_and_queens(us)));
- break;
-
- case BISHOP:
- if(bit_is_set(this->bishop_attacks(ksq), to))
- set_bit(&checkersBB, to);
- if(bit_is_set(dcCandidates, from))
- checkersBB |=
- (this->rook_attacks(ksq) & this->rooks_and_queens(us));
- break;
-
- case ROOK:
- if(bit_is_set(this->rook_attacks(ksq), to))
- set_bit(&checkersBB, to);
- if(bit_is_set(dcCandidates, from))
- checkersBB |=
- (this->bishop_attacks(ksq) & this->bishops_and_queens(us));
- break;
-
- case QUEEN:
- if(bit_is_set(this->queen_attacks(ksq), to))
- set_bit(&checkersBB, to);
- break;
-
- case KING:
- if(bit_is_set(dcCandidates, from))
- checkersBB |=
- ((this->rook_attacks(ksq) & this->rooks_and_queens(us)) |
- (this->bishop_attacks(ksq) & this->bishops_and_queens(us)));
- break;
-
- default:
- assert(false);
- break;
- }
- }
+ // Remove captured piece
+ clear_bit(&(byColorBB[them]), capsq);
+ clear_bit(&(byTypeBB[capture]), capsq);
+ clear_bit(&(byTypeBB[0]), capsq);
- // Finish
- key ^= zobSideToMove;
- sideToMove = opposite_color(sideToMove);
- gamePly++;
+ // Update hash key
+ key ^= zobrist[them][capture][capsq];
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ // Update incremental scores
+ st->value -= pst(them, capture, capsq);
- assert(this->is_ok());
+ // Update piece count
+ pieceCount[them][capture]--;
+
+ // Update material hash key
+ st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]];
+
+ // Update piece list, move the last piece at index[capsq] position
+ //
+ // WARNING: This is a not perfectly revresible operation. When we
+ // will reinsert the captured piece in undo_move() we will put it
+ // at the end of the list and not in its original place, it means
+ // index[] and pieceList[] are not guaranteed to be invariant to a
+ // do_move() + undo_move() sequence.
+ Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]];
+ index[lastPieceSquare] = index[capsq];
+ pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare;
+ pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE;
+
+ // Reset rule 50 counter
+ st->rule50 = 0;
}
/// Position::do_castle_move() is a private method used to make a castling
-/// move. It is called from the main Position::do_move function. Note that
+/// move. It is called from the main Position::do_move function. Note that
/// castling moves are encoded as "king captures friendly rook" moves, for
/// instance white short castling in a non-Chess960 game is encoded as e1h1.
void Position::do_castle_move(Move m) {
- Color us, them;
- Square kfrom, kto, rfrom, rto;
- assert(this->is_ok());
assert(move_is_ok(m));
assert(move_is_castle(m));
- us = this->side_to_move();
- them = opposite_color(us);
+ Color us = side_to_move();
+ Color them = opposite_color(us);
- // Find source squares for king and rook:
- kfrom = move_from(m);
- rfrom = move_to(m); // HACK: See comment at beginning of function.
+ // Reset capture field
+ st->capturedType = PIECE_TYPE_NONE;
- assert(this->piece_on(kfrom) == king_of_color(us));
- assert(this->piece_on(rfrom) == rook_of_color(us));
+ // Find source squares for king and rook
+ Square kfrom = move_from(m);
+ Square rfrom = move_to(m); // HACK: See comment at beginning of function
+ Square kto, rto;
- // Find destination squares for king and rook:
- if(rfrom > kfrom) { // O-O
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- }
- else { // O-O-O
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
+ assert(piece_on(kfrom) == make_piece(us, KING));
+ assert(piece_on(rfrom) == make_piece(us, ROOK));
+
+ // Find destination squares for king and rook
+ if (rfrom > kfrom) // O-O
+ {
+ kto = relative_square(us, SQ_G1);
+ rto = relative_square(us, SQ_F1);
+ } else { // O-O-O
+ kto = relative_square(us, SQ_C1);
+ rto = relative_square(us, SQ_D1);
}
// Remove pieces from source squares:
set_bit(&(byTypeBB[ROOK]), rto);
set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares
- // Update board array:
- board[kfrom] = board[rfrom] = EMPTY;
- board[kto] = king_of_color(us);
- board[rto] = rook_of_color(us);
-
- // Update king square:
- kingSquare[us] = kto;
+ // Update board array
+ Piece king = make_piece(us, KING);
+ Piece rook = make_piece(us, ROOK);
+ board[kfrom] = board[rfrom] = PIECE_NONE;
+ board[kto] = king;
+ board[rto] = rook;
- // Update piece lists:
+ // Update piece lists
pieceList[us][KING][index[kfrom]] = kto;
pieceList[us][ROOK][index[rfrom]] = rto;
- int tmp = index[rfrom];
+ int tmp = index[rfrom]; // In Chess960 could be rto == kfrom
index[kto] = index[kfrom];
index[rto] = tmp;
- // Update incremental scores:
- mgValue -= this->mg_pst(us, KING, kfrom);
- mgValue += this->mg_pst(us, KING, kto);
- egValue -= this->eg_pst(us, KING, kfrom);
- egValue += this->eg_pst(us, KING, kto);
- mgValue -= this->mg_pst(us, ROOK, rfrom);
- mgValue += this->mg_pst(us, ROOK, rto);
- egValue -= this->eg_pst(us, ROOK, rfrom);
- egValue += this->eg_pst(us, ROOK, rto);
-
- // Update hash key:
- key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
- key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
-
- // Clear en passant square:
- if(epSquare != SQ_NONE) {
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
- }
-
- // Update castling rights:
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[kfrom];
- key ^= zobCastle[castleRights];
+ // Update incremental scores
+ st->value += pst_delta(king, kfrom, kto);
+ st->value += pst_delta(rook, rfrom, rto);
- // Reset rule 50 counter:
- rule50 = 0;
+ // Update hash key
+ st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto];
+ st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto];
- // Update checkers BB:
- checkersBB = attacks_to(this->king_square(them), us);
-}
-
-
-/// Position::do_promotion_move() is a private method used to make a promotion
-/// move. It is called from the main Position::do_move function. The
-/// UndoInfo object, which has been initialized in Position::do_move, is
-/// used to store the captured piece (if any).
-
-void Position::do_promotion_move(Move m, UndoInfo &u) {
- Color us, them;
- Square from, to;
- PieceType capture, promotion;
-
- assert(this->is_ok());
- assert(move_is_ok(m));
- assert(move_promotion(m));
-
- us = this->side_to_move();
- them = opposite_color(us);
-
- from = move_from(m);
- to = move_to(m);
+ // Clear en passant square
+ if (st->epSquare != SQ_NONE)
+ {
+ st->key ^= zobEp[st->epSquare];
+ st->epSquare = SQ_NONE;
+ }
- assert(pawn_rank(us, to) == RANK_8);
- assert(this->piece_on(from) == pawn_of_color(us));
- assert(this->color_of_piece_on(to) == them || this->square_is_empty(to));
+ // Update castling rights
+ st->key ^= zobCastle[st->castleRights];
+ st->castleRights &= castleRightsMask[kfrom];
+ st->key ^= zobCastle[st->castleRights];
- capture = this->type_of_piece_on(to);
+ // Reset rule 50 counter
+ st->rule50 = 0;
- if(capture) {
- assert(capture != KING);
+ // Update checkers BB
+ st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us);
- // Remove captured piece:
- clear_bit(&(byColorBB[them]), to);
- clear_bit(&(byTypeBB[capture]), to);
+ // Finish
+ sideToMove = opposite_color(sideToMove);
+ st->value += (sideToMove == WHITE ? TempoValue : -TempoValue);
- // Update hash key:
- key ^= zobrist[them][capture][to];
+ assert(is_ok());
+}
- // Update incremental scores:
- mgValue -= this->mg_pst(them, capture, to);
- egValue -= this->eg_pst(them, capture, to);
- // Update material. Because our move is a promotion, we know that the
- // captured piece is not a pawn.
- assert(capture != PAWN);
- npMaterial[them] -= piece_value_midgame(capture);
+/// Position::undo_move() unmakes a move. When it returns, the position should
+/// be restored to exactly the same state as before the move was made.
- // Update material hash key:
- materialKey ^= zobMaterial[them][capture][pieceCount[them][capture]];
+void Position::undo_move(Move m) {
- // Update piece count:
- pieceCount[them][capture]--;
+ assert(is_ok());
+ assert(move_is_ok(m));
- // Update piece list:
- pieceList[them][capture][index[to]] =
- pieceList[them][capture][pieceCount[them][capture]];
- index[pieceList[them][capture][index[to]]] = index[to];
+ sideToMove = opposite_color(sideToMove);
- // Remember the captured piece, in order to be able to undo the move
- // correctly:
- u.capture = capture;
+ if (move_is_castle(m))
+ {
+ undo_castle_move(m);
+ return;
}
- // Remove pawn:
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[PAWN]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = EMPTY;
-
- // Insert promoted piece:
- promotion = move_promotion(m);
- assert(promotion >= KNIGHT && promotion <= QUEEN);
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[promotion]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = piece_of_color_and_type(us, promotion);
-
- // Update hash key:
- key ^= zobrist[us][PAWN][from] ^ zobrist[us][promotion][to];
-
- // Update pawn hash key:
- pawnKey ^= zobrist[us][PAWN][from];
-
- // Update material key:
- materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]];
- materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1];
-
- // Update piece counts:
- pieceCount[us][PAWN]--;
- pieceCount[us][promotion]++;
-
- // Update piece lists:
- pieceList[us][PAWN][index[from]] =
- pieceList[us][PAWN][pieceCount[us][PAWN]];
- index[pieceList[us][PAWN][index[from]]] = index[from];
- pieceList[us][promotion][pieceCount[us][promotion] - 1] = to;
- index[to] = pieceCount[us][promotion] - 1;
-
- // Update incremental scores:
- mgValue -= this->mg_pst(us, PAWN, from);
- mgValue += this->mg_pst(us, promotion, to);
- egValue -= this->eg_pst(us, PAWN, from);
- egValue += this->eg_pst(us, promotion, to);
-
- // Update material:
- npMaterial[us] += piece_value_midgame(promotion);
-
- // Clear the en passant square:
- if(epSquare != SQ_NONE) {
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
+ Color us = side_to_move();
+ Color them = opposite_color(us);
+ Square from = move_from(m);
+ Square to = move_to(m);
+ bool ep = move_is_ep(m);
+ bool pm = move_is_promotion(m);
+
+ PieceType pt = type_of_piece_on(to);
+
+ assert(square_is_empty(from));
+ assert(color_of_piece_on(to) == us);
+ assert(!pm || relative_rank(us, to) == RANK_8);
+ assert(!ep || to == st->previous->epSquare);
+ assert(!ep || relative_rank(us, to) == RANK_6);
+ assert(!ep || piece_on(to) == make_piece(us, PAWN));
+
+ if (pm) // promotion ?
+ {
+ PieceType promotion = move_promotion_piece(m);
+ pt = PAWN;
+
+ assert(promotion >= KNIGHT && promotion <= QUEEN);
+ assert(piece_on(to) == make_piece(us, promotion));
+
+ // Replace promoted piece with a pawn
+ clear_bit(&(byTypeBB[promotion]), to);
+ set_bit(&(byTypeBB[PAWN]), to);
+
+ // Update piece counts
+ pieceCount[us][promotion]--;
+ pieceCount[us][PAWN]++;
+
+ // Update piece list replacing promotion piece with a pawn
+ Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]];
+ index[lastPromotionSquare] = index[to];
+ pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare;
+ pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE;
+ index[to] = pieceCount[us][PAWN] - 1;
+ pieceList[us][PAWN][index[to]] = to;
}
- // Update castle rights:
- key ^= zobCastle[castleRights];
- castleRights &= castleRightsMask[to];
- key ^= zobCastle[castleRights];
-
- // Reset rule 50 counter:
- rule50 = 0;
-
- // Update checkers BB:
- checkersBB = attacks_to(this->king_square(them), us);
-}
-
+ // Put the piece back at the source square
+ Bitboard move_bb = make_move_bb(to, from);
+ do_move_bb(&(byColorBB[us]), move_bb);
+ do_move_bb(&(byTypeBB[pt]), move_bb);
+ do_move_bb(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares
-/// Position::do_ep_move() is a private method used to make an en passant
-/// capture. It is called from the main Position::do_move function. Because
-/// the captured piece is always a pawn, we don't need to pass an UndoInfo
-/// object in which to store the captured piece.
+ board[from] = make_piece(us, pt);
+ board[to] = PIECE_NONE;
-void Position::do_ep_move(Move m) {
- Color us, them;
- Square from, to, capsq;
-
- assert(this->is_ok());
- assert(move_is_ok(m));
- assert(move_is_ep(m));
-
- us = this->side_to_move();
- them = opposite_color(us);
-
- // Find from, to and capture squares:
- from = move_from(m);
- to = move_to(m);
- capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
-
- assert(to == epSquare);
- assert(pawn_rank(us, to) == RANK_6);
- assert(this->piece_on(to) == EMPTY);
- assert(this->piece_on(from) == pawn_of_color(us));
- assert(this->piece_on(capsq) == pawn_of_color(them));
-
- // Remove captured piece:
- clear_bit(&(byColorBB[them]), capsq);
- clear_bit(&(byTypeBB[PAWN]), capsq);
- clear_bit(&(byTypeBB[0]), capsq); // HACK: byTypeBB[0] == occupied squares
- board[capsq] = EMPTY;
-
- // Remove moving piece from source square:
- clear_bit(&(byColorBB[us]), from);
- clear_bit(&(byTypeBB[PAWN]), from);
- clear_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
-
- // Put moving piece on destination square:
- set_bit(&(byColorBB[us]), to);
- set_bit(&(byTypeBB[PAWN]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = board[from];
- board[from] = EMPTY;
+ // Update piece list
+ index[from] = index[to];
+ pieceList[us][pt][index[from]] = from;
- // Update material hash key:
- materialKey ^= zobMaterial[them][PAWN][pieceCount[them][PAWN]];
+ if (st->capturedType)
+ {
+ Square capsq = to;
- // Update piece count:
- pieceCount[them][PAWN]--;
+ if (ep)
+ capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
- // Update piece list:
- pieceList[us][PAWN][index[from]] = to;
- index[to] = index[from];
- pieceList[them][PAWN][index[capsq]] =
- pieceList[them][PAWN][pieceCount[them][PAWN]];
- index[pieceList[them][PAWN][index[capsq]]] = index[capsq];
-
- // Update hash key:
- key ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- key ^= zobrist[them][PAWN][capsq];
- key ^= zobEp[epSquare];
-
- // Update pawn hash key:
- pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
- pawnKey ^= zobrist[them][PAWN][capsq];
-
- // Update incremental scores:
- mgValue -= this->mg_pst(them, PAWN, capsq);
- mgValue -= this->mg_pst(us, PAWN, from);
- mgValue += this->mg_pst(us, PAWN, to);
- egValue -= this->eg_pst(them, PAWN, capsq);
- egValue -= this->eg_pst(us, PAWN, from);
- egValue += this->eg_pst(us, PAWN, to);
-
- // Reset en passant square:
- epSquare = SQ_NONE;
-
- // Reset rule 50 counter:
- rule50 = 0;
-
- // Update checkers BB:
- checkersBB = attacks_to(this->king_square(them), us);
-}
+ assert(st->capturedType != KING);
+ assert(!ep || square_is_empty(capsq));
+ // Restore the captured piece
+ set_bit(&(byColorBB[them]), capsq);
+ set_bit(&(byTypeBB[st->capturedType]), capsq);
+ set_bit(&(byTypeBB[0]), capsq);
-/// Position::undo_move() unmakes a move. When it returns, the position should
-/// be restored to exactly the same state as before the move was made. It is
-/// important that Position::undo_move is called with the same move and UndoInfo
-/// object as the earlier call to Position::do_move.
+ board[capsq] = make_piece(them, st->capturedType);
-void Position::undo_move(Move m, const UndoInfo &u) {
- assert(this->is_ok());
- assert(move_is_ok(m));
-
- gamePly--;
- sideToMove = opposite_color(sideToMove);
+ // Update piece count
+ pieceCount[them][st->capturedType]++;
- // Restore information from our UndoInfo object (except the captured piece,
- // which is taken care of later):
- this->restore(u);
-
- if(move_is_castle(m))
- this->undo_castle_move(m);
- else if(move_promotion(m))
- this->undo_promotion_move(m, u);
- else if(move_is_ep(m))
- this->undo_ep_move(m);
- else {
- Color us, them;
- Square from, to;
- PieceType piece, capture;
-
- us = this->side_to_move();
- them = opposite_color(us);
-
- from = move_from(m);
- to = move_to(m);
-
- assert(this->piece_on(from) == EMPTY);
- assert(color_of_piece_on(to) == us);
-
- // Put the piece back at the source square:
- piece = this->type_of_piece_on(to);
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[piece]), from);
- set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = piece_of_color_and_type(us, piece);
-
- // Clear the destination square
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[piece]), to);
- clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
-
- // If the moving piece was a king, update the king square:
- if(piece == KING)
- kingSquare[us] = from;
-
- // Update piece list:
- pieceList[us][piece][index[to]] = from;
- index[from] = index[to];
-
- capture = u.capture;
-
- if(capture) {
- assert(capture != KING);
- // Replace the captured piece:
- set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[capture]), to);
- set_bit(&(byTypeBB[0]), to);
- board[to] = piece_of_color_and_type(them, capture);
-
- // Update material:
- if(capture != PAWN)
- npMaterial[them] += piece_value_midgame(capture);
-
- // Update piece list:
- pieceList[them][capture][pieceCount[them][capture]] = to;
- index[to] = pieceCount[them][capture];
-
- // Update piece count:
- pieceCount[them][capture]++;
- }
- else
- board[to] = EMPTY;
+ // Update piece list, add a new captured piece in capsq square
+ index[capsq] = pieceCount[them][st->capturedType] - 1;
+ pieceList[them][st->capturedType][index[capsq]] = capsq;
}
- assert(this->is_ok());
+ // Finally point our state pointer back to the previous state
+ st = st->previous;
+
+ assert(is_ok());
}
/// Position::undo_castle_move() is a private method used to unmake a castling
-/// move. It is called from the main Position::undo_move function. Note that
+/// move. It is called from the main Position::undo_move function. Note that
/// castling moves are encoded as "king captures friendly rook" moves, for
/// instance white short castling in a non-Chess960 game is encoded as e1h1.
void Position::undo_castle_move(Move m) {
- Color us, them;
- Square kfrom, kto, rfrom, rto;
assert(move_is_ok(m));
assert(move_is_castle(m));
// When we have arrived here, some work has already been done by
// Position::undo_move. In particular, the side to move has been switched,
// so the code below is correct.
- us = this->side_to_move();
- them = opposite_color(us);
-
- // Find source squares for king and rook:
- kfrom = move_from(m);
- rfrom = move_to(m); // HACK: See comment at beginning of function.
-
- // Find destination squares for king and rook:
- if(rfrom > kfrom) { // O-O
- kto = relative_square(us, SQ_G1);
- rto = relative_square(us, SQ_F1);
- }
- else { // O-O-O
- kto = relative_square(us, SQ_C1);
- rto = relative_square(us, SQ_D1);
+ Color us = side_to_move();
+
+ // Find source squares for king and rook
+ Square kfrom = move_from(m);
+ Square rfrom = move_to(m); // HACK: See comment at beginning of function
+ Square kto, rto;
+
+ // Find destination squares for king and rook
+ if (rfrom > kfrom) // O-O
+ {
+ kto = relative_square(us, SQ_G1);
+ rto = relative_square(us, SQ_F1);
+ } else { // O-O-O
+ kto = relative_square(us, SQ_C1);
+ rto = relative_square(us, SQ_D1);
}
- assert(this->piece_on(kto) == king_of_color(us));
- assert(this->piece_on(rto) == rook_of_color(us));
+ assert(piece_on(kto) == make_piece(us, KING));
+ assert(piece_on(rto) == make_piece(us, ROOK));
// Remove pieces from destination squares:
clear_bit(&(byColorBB[us]), kto);
set_bit(&(byTypeBB[ROOK]), rfrom);
set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares
- // Update board:
- board[rto] = board[kto] = EMPTY;
- board[rfrom] = rook_of_color(us);
- board[kfrom] = king_of_color(us);
+ // Update board
+ board[rto] = board[kto] = PIECE_NONE;
+ board[rfrom] = make_piece(us, ROOK);
+ board[kfrom] = make_piece(us, KING);
- // Update king square:
- kingSquare[us] = kfrom;
-
- // Update piece lists:
+ // Update piece lists
pieceList[us][KING][index[kto]] = kfrom;
pieceList[us][ROOK][index[rto]] = rfrom;
- int tmp = index[rto]; // Necessary because we may have rto == kfrom in FRC.
+ int tmp = index[rto]; // In Chess960 could be rto == kfrom
index[kfrom] = index[kto];
index[rfrom] = tmp;
-}
+ // Finally point our state pointer back to the previous state
+ st = st->previous;
-/// Position::undo_promotion_move() is a private method used to unmake a
-/// promotion move. It is called from the main Position::do_move
-/// function. The UndoInfo object, which has been initialized in
-/// Position::do_move, is used to put back the captured piece (if any).
-
-void Position::undo_promotion_move(Move m, const UndoInfo &u) {
- Color us, them;
- Square from, to;
- PieceType capture, promotion;
-
- assert(move_is_ok(m));
- assert(move_promotion(m));
-
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- us = this->side_to_move();
- them = opposite_color(us);
-
- from = move_from(m);
- to = move_to(m);
-
- assert(pawn_rank(us, to) == RANK_8);
- assert(this->piece_on(from) == EMPTY);
-
- // Remove promoted piece:
- promotion = move_promotion(m);
- assert(this->piece_on(to)==piece_of_color_and_type(us, promotion));
- assert(promotion >= KNIGHT && promotion <= QUEEN);
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[promotion]), to);
- clear_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
-
- // Insert pawn at source square:
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[PAWN]), from);
- set_bit(&(byTypeBB[0]), from); // HACK: byTypeBB[0] == occupied squares
- board[from] = pawn_of_color(us);
-
- // Update material:
- npMaterial[us] -= piece_value_midgame(promotion);
-
- // Update piece list:
- pieceList[us][PAWN][pieceCount[us][PAWN]] = from;
- index[from] = pieceCount[us][PAWN];
- pieceList[us][promotion][index[to]] =
- pieceList[us][promotion][pieceCount[us][promotion] - 1];
- index[pieceList[us][promotion][index[to]]] = index[to];
-
- // Update piece counts:
- pieceCount[us][promotion]--;
- pieceCount[us][PAWN]++;
-
- capture = u.capture;
- if(capture) {
- assert(capture != KING);
-
- // Insert captured piece:
- set_bit(&(byColorBB[them]), to);
- set_bit(&(byTypeBB[capture]), to);
- set_bit(&(byTypeBB[0]), to); // HACK: byTypeBB[0] == occupied squares
- board[to] = piece_of_color_and_type(them, capture);
+ assert(is_ok());
+}
- // Update material. Because the move is a promotion move, we know
- // that the captured piece cannot be a pawn.
- assert(capture != PAWN);
- npMaterial[them] += piece_value_midgame(capture);
- // Update piece list:
- pieceList[them][capture][pieceCount[them][capture]] = to;
- index[to] = pieceCount[them][capture];
+/// Position::do_null_move makes() a "null move": It switches the side to move
+/// and updates the hash key without executing any move on the board.
- // Update piece count:
- pieceCount[them][capture]++;
- }
- else
- board[to] = EMPTY;
-}
+void Position::do_null_move(StateInfo& backupSt) {
+ assert(is_ok());
+ assert(!is_check());
-/// Position::undo_ep_move() is a private method used to unmake an en passant
-/// capture. It is called from the main Position::undo_move function. Because
-/// the captured piece is always a pawn, we don't need to pass an UndoInfo
-/// object from which to retrieve the captured piece.
+ // Back up the information necessary to undo the null move to the supplied
+ // StateInfo object.
+ // Note that differently from normal case here backupSt is actually used as
+ // a backup storage not as a new state to be used.
+ backupSt.key = st->key;
+ backupSt.epSquare = st->epSquare;
+ backupSt.value = st->value;
+ backupSt.previous = st->previous;
+ backupSt.pliesFromNull = st->pliesFromNull;
+ st->previous = &backupSt;
-void Position::undo_ep_move(Move m) {
- Color us, them;
- Square from, to, capsq;
+ // Save the current key to the history[] array, in order to be able to
+ // detect repetition draws.
+ history[st->gamePly++] = st->key;
- assert(move_is_ok(m));
- assert(move_is_ep(m));
+ // Update the necessary information
+ if (st->epSquare != SQ_NONE)
+ st->key ^= zobEp[st->epSquare];
- // When we have arrived here, some work has already been done by
- // Position::undo_move. In particular, the side to move has been switched,
- // so the code below is correct.
- us = this->side_to_move();
- them = opposite_color(us);
-
- // Find from, to and captures squares:
- from = move_from(m);
- to = move_to(m);
- capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S);
-
- assert(to == this->ep_square());
- assert(pawn_rank(us, to) == RANK_6);
- assert(this->piece_on(to) == pawn_of_color(us));
- assert(this->piece_on(from) == EMPTY);
- assert(this->piece_on(capsq) == EMPTY);
-
- // Replace captured piece:
- set_bit(&(byColorBB[them]), capsq);
- set_bit(&(byTypeBB[PAWN]), capsq);
- set_bit(&(byTypeBB[0]), capsq);
- board[capsq] = pawn_of_color(them);
-
- // Remove moving piece from destination square:
- clear_bit(&(byColorBB[us]), to);
- clear_bit(&(byTypeBB[PAWN]), to);
- clear_bit(&(byTypeBB[0]), to);
- board[to] = EMPTY;
-
- // Replace moving piece at source square:
- set_bit(&(byColorBB[us]), from);
- set_bit(&(byTypeBB[PAWN]), from);
- set_bit(&(byTypeBB[0]), from);
- board[from] = pawn_of_color(us);
-
- // Update piece list:
- pieceList[us][PAWN][index[to]] = from;
- index[from] = index[to];
- pieceList[them][PAWN][pieceCount[them][PAWN]] = capsq;
- index[capsq] = pieceCount[them][PAWN];
+ st->key ^= zobSideToMove;
+ prefetch((char*)TT.first_entry(st->key));
- // Update piece count:
- pieceCount[them][PAWN]++;
+ sideToMove = opposite_color(sideToMove);
+ st->epSquare = SQ_NONE;
+ st->rule50++;
+ st->pliesFromNull = 0;
+ st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue;
}
-/// Position::do_null_move makes() a "null move": It switches the side to move
-/// and updates the hash key without executing any move on the board.
+/// Position::undo_null_move() unmakes a "null move".
-void Position::do_null_move(UndoInfo &u) {
- assert(this->is_ok());
- assert(!this->is_check());
+void Position::undo_null_move() {
- // Back up the information necessary to undo the null move to the supplied
- // UndoInfo object. In the case of a null move, the only thing we need to
- // remember is the last move made and the en passant square.
- u.lastMove = lastMove;
- u.epSquare = epSquare;
+ assert(is_ok());
+ assert(!is_check());
- // Save the current key to the history[] array, in order to be able to
- // detect repetition draws:
- history[gamePly] = key;
+ // Restore information from the our backup StateInfo object
+ StateInfo* backupSt = st->previous;
+ st->key = backupSt->key;
+ st->epSquare = backupSt->epSquare;
+ st->value = backupSt->value;
+ st->previous = backupSt->previous;
+ st->pliesFromNull = backupSt->pliesFromNull;
- // Update the necessary information.
+ // Update the necessary information
sideToMove = opposite_color(sideToMove);
- if(epSquare != SQ_NONE)
- key ^= zobEp[epSquare];
- epSquare = SQ_NONE;
- rule50++;
- gamePly++;
- key ^= zobSideToMove;
-
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
-
- assert(this->is_ok());
+ st->rule50--;
+ st->gamePly--;
}
-/// Position::undo_null_move() unmakes a "null move".
+/// Position::see() is a static exchange evaluator: It tries to estimate the
+/// material gain or loss resulting from a move. There are three versions of
+/// this function: One which takes a destination square as input, one takes a
+/// move, and one which takes a 'from' and a 'to' square. The function does
+/// not yet understand promotions captures.
-void Position::undo_null_move(const UndoInfo &u) {
- assert(this->is_ok());
- assert(!this->is_check());
+int Position::see(Move m) const {
- // Restore information from the supplied UndoInfo object:
- lastMove = u.lastMove;
- epSquare = u.epSquare;
- if(epSquare != SQ_NONE)
- key ^= zobEp[epSquare];
+ assert(move_is_ok(m));
+ return see(move_from(m), move_to(m));
+}
- // Update the necessary information.
- sideToMove = opposite_color(sideToMove);
- rule50--;
- gamePly--;
- key ^= zobSideToMove;
+int Position::see_sign(Move m) const {
- mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame;
- egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame;
+ assert(move_is_ok(m));
- assert(this->is_ok());
-}
+ Square from = move_from(m);
+ Square to = move_to(m);
+ // Early return if SEE cannot be negative because captured piece value
+ // is not less then capturing one. Note that king moves always return
+ // here because king midgame value is set to 0.
+ if (midgame_value_of_piece_on(to) >= midgame_value_of_piece_on(from))
+ return 1;
-/// Position::see() is a static exchange evaluator: It tries to estimate the
-/// material gain or loss resulting from a move. There are two versions of
-/// this function: One which takes a move as input, and one which takes a
-/// 'from' and a 'to' square. The function does not yet understand promotions
-/// or en passant captures.
+ return see(from, to);
+}
int Position::see(Square from, Square to) const {
- // Approximate material values, with pawn = 1:
- static const int seeValues[18] = {
- 0, 1, 3, 3, 5, 10, 100, 0, 0, 1, 3, 3, 5, 10, 100, 0, 0, 0
- };
- Color us, them;
- Piece piece, capture;
- Bitboard attackers, occ, b;
+
+ Bitboard occupied, attackers, stmAttackers, b;
+ int swapList[32], slIndex = 1;
+ PieceType capturedType, pt;
+ Color stm;
assert(square_is_ok(from));
assert(square_is_ok(to));
- // Initialize colors:
- us = this->color_of_piece_on(from);
- them = opposite_color(us);
+ capturedType = type_of_piece_on(to);
+
+ // King cannot be recaptured
+ if (capturedType == KING)
+ return seeValues[capturedType];
+
+ occupied = occupied_squares();
+
+ // Handle en passant moves
+ if (st->epSquare == to && type_of_piece_on(from) == PAWN)
+ {
+ Square capQq = (side_to_move() == WHITE ? to - DELTA_N : to - DELTA_S);
- // Initialize pieces:
- piece = this->piece_on(from);
- capture = this->piece_on(to);
+ assert(capturedType == PIECE_TYPE_NONE);
+ assert(type_of_piece_on(capQq) == PAWN);
+
+ // Remove the captured pawn
+ clear_bit(&occupied, capQq);
+ capturedType = PAWN;
+ }
// Find all attackers to the destination square, with the moving piece
- // removed, but possibly an X-ray attacker added behind it:
- occ = this->occupied_squares();
- clear_bit(&occ, from);
- attackers =
- (rook_attacks_bb(to, occ) & this->rooks_and_queens()) |
- (bishop_attacks_bb(to, occ) & this->bishops_and_queens()) |
- (this->knight_attacks(to) & this->knights()) |
- (this->king_attacks(to) & this->kings()) |
- (this->white_pawn_attacks(to) & this->pawns(BLACK)) |
- (this->black_pawn_attacks(to) & this->pawns(WHITE));
- attackers &= occ;
-
- // If the opponent has no attackers, we are finished:
- if((attackers & this->pieces_of_color(them)) == EmptyBoardBB)
- return seeValues[capture];
+ // removed, but possibly an X-ray attacker added behind it.
+ clear_bit(&occupied, from);
+ attackers = (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occupied)& pieces(BISHOP, QUEEN))
+ | (attacks_from<KNIGHT>(to) & pieces(KNIGHT))
+ | (attacks_from<KING>(to) & pieces(KING))
+ | (attacks_from<PAWN>(to, WHITE) & pieces(PAWN, BLACK))
+ | (attacks_from<PAWN>(to, BLACK) & pieces(PAWN, WHITE));
+
+ // If the opponent has no attackers we are finished
+ stm = opposite_color(color_of_piece_on(from));
+ stmAttackers = attackers & pieces_of_color(stm);
+ if (!stmAttackers)
+ return seeValues[capturedType];
// The destination square is defended, which makes things rather more
- // difficult to compute. We proceed by building up a "swap list" containing
+ // difficult to compute. We proceed by building up a "swap list" containing
// the material gain or loss at each stop in a sequence of captures to the
- // destianation square, where the sides alternately capture, and always
- // capture with the least valuable piece. After each capture, we look for
+ // destination square, where the sides alternately capture, and always
+ // capture with the least valuable piece. After each capture, we look for
// new X-ray attacks from behind the capturing piece.
- int lastCapturingPieceValue = seeValues[piece];
- int swapList[32], n = 1;
- Color c = them;
- PieceType pt;
-
- swapList[0] = seeValues[capture];
+ swapList[0] = seeValues[capturedType];
+ capturedType = type_of_piece_on(from);
do {
- // Locate the least valuable attacker for the side to move. The loop
- // below looks like it is potentially infinite, but it isn't. We know
- // that the side to move still has at least one attacker left.
- for(pt = PAWN; !(attackers&this->pieces_of_color_and_type(c, pt)); pt++)
- assert(pt < KING);
-
- // Remove the attacker we just found from the 'attackers' bitboard,
- // and scan for new X-ray attacks behind the attacker:
- b = attackers & this->pieces_of_color_and_type(c, pt);
- occ ^= (b & -b);
- attackers |=
- (rook_attacks_bb(to, occ) & this->rooks_and_queens()) |
- (bishop_attacks_bb(to, occ) & this->bishops_and_queens());
- attackers &= occ;
-
- // Add the new entry to the swap list:
- assert(n < 32);
- swapList[n] = -swapList[n - 1] + lastCapturingPieceValue;
- n++;
-
- // Remember the value of the capturing piece, and change the side to move
- // before beginning the next iteration:
- lastCapturingPieceValue = seeValues[pt];
- c = opposite_color(c);
-
- // Stop after a king capture:
- if(pt == KING && (attackers & this->pieces_of_color(c))) {
- assert(n < 32);
- swapList[n++] = 100;
- break;
- }
- } while(attackers & this->pieces_of_color(c));
+ // Locate the least valuable attacker for the side to move. The loop
+ // below looks like it is potentially infinite, but it isn't. We know
+ // that the side to move still has at least one attacker left.
+ for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++)
+ assert(pt < KING);
+
+ // Remove the attacker we just found from the 'occupied' bitboard,
+ // and scan for new X-ray attacks behind the attacker.
+ b = stmAttackers & pieces(pt);
+ occupied ^= (b & (~b + 1));
+ attackers |= (rook_attacks_bb(to, occupied) & pieces(ROOK, QUEEN))
+ | (bishop_attacks_bb(to, occupied) & pieces(BISHOP, QUEEN));
+
+ attackers &= occupied; // Cut out pieces we've already done
+
+ // Add the new entry to the swap list
+ assert(slIndex < 32);
+ swapList[slIndex] = -swapList[slIndex - 1] + seeValues[capturedType];
+ slIndex++;
+
+ // Remember the value of the capturing piece, and change the side to
+ // move before beginning the next iteration.
+ capturedType = pt;
+ stm = opposite_color(stm);
+ stmAttackers = attackers & pieces_of_color(stm);
+
+ // Stop before processing a king capture
+ if (capturedType == KING && stmAttackers)
+ {
+ assert(slIndex < 32);
+ swapList[slIndex++] = QueenValueMidgame*10;
+ break;
+ }
+ } while (stmAttackers);
// Having built the swap list, we negamax through it to find the best
- // achievable score from the point of view of the side to move:
- while(--n) swapList[n-1] = Min(-swapList[n], swapList[n-1]);
+ // achievable score from the point of view of the side to move.
+ while (--slIndex)
+ swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]);
return swapList[0];
}
-int Position::see(Move m) const {
- assert(move_is_ok(m));
- return this->see(move_from(m), move_to(m));
-}
-
-
/// Position::clear() erases the position object to a pristine state, with an
/// empty board, white to move, and no castling rights.
void Position::clear() {
- int i, j;
- for(i = 0; i < 64; i++) {
- board[i] = EMPTY;
- index[i] = 0;
- }
+ st = &startState;
+ memset(st, 0, sizeof(StateInfo));
+ st->epSquare = SQ_NONE;
+ startPosPlyCounter = 0;
+ nodes = 0;
- for(i = 0; i < 2; i++)
- byColorBB[i] = EmptyBoardBB;
+ memset(byColorBB, 0, sizeof(Bitboard) * 2);
+ memset(byTypeBB, 0, sizeof(Bitboard) * 8);
+ memset(pieceCount, 0, sizeof(int) * 2 * 8);
+ memset(index, 0, sizeof(int) * 64);
- for(i = 0; i < 7; i++) {
- byTypeBB[i] = EmptyBoardBB;
- pieceCount[0][i] = pieceCount[1][i] = 0;
- for(j = 0; j < 8; j++)
- pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
- }
+ for (int i = 0; i < 64; i++)
+ board[i] = PIECE_NONE;
- checkersBB = EmptyBoardBB;
+ for (int i = 0; i < 8; i++)
+ for (int j = 0; j < 16; j++)
+ pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
- lastMove = MOVE_NONE;
+ for (Square sq = SQ_A1; sq <= SQ_H8; sq++)
+ castleRightsMask[sq] = ALL_CASTLES;
sideToMove = WHITE;
- castleRights = NO_CASTLES;
initialKFile = FILE_E;
initialKRFile = FILE_H;
initialQRFile = FILE_A;
- epSquare = SQ_NONE;
- rule50 = 0;
- gamePly = 0;
-}
-
-
-/// Position::reset_game_ply() simply sets gamePly to 0. It is used from the
-/// UCI interface code, whenever a non-reversible move is made in a
-/// 'position fen <fen> moves m1 m2 ...' command. This makes it possible
-/// for the program to handle games of arbitrary length, as long as the GUI
-/// handles draws by the 50 move rule correctly.
-
-void Position::reset_game_ply() {
- gamePly = 0;
}
/// Position::put_piece() puts a piece on the given square of the board,
-/// updating the board array, bitboards, and piece counts.
+/// updating the board array, pieces list, bitboards, and piece counts.
void Position::put_piece(Piece p, Square s) {
+
Color c = color_of_piece(p);
PieceType pt = type_of_piece(p);
board[s] = p;
- index[s] = pieceCount[c][pt];
+ index[s] = pieceCount[c][pt]++;
pieceList[c][pt][index[s]] = s;
set_bit(&(byTypeBB[pt]), s);
set_bit(&(byColorBB[c]), s);
- set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares.
-
- pieceCount[c][pt]++;
-
- if(pt == KING)
- kingSquare[c] = s;
+ set_bit(&(byTypeBB[0]), s); // HACK: byTypeBB[0] contains all occupied squares.
}
-/// Position::allow_oo() gives the given side the right to castle kingside.
-/// Used when setting castling rights during parsing of FEN strings.
-
-void Position::allow_oo(Color c) {
- castleRights |= (1 + int(c));
-}
-
-
-/// Position::allow_ooo() gives the given side the right to castle queenside.
-/// Used when setting castling rights during parsing of FEN strings.
-
-void Position::allow_ooo(Color c) {
- castleRights |= (4 + 4*int(c));
-}
-
-
-/// Position::compute_key() computes the hash key of the position. The hash
+/// Position::compute_key() computes the hash key of the position. The hash
/// key is usually updated incrementally as moves are made and unmade, the
/// compute_key() function is only used when a new position is set up, and
/// to verify the correctness of the hash key when running in debug mode.
Key Position::compute_key() const {
- Key result = Key(0ULL);
- for(Square s = SQ_A1; s <= SQ_H8; s++)
- if(this->square_is_occupied(s))
- result ^=
- zobrist[this->color_of_piece_on(s)][this->type_of_piece_on(s)][s];
+ Key result = zobCastle[st->castleRights];
+
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ if (square_is_occupied(s))
+ result ^= zobrist[color_of_piece_on(s)][type_of_piece_on(s)][s];
- if(this->ep_square() != SQ_NONE)
- result ^= zobEp[this->ep_square()];
- result ^= zobCastle[castleRights];
- if(this->side_to_move() == BLACK) result ^= zobSideToMove;
+ if (ep_square() != SQ_NONE)
+ result ^= zobEp[ep_square()];
+
+ if (side_to_move() == BLACK)
+ result ^= zobSideToMove;
return result;
}
-/// Position::compute_pawn_key() computes the hash key of the position. The
+/// Position::compute_pawn_key() computes the hash key of the position. The
/// hash key is usually updated incrementally as moves are made and unmade,
/// the compute_pawn_key() function is only used when a new position is set
/// up, and to verify the correctness of the pawn hash key when running in
/// debug mode.
Key Position::compute_pawn_key() const {
- Key result = Key(0ULL);
+
Bitboard b;
- Square s;
+ Key result = 0;
- for(Color c = WHITE; c <= BLACK; c++) {
- b = this->pawns(c);
- while(b) {
- s = pop_1st_bit(&b);
- result ^= zobrist[c][PAWN][s];
- }
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ b = pieces(PAWN, c);
+ while (b)
+ result ^= zobrist[c][PAWN][pop_1st_bit(&b)];
}
return result;
}
/// debug mode.
Key Position::compute_material_key() const {
- Key result = Key(0ULL);
- for(Color c = WHITE; c <= BLACK; c++)
- for(PieceType pt = PAWN; pt <= QUEEN; pt++) {
- int count = this->piece_count(c, pt);
- for(int i = 0; i <= count; i++)
- result ^= zobMaterial[c][pt][i];
- }
+
+ int count;
+ Key result = 0;
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= QUEEN; pt++)
+ {
+ count = piece_count(c, pt);
+ for (int i = 0; i < count; i++)
+ result ^= zobrist[c][pt][i];
+ }
return result;
}
-/// Position::compute_mg_value() and Position::compute_eg_value() compute the
-/// incremental scores for the middle game and the endgame. These functions
-/// are used to initialize the incremental scores when a new position is set
-/// up, and to verify that the scores are correctly updated by do_move
-/// and undo_move when the program is running in debug mode.
+/// Position::compute_value() compute the incremental scores for the middle
+/// game and the endgame. These functions are used to initialize the incremental
+/// scores when a new position is set up, and to verify that the scores are correctly
+/// updated by do_move and undo_move when the program is running in debug mode.
+Score Position::compute_value() const {
-Value Position::compute_mg_value() const {
- Value result = Value(0);
Bitboard b;
- Square s;
-
- for(Color c = WHITE; c <= BLACK; c++)
- for(PieceType pt = PAWN; pt <= KING; pt++) {
- b = this->pieces_of_color_and_type(c, pt);
- while(b) {
- s = pop_1st_bit(&b);
- assert(this->piece_on(s) == piece_of_color_and_type(c, pt));
- result += this->mg_pst(c, pt, s);
+ Score result = SCORE_ZERO;
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ {
+ b = pieces(pt, c);
+ while (b)
+ result += pst(c, pt, pop_1st_bit(&b));
}
- }
- result += (this->side_to_move() == WHITE)?
- (TempoValueMidgame / 2) : -(TempoValueMidgame / 2);
- return result;
-}
-Value Position::compute_eg_value() const {
- Value result = Value(0);
- Bitboard b;
- Square s;
-
- for(Color c = WHITE; c <= BLACK; c++)
- for(PieceType pt = PAWN; pt <= KING; pt++) {
- b = this->pieces_of_color_and_type(c, pt);
- while(b) {
- s = pop_1st_bit(&b);
- assert(this->piece_on(s) == piece_of_color_and_type(c, pt));
- result += this->eg_pst(c, pt, s);
- }
- }
- result += (this->side_to_move() == WHITE)?
- (TempoValueEndgame / 2) : -(TempoValueEndgame / 2);
+ result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2);
return result;
}
/// Position::compute_non_pawn_material() computes the total non-pawn middle
-/// game material score for the given side. Material scores are updated
+/// game material value for the given side. Material values are updated
/// incrementally during the search, this function is only used while
/// initializing a new Position object.
Value Position::compute_non_pawn_material(Color c) const {
- Value result = Value(0);
- Square s;
-
- for(PieceType pt = KNIGHT; pt <= QUEEN; pt++) {
- Bitboard b = this->pieces_of_color_and_type(c, pt);
- while(b) {
- s = pop_1st_bit(&b);
- assert(this->piece_on(s) == piece_of_color_and_type(c, pt));
- result += piece_value_midgame(pt);
- }
- }
- return result;
-}
+ Value result = VALUE_ZERO;
-/// Position::is_mate() returns true or false depending on whether the
-/// side to move is checkmated. Note that this function is currently very
-/// slow, and shouldn't be used frequently inside the search.
-
-bool Position::is_mate() {
- if(this->is_check()) {
- MovePicker mp = MovePicker(*this, false, MOVE_NONE, MOVE_NONE, MOVE_NONE,
- MOVE_NONE, Depth(0));
- return mp.get_next_move() == MOVE_NONE;
- }
- else
- return false;
+ for (PieceType pt = KNIGHT; pt <= QUEEN; pt++)
+ result += piece_count(c, pt) * PieceValueMidgame[pt];
+
+ return result;
}
/// Position::is_draw() tests whether the position is drawn by material,
-/// repetition, or the 50 moves rule. It does not detect stalemates, this
+/// repetition, or the 50 moves rule. It does not detect stalemates, this
/// must be done by the search.
bool Position::is_draw() const {
+
// Draw by material?
- if(!this->pawns() &&
- this->non_pawn_material(WHITE) + this->non_pawn_material(BLACK)
- <= BishopValueMidgame)
- return true;
+ if ( !pieces(PAWN)
+ && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMidgame))
+ return true;
// Draw by the 50 moves rule?
- if(rule50 > 100 || (rule50 == 100 && !this->is_check()))
- return true;
+ if (st->rule50 > 99 && !is_mate())
+ return true;
// Draw by repetition?
- for(int i = 2; i < Min(gamePly, rule50); i += 2)
- if(history[gamePly - i] == key)
- return true;
+ for (int i = 4, e = Min(Min(st->gamePly, st->rule50), st->pliesFromNull); i <= e; i += 2)
+ if (history[st->gamePly - i] == st->key)
+ return true;
return false;
}
-/// Position::has_mate_threat() tests whether a given color has a mate in one
-/// from the current position. This function is quite slow, but it doesn't
-/// matter, because it is currently only called from PV nodes, which are rare.
-
-bool Position::has_mate_threat(Color c) {
- UndoInfo u1, u2;
- Color stm = this->side_to_move();
-
- // The following lines are useless and silly, but prevents gcc from
- // emitting a stupid warning stating that u1.lastMove and u1.epSquare might
- // be used uninitialized.
- u1.lastMove = lastMove;
- u1.epSquare = epSquare;
-
- if(this->is_check())
- return false;
-
- // If the input color is not equal to the side to move, do a null move
- if(c != stm) this->do_null_move(u1);
-
- MoveStack mlist[120];
- int count;
- bool result = false;
-
- // Generate legal moves
- count = generate_legal_moves(*this, mlist);
-
- // Loop through the moves, and see if one of them is mate.
- for(int i = 0; i < count; i++) {
- this->do_move(mlist[i].move, u2);
- if(this->is_mate()) result = true;
- this->undo_move(mlist[i].move, u2);
- }
+/// Position::is_mate() returns true or false depending on whether the
+/// side to move is checkmated.
- // Undo null move, if necessary
- if(c != stm) this->undo_null_move(u1);
+bool Position::is_mate() const {
- return result;
+ MoveStack moves[MOVES_MAX];
+ return is_check() && generate<MV_LEGAL>(*this, moves) == moves;
}
-/// Position::init_zobrist() is a static member function which initializes the
-/// various arrays used to compute hash keys.
+/// Position::init_zobrist() is a static member function which initializes at
+/// startup the various arrays used to compute hash keys.
void Position::init_zobrist() {
- for(int i = 0; i < 2; i++)
- for(int j = 0; j < 8; j++)
- for(int k = 0; k < 64; k++)
- zobrist[i][j][k] = Key(genrand_int64());
-
- for(int i = 0; i < 64; i++)
- zobEp[i] = Key(genrand_int64());
+ int i,j, k;
+ RKISS rk;
- for(int i = 0; i < 16; i++)
- zobCastle[i] = genrand_int64();
+ for (i = 0; i < 2; i++) for (j = 0; j < 8; j++) for (k = 0; k < 64; k++)
+ zobrist[i][j][k] = rk.rand<Key>();
- zobSideToMove = genrand_int64();
+ for (i = 0; i < 64; i++)
+ zobEp[i] = rk.rand<Key>();
- for(int i = 0; i < 2; i++)
- for(int j = 0; j < 8; j++)
- for(int k = 0; k < 16; k++)
- zobMaterial[i][j][k] = (k > 0)? Key(genrand_int64()) : Key(0LL);
+ for (i = 0; i < 16; i++)
+ zobCastle[i] = rk.rand<Key>();
- for(int i = 0; i < 16; i++)
- zobMaterial[0][KING][i] = zobMaterial[1][KING][i] = Key(0ULL);
+ zobSideToMove = rk.rand<Key>();
+ zobExclusion = rk.rand<Key>();
}
/// Position::init_piece_square_tables() initializes the piece square tables.
-/// This is a two-step operation: First, the white halves of the tables are
-/// copied from the MgPST[][] and EgPST[][] arrays, with a small random number
-/// added to each entry if the "Randomness" UCI parameter is non-zero.
-/// Second, the black halves of the tables are initialized by mirroring
-/// and changing the sign of the corresponding white scores.
+/// This is a two-step operation: First, the white halves of the tables are
+/// copied from the MgPST[][] and EgPST[][] arrays. Second, the black halves
+/// of the tables are initialized by mirroring and changing the sign of the
+/// corresponding white scores.
void Position::init_piece_square_tables() {
- int r = get_option_value_int("Randomness"), i;
- for(Square s = SQ_A1; s <= SQ_H8; s++) {
- for(Piece p = WP; p <= WK; p++) {
- i = (r == 0)? 0 : (genrand_int32() % (r*2) - r);
- MgPieceSquareTable[p][s] = Value(MgPST[p][s] + i);
- EgPieceSquareTable[p][s] = Value(EgPST[p][s] + i);
- }
- }
- for(Square s = SQ_A1; s <= SQ_H8; s++)
- for(Piece p = BP; p <= BK; p++) {
- MgPieceSquareTable[p][s] = -MgPieceSquareTable[p-8][flip_square(s)];
- EgPieceSquareTable[p][s] = -EgPieceSquareTable[p-8][flip_square(s)];
- }
+
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ for (Piece p = WP; p <= WK; p++)
+ PieceSquareTable[p][s] = make_score(MgPST[p][s], EgPST[p][s]);
+
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ for (Piece p = BP; p <= BK; p++)
+ PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)];
}
/// Position::flipped_copy() makes a copy of the input position, but with
-/// the white and black sides reversed. This is only useful for debugging,
+/// the white and black sides reversed. This is only useful for debugging,
/// especially for finding evaluation symmetry bugs.
-void Position::flipped_copy(const Position &pos) {
+void Position::flipped_copy(const Position& pos) {
+
assert(pos.is_ok());
- this->clear();
+ clear();
+ threadID = pos.thread();
// Board
- for(Square s = SQ_A1; s <= SQ_H8; s++)
- if(!pos.square_is_empty(s))
- this->put_piece(Piece(int(pos.piece_on(s)) ^ 8), flip_square(s));
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ if (!pos.square_is_empty(s))
+ put_piece(Piece(pos.piece_on(s) ^ 8), flip_square(s));
// Side to move
sideToMove = opposite_color(pos.side_to_move());
// Castling rights
- if(pos.can_castle_kingside(WHITE)) this->allow_oo(BLACK);
- if(pos.can_castle_queenside(WHITE)) this->allow_ooo(BLACK);
- if(pos.can_castle_kingside(BLACK)) this->allow_oo(WHITE);
- if(pos.can_castle_queenside(BLACK)) this->allow_ooo(WHITE);
+ if (pos.can_castle_kingside(WHITE)) do_allow_oo(BLACK);
+ if (pos.can_castle_queenside(WHITE)) do_allow_ooo(BLACK);
+ if (pos.can_castle_kingside(BLACK)) do_allow_oo(WHITE);
+ if (pos.can_castle_queenside(BLACK)) do_allow_ooo(WHITE);
- initialKFile = pos.initialKFile;
+ initialKFile = pos.initialKFile;
initialKRFile = pos.initialKRFile;
initialQRFile = pos.initialQRFile;
- for(Square sq = SQ_A1; sq <= SQ_H8; sq++)
- castleRightsMask[sq] = ALL_CASTLES;
- castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO|WHITE_OOO);
- castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO|BLACK_OOO);
- castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
- castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
- castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
- castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
+ castleRightsMask[make_square(initialKFile, RANK_1)] ^= (WHITE_OO | WHITE_OOO);
+ castleRightsMask[make_square(initialKFile, RANK_8)] ^= (BLACK_OO | BLACK_OOO);
+ castleRightsMask[make_square(initialKRFile, RANK_1)] ^= WHITE_OO;
+ castleRightsMask[make_square(initialKRFile, RANK_8)] ^= BLACK_OO;
+ castleRightsMask[make_square(initialQRFile, RANK_1)] ^= WHITE_OOO;
+ castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
// En passant square
- if(pos.epSquare != SQ_NONE)
- epSquare = flip_square(pos.epSquare);
+ if (pos.st->epSquare != SQ_NONE)
+ st->epSquare = flip_square(pos.st->epSquare);
// Checkers
- this->find_checkers();
+ find_checkers();
// Hash keys
- key = this->compute_key();
- pawnKey = this->compute_pawn_key();
- materialKey = this->compute_material_key();
+ st->key = compute_key();
+ st->pawnKey = compute_pawn_key();
+ st->materialKey = compute_material_key();
// Incremental scores
- mgValue = this->compute_mg_value();
- egValue = this->compute_eg_value();
+ st->value = compute_value();
// Material
- npMaterial[WHITE] = this->compute_non_pawn_material(WHITE);
- npMaterial[BLACK] = this->compute_non_pawn_material(BLACK);
+ st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
+ st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
- assert(this->is_ok());
+ assert(is_ok());
}
/// Position::is_ok() performs some consitency checks for the position object.
/// This is meant to be helpful when debugging.
-bool Position::is_ok() const {
+bool Position::is_ok(int* failedStep) const {
// What features of the position should be verified?
- static const bool debugBitboards = false;
- static const bool debugKingCount = false;
- static const bool debugKingCapture = false;
- static const bool debugCheckerCount = false;
- static const bool debugKey = false;
- static const bool debugMaterialKey = false;
- static const bool debugPawnKey = false;
- static const bool debugIncrementalEval = false;
- static const bool debugNonPawnMaterial = false;
- static const bool debugPieceCounts = false;
- static const bool debugPieceList = false;
+ const bool debugAll = false;
+
+ const bool debugBitboards = debugAll || false;
+ const bool debugKingCount = debugAll || false;
+ const bool debugKingCapture = debugAll || false;
+ const bool debugCheckerCount = debugAll || false;
+ const bool debugKey = debugAll || false;
+ const bool debugMaterialKey = debugAll || false;
+ const bool debugPawnKey = debugAll || false;
+ const bool debugIncrementalEval = debugAll || false;
+ const bool debugNonPawnMaterial = debugAll || false;
+ const bool debugPieceCounts = debugAll || false;
+ const bool debugPieceList = debugAll || false;
+ const bool debugCastleSquares = debugAll || false;
+
+ if (failedStep) *failedStep = 1;
// Side to move OK?
- if(!color_is_ok(this->side_to_move()))
- return false;
+ if (!color_is_ok(side_to_move()))
+ return false;
// Are the king squares in the position correct?
- if(this->piece_on(this->king_square(WHITE)) != WK)
- return false;
- if(this->piece_on(this->king_square(BLACK)) != BK)
- return false;
+ if (failedStep) (*failedStep)++;
+ if (piece_on(king_square(WHITE)) != WK)
+ return false;
+
+ if (failedStep) (*failedStep)++;
+ if (piece_on(king_square(BLACK)) != BK)
+ return false;
// Castle files OK?
- if(!file_is_ok(initialKRFile))
- return false;
- if(!file_is_ok(initialQRFile))
- return false;
+ if (failedStep) (*failedStep)++;
+ if (!file_is_ok(initialKRFile))
+ return false;
- // Do both sides have exactly one king?
- if(debugKingCount) {
- int kingCount[2] = {0, 0};
- for(Square s = SQ_A1; s <= SQ_H8; s++)
- if(this->type_of_piece_on(s) == KING)
- kingCount[this->color_of_piece_on(s)]++;
- if(kingCount[0] != 1 || kingCount[1] != 1)
+ if (!file_is_ok(initialQRFile))
return false;
+
+ // Do both sides have exactly one king?
+ if (failedStep) (*failedStep)++;
+ if (debugKingCount)
+ {
+ int kingCount[2] = {0, 0};
+ for (Square s = SQ_A1; s <= SQ_H8; s++)
+ if (type_of_piece_on(s) == KING)
+ kingCount[color_of_piece_on(s)]++;
+
+ if (kingCount[0] != 1 || kingCount[1] != 1)
+ return false;
}
// Can the side to move capture the opponent's king?
- if(debugKingCapture) {
- Color us = this->side_to_move();
- Color them = opposite_color(us);
- Square ksq = this->king_square(them);
- if(this->square_is_attacked(ksq, us))
- return false;
+ if (failedStep) (*failedStep)++;
+ if (debugKingCapture)
+ {
+ Color us = side_to_move();
+ Color them = opposite_color(us);
+ Square ksq = king_square(them);
+ if (attackers_to(ksq) & pieces_of_color(us))
+ return false;
}
// Is there more than 2 checkers?
- if(debugCheckerCount && count_1s(checkersBB) > 2)
- return false;
-
- // Bitboards OK?
- if(debugBitboards) {
- // The intersection of the white and black pieces must be empty:
- if((this->pieces_of_color(WHITE) & this->pieces_of_color(BLACK))
- != EmptyBoardBB)
+ if (failedStep) (*failedStep)++;
+ if (debugCheckerCount && count_1s<CNT32>(st->checkersBB) > 2)
return false;
- // The union of the white and black pieces must be equal to all
- // occupied squares:
- if((this->pieces_of_color(WHITE) | this->pieces_of_color(BLACK))
- != this->occupied_squares())
- return false;
+ // Bitboards OK?
+ if (failedStep) (*failedStep)++;
+ if (debugBitboards)
+ {
+ // The intersection of the white and black pieces must be empty
+ if ((pieces_of_color(WHITE) & pieces_of_color(BLACK)) != EmptyBoardBB)
+ return false;
- // Separate piece type bitboards must have empty intersections:
- for(PieceType p1 = PAWN; p1 <= KING; p1++)
- for(PieceType p2 = PAWN; p2 <= KING; p2++)
- if(p1 != p2 && (this->pieces_of_type(p1) & this->pieces_of_type(p2)))
+ // The union of the white and black pieces must be equal to all
+ // occupied squares
+ if ((pieces_of_color(WHITE) | pieces_of_color(BLACK)) != occupied_squares())
return false;
+
+ // Separate piece type bitboards must have empty intersections
+ for (PieceType p1 = PAWN; p1 <= KING; p1++)
+ for (PieceType p2 = PAWN; p2 <= KING; p2++)
+ if (p1 != p2 && (pieces(p1) & pieces(p2)))
+ return false;
}
// En passant square OK?
- if(this->ep_square() != SQ_NONE) {
- // The en passant square must be on rank 6, from the point of view of the
- // side to move.
- if(pawn_rank(this->side_to_move(), this->ep_square()) != RANK_6)
- return false;
+ if (failedStep) (*failedStep)++;
+ if (ep_square() != SQ_NONE)
+ {
+ // The en passant square must be on rank 6, from the point of view of the
+ // side to move.
+ if (relative_rank(side_to_move(), ep_square()) != RANK_6)
+ return false;
}
// Hash key OK?
- if(debugKey && key != this->compute_key())
- return false;
+ if (failedStep) (*failedStep)++;
+ if (debugKey && st->key != compute_key())
+ return false;
// Pawn hash key OK?
- if(debugPawnKey && pawnKey != this->compute_pawn_key())
- return false;
+ if (failedStep) (*failedStep)++;
+ if (debugPawnKey && st->pawnKey != compute_pawn_key())
+ return false;
// Material hash key OK?
- if(debugMaterialKey && materialKey != this->compute_material_key())
- return false;
+ if (failedStep) (*failedStep)++;
+ if (debugMaterialKey && st->materialKey != compute_material_key())
+ return false;
// Incremental eval OK?
- if(debugIncrementalEval) {
- if(mgValue != this->compute_mg_value())
- return false;
- if(egValue != this->compute_eg_value())
+ if (failedStep) (*failedStep)++;
+ if (debugIncrementalEval && st->value != compute_value())
return false;
- }
// Non-pawn material OK?
- if(debugNonPawnMaterial) {
- if(npMaterial[WHITE] != compute_non_pawn_material(WHITE))
- return false;
- if(npMaterial[BLACK] != compute_non_pawn_material(BLACK))
- return false;
+ if (failedStep) (*failedStep)++;
+ if (debugNonPawnMaterial)
+ {
+ if (st->npMaterial[WHITE] != compute_non_pawn_material(WHITE))
+ return false;
+
+ if (st->npMaterial[BLACK] != compute_non_pawn_material(BLACK))
+ return false;
}
// Piece counts OK?
- if(debugPieceCounts)
- for(Color c = WHITE; c <= BLACK; c++)
- for(PieceType pt = PAWN; pt <= KING; pt++)
- if(pieceCount[c][pt] != count_1s(this->pieces_of_color_and_type(c, pt)))
+ if (failedStep) (*failedStep)++;
+ if (debugPieceCounts)
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ if (pieceCount[c][pt] != count_1s<CNT32>(pieces(pt, c)))
+ return false;
+
+ if (failedStep) (*failedStep)++;
+ if (debugPieceList)
+ for (Color c = WHITE; c <= BLACK; c++)
+ for (PieceType pt = PAWN; pt <= KING; pt++)
+ for (int i = 0; i < pieceCount[c][pt]; i++)
+ {
+ if (piece_on(piece_list(c, pt, i)) != make_piece(c, pt))
+ return false;
+
+ if (index[piece_list(c, pt, i)] != i)
+ return false;
+ }
+
+ if (failedStep) (*failedStep)++;
+ if (debugCastleSquares)
+ {
+ for (Color c = WHITE; c <= BLACK; c++)
+ {
+ if (can_castle_kingside(c) && piece_on(initial_kr_square(c)) != make_piece(c, ROOK))
+ return false;
+
+ if (can_castle_queenside(c) && piece_on(initial_qr_square(c)) != make_piece(c, ROOK))
+ return false;
+ }
+ if (castleRightsMask[initial_kr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OO))
+ return false;
+ if (castleRightsMask[initial_qr_square(WHITE)] != (ALL_CASTLES ^ WHITE_OOO))
+ return false;
+ if (castleRightsMask[initial_kr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OO))
+ return false;
+ if (castleRightsMask[initial_qr_square(BLACK)] != (ALL_CASTLES ^ BLACK_OOO))
return false;
-
- if(debugPieceList) {
- for(Color c = WHITE; c <= BLACK; c++)
- for(PieceType pt = PAWN; pt <= KING; pt++)
- for(int i = 0; i < pieceCount[c][pt]; i++) {
- if(this->piece_on(this->piece_list(c, pt, i)) !=
- piece_of_color_and_type(c, pt))
- return false;
- if(index[this->piece_list(c, pt, i)] != i)
- return false;
- }
}
+ if (failedStep) *failedStep = 0;
return true;
}
projects / stockfish / blobdiff