X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=907357bd1f90ba09f6197f15763248970997965b;hp=4935a2c643ed965992944a4563695619b7ac9b70;hb=c549f71f64a29fd06f8537de697bc67fdc642753;hpb=e896368496d4156f3f8c1dda5a95686804088e73 diff --git a/src/position.cpp b/src/position.cpp index 4935a2c6..907357bd 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -1,7 +1,7 @@ /* 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 + Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -22,6 +22,7 @@ #include #include #include +#include #include "bitcount.h" #include "movegen.h" @@ -69,7 +70,7 @@ namespace { const Score TempoValue = make_score(48, 22); // To convert a Piece to and from a FEN char - const string PieceToChar(".PNBRQK pnbrqk "); + const string PieceToChar(" PNBRQK pnbrqk ."); } @@ -78,7 +79,7 @@ namespace { CheckInfo::CheckInfo(const Position& pos) { Color them = flip(pos.side_to_move()); - Square ksq = pos.king_square(them); + ksq = pos.king_square(them); pinned = pos.pinned_pieces(); dcCandidates = pos.discovered_check_candidates(); @@ -88,7 +89,7 @@ CheckInfo::CheckInfo(const Position& pos) { checkSq[BISHOP] = pos.attacks_from(ksq); checkSq[ROOK] = pos.attacks_from(ksq); checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK]; - checkSq[KING] = EmptyBoardBB; + checkSq[KING] = 0; } @@ -96,9 +97,11 @@ CheckInfo::CheckInfo(const Position& pos) { /// 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) { +void Position::copy(const Position& pos, int th) { memcpy(this, &pos, sizeof(Position)); + startState = *st; + st = &startState; threadID = th; nodes = 0; @@ -120,29 +123,35 @@ void Position::from_fen(const string& fenStr, bool isChess960) { /* A FEN string defines a particular position using only the ASCII character set. - A FEN string contains six fields. The separator between fields is a space. The fields are: + A FEN string contains six fields separated by a space. The fields are: - 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. + 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 "/" + separates 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). + 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. + 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. + 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. + 6) Fullmove number. The number of the full move. It starts at 1, and is + incremented after Black's move. */ char col, row, token; @@ -156,11 +165,11 @@ void Position::from_fen(const string& fenStr, bool isChess960) { // 1. Piece placement while ((fen >> token) && !isspace(token)) { - if (token == '/') - sq -= Square(16); // Jump back of 2 rows + if (isdigit(token)) + sq += Square(token - '0'); // Advance the given number of files - else if (isdigit(token)) - sq += Square(token - '0'); // Skip the given number of files + else if (token == '/') + sq = make_square(FILE_A, rank_of(sq) - Rank(2)); else if ((p = PieceToChar.find(token)) != string::npos) { @@ -183,15 +192,14 @@ void Position::from_fen(const string& fenStr, bool isChess960) { { Square rsq; Color c = islower(token) ? BLACK : WHITE; - Piece rook = make_piece(c, ROOK); token = char(toupper(token)); if (token == 'K') - for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; rsq--) {} + for (rsq = relative_square(c, SQ_H1); type_of(piece_on(rsq)) != ROOK; rsq--) {} else if (token == 'Q') - for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; rsq++) {} + for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; rsq++) {} else if (token >= 'A' && token <= 'H') rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); @@ -199,7 +207,7 @@ void Position::from_fen(const string& fenStr, bool isChess960) { else continue; - set_castle_right(king_square(c), rsq); + set_castle_right(c, rsq); } // 4. En passant square. Ignore if no pawn capture is possible @@ -217,7 +225,7 @@ void Position::from_fen(const string& fenStr, bool isChess960) { // Convert from fullmove starting from 1 to ply starting from 0, // handle also common incorrect FEN with fullmove = 0. - startPosPly = Max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK); + startPosPly = std::max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -233,14 +241,14 @@ void Position::from_fen(const string& fenStr, bool isChess960) { /// Position::set_castle_right() is an helper function used to set castling -/// rights given the corresponding king and rook starting squares. +/// rights given the corresponding color and the rook starting square. -void Position::set_castle_right(Square ksq, Square rsq) { +void Position::set_castle_right(Color c, Square rsq) { - int f = (rsq < ksq ? WHITE_OOO : WHITE_OO) << color_of(piece_on(ksq)); + int f = (rsq < king_square(c) ? WHITE_OOO : WHITE_OO) << c; st->castleRights |= f; - castleRightsMask[ksq] ^= f; + castleRightsMask[king_square(c)] ^= f; castleRightsMask[rsq] ^= f; castleRookSquare[f] = rsq; } @@ -263,20 +271,20 @@ const string Position::to_fen() const { { sq = make_square(file, rank); - if (!square_is_empty(sq)) + if (square_is_empty(sq)) + emptyCnt++; + else { - if (emptyCnt) + if (emptyCnt > 0) { fen << emptyCnt; emptyCnt = 0; } fen << PieceToChar[piece_on(sq)]; } - else - emptyCnt++; } - if (emptyCnt) + if (emptyCnt > 0) fen << emptyCnt; if (rank > RANK_1) @@ -285,24 +293,23 @@ const string Position::to_fen() const { fen << (sideToMove == WHITE ? " w " : " b "); - if (st->castleRights != CASTLES_NONE) - { - if (can_castle(WHITE_OO)) - fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K'); + if (can_castle(WHITE_OO)) + fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OO))))) : 'K'); + + if (can_castle(WHITE_OOO)) + fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q'); - if (can_castle(WHITE_OOO)) - fen << (chess960 ? char(toupper(file_to_char(file_of(castle_rook_square(WHITE_OOO))))) : 'Q'); + if (can_castle(BLACK_OO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k'); - if (can_castle(BLACK_OO)) - fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k'); + if (can_castle(BLACK_OOO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q'); - if (can_castle(BLACK_OOO)) - fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q'); - } else + if (st->castleRights == CASTLES_NONE) fen << '-'; - fen << (ep_square() == SQ_NONE ? " -" : " " + square_to_string(ep_square())) - << " " << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2; + fen << (ep_square() == SQ_NONE ? " - " : " " + square_to_string(ep_square()) + " ") + << st->rule50 << " " << 1 + (startPosPly - int(sideToMove == BLACK)) / 2; return fen.str(); } @@ -318,8 +325,7 @@ void Position::print(Move move) const { if (move) { Position p(*this, thread()); - string dd = (sideToMove == BLACK ? ".." : ""); - cout << "\nMove is: " << dd << move_to_san(p, move); + cout << "\nMove is: " << (sideToMove == BLACK ? ".." : "") << move_to_san(p, move); } for (Rank rank = RANK_8; rank >= RANK_1; rank--) @@ -329,11 +335,11 @@ void Position::print(Move move) const { { Square sq = make_square(file, rank); Piece piece = piece_on(sq); + char c = (color_of(piece) == BLACK ? '=' : ' '); - if (piece == PIECE_NONE && color_of(sq) == DARK) - piece = PIECE_NONE_DARK_SQ; + if (piece == NO_PIECE && !opposite_colors(sq, SQ_A1)) + piece++; // Index the dot - char c = (color_of(piece_on(sq)) == BLACK ? '=' : ' '); cout << c << PieceToChar[piece] << c << '|'; } } @@ -345,18 +351,17 @@ void Position::print(Move move) const { /// king) pieces for the given color. Or, when template parameter FindPinned is /// false, the function return the pieces of the given color candidate for a /// discovery check against the enemy king. - template Bitboard Position::hidden_checkers() const { // Pinned pieces protect our king, dicovery checks attack the enemy king - Bitboard b, result = EmptyBoardBB; + Bitboard b, result = 0; Bitboard pinners = pieces(FindPinned ? flip(sideToMove) : sideToMove); Square ksq = king_square(FindPinned ? sideToMove : flip(sideToMove)); // Pinners are sliders, that give check when candidate pinned is removed - pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) - | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]); + pinners &= (pieces(ROOK, QUEEN) & PseudoAttacks[ROOK][ksq]) + | (pieces(BISHOP, QUEEN) & PseudoAttacks[BISHOP][ksq]); while (pinners) { @@ -369,26 +374,12 @@ Bitboard Position::hidden_checkers() const { return result; } +// Explicit template instantiations +template Bitboard Position::hidden_checkers() const; +template Bitboard Position::hidden_checkers() const; -/// Position:pinned_pieces() returns a bitboard of all pinned (against the -/// king) pieces for the side to move. - -Bitboard Position::pinned_pieces() const { - - return hidden_checkers(); -} - - -/// Position:discovered_check_candidates() returns a bitboard containing all -/// pieces for the side to move which are candidates for giving a discovered -/// check. - -Bitboard Position::discovered_check_candidates() const { - - return hidden_checkers(); -} -/// Position::attackers_to() computes a bitboard of all pieces which attacks a +/// Position::attackers_to() computes a bitboard of all pieces which attack a /// given square. Slider attacks use occ bitboard as occupancy. Bitboard Position::attackers_to(Square s, Bitboard occ) const { @@ -401,6 +392,7 @@ Bitboard Position::attackers_to(Square s, Bitboard occ) const { | (attacks_from(s) & pieces(KING)); } + /// Position::attacks_from() computes a bitboard of all attacks of a given piece /// put in a given square. Slider attacks use occ bitboard as occupancy. @@ -408,12 +400,12 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { assert(square_is_ok(s)); - switch (p) + switch (type_of(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]; + case BISHOP: return bishop_attacks_bb(s, occ); + case ROOK : return rook_attacks_bb(s, occ); + case QUEEN : return bishop_attacks_bb(s, occ) | rook_attacks_bb(s, occ); + default : return StepAttacksBB[p][s]; } } @@ -427,22 +419,25 @@ bool Position::move_attacks_square(Move m, Square s) const { assert(square_is_ok(s)); Bitboard occ, xray; - Square f = move_from(m), t = move_to(m); + Square from = from_sq(m); + Square to = to_sq(m); + Piece piece = piece_on(from); - assert(!square_is_empty(f)); + assert(!square_is_empty(from)); - if (bit_is_set(attacks_from(piece_on(f), t), s)) + // Update occupancy as if the piece is moving + occ = occupied_squares(); + do_move_bb(&occ, make_move_bb(from, to)); + + // The piece moved in 'to' attacks the square 's' ? + if (bit_is_set(attacks_from(piece, to, occ), 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(color_of(piece_on(f))); + // Scan for possible X-ray attackers behind the moved piece + xray = (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece))) + |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN, color_of(piece))); - // If we have attacks we need to verify that are caused by our move - // and are not already existent ones. + // Verify attackers are triggered by our move and not already existing return xray && (xray ^ (xray & attacks_from(s))); } @@ -455,7 +450,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(pinned == pinned_pieces()); Color us = side_to_move(); - Square from = move_from(m); + Square from = from_sq(m); assert(color_of(piece_on(from)) == us); assert(piece_on(king_square(us)) == make_piece(us, KING)); @@ -466,7 +461,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { if (is_enpassant(m)) { Color them = flip(us); - Square to = move_to(m); + Square to = to_sq(m); Square capsq = to + pawn_push(them); Square ksq = king_square(us); Bitboard b = occupied_squares(); @@ -474,7 +469,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { 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(piece_on(to) == NO_PIECE); clear_bit(&b, from); clear_bit(&b, capsq); @@ -488,19 +483,19 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { // square is attacked by the opponent. Castling moves are checked // for legality during move generation. if (type_of(piece_on(from)) == KING) - return is_castle(m) || !(attackers_to(move_to(m)) & pieces(flip(us))); + return is_castle(m) || !(attackers_to(to_sq(m)) & pieces(flip(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. return !pinned || !bit_is_set(pinned, from) - || squares_aligned(from, move_to(m), king_square(us)); + || squares_aligned(from, to_sq(m), king_square(us)); } /// Position::move_is_legal() takes a random move and tests whether the move -/// is legal. This version is not very fast and should be used only -/// in non time-critical paths. +/// 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 { @@ -520,8 +515,8 @@ bool Position::is_pseudo_legal(const Move m) const { Color us = sideToMove; Color them = flip(sideToMove); - Square from = move_from(m); - Square to = move_to(m); + Square from = from_sq(m); + Square to = to_sq(m); Piece pc = piece_on(from); // Use a slower but simpler function for uncommon cases @@ -529,12 +524,12 @@ bool Position::is_pseudo_legal(const Move m) const { return move_is_legal(m); // Is not a promotion, so promotion piece must be empty - if (promotion_piece_type(m) - 2 != PIECE_TYPE_NONE) + if (promotion_piece_type(m) - 2 != NO_PIECE_TYPE) return false; // If the from square is not occupied by a piece belonging to the side to // move, the move is obviously not legal. - if (pc == PIECE_NONE || color_of(pc) != us) + if (pc == NO_PIECE || color_of(pc) != us) return false; // The destination square cannot be occupied by a friendly piece @@ -617,7 +612,7 @@ bool Position::is_pseudo_legal(const Move m) const { { Bitboard b = occupied_squares(); clear_bit(&b, from); - if (attackers_to(move_to(m), b) & pieces(flip(us))) + if (attackers_to(to_sq(m), b) & pieces(flip(us))) return false; } else @@ -630,7 +625,7 @@ bool Position::is_pseudo_legal(const Move m) const { // Our move must be a blocking evasion or a capture of the checking piece target = squares_between(checksq, king_square(us)) | checkers(); - if (!bit_is_set(target, move_to(m))) + if (!bit_is_set(target, to_sq(m))) return false; } } @@ -645,10 +640,10 @@ bool Position::move_gives_check(Move m, const CheckInfo& ci) const { assert(is_ok(m)); assert(ci.dcCandidates == discovered_check_candidates()); - assert(color_of(piece_on(move_from(m))) == side_to_move()); + assert(color_of(piece_moved(m)) == side_to_move()); - Square from = move_from(m); - Square to = move_to(m); + Square from = from_sq(m); + Square to = to_sq(m); PieceType pt = type_of(piece_on(from)); // Direct check ? @@ -735,11 +730,11 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI assert(&newSt != st); nodes++; - Key key = st->key; + Key k = 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. + // 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; Value npMaterial[2]; @@ -754,7 +749,7 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st = &newSt; // Update side to move - key ^= zobSideToMove; + k ^= zobSideToMove; // Increment the 50 moves rule draw counter. Resetting it to zero in the // case of non-reversible moves is taken care of later. @@ -763,37 +758,84 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (is_castle(m)) { - st->key = key; + st->key = k; do_castle_move(m); return; } Color us = side_to_move(); Color them = flip(us); - Square from = move_from(m); - Square to = move_to(m); - bool ep = is_enpassant(m); - bool pm = is_promotion(m); - + Square from = from_sq(m); + Square to = to_sq(m); Piece piece = piece_on(from); PieceType pt = type_of(piece); - PieceType capture = ep ? PAWN : type_of(piece_on(to)); + PieceType capture = is_enpassant(m) ? 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); + assert(color_of(piece) == us); + assert(color_of(piece_on(to)) != us); + assert(capture != KING); if (capture) - do_capture_move(key, capture, them, to, ep); + { + Square capsq = to; + + // If the captured piece is a pawn, update pawn hash key, otherwise + // update non-pawn material. + if (capture == PAWN) + { + if (is_enpassant(m)) + { + capsq += pawn_push(them); + + assert(pt == PAWN); + assert(to == st->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(to) == NO_PIECE); + assert(piece_on(capsq) == make_piece(them, PAWN)); + + board[capsq] = NO_PIECE; + } + + st->pawnKey ^= zobrist[them][PAWN][capsq]; + } + else + st->npMaterial[them] -= PieceValueMidgame[capture]; + + // Remove the captured piece + clear_bit(&byColorBB[them], capsq); + clear_bit(&byTypeBB[capture], capsq); + clear_bit(&occupied, capsq); + + // Update piece list, move the last piece at index[capsq] position and + // shrink the list. + // + // WARNING: This is a not 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 lastSquare = pieceList[them][capture][--pieceCount[them][capture]]; + index[lastSquare] = index[capsq]; + pieceList[them][capture][index[lastSquare]] = lastSquare; + pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; + + // Update hash keys + k ^= zobrist[them][capture][capsq]; + st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + + // Update incremental scores + st->value -= pst(make_piece(them, capture), capsq); + + // Reset rule 50 counter + st->rule50 = 0; + } // Update hash key - key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; + k ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; // Reset en passant square if (st->epSquare != SQ_NONE) { - key ^= zobEp[st->epSquare]; + k ^= zobEp[st->epSquare]; st->epSquare = SQ_NONE; } @@ -801,87 +843,79 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if ( st->castleRights != CASTLES_NONE && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES) { - key ^= zobCastle[st->castleRights]; + k ^= zobCastle[st->castleRights]; st->castleRights &= castleRightsMask[from] & castleRightsMask[to]; - key ^= zobCastle[st->castleRights]; + k ^= zobCastle[st->castleRights]; } // Prefetch TT access as soon as we know key is updated - prefetch((char*)TT.first_entry(key)); + prefetch((char*)TT.first_entry(k)); // 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 + do_move_bb(&occupied, move_bb); board[to] = board[from]; - board[from] = PIECE_NONE; + board[from] = NO_PIECE; - // 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. + // Update piece lists, 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 the moving piece is 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) + // Set en-passant square, only if moved pawn can be captured + if ( (to ^ from) == 16 + && (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them))) { - if (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them)) - { - st->epSquare = Square((int(from) + int(to)) / 2); - key ^= zobEp[st->epSquare]; - } + st->epSquare = Square((from + to) / 2); + k ^= zobEp[st->epSquare]; } - if (pm) // promotion ? + if (is_promotion(m)) { PieceType promotion = promotion_piece_type(m); + assert(relative_rank(us, to) == RANK_8); assert(promotion >= KNIGHT && promotion <= QUEEN); - // Insert promoted piece instead of pawn + // Replace the pawn with the promoted piece clear_bit(&byTypeBB[PAWN], to); set_bit(&byTypeBB[promotion], to); board[to] = make_piece(us, promotion); - // Update piece counts - pieceCount[us][promotion]++; - pieceCount[us][PAWN]--; - - // Update material key - st->materialKey ^= zobrist[us][PAWN][pieceCount[us][PAWN]]; - st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]-1]; - // 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; + Square lastSquare = pieceList[us][PAWN][--pieceCount[us][PAWN]]; + index[lastSquare] = index[to]; + pieceList[us][PAWN][index[lastSquare]] = lastSquare; pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; - index[to] = pieceCount[us][promotion] - 1; + index[to] = pieceCount[us][promotion]; pieceList[us][promotion][index[to]] = to; - // Partially revert hash keys update - key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; + // Update hash keys + k ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; st->pawnKey ^= zobrist[us][PAWN][to]; + st->materialKey ^= zobrist[us][promotion][pieceCount[us][promotion]++] + ^ zobrist[us][PAWN][pieceCount[us][PAWN]]; - // Partially revert and update incremental scores - st->value -= pst(make_piece(us, PAWN), to); - st->value += pst(make_piece(us, promotion), to); + // Update incremental score + st->value += pst(make_piece(us, promotion), to) + - pst(make_piece(us, PAWN), to); // Update material st->npMaterial[us] += PieceValueMidgame[promotion]; } + + // Update pawn hash key + st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; + + // Reset rule 50 draw counter + st->rule50 = 0; } // Prefetch pawn and material hash tables @@ -895,14 +929,14 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI st->capturedType = capture; // Update the key with the final value - st->key = key; + st->key = k; // Update checkers bitboard, piece must be already moved - st->checkersBB = EmptyBoardBB; + st->checkersBB = 0; if (moveIsCheck) { - if (ep | pm) + if (is_special(m)) st->checkersBB = attackers_to(king_square(them)) & pieces(us); else { @@ -914,10 +948,10 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) { if (pt != ROOK) - st->checkersBB |= (attacks_from(king_square(them)) & pieces(ROOK, QUEEN, us)); + st->checkersBB |= attacks_from(king_square(them)) & pieces(ROOK, QUEEN, us); if (pt != BISHOP) - st->checkersBB |= (attacks_from(king_square(them)) & pieces(BISHOP, QUEEN, us)); + st->checkersBB |= attacks_from(king_square(them)) & pieces(BISHOP, QUEEN, us); } } } @@ -930,66 +964,102 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI } -/// Position::do_capture_move() is a private method used to update captured -/// piece info. It is called from the main Position::do_move function. +/// 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. + +void Position::undo_move(Move m) { + + assert(is_ok(m)); + + sideToMove = flip(sideToMove); + + if (is_castle(m)) + { + do_castle_move(m); + return; + } + + Color us = side_to_move(); + Color them = flip(us); + Square from = from_sq(m); + Square to = to_sq(m); + Piece piece = piece_on(to); + PieceType pt = type_of(piece); + PieceType capture = st->capturedType; + + assert(square_is_empty(from)); + assert(color_of(piece) == us); + assert(capture != KING); + + if (is_promotion(m)) + { + PieceType promotion = promotion_piece_type(m); -void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) { + assert(promotion == pt); + assert(relative_rank(us, to) == RANK_8); + assert(promotion >= KNIGHT && promotion <= QUEEN); - assert(capture != KING); + // Replace the promoted piece with the pawn + clear_bit(&byTypeBB[promotion], to); + set_bit(&byTypeBB[PAWN], to); + board[to] = make_piece(us, PAWN); - Square capsq = to; + // Update piece lists, move the last promoted piece at index[to] position + // and shrink the list. Add a new pawn to the list. + Square lastSquare = pieceList[us][promotion][--pieceCount[us][promotion]]; + index[lastSquare] = index[to]; + pieceList[us][promotion][index[lastSquare]] = lastSquare; + pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE; + index[to] = pieceCount[us][PAWN]++; + pieceList[us][PAWN][index[to]] = to; - // If the captured piece was a pawn, update pawn hash key, - // otherwise update non-pawn material. - if (capture == PAWN) - { - if (ep) // en passant ? - { - capsq = to + pawn_push(them); + pt = PAWN; + } - assert(to == st->epSquare); - assert(relative_rank(flip(them), to) == RANK_6); - assert(piece_on(to) == PIECE_NONE); - assert(piece_on(capsq) == make_piece(them, PAWN)); + // 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(&occupied, move_bb); - board[capsq] = PIECE_NONE; - } - st->pawnKey ^= zobrist[them][PAWN][capsq]; - } - else - st->npMaterial[them] -= PieceValueMidgame[capture]; + board[from] = board[to]; + board[to] = NO_PIECE; - // Remove captured piece - clear_bit(&byColorBB[them], capsq); - clear_bit(&byTypeBB[capture], capsq); - clear_bit(&byTypeBB[0], capsq); + // Update piece lists, index[to] is not updated and becomes stale. This + // works as long as index[] is accessed just by known occupied squares. + index[from] = index[to]; + pieceList[us][pt][index[from]] = from; - // Update hash key - key ^= zobrist[them][capture][capsq]; + if (capture) + { + Square capsq = to; - // Update incremental scores - st->value -= pst(make_piece(them, capture), capsq); + if (is_enpassant(m)) + { + capsq -= pawn_push(us); - // Update piece count - pieceCount[them][capture]--; + assert(pt == PAWN); + assert(to == st->previous->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(capsq) == NO_PIECE); + } - // Update material hash key - st->materialKey ^= zobrist[them][capture][pieceCount[them][capture]]; + // Restore the captured piece + set_bit(&byColorBB[them], capsq); + set_bit(&byTypeBB[capture], capsq); + set_bit(&occupied, capsq); - // 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; + board[capsq] = make_piece(them, capture); - // Reset rule 50 counter - st->rule50 = 0; + // Update piece list, add a new captured piece in capsq square + index[capsq] = pieceCount[them][capture]++; + pieceList[them][capture][index[capsq]] = capsq; + } + + // Finally point our state pointer back to the previous state + st = st->previous; + + assert(pos_is_ok()); } @@ -1006,8 +1076,8 @@ void Position::do_castle_move(Move m) { Square kto, kfrom, rfrom, rto, kAfter, rAfter; Color us = side_to_move(); - Square kBefore = move_from(m); - Square rBefore = move_to(m); + Square kBefore = from_sq(m); + Square rBefore = to_sq(m); // Find after-castle squares for king and rook if (rBefore > kBefore) // O-O @@ -1033,23 +1103,23 @@ void Position::do_castle_move(Move m) { // Remove pieces from source squares clear_bit(&byColorBB[us], kfrom); clear_bit(&byTypeBB[KING], kfrom); - clear_bit(&byTypeBB[0], kfrom); + clear_bit(&occupied, kfrom); clear_bit(&byColorBB[us], rfrom); clear_bit(&byTypeBB[ROOK], rfrom); - clear_bit(&byTypeBB[0], rfrom); + clear_bit(&occupied, rfrom); // Put pieces on destination squares set_bit(&byColorBB[us], kto); set_bit(&byTypeBB[KING], kto); - set_bit(&byTypeBB[0], kto); + set_bit(&occupied, kto); set_bit(&byColorBB[us], rto); set_bit(&byTypeBB[ROOK], rto); - set_bit(&byTypeBB[0], rto); + set_bit(&occupied, rto); // Update board Piece king = make_piece(us, KING); Piece rook = make_piece(us, ROOK); - board[kfrom] = board[rfrom] = PIECE_NONE; + board[kfrom] = board[rfrom] = NO_PIECE; board[kto] = king; board[rto] = rook; @@ -1063,7 +1133,7 @@ void Position::do_castle_move(Move m) { if (Do) { // Reset capture field - st->capturedType = PIECE_TYPE_NONE; + st->capturedType = NO_PIECE_TYPE; // Update incremental scores st->value += pst_delta(king, kfrom, kto); @@ -1103,163 +1173,49 @@ void Position::do_castle_move(Move m) { } -/// 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. - -void Position::undo_move(Move m) { - - assert(is_ok(m)); - - sideToMove = flip(sideToMove); - - if (is_castle(m)) - { - do_castle_move(m); - return; - } - - Color us = side_to_move(); - Color them = flip(us); - Square from = move_from(m); - Square to = move_to(m); - bool ep = is_enpassant(m); - bool pm = 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 = promotion_piece_type(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; - } - - // 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 - - board[from] = make_piece(us, pt); - board[to] = PIECE_NONE; - - // Update piece list - index[from] = index[to]; - pieceList[us][pt][index[from]] = from; - - if (st->capturedType) - { - Square capsq = to; - - if (ep) - capsq = to - pawn_push(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); - - board[capsq] = make_piece(them, st->capturedType); - - // Update piece count - pieceCount[them][st->capturedType]++; - - // 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; - } - - // Finally point our state pointer back to the previous state - st = st->previous; - - assert(pos_is_ok()); -} - - -/// 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::do_null_move() is used to do/undo a "null move": It flips the side +/// to move and updates the hash key without executing any move on the board. +template void Position::do_null_move(StateInfo& backupSt) { assert(!in_check()); // 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; - - // Update the necessary information - if (st->epSquare != SQ_NONE) - st->key ^= zobEp[st->epSquare]; - - st->key ^= zobSideToMove; - prefetch((char*)TT.first_entry(st->key)); + // StateInfo object. Note that differently from normal case here backupSt + // is actually used as a backup storage not as the new state. This reduces + // the number of fields to be copied. + StateInfo* src = Do ? st : &backupSt; + StateInfo* dst = Do ? &backupSt : st; + + dst->key = src->key; + dst->epSquare = src->epSquare; + dst->value = src->value; + dst->rule50 = src->rule50; + dst->pliesFromNull = src->pliesFromNull; sideToMove = flip(sideToMove); - st->epSquare = SQ_NONE; - st->rule50++; - st->pliesFromNull = 0; - st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; - - assert(pos_is_ok()); -} - - -/// Position::undo_null_move() unmakes a "null move". -void Position::undo_null_move() { - - assert(!in_check()); + if (Do) + { + if (st->epSquare != SQ_NONE) + st->key ^= zobEp[st->epSquare]; - // 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; + st->key ^= zobSideToMove; + prefetch((char*)TT.first_entry(st->key)); - // Update the necessary information - sideToMove = flip(sideToMove); - st->rule50--; + st->epSquare = SQ_NONE; + st->rule50++; + st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; + } assert(pos_is_ok()); } +// Explicit template instantiations +template void Position::do_null_move(StateInfo& backupSt); +template void Position::do_null_move(StateInfo& backupSt); + /// 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 @@ -1271,8 +1227,8 @@ int Position::see_sign(Move m) const { assert(is_ok(m)); - Square from = move_from(m); - Square to = move_to(m); + Square from = from_sq(m); + Square to = to_sq(m); // Early return if SEE cannot be negative because captured piece value // is not less then capturing one. Note that king moves always return @@ -1286,7 +1242,7 @@ int Position::see_sign(Move m) const { int Position::see(Move m) const { Square from, to; - Bitboard occupied, attackers, stmAttackers, b; + Bitboard occ, attackers, stmAttackers, b; int swapList[32], slIndex = 1; PieceType capturedType, pt; Color stm; @@ -1299,28 +1255,28 @@ int Position::see(Move m) const { if (is_castle(m)) return 0; - from = move_from(m); - to = move_to(m); + from = from_sq(m); + to = to_sq(m); capturedType = type_of(piece_on(to)); - occupied = occupied_squares(); + occ = occupied_squares(); // Handle en passant moves - if (st->epSquare == to && type_of(piece_on(from)) == PAWN) + if (is_enpassant(m)) { Square capQq = to - pawn_push(side_to_move()); - assert(capturedType == PIECE_TYPE_NONE); + assert(capturedType == NO_PIECE_TYPE); assert(type_of(piece_on(capQq)) == PAWN); // Remove the captured pawn - clear_bit(&occupied, capQq); + clear_bit(&occ, capQq); capturedType = PAWN; } // Find all attackers to the destination square, with the moving piece // removed, but possibly an X-ray attacker added behind it. - clear_bit(&occupied, from); - attackers = attackers_to(to, occupied); + clear_bit(&occ, from); + attackers = attackers_to(to, occ); // If the opponent has no attackers we are finished stm = flip(color_of(piece_on(from))); @@ -1347,11 +1303,11 @@ int Position::see(Move m) const { // 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)); + occ ^= (b & (~b + 1)); + attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)); - attackers &= occupied; // Cut out pieces we've already done + attackers &= occ; // Cut out pieces we've already done // Add the new entry to the swap list assert(slIndex < 32); @@ -1376,7 +1332,7 @@ int Position::see(Move m) const { // 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 (--slIndex) - swapList[slIndex-1] = Min(-swapList[slIndex], swapList[slIndex-1]); + swapList[slIndex-1] = std::min(-swapList[slIndex], swapList[slIndex-1]); return swapList[0]; } @@ -1402,11 +1358,12 @@ void Position::clear() { for (Square sq = SQ_A1; sq <= SQ_H8; sq++) { - board[sq] = PIECE_NONE; + board[sq] = NO_PIECE; castleRightsMask[sq] = ALL_CASTLES; } sideToMove = WHITE; nodes = 0; + occupied = 0; } @@ -1424,7 +1381,7 @@ void Position::put_piece(Piece p, Square s) { set_bit(&byTypeBB[pt], s); set_bit(&byColorBB[c], s); - set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares. + set_bit(&occupied, s); } @@ -1541,13 +1498,13 @@ bool Position::is_draw() const { return true; // Draw by the 50 moves rule? - if (st->rule50 > 99 && !is_mate()) + if (st->rule50 > 99 && (!in_check() || MoveList(*this).size())) return true; // Draw by repetition? if (!SkipRepetition) { - int i = 4, e = Min(st->rule50, st->pliesFromNull); + int i = 4, e = std::min(st->rule50, st->pliesFromNull); if (i <= e) { @@ -1573,15 +1530,6 @@ template bool Position::is_draw() const; template bool Position::is_draw() const; -/// Position::is_mate() returns true or false depending on whether the -/// side to move is checkmated. - -bool Position::is_mate() const { - - return in_check() && !MoveList(*this).size(); -} - - /// Position::init() is a static member function which initializes at startup /// the various arrays used to compute hash keys and the piece square tables. /// The latter is a two-step operation: First, the white halves of the tables @@ -1606,7 +1554,7 @@ void Position::init() { zobSideToMove = rk.rand(); zobExclusion = rk.rand(); - for (Piece p = WP; p <= WK; p++) + for (Piece p = W_PAWN; p <= W_KING; p++) { Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]); @@ -1640,13 +1588,13 @@ void Position::flip_me() { // Castling rights if (pos.can_castle(WHITE_OO)) - set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OO))); + set_castle_right(BLACK, flip(pos.castle_rook_square(WHITE_OO))); if (pos.can_castle(WHITE_OOO)) - set_castle_right(king_square(BLACK), flip(pos.castle_rook_square(WHITE_OOO))); + set_castle_right(BLACK, flip(pos.castle_rook_square(WHITE_OOO))); if (pos.can_castle(BLACK_OO)) - set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OO))); + set_castle_right(WHITE, flip(pos.castle_rook_square(BLACK_OO))); if (pos.can_castle(BLACK_OOO)) - set_castle_right(king_square(WHITE), flip(pos.castle_rook_square(BLACK_OOO))); + set_castle_right(WHITE, flip(pos.castle_rook_square(BLACK_OOO))); // En passant square if (pos.st->epSquare != SQ_NONE) @@ -1700,11 +1648,11 @@ bool Position::pos_is_ok(int* failedStep) const { // Are the king squares in the position correct? if (failedStep) (*failedStep)++; - if (piece_on(king_square(WHITE)) != WK) + if (piece_on(king_square(WHITE)) != W_KING) return false; if (failedStep) (*failedStep)++; - if (piece_on(king_square(BLACK)) != BK) + if (piece_on(king_square(BLACK)) != B_KING) return false; // Do both sides have exactly one king? @@ -1733,7 +1681,7 @@ bool Position::pos_is_ok(int* failedStep) const { // Is there more than 2 checkers? if (failedStep) (*failedStep)++; - if (debugCheckerCount && count_1s(st->checkersBB) > 2) + if (debugCheckerCount && popcount(st->checkersBB) > 2) return false; // Bitboards OK? @@ -1741,7 +1689,7 @@ bool Position::pos_is_ok(int* failedStep) const { if (debugBitboards) { // The intersection of the white and black pieces must be empty - if ((pieces(WHITE) & pieces(BLACK)) != EmptyBoardBB) + if (!(pieces(WHITE) & pieces(BLACK))) return false; // The union of the white and black pieces must be equal to all @@ -1802,7 +1750,7 @@ bool Position::pos_is_ok(int* failedStep) const { if (debugPieceCounts) for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) - if (pieceCount[c][pt] != count_1s(pieces(pt, c))) + if (pieceCount[c][pt] != popcount(pieces(pt, c))) return false; if (failedStep) (*failedStep)++; @@ -1825,7 +1773,7 @@ bool Position::pos_is_ok(int* failedStep) const { if (!can_castle(f)) continue; - Piece rook = (f & (WHITE_OO | WHITE_OOO) ? WR : BR); + Piece rook = (f & (WHITE_OO | WHITE_OOO) ? W_ROOK : B_ROOK); if ( castleRightsMask[castleRookSquare[f]] != (ALL_CASTLES ^ f) || piece_on(castleRookSquare[f]) != rook)