/*
- 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 Marco Costalba
- 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.
void Position::from_fen(const std::string &fen) {
- static const std::string piecesStr = "KQRBNPkqrbnp";
+ static const std::string pieceLetters = "KQRBNPkqrbnp";
static const Piece pieces[] = { WK, WQ, WR, WB, WN, WP, BK, BQ, BR, BB, BN, BP };
clear();
rank--;
continue;
}
- size_t idx = piecesStr.find(fen[i]);
+ size_t idx = pieceLetters.find(fen[i]);
if (idx == std::string::npos)
{
std::cout << "Error in FEN at character " << i << std::endl;
// Side to move
i++;
- if (fen[i] != 'w' && fen[i] == 'b')
+ if (fen[i] != 'w' && fen[i] != 'b')
{
std::cout << "Error in FEN at character " << i << std::endl;
return;
/// probably only useful for debugging.
const std::string Position::to_fen() const {
- char pieceLetters[] = " PNBRQK pnbrqk";
- std::string result;
+
+ static const std::string pieceLetters = " PNBRQK pnbrqk";
+ std::string fen;
int skip;
- 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(square_is_occupied(square)) {
- if(skip > 0) result += (char)skip + '0';
- result += pieceLetters[piece_on(square)];
- skip = 0;
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--)
+ {
+ skip = 0;
+ for (File file = FILE_A; file <= FILE_H; file++)
+ {
+ Square sq = make_square(file, rank);
+ if (!square_is_occupied(sq))
+ { skip++;
+ continue;
+ }
+ if (skip > 0)
+ {
+ fen += (char)skip + '0';
+ skip = 0;
+ }
+ fen += pieceLetters[piece_on(sq)];
}
- else skip++;
- }
- if(skip > 0) result += (char)skip + '0';
- result += (rank > RANK_1)? '/' : ' ';
- }
+ if (skip > 0)
+ fen += (char)skip + '0';
- result += (sideToMove == WHITE)? 'w' : 'b';
- result += ' ';
- if(castleRights == NO_CASTLES) result += '-';
- else {
- if(can_castle_kingside(WHITE)) result += 'K';
- if(can_castle_queenside(WHITE)) result += 'Q';
- if(can_castle_kingside(BLACK)) result += 'k';
- if(can_castle_queenside(BLACK)) result += 'q';
+ fen += (rank > RANK_1 ? '/' : ' ');
}
+ fen += (sideToMove == WHITE ? 'w' : 'b') + ' ';
+ if (castleRights != NO_CASTLES)
+ {
+ if (can_castle_kingside(WHITE)) fen += 'K';
+ if (can_castle_queenside(WHITE)) fen += 'Q';
+ if (can_castle_kingside(BLACK)) fen += 'k';
+ if (can_castle_queenside(BLACK)) fen += 'q';
+ } else
+ fen += '-';
+
+ fen += ' ';
+ if (ep_square() != SQ_NONE)
+ fen += square_to_string(ep_square());
+ else
+ fen += '-';
- result += ' ';
- if(ep_square() == SQ_NONE) result += '-';
- else result += square_to_string(ep_square());
-
- return result;
+ return fen;
}
}
-/// Position:pinned_pieces() returns a bitboard of all pinned (against the
-/// king) pieces for the given color.
+/// Position:pinned_pieces<>() returns a bitboard of all pinned (against the
+/// king) pieces for the given color and for the given pinner type.
+template<PieceType Piece>
+Bitboard Position::pinned_pieces(Color c, Square ksq) const {
-Bitboard Position::pinned_pieces(Color c) const {
- Bitboard b1, b2, pinned, pinners, sliders;
- Square ksq = king_square(c), s;
- Color them = opposite_color(c);
+ Square s;
+ Bitboard sliders, pinned = EmptyBoardBB;
+
+ if (Piece == ROOK) // Resolved at compile time
+ sliders = rooks_and_queens(opposite_color(c)) & RookPseudoAttacks[ksq];
+ else
+ sliders = bishops_and_queens(opposite_color(c)) & BishopPseudoAttacks[ksq];
- pinned = EmptyBoardBB;
- b1 = occupied_squares();
+ if (sliders && (sliders & ~checkersBB))
+ {
+ // Our king blockers are candidate pinned pieces
+ Bitboard candidate_pinned = piece_attacks<Piece>(ksq) & pieces_of_color(c);
+
+ // Pinners are sliders, not checkers, that give check when
+ // candidate pinned are removed.
+ Bitboard pinners = sliders & ~checkersBB;
+ if (Piece == ROOK)
+ pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
+ else
+ pinners &= bishop_attacks_bb(ksq, occupied_squares() ^ candidate_pinned);
- sliders = rooks_and_queens(them) & ~checkers();
- if(sliders & RookPseudoAttacks[ksq]) {
- b2 = rook_attacks(ksq) & 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);
- }
+ // Finally for each pinner find the corresponding pinned piece
+ // among the candidates.
+ while (pinners)
+ {
+ s = pop_1st_bit(&pinners);
+ pinned |= (squares_between(s, ksq) & candidate_pinned);
+ }
}
+ return pinned;
+}
- sliders = bishops_and_queens(them) & ~checkers();
- if(sliders & BishopPseudoAttacks[ksq]) {
- b2 = bishop_attacks(ksq) & 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;
+/// Position:pinned_pieces() returns a bitboard of all pinned (against the
+/// king) pieces for the given color.
+Bitboard Position::pinned_pieces(Color c) const {
+
+ Square ksq = king_square(c);
+ return pinned_pieces<ROOK>(c, ksq) | pinned_pieces<BISHOP>(c, ksq);
}
+
/// 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
sliders = rooks_and_queens(c);
if(sliders & RookPseudoAttacks[ksq]) {
- b2 = rook_attacks(ksq) & pieces_of_color(c);
+ b2 = piece_attacks<ROOK>(ksq) & pieces_of_color(c);
checkers = rook_attacks_bb(ksq, b1 ^ b2) & sliders;
while(checkers) {
s = pop_1st_bit(&checkers);
sliders = bishops_and_queens(c);
if(sliders & BishopPseudoAttacks[ksq]) {
- b2 = bishop_attacks(ksq) & pieces_of_color(c);
+ b2 = piece_attacks<BISHOP>(ksq) & pieces_of_color(c);
checkers = bishop_attacks_bb(ksq, b1 ^ b2) & sliders;
while(checkers) {
s = pop_1st_bit(&checkers);
bool Position::square_is_attacked(Square s, Color c) const {
return
(pawn_attacks(opposite_color(c), s) & pawns(c)) ||
- (knight_attacks(s) & knights(c)) ||
- (king_attacks(s) & kings(c)) ||
- (rook_attacks(s) & rooks_and_queens(c)) ||
- (bishop_attacks(s) & bishops_and_queens(c));
+ (piece_attacks<KNIGHT>(s) & knights(c)) ||
+ (piece_attacks<KING>(s) & kings(c)) ||
+ (piece_attacks<ROOK>(s) & rooks_and_queens(c)) ||
+ (piece_attacks<BISHOP>(s) & bishops_and_queens(c));
}
Bitboard Position::attacks_to(Square s) const {
return
- (black_pawn_attacks(s) & pawns(WHITE)) |
- (white_pawn_attacks(s) & pawns(BLACK)) |
- (knight_attacks(s) & pieces_of_type(KNIGHT)) |
- (rook_attacks(s) & rooks_and_queens()) |
- (bishop_attacks(s) & bishops_and_queens()) |
- (king_attacks(s) & pieces_of_type(KING));
+ (pawn_attacks(BLACK, s) & pawns(WHITE)) |
+ (pawn_attacks(WHITE, s) & pawns(BLACK)) |
+ (piece_attacks<KNIGHT>(s) & pieces_of_type(KNIGHT)) |
+ (piece_attacks<ROOK>(s) & rooks_and_queens()) |
+ (piece_attacks<BISHOP>(s) & bishops_and_queens()) |
+ (piece_attacks<KING>(s) & pieces_of_type(KING));
}
Bitboard Position::attacks_to(Square s, Color c) const {
assert(square_is_ok(t));
switch(piece_on(f)) {
- case WP: return white_pawn_attacks_square(f, t);
- case BP: return black_pawn_attacks_square(f, t);
- case WN: case BN: return knight_attacks_square(f, t);
- case WB: case BB: return bishop_attacks_square(f, t);
- case WR: case BR: return rook_attacks_square(f, t);
- case WQ: case BQ: return queen_attacks_square(f, t);
- case WK: case BK: return king_attacks_square(f, t);
+ case WP: return pawn_attacks_square(WHITE, f, t);
+ case BP: return pawn_attacks_square(BLACK, f, t);
+ case WN: case BN: return piece_attacks_square<KNIGHT>(f, t);
+ case WB: case BB: return piece_attacks_square<BISHOP>(f, t);
+ case WR: case BR: return piece_attacks_square<ROOK>(f, t);
+ case WQ: case BQ: return piece_attacks_square<QUEEN>(f, t);
+ case WK: case BK: return piece_attacks_square<KING>(f, t);
default: return false;
}
switch(move_promotion(m)) {
case KNIGHT:
- return knight_attacks_square(to, ksq);
+ return piece_attacks_square<KNIGHT>(to, ksq);
case BISHOP:
return bit_is_set(bishop_attacks_bb(to, b), ksq);
case ROOK:
return true;
// Normal check?
else
- return bit_is_set(knight_attacks(ksq), to);
+ return bit_is_set(piece_attacks<KNIGHT>(ksq), to);
case BISHOP:
// Discovered check?
return true;
// Normal check?
else
- return bit_is_set(bishop_attacks(ksq), to);
+ return bit_is_set(piece_attacks<BISHOP>(ksq), to);
case ROOK:
// Discovered check?
return true;
// Normal check?
else
- return bit_is_set(rook_attacks(ksq), to);
+ return bit_is_set(piece_attacks<ROOK>(ksq), to);
case QUEEN:
// Discovered checks are impossible!
assert(!bit_is_set(dcCandidates, from));
// Normal check?
- return bit_is_set(queen_attacks(ksq), to);
+ return bit_is_set(piece_attacks<QUEEN>(ksq), to);
case KING:
// Discovered check?
assert(square_is_occupied(f));
switch(piece_on(f)) {
- case WP: return white_pawn_attacks_square(t, s);
- case BP: return black_pawn_attacks_square(t, s);
- case WN: case BN: return knight_attacks_square(t, s);
- case WB: case BB: return bishop_attacks_square(t, s);
- case WR: case BR: return rook_attacks_square(t, s);
- case WQ: case BQ: return queen_attacks_square(t, s);
- case WK: case BK: return king_attacks_square(t, s);
+ case WP: return pawn_attacks_square(WHITE, t, s);
+ case BP: return pawn_attacks_square(BLACK, t, s);
+ case WN: case BN: return piece_attacks_square<KNIGHT>(t, s);
+ case WB: case BB: return piece_attacks_square<BISHOP>(t, s);
+ case WR: case BR: return piece_attacks_square<ROOK>(t, s);
+ case WQ: case BQ: return piece_attacks_square<QUEEN>(t, s);
+ case WK: case BK: return piece_attacks_square<KING>(t, s);
default: assert(false);
}
}
if(piece == PAWN) {
if(abs(int(to) - int(from)) == 16) {
- if((us == WHITE && (white_pawn_attacks(from + DELTA_N) &
+ if((us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) &
pawns(BLACK))) ||
- (us == BLACK && (black_pawn_attacks(from + DELTA_S) &
+ (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) &
pawns(WHITE)))) {
epSquare = Square((int(from) + int(to)) / 2);
key ^= zobEp[epSquare];
set_bit(&checkersBB, to);
if(bit_is_set(dcCandidates, from))
checkersBB |=
- ((rook_attacks(ksq) & rooks_and_queens(us)) |
- (bishop_attacks(ksq) & bishops_and_queens(us)));
+ ((piece_attacks<ROOK>(ksq) & rooks_and_queens(us)) |
+ (piece_attacks<BISHOP>(ksq) & bishops_and_queens(us)));
break;
case KNIGHT:
- if(bit_is_set(knight_attacks(ksq), to))
+ if(bit_is_set(piece_attacks<KNIGHT>(ksq), to))
set_bit(&checkersBB, to);
if(bit_is_set(dcCandidates, from))
checkersBB |=
- ((rook_attacks(ksq) & rooks_and_queens(us)) |
- (bishop_attacks(ksq) & bishops_and_queens(us)));
+ ((piece_attacks<ROOK>(ksq) & rooks_and_queens(us)) |
+ (piece_attacks<BISHOP>(ksq) & bishops_and_queens(us)));
break;
case BISHOP:
- if(bit_is_set(bishop_attacks(ksq), to))
+ if(bit_is_set(piece_attacks<BISHOP>(ksq), to))
set_bit(&checkersBB, to);
if(bit_is_set(dcCandidates, from))
checkersBB |=
- (rook_attacks(ksq) & rooks_and_queens(us));
+ (piece_attacks<ROOK>(ksq) & rooks_and_queens(us));
break;
case ROOK:
- if(bit_is_set(rook_attacks(ksq), to))
+ if(bit_is_set(piece_attacks<ROOK>(ksq), to))
set_bit(&checkersBB, to);
if(bit_is_set(dcCandidates, from))
checkersBB |=
- (bishop_attacks(ksq) & bishops_and_queens(us));
+ (piece_attacks<BISHOP>(ksq) & bishops_and_queens(us));
break;
case QUEEN:
- if(bit_is_set(queen_attacks(ksq), to))
+ if(bit_is_set(piece_attacks<QUEEN>(ksq), to))
set_bit(&checkersBB, to);
break;
case KING:
if(bit_is_set(dcCandidates, from))
checkersBB |=
- ((rook_attacks(ksq) & rooks_and_queens(us)) |
- (bishop_attacks(ksq) & bishops_and_queens(us)));
+ ((piece_attacks<ROOK>(ksq) & rooks_and_queens(us)) |
+ (piece_attacks<BISHOP>(ksq) & bishops_and_queens(us)));
break;
default:
attackers =
(rook_attacks_bb(to, occ) & rooks_and_queens()) |
(bishop_attacks_bb(to, occ) & bishops_and_queens()) |
- (knight_attacks(to) & knights()) |
- (king_attacks(to) & kings()) |
- (white_pawn_attacks(to) & pawns(BLACK)) |
- (black_pawn_attacks(to) & pawns(WHITE));
+ (piece_attacks<KNIGHT>(to) & knights()) |
+ (piece_attacks<KING>(to) & kings()) |
+ (pawn_attacks(WHITE, to) & pawns(BLACK)) |
+ (pawn_attacks(BLACK, to) & pawns(WHITE));
attackers &= occ;
// If the opponent has no attackers, we are finished:
/// 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 debugPieceCounts = false;
static const bool debugPieceList = false;
+ if (failedStep) *failedStep = 1;
+
// Side to move OK?
if(!color_is_ok(side_to_move()))
return false;
// Are the king squares in the position correct?
+ 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 (failedStep) (*failedStep)++;
if(!file_is_ok(initialKRFile))
return false;
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++)
}
// Can the side to move capture the opponent's king?
+ if (failedStep) (*failedStep)++;
if(debugKingCapture) {
Color us = side_to_move();
Color them = opposite_color(us);
}
// Is there more than 2 checkers?
+ if (failedStep) (*failedStep)++;
if(debugCheckerCount && count_1s(checkersBB) > 2)
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))
}
// En passant square OK?
+ 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.
}
// Hash key OK?
+ if (failedStep) (*failedStep)++;
if(debugKey && key != compute_key())
return false;
// Pawn hash key OK?
+ if (failedStep) (*failedStep)++;
if(debugPawnKey && pawnKey != compute_pawn_key())
return false;
// Material hash key OK?
+ if (failedStep) (*failedStep)++;
if(debugMaterialKey && materialKey != compute_material_key())
return false;
// Incremental eval OK?
+ if (failedStep) (*failedStep)++;
if(debugIncrementalEval) {
if(mgValue != compute_mg_value())
return false;
}
// Non-pawn material OK?
+ if (failedStep) (*failedStep)++;
if(debugNonPawnMaterial) {
if(npMaterial[WHITE] != compute_non_pawn_material(WHITE))
return false;
}
// Piece counts OK?
+ 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(pieces_of_color_and_type(c, pt)))
return false;
+ if (failedStep) (*failedStep)++;
if(debugPieceList) {
for(Color c = WHITE; c <= BLACK; c++)
for(PieceType pt = PAWN; pt <= KING; pt++)
return false;
}
}
-
+ if (failedStep) *failedStep = 0;
return true;
}
projects / stockfish / blobdiff