X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=e3ee3d26ea59e20965036dc5788e741ad88324dd;hp=77c0647a940b33165bd4217bfe1a090b5030a3d2;hb=6e00aa6bae8a9634b3aea4b7b0bde652a588e9de;hpb=01a191936eeb3dc3366554b1423c53da2a1ae56a diff --git a/src/position.cpp b/src/position.cpp index 77c0647a..e3ee3d26 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 @@ -19,9 +19,9 @@ #include #include -#include #include #include +#include #include "bitcount.h" #include "movegen.h" @@ -30,19 +30,18 @@ #include "rkiss.h" #include "thread.h" #include "tt.h" -#include "ucioption.h" using std::string; using std::cout; using std::endl; Key Position::zobrist[2][8][64]; -Key Position::zobEp[64]; +Key Position::zobEp[8]; Key Position::zobCastle[16]; Key Position::zobSideToMove; Key Position::zobExclusion; -Score Position::PieceSquareTable[16][64]; +Score Position::pieceSquareTable[16][64]; // Material values arrays, indexed by Piece const Value PieceValueMidgame[17] = { @@ -70,7 +69,7 @@ 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 ."); } @@ -78,19 +77,18 @@ namespace { CheckInfo::CheckInfo(const Position& pos) { - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square ksq = pos.king_square(them); + Color them = ~pos.side_to_move(); + ksq = pos.king_square(them); - dcCandidates = pos.discovered_check_candidates(us); - pinned = pos.pinned_pieces(us); + pinned = pos.pinned_pieces(); + dcCandidates = pos.discovered_check_candidates(); checkSq[PAWN] = pos.attacks_from(ksq, them); checkSq[KNIGHT] = pos.attacks_from(ksq); checkSq[BISHOP] = pos.attacks_from(ksq); checkSq[ROOK] = pos.attacks_from(ksq); checkSq[QUEEN] = checkSq[BISHOP] | checkSq[ROOK]; - checkSq[KING] = EmptyBoardBB; + checkSq[KING] = 0; } @@ -98,12 +96,15 @@ 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)); - detach(); // Always detach() in copy c'tor to avoid surprises + startState = *st; + st = &startState; threadID = th; nodes = 0; + + assert(pos_is_ok()); } Position::Position(const string& fen, bool isChess960, int th) { @@ -113,67 +114,61 @@ Position::Position(const string& fen, bool isChess960, int 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 -} - - /// Position::from_fen() initializes the position object with the given FEN /// 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 string& fen, bool isChess960) { +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; size_t p; Square sq = SQ_A8; - std::istringstream ss(fen); + std::istringstream fen(fenStr); clear(); - ss >> std::noskipws; + fen >> std::noskipws; // 1. Piece placement - while ((ss >> token) && !isspace(token)) + 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) { @@ -183,31 +178,53 @@ void Position::from_fen(const string& fen, bool isChess960) { } // 2. Active color - ss >> token; + fen >> token; sideToMove = (token == 'w' ? WHITE : BLACK); - ss >> token; + fen >> token; + + // 3. Castling availability. 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 castling tag is + // replaced by the file letter of the involved rook, as for the Shredder-FEN. + while ((fen >> token) && !isspace(token)) + { + Square rsq; + Color c = islower(token) ? BLACK : WHITE; + + token = char(toupper(token)); + + if (token == 'K') + 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); type_of(piece_on(rsq)) != ROOK; rsq++) {} - // 3. Castling availability - while ((ss >> token) && !isspace(token)) - set_castling_rights(token); + else if (token >= 'A' && token <= 'H') + rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + + else + continue; + + set_castle_right(c, rsq); + } // 4. En passant square. Ignore if no pawn capture is possible - if ( ((ss >> col) && (col >= 'a' && col <= 'h')) - && ((ss >> row) && (row == '3' || row == '6'))) + if ( ((fen >> col) && (col >= 'a' && col <= 'h')) + && ((fen >> row) && (row == '3' || row == '6'))) { st->epSquare = make_square(File(col - 'a'), Rank(row - '1')); - Color them = opposite_color(sideToMove); - if (!(attacks_from(st->epSquare, them) & pieces(PAWN, sideToMove))) + if (!(attackers_to(st->epSquare) & pieces(PAWN, sideToMove))) st->epSquare = SQ_NONE; } // 5-6. Halfmove clock and fullmove number - ss >> std::skipws >> st->rule50 >> fullMoves; + fen >> std::skipws >> st->rule50 >> startPosPly; - // Various initialisations - chess960 = isChess960; - find_checkers(); + // Convert from fullmove starting from 1 to ply starting from 0, + // handle also common incorrect FEN with fullmove = 0. + startPosPly = std::max(2 * (startPosPly - 1), 0) + int(sideToMove == BLACK); st->key = compute_key(); st->pawnKey = compute_pawn_key(); @@ -215,53 +232,37 @@ void Position::from_fen(const string& fen, bool isChess960) { st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); -} - - -/// Position::set_castle() is an helper function used to set -/// correct castling related flags. - -void Position::set_castle(int f, Square ksq, Square rsq) { + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); + chess960 = isChess960; - st->castleRights |= f; - castleRightsMask[ksq] ^= f; - castleRightsMask[rsq] ^= f; - castleRookSquare[f] = rsq; + assert(pos_is_ok()); } -/// 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. - -void Position::set_castling_rights(char token) { - - Color c = islower(token) ? BLACK : WHITE; - - Square sqA = relative_square(c, SQ_A1); - Square sqH = relative_square(c, SQ_H1); - Square rsq, ksq = king_square(c); +/// Position::set_castle_right() is an helper function used to set castling +/// rights given the corresponding color and the rook starting square. - token = toupper(token); +void Position::set_castle_right(Color c, Square rfrom) { - if (token == 'K') - for (rsq = sqH; piece_on(rsq) != make_piece(c, ROOK); rsq--) {} + Square kfrom = king_square(c); + bool kingSide = kfrom < rfrom; + int cr = (kingSide ? WHITE_OO : WHITE_OOO) << c; - else if (token == 'Q') - for (rsq = sqA; piece_on(rsq) != make_piece(c, ROOK); rsq++) {} + st->castleRights |= cr; + castleRightsMask[kfrom] |= cr; + castleRightsMask[rfrom] |= cr; + castleRookSquare[cr] = rfrom; - else if (token >= 'A' && token <= 'H') - rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); + Square kto = relative_square(c, kingSide ? SQ_G1 : SQ_C1); + Square rto = relative_square(c, kingSide ? SQ_F1 : SQ_D1); - else return; + for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++) + if (s != kfrom && s != rfrom) + castlePath[cr] |= s; - if (square_file(rsq) < square_file(ksq)) - set_castle(WHITE_OOO << c, ksq, rsq); - else - set_castle(WHITE_OO << c, ksq, rsq); + for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++) + if (s != kfrom && s != rfrom) + castlePath[cr] |= s; } @@ -270,54 +271,59 @@ void Position::set_castling_rights(char token) { const string Position::to_fen() const { - string fen; + std::ostringstream fen; Square sq; - char emptyCnt; + int emptyCnt; - for (Rank rank = RANK_8; rank >= RANK_1; rank--, fen += '/') + for (Rank rank = RANK_8; rank >= RANK_1; rank--) { - emptyCnt = '0'; + emptyCnt = 0; for (File file = FILE_A; file <= FILE_H; file++) { sq = make_square(file, rank); - if (!square_is_empty(sq)) + if (square_is_empty(sq)) + emptyCnt++; + else { - if (emptyCnt != '0') + if (emptyCnt > 0) { - fen += emptyCnt; - emptyCnt = '0'; + fen << emptyCnt; + emptyCnt = 0; } - fen += PieceToChar[piece_on(sq)]; - } else - emptyCnt++; + fen << PieceToChar[piece_on(sq)]; + } } - if (emptyCnt != '0') - fen += emptyCnt; + if (emptyCnt > 0) + fen << emptyCnt; + + if (rank > RANK_1) + fen << '/'; } - fen += (sideToMove == WHITE ? " w " : " b "); + fen << (sideToMove == WHITE ? " w " : " b "); - if (st->castleRights != CASTLES_NONE) - { - if (can_castle(WHITE_OO)) - fen += chess960 ? char(toupper(file_to_char(square_file(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(BLACK_OO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OO))) : 'k'); - if (can_castle(WHITE_OOO)) - fen += chess960 ? char(toupper(file_to_char(square_file(castle_rook_square(WHITE_OOO))))) : 'Q'; + if (can_castle(BLACK_OOO)) + fen << (chess960 ? file_to_char(file_of(castle_rook_square(BLACK_OOO))) : 'q'); - if (can_castle(BLACK_OO)) - fen += chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OO))) : 'k'; + if (st->castleRights == CASTLES_NONE) + fen << '-'; - if (can_castle(BLACK_OOO)) - fen += chess960 ? file_to_char(square_file(castle_rook_square(BLACK_OOO))) : 'q'; - } else - 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())); - return fen; + return fen.str(); } @@ -331,8 +337,7 @@ void Position::print(Move move) const { if (move) { Position p(*this, thread()); - string dd = (piece_color(piece_on(move_from(move))) == 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--) @@ -342,11 +347,11 @@ 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 && square_color(sq) == DARK) - piece = PIECE_NONE_DARK_SQ; + if (piece == NO_PIECE && !opposite_colors(sq, SQ_A1)) + piece++; // Index the dot - char c = (piece_color(piece_on(sq)) == BLACK ? '=' : ' '); cout << c << PieceToChar[piece] << c << '|'; } } @@ -355,111 +360,63 @@ void Position::print(Move move) const { /// 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. - +/// 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(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)); +Bitboard Position::hidden_checkers() const { - // Pinners are sliders, not checkers, that give check when candidate pinned is removed - pinners &= (pieces(ROOK, QUEEN) & RookPseudoAttacks[ksq]) | (pieces(BISHOP, QUEEN) & BishopPseudoAttacks[ksq]); + // Pinned pieces protect our king, dicovery checks attack the enemy king + Bitboard b, result = 0; + Bitboard pinners = pieces(FindPinned ? ~sideToMove : sideToMove); + Square ksq = king_square(FindPinned ? sideToMove : ~sideToMove); - if (FindPinned && pinners) - pinners &= ~st->checkersBB; + // Pinners are sliders, that give check when candidate pinned is removed + pinners &= (pieces(ROOK, QUEEN) & PseudoAttacks[ROOK][ksq]) + | (pieces(BISHOP, QUEEN) & PseudoAttacks[BISHOP][ksq]); while (pinners) { - Square s = pop_1st_bit(&pinners); - Bitboard b = squares_between(s, ksq) & occupied_squares(); + b = squares_between(ksq, pop_1st_bit(&pinners)) & pieces(); - assert(b); - - if ( !(b & (b - 1)) // Only one bit set? - && (b & pieces_of_color(c))) // Is an our piece? + if (b && single_bit(b) && (b & pieces(sideToMove))) result |= b; } 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 given color. Note that checkersBB bitboard must -/// be already updated. - -Bitboard Position::pinned_pieces(Color c) const { - - return hidden_checkers(c); -} - - -/// Position:discovered_check_candidates() returns a bitboard containing all -/// pieces for the given side which are candidates for giving a discovered -/// check. Contrary to pinned_pieces() here there is no need of checkersBB -/// to be already updated. - -Bitboard Position::discovered_check_candidates(Color c) const { - - return hidden_checkers(c); -} - -/// Position::attackers_to() computes a bitboard containing all pieces which -/// attacks a given square. -Bitboard Position::attackers_to(Square s) const { - - return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) - | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) - | (attacks_from(s) & pieces(KNIGHT)) - | (attacks_from(s) & pieces(ROOK, QUEEN)) - | (attacks_from(s) & pieces(BISHOP, QUEEN)) - | (attacks_from(s) & pieces(KING)); -} +/// 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 { return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) | (attacks_from(s) & pieces(KNIGHT)) - | (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) - | (bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN)) + | (attacks_bb(s, occ) & pieces(ROOK, QUEEN)) + | (attacks_bb(s, occ) & pieces(BISHOP, QUEEN)) | (attacks_from(s) & pieces(KING)); } -/// Position::attacks_from() computes a bitboard of all attacks -/// of a given piece put in a given square. - -Bitboard Position::attacks_from(Piece p, Square s) const { - assert(square_is_ok(s)); - - switch (p) - { - case WB: case BB: return attacks_from(s); - case WR: case BR: return attacks_from(s); - case WQ: case BQ: return attacks_from(s); - default: return StepAttacksBB[p][s]; - } -} +/// 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. Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { - assert(square_is_ok(s)); + assert(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 attacks_bb(s, occ); + case ROOK : return attacks_bb(s, occ); + case QUEEN : return attacks_bb(s, occ) | attacks_bb(s, occ); + default : return StepAttacksBB[p][s]; } } @@ -469,147 +426,124 @@ Bitboard Position::attacks_from(Piece p, Square s, Bitboard occ) { bool Position::move_attacks_square(Move m, Square s) const { - assert(move_is_ok(m)); - assert(square_is_ok(s)); + assert(is_ok(m)); + assert(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_moved(m); - 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 = pieces() ^ from ^ to; + + // The piece moved in 'to' attacks the square 's' ? + if (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_of_color(piece_color(piece_on(f))); + // Scan for possible X-ray attackers behind the moved piece + xray = (attacks_bb(s, occ) & pieces(ROOK, QUEEN, color_of(piece))) + |(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))); } -/// 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::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() { - - Color us = side_to_move(); - st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us)); -} - - /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { - assert(is_ok()); - assert(move_is_ok(m)); - assert(pinned == pinned_pieces(side_to_move())); + assert(is_ok(m)); + assert(pinned == pinned_pieces()); - Color us = side_to_move(); - Square from = move_from(m); + Color us = sideToMove; + Square from = from_sq(m); - assert(piece_color(piece_on(from)) == us); + assert(color_of(piece_moved(m)) == us); assert(piece_on(king_square(us)) == make_piece(us, KING)); - // 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)) + // 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 (is_enpassant(m)) { - Color them = opposite_color(us); - Square to = move_to(m); - Square capsq = make_square(square_file(to), square_rank(from)); + Color them = ~us; + Square to = to_sq(m); + Square capsq = to + pawn_push(them); Square ksq = king_square(us); - Bitboard b = occupied_squares(); + Bitboard b = (pieces() ^ from ^ capsq) | to; assert(to == ep_square()); - assert(piece_on(from) == make_piece(us, PAWN)); + assert(piece_moved(m) == make_piece(us, PAWN)); assert(piece_on(capsq) == make_piece(them, PAWN)); - assert(piece_on(to) == PIECE_NONE); - - clear_bit(&b, from); - clear_bit(&b, capsq); - set_bit(&b, to); + assert(piece_on(to) == NO_PIECE); - return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them)) - && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); + return !(attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them)) + && !(attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); } // If the moving piece is a king, check whether the destination // square is attacked by the opponent. Castling moves are checked // for legality during move generation. - if (piece_type(piece_on(from)) == KING) - return move_is_castle(m) || !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us))); + if (type_of(piece_on(from)) == KING) + return is_castle(m) || !(attackers_to(to_sq(m)) & pieces(~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)); + || !(pinned & from) + || squares_aligned(from, to_sq(m), king_square(us)); } -/// Position::move_is_pl_slow() takes a move and tests whether the move -/// is pseudo legal. This version is not very fast and should be used -/// only in non time-critical paths. - -bool Position::move_is_pl_slow(const Move m) const { - - MoveStack mlist[MAX_MOVES]; - MoveStack *cur, *last; +/// 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. - last = in_check() ? generate(*this, mlist) - : generate(*this, mlist); +bool Position::move_is_legal(const Move m) const { - for (cur = mlist; cur != last; cur++) - if (cur->move == m) + for (MoveList ml(*this); !ml.end(); ++ml) + if (ml.move() == m) return true; return false; } -/// Fast version of Position::move_is_pl() that takes a move and a bitboard -/// of pinned pieces as input, and tests whether the move is pseudo legal. +/// Position::is_pseudo_legal() takes a random move and tests whether the move +/// is pseudo legal. It is used to validate moves from TT that can be corrupted +/// due to SMP concurrent access or hash position key aliasing. -bool Position::move_is_pl(const Move m) const { - - assert(is_ok()); +bool Position::is_pseudo_legal(const Move m) const { Color us = sideToMove; - Color them = opposite_color(sideToMove); - Square from = move_from(m); - Square to = move_to(m); - Piece pc = piece_on(from); + Color them = ~sideToMove; + Square from = from_sq(m); + Square to = to_sq(m); + Piece pc = piece_moved(m); // Use a slower but simpler function for uncommon cases - if (move_is_special(m)) - return move_is_pl_slow(m); + if (is_special(m)) + 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_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 || piece_color(pc) != us) + if (pc == NO_PIECE || color_of(pc) != us) return false; // The destination square cannot be occupied by a friendly piece - if (piece_color(piece_on(to)) == us) + if (color_of(piece_on(to)) == us) return false; // Handle the special case of a pawn move - if (piece_type(pc) == PAWN) + if (type_of(pc) == PAWN) { // Move direction must be compatible with pawn color int direction = to - from; @@ -618,7 +552,7 @@ bool Position::move_is_pl(const Move m) const { // 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) + if (rank_of(to) == RANK_8 || rank_of(to) == RANK_1) return false; // Proceed according to the square delta between the origin and @@ -631,11 +565,11 @@ bool Position::move_is_pl(const Move m) const { case DELTA_SE: // Capture. The destination square must be occupied by an enemy // piece (en passant captures was handled earlier). - if (piece_color(piece_on(to)) != them) + if (color_of(piece_on(to)) != them) return false; // From and to files must be one file apart, avoids a7h5 - if (abs(square_file(from) - square_file(to)) != 1) + if (abs(file_of(from) - file_of(to)) != 1) return false; break; @@ -650,7 +584,7 @@ bool Position::move_is_pl(const Move m) const { // 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 + if ( rank_of(to) != RANK_4 || !square_is_empty(to) || !square_is_empty(from + DELTA_N)) return false; @@ -660,7 +594,7 @@ bool Position::move_is_pl(const Move m) const { // 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 + if ( rank_of(to) != RANK_5 || !square_is_empty(to) || !square_is_empty(from + DELTA_S)) return false; @@ -670,157 +604,101 @@ bool Position::move_is_pl(const Move m) const { return false; } } - else if (!bit_is_set(attacks_from(pc, from), to)) + else if (!(attacks_from(pc, from) & to)) return false; + // Evasions generator already takes care to avoid some kind of illegal moves + // and pl_move_is_legal() relies on this. So we have to take care that the + // same kind of moves are filtered out here. if (in_check()) { - // In case of king moves under check we have to remove king so to catch - // as invalid moves like b1a1 when opposite queen is on c1. - if (piece_type(piece_on(from)) == KING) + if (type_of(pc) != KING) { - Bitboard b = occupied_squares(); - clear_bit(&b, from); - if (attackers_to(move_to(m), b) & pieces_of_color(opposite_color(us))) - return false; - } - else - { - Bitboard target = checkers(); - Square checksq = pop_1st_bit(&target); + Bitboard b = checkers(); + Square checksq = pop_1st_bit(&b); - if (target) // double check ? In this case a king move is required + if (b) // double check ? In this case a king move is required return false; // 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 (!((squares_between(checksq, king_square(us)) | checkers()) & to)) return false; } + // In case of king moves under check we have to remove king so to catch + // as invalid moves like b1a1 when opposite queen is on c1. + else if (attackers_to(to, pieces() ^ from) & pieces(~us)) + return false; } return true; } -/// Position::move_gives_check() tests whether a pseudo-legal move is a check +/// Position::move_gives_check() tests whether a pseudo-legal move gives a check bool Position::move_gives_check(Move m, const CheckInfo& ci) const { - assert(is_ok()); - assert(move_is_ok(m)); - assert(ci.dcCandidates == discovered_check_candidates(side_to_move())); - assert(piece_color(piece_on(move_from(m))) == side_to_move()); + assert(is_ok(m)); + assert(ci.dcCandidates == discovered_check_candidates()); + assert(color_of(piece_moved(m)) == sideToMove); - Square from = move_from(m); - Square to = move_to(m); - PieceType pt = piece_type(piece_on(from)); + Square from = from_sq(m); + Square to = to_sq(m); + PieceType pt = type_of(piece_on(from)); // Direct check ? - if (bit_is_set(ci.checkSq[pt], to)) + if (ci.checkSq[pt] & to) return true; // Discovery check ? - if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) + if (ci.dcCandidates && (ci.dcCandidates & from)) { // For pawn and king moves we need to verify also direction if ( (pt != PAWN && pt != KING) - || !squares_aligned(from, to, king_square(opposite_color(side_to_move())))) + || !squares_aligned(from, to, king_square(~sideToMove))) return true; } // Can we skip the ugly special cases ? - if (!move_is_special(m)) + if (!is_special(m)) return false; - Color us = side_to_move(); - Bitboard b = occupied_squares(); - Square ksq = king_square(opposite_color(us)); + Color us = sideToMove; + Square ksq = king_square(~us); // Promotion with check ? - if (move_is_promotion(m)) - { - clear_bit(&b, from); - - switch (promotion_piece_type(m)) - { - case KNIGHT: - return bit_is_set(attacks_from(to), ksq); - case BISHOP: - return bit_is_set(bishop_attacks_bb(to, b), ksq); - case ROOK: - return bit_is_set(rook_attacks_bb(to, b), ksq); - case QUEEN: - return bit_is_set(queen_attacks_bb(to, b), ksq); - default: - assert(false); - } - } + if (is_promotion(m)) + return attacks_from(Piece(promotion_type(m)), to, pieces() ^ from) & ksq; // 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)) + if (is_enpassant(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(ksq, b) & pieces(ROOK, QUEEN, us)) - ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us)); + Square capsq = make_square(file_of(to), rank_of(from)); + Bitboard b = (pieces() ^ from ^ capsq) | to; + + return (attacks_bb< ROOK>(ksq, b) & pieces( ROOK, QUEEN, us)) + | (attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us)); } // Castling with check ? - if (move_is_castle(m)) + if (is_castle(m)) { - Square kfrom, kto, rfrom, rto; - kfrom = from; - rfrom = to; + Square kfrom = from; + Square rfrom = to; // 'King captures the rook' notation + Square kto = relative_square(us, rfrom > kfrom ? SQ_G1 : SQ_C1); + Square rto = relative_square(us, rfrom > kfrom ? SQ_F1 : SQ_D1); + Bitboard b = (pieces() ^ kfrom ^ rfrom) | rto | kto; - 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), ksq); + return 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. - -void Position::do_setup_move(Move m) { - - StateInfo newSt; - - // Update the number of full moves after black's move - if (sideToMove == BLACK) - fullMoves++; - - 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; - - // Our StateInfo newSt is about going out of scope so copy - // its content 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. @@ -833,22 +711,21 @@ void Position::do_move(Move m, StateInfo& newSt) { void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveIsCheck) { - assert(is_ok()); - assert(move_is_ok(m)); + assert(is_ok(m)); 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; - int castleRights, rule50, gamePly, pliesFromNull; - Square epSquare; - Score value; Value npMaterial[2]; + int castleRights, rule50, pliesFromNull; + Score value; + Square epSquare; }; memcpy(&newSt, st, sizeof(ReducedStateInfo)); @@ -856,144 +733,178 @@ void Position::do_move(Move m, StateInfo& newSt, const CheckInfo& ci, bool moveI 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; + 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. + // case of a capture or a pawn move is taken care of later. st->rule50++; st->pliesFromNull++; - if (move_is_castle(m)) + if (is_castle(m)) { - st->key = key; - do_castle_move(m); + st->key = k; + do_castle_move(m); return; } - 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); - + Color us = sideToMove; + Color them = ~us; + Square from = from_sq(m); + Square to = to_sq(m); Piece piece = piece_on(from); - PieceType pt = piece_type(piece); - PieceType capture = ep ? PAWN : piece_type(piece_on(to)); + PieceType pt = type_of(piece); + PieceType capture = is_enpassant(m) ? PAWN : type_of(piece_on(to)); - assert(piece_color(piece_on(from)) == us); - assert(piece_color(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 + byTypeBB[ALL_PIECES] ^= capsq; + byTypeBB[capture] ^= capsq; + byColorBB[them] ^= 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[file_of(st->epSquare)]; st->epSquare = SQ_NONE; } // Update castle rights if needed - if ( st->castleRights != CASTLES_NONE - && (castleRightsMask[from] & castleRightsMask[to]) != ALL_CASTLES) + if (st->castleRights && (castleRightsMask[from] | castleRightsMask[to])) { - key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[from] & castleRightsMask[to]; - key ^= zobCastle[st->castleRights]; + int cr = castleRightsMask[from] | castleRightsMask[to]; + k ^= zobCastle[st->castleRights & cr]; + st->castleRights &= ~cr; } // 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 + Bitboard from_to_bb = SquareBB[from] | SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[pt] ^= from_to_bb; + byColorBB[us] ^= from_to_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 ( (int(to) ^ int(from)) == 16 + && (attacks_from(from + pawn_push(us), us) & pieces(PAWN, them))) { - if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) - { - st->epSquare = Square((int(from) + int(to)) / 2); - key ^= zobEp[st->epSquare]; - } + st->epSquare = Square((from + to) / 2); + k ^= zobEp[file_of(st->epSquare)]; } - if (pm) // promotion ? + if (is_promotion(m)) { - PieceType promotion = promotion_piece_type(m); + PieceType promotion = promotion_type(m); + assert(relative_rank(us, to) == RANK_8); assert(promotion >= KNIGHT && promotion <= QUEEN); - // Insert promoted piece instead of pawn - clear_bit(&(byTypeBB[PAWN]), to); - set_bit(&(byTypeBB[promotion]), to); + // Replace the pawn with the promoted piece + byTypeBB[PAWN] ^= to; + 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 - Threads[threadID].pawnTable.prefetch(st->pawnKey); - Threads[threadID].materialTable.prefetch(st->materialKey); + prefetch((char*)Threads[threadID].pawnTable.entries[st->pawnKey]); + prefetch((char*)Threads[threadID].materialTable.entries[st->materialKey]); // Update incremental scores st->value += pst_delta(piece, from, to); @@ -1002,199 +913,38 @@ 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) - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); + if (is_special(m)) + st->checkersBB = attackers_to(king_square(them)) & pieces(us); else { // Direct checks - if (bit_is_set(ci.checkSq[pt], to)) - st->checkersBB = SetMaskBB[to]; + if (ci.checkSq[pt] & to) + st->checkersBB |= to; // Discovery checks - if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) + if (ci.dcCandidates && (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); } } } // Finish - sideToMove = opposite_color(sideToMove); - st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); - - assert(is_ok()); -} - - -/// Position::do_capture_move() is a private method used to update captured -/// piece info. It is called from the main Position::do_move function. - -void Position::do_capture_move(Key& key, PieceType capture, Color them, Square to, bool ep) { - - assert(capture != KING); - - Square capsq = 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 = (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; - } - st->pawnKey ^= zobrist[them][PAWN][capsq]; - } - else - st->npMaterial[them] -= PieceValueMidgame[capture]; - - // Remove captured piece - clear_bit(&(byColorBB[them]), capsq); - clear_bit(&(byTypeBB[capture]), capsq); - clear_bit(&(byTypeBB[0]), capsq); - - // Update hash key - key ^= zobrist[them][capture][capsq]; - - // Update incremental scores - st->value -= pst(make_piece(them, capture), capsq); - - // 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 -/// 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) { - - assert(move_is_ok(m)); - assert(move_is_castle(m)); - - Color us = side_to_move(); - Color them = opposite_color(us); - - // Reset capture field - st->capturedType = PIECE_TYPE_NONE; - - // 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; - - 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: - clear_bit(&(byColorBB[us]), kfrom); - clear_bit(&(byTypeBB[KING]), kfrom); - clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares - clear_bit(&(byColorBB[us]), rfrom); - clear_bit(&(byTypeBB[ROOK]), rfrom); - clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares - - // Put pieces on destination squares: - set_bit(&(byColorBB[us]), kto); - set_bit(&(byTypeBB[KING]), kto); - set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares - set_bit(&(byColorBB[us]), rto); - set_bit(&(byTypeBB[ROOK]), rto); - set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares - - // 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 - pieceList[us][KING][index[kfrom]] = kto; - pieceList[us][ROOK][index[rfrom]] = rto; - int tmp = index[rfrom]; // In Chess960 could be rto == kfrom - index[kto] = index[kfrom]; - index[rto] = tmp; - - // Update incremental scores - st->value += pst_delta(king, kfrom, kto); - st->value += pst_delta(rook, rfrom, rto); - - // Update hash key - st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; - st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; - - // Clear en passant square - if (st->epSquare != SQ_NONE) - { - st->key ^= zobEp[st->epSquare]; - st->epSquare = SQ_NONE; - } - - // Update castling rights - st->key ^= zobCastle[st->castleRights]; - st->castleRights &= castleRightsMask[kfrom]; - st->key ^= zobCastle[st->castleRights]; - - // Reset rule 50 counter - st->rule50 = 0; - - // Update checkers BB - st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); - - // Finish - sideToMove = opposite_color(sideToMove); + sideToMove = ~sideToMove; st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); - assert(is_ok()); + assert(pos_is_ok()); } @@ -1203,230 +953,249 @@ void Position::do_castle_move(Move m) { void Position::undo_move(Move m) { - assert(is_ok()); - assert(move_is_ok(m)); + assert(is_ok(m)); - sideToMove = opposite_color(sideToMove); + sideToMove = ~sideToMove; - if (move_is_castle(m)) + if (is_castle(m)) { - undo_castle_move(m); + do_castle_move(m); return; } - 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 = piece_type(piece_on(to)); + Color us = sideToMove; + Color them = ~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(piece_color(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)); + assert(color_of(piece) == us); + assert(capture != KING); - if (pm) // promotion ? + if (is_promotion(m)) { - PieceType promotion = promotion_piece_type(m); - pt = PAWN; + PieceType promotion = promotion_type(m); + assert(promotion == pt); + assert(relative_rank(us, to) == RANK_8); 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); + // Replace the promoted piece with the pawn + byTypeBB[promotion] ^= to; + byTypeBB[PAWN] |= to; + board[to] = make_piece(us, PAWN); - // 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; + // 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] - 1; + index[to] = pieceCount[us][PAWN]++; pieceList[us][PAWN][index[to]] = to; + + pt = 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(&(byTypeBB[0]), move_bb); // HACK: byTypeBB[0] == occupied squares + Bitboard from_to_bb = SquareBB[from] | SquareBB[to]; + byTypeBB[ALL_PIECES] ^= from_to_bb; + byTypeBB[pt] ^= from_to_bb; + byColorBB[us] ^= from_to_bb; - board[from] = make_piece(us, pt); - board[to] = PIECE_NONE; + board[from] = board[to]; + board[to] = NO_PIECE; - // Update piece list + // 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; - if (st->capturedType) + if (capture) { Square capsq = to; - if (ep) - capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); + if (is_enpassant(m)) + { + capsq -= pawn_push(us); - assert(st->capturedType != KING); - assert(!ep || square_is_empty(capsq)); + assert(pt == PAWN); + assert(to == st->previous->epSquare); + assert(relative_rank(us, to) == RANK_6); + assert(piece_on(capsq) == NO_PIECE); + } // Restore the captured piece - set_bit(&(byColorBB[them]), capsq); - set_bit(&(byTypeBB[st->capturedType]), capsq); - set_bit(&(byTypeBB[0]), capsq); + byTypeBB[ALL_PIECES] |= capsq; + byTypeBB[capture] |= capsq; + byColorBB[them] |= capsq; - board[capsq] = make_piece(them, st->capturedType); - - // Update piece count - pieceCount[them][st->capturedType]++; + board[capsq] = make_piece(them, capture); // 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; + 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(is_ok()); + assert(pos_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 -/// 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) { +/// Position::do_castle_move() is a private method used to do/undo a castling +/// move. 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. +template +void Position::do_castle_move(Move m) { - assert(move_is_ok(m)); - assert(move_is_castle(m)); + assert(is_ok(m)); + assert(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. - Color us = side_to_move(); + Square kto, kfrom, rfrom, rto, kAfter, rAfter; - // 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; + Color us = sideToMove; + Square kBefore = from_sq(m); + Square rBefore = to_sq(m); - // Find destination squares for king and rook - if (rfrom > kfrom) // O-O + // Find after-castle squares for king and rook + if (rBefore > kBefore) // 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); + kAfter = relative_square(us, SQ_G1); + rAfter = relative_square(us, SQ_F1); + } + else // O-O-O + { + kAfter = relative_square(us, SQ_C1); + rAfter = relative_square(us, SQ_D1); } - 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); - clear_bit(&(byTypeBB[KING]), kto); - clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares - clear_bit(&(byColorBB[us]), rto); - clear_bit(&(byTypeBB[ROOK]), rto); - clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares - - // Put pieces on source squares: - set_bit(&(byColorBB[us]), kfrom); - set_bit(&(byTypeBB[KING]), kfrom); - set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares - set_bit(&(byColorBB[us]), rfrom); - set_bit(&(byTypeBB[ROOK]), rfrom); - set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares + kfrom = Do ? kBefore : kAfter; + rfrom = Do ? rBefore : rAfter; + + kto = Do ? kAfter : kBefore; + rto = Do ? rAfter : rBefore; + + assert(piece_on(kfrom) == make_piece(us, KING)); + assert(piece_on(rfrom) == make_piece(us, ROOK)); + + // Remove pieces from source squares + byTypeBB[ALL_PIECES] ^= kfrom; + byTypeBB[KING] ^= kfrom; + byColorBB[us] ^= kfrom; + byTypeBB[ALL_PIECES] ^= rfrom; + byTypeBB[ROOK] ^= rfrom; + byColorBB[us] ^= rfrom; + + // Put pieces on destination squares + byTypeBB[ALL_PIECES] |= kto; + byTypeBB[KING] |= kto; + byColorBB[us] |= kto; + byTypeBB[ALL_PIECES] |= rto; + byTypeBB[ROOK] |= rto; + byColorBB[us] |= rto; // Update board - board[rto] = board[kto] = PIECE_NONE; - board[rfrom] = make_piece(us, ROOK); - board[kfrom] = make_piece(us, KING); + Piece king = make_piece(us, KING); + Piece rook = make_piece(us, ROOK); + board[kfrom] = board[rfrom] = NO_PIECE; + board[kto] = king; + board[rto] = rook; // Update piece lists - pieceList[us][KING][index[kto]] = kfrom; - pieceList[us][ROOK][index[rto]] = rfrom; - int tmp = index[rto]; // In Chess960 could be rto == kfrom - index[kfrom] = index[kto]; - index[rfrom] = tmp; + pieceList[us][KING][index[kfrom]] = kto; + pieceList[us][ROOK][index[rfrom]] = rto; + int tmp = index[rfrom]; // In Chess960 could be kto == rfrom + index[kto] = index[kfrom]; + index[rto] = tmp; - // Finally point our state pointer back to the previous state - st = st->previous; + if (Do) + { + // Reset capture field + st->capturedType = NO_PIECE_TYPE; - assert(is_ok()); -} + // Update incremental scores + st->value += pst_delta(king, kfrom, kto); + st->value += pst_delta(rook, rfrom, rto); + // Update hash key + st->key ^= zobrist[us][KING][kfrom] ^ zobrist[us][KING][kto]; + st->key ^= zobrist[us][ROOK][rfrom] ^ zobrist[us][ROOK][rto]; -/// 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. + // Clear en passant square + if (st->epSquare != SQ_NONE) + { + st->key ^= zobEp[file_of(st->epSquare)]; + st->epSquare = SQ_NONE; + } + // Update castling rights + st->key ^= zobCastle[st->castleRights & castleRightsMask[kfrom]]; + st->castleRights &= ~castleRightsMask[kfrom]; + + // Update checkers BB + st->checkersBB = attackers_to(king_square(~us)) & pieces(us); + + // Finish + sideToMove = ~sideToMove; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); + } + else + // Undo: point our state pointer back to the previous state + st = st->previous; + + assert(pos_is_ok()); +} + + +/// 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(is_ok()); 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; - - // Save the current key to the history[] array, in order to be able to - // detect repetition draws. - history[st->gamePly++] = st->key; - - // Update the necessary information - if (st->epSquare != SQ_NONE) - st->key ^= zobEp[st->epSquare]; + // 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; - st->key ^= zobSideToMove; - prefetch((char*)TT.first_entry(st->key)); - - sideToMove = opposite_color(sideToMove); - st->epSquare = SQ_NONE; - st->rule50++; - st->pliesFromNull = 0; - st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; -} + dst->key = src->key; + dst->epSquare = src->epSquare; + dst->value = src->value; + dst->rule50 = src->rule50; + dst->pliesFromNull = src->pliesFromNull; + sideToMove = ~sideToMove; -/// Position::undo_null_move() unmakes a "null move". + if (Do) + { + if (st->epSquare != SQ_NONE) + st->key ^= zobEp[file_of(st->epSquare)]; -void Position::undo_null_move() { + st->key ^= zobSideToMove; + prefetch((char*)TT.first_entry(st->key)); - assert(is_ok()); - assert(!in_check()); + st->epSquare = SQ_NONE; + st->rule50++; + st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; + } - // 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 - sideToMove = opposite_color(sideToMove); - st->rule50--; - st->gamePly--; + 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 @@ -1436,15 +1205,12 @@ void Position::undo_null_move() { int Position::see_sign(Move m) const { - assert(move_is_ok(m)); - - Square from = move_from(m); - Square to = move_to(m); + assert(is_ok(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 (piece_value_midgame(piece_on(to)) >= piece_value_midgame(piece_on(from))) + if (PieceValueMidgame[piece_on(to_sq(m))] >= PieceValueMidgame[piece_moved(m)]) return 1; return see(m); @@ -1453,45 +1219,45 @@ 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; - assert(move_is_ok(m)); + assert(is_ok(m)); // As castle moves are implemented as capturing the rook, they have // SEE == RookValueMidgame most of the times (unless the rook is under // attack). - if (move_is_castle(m)) + if (is_castle(m)) return 0; - from = move_from(m); - to = move_to(m); - capturedType = piece_type(piece_on(to)); - occupied = occupied_squares(); + from = from_sq(m); + to = to_sq(m); + capturedType = type_of(piece_on(to)); + occ = pieces(); // Handle en passant moves - if (st->epSquare == to && piece_type(piece_on(from)) == PAWN) + if (is_enpassant(m)) { - Square capQq = (side_to_move() == WHITE ? to - DELTA_N : to - DELTA_S); + Square capQq = to - pawn_push(sideToMove); - assert(capturedType == PIECE_TYPE_NONE); - assert(piece_type(piece_on(capQq)) == PAWN); + assert(!capturedType); + assert(type_of(piece_on(capQq)) == PAWN); // Remove the captured pawn - clear_bit(&occupied, capQq); + 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); + occ ^= from; + attackers = attackers_to(to, occ); // If the opponent has no attackers we are finished - stm = opposite_color(piece_color(piece_on(from))); - stmAttackers = attackers & pieces_of_color(stm); + stm = ~color_of(piece_on(from)); + stmAttackers = attackers & pieces(stm); if (!stmAttackers) return PieceValueMidgame[capturedType]; @@ -1502,7 +1268,7 @@ int Position::see(Move m) const { // capture with the least valuable piece. After each capture, we look for // new X-ray attacks from behind the capturing piece. swapList[0] = PieceValueMidgame[capturedType]; - capturedType = piece_type(piece_on(from)); + capturedType = type_of(piece_on(from)); do { // Locate the least valuable attacker for the side to move. The loop @@ -1514,11 +1280,11 @@ 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 |= (attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (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); @@ -1528,8 +1294,8 @@ int Position::see(Move m) const { // 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); + stm = ~stm; + stmAttackers = attackers & pieces(stm); // Stop before processing a king capture if (capturedType == KING && stmAttackers) @@ -1543,7 +1309,7 @@ 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]; } @@ -1554,27 +1320,16 @@ int Position::see(Move m) const { void Position::clear() { + memset(this, 0, sizeof(Position)); + startState.epSquare = SQ_NONE; st = &startState; - memset(st, 0, sizeof(StateInfo)); - st->epSquare = SQ_NONE; - - 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 (int i = 0; i < 8; i++) for (int j = 0; j < 16; j++) pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; for (Square sq = SQ_A1; sq <= SQ_H8; sq++) - { - board[sq] = PIECE_NONE; - castleRightsMask[sq] = ALL_CASTLES; - } - sideToMove = WHITE; - fullMoves = 1; - nodes = 0; + board[sq] = NO_PIECE; } @@ -1583,16 +1338,16 @@ void Position::clear() { void Position::put_piece(Piece p, Square s) { - Color c = piece_color(p); - PieceType pt = piece_type(p); + Color c = color_of(p); + PieceType pt = type_of(p); board[s] = p; 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. + byTypeBB[ALL_PIECES] |= s; + byTypeBB[pt] |= s; + byColorBB[c] |= s; } @@ -1607,12 +1362,12 @@ Key Position::compute_key() const { for (Square s = SQ_A1; s <= SQ_H8; s++) if (!square_is_empty(s)) - result ^= zobrist[piece_color(piece_on(s))][piece_type(piece_on(s))][s]; + result ^= zobrist[color_of(piece_on(s))][type_of(piece_on(s))][s]; if (ep_square() != SQ_NONE) - result ^= zobEp[ep_square()]; + result ^= zobEp[file_of(ep_square())]; - if (side_to_move() == BLACK) + if (sideToMove == BLACK) result ^= zobSideToMove; return result; @@ -1652,7 +1407,7 @@ Key Position::compute_material_key() const { for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= QUEEN; pt++) - for (int i = 0, cnt = piece_count(c, pt); i < cnt; i++) + for (int i = 0; i < piece_count(c, pt); i++) result ^= zobrist[c][pt][i]; return result; @@ -1676,7 +1431,7 @@ Score Position::compute_value() const { result += pst(make_piece(c, pt), pop_1st_bit(&b)); } - result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2); + result += (sideToMove == WHITE ? TempoValue / 2 : -TempoValue / 2); return result; } @@ -1709,39 +1464,43 @@ 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) - 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; + { + int i = 4, e = std::min(st->rule50, st->pliesFromNull); - return false; -} + if (i <= e) + { + StateInfo* stp = st->previous->previous; -// Explicit template instantiations -template bool Position::is_draw() const; -template bool Position::is_draw() const; + do { + stp = stp->previous->previous; + if (stp->key == st->key) + return true; -/// Position::is_mate() returns true or false depending on whether the -/// side to move is checkmated. + i +=2; -bool Position::is_mate() const { + } while (i <= e); + } + } - MoveStack moves[MAX_MOVES]; - return in_check() && generate(*this, moves) == moves; + return false; } +// Explicit template instantiations +template bool Position::is_draw() const; +template bool Position::is_draw() const; + -/// 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 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. +/// 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 +/// are copied from PSQT[] tables. Second, the black halves of the tables are +/// initialized by flipping and changing the sign of the white scores. void Position::init() { @@ -1752,31 +1511,39 @@ void Position::init() { for (Square s = SQ_A1; s <= SQ_H8; s++) zobrist[c][pt][s] = rk.rand(); - for (Square s = SQ_A1; s <= SQ_H8; s++) - zobEp[s] = rk.rand(); + for (File f = FILE_A; f <= FILE_H; f++) + zobEp[f] = rk.rand(); - for (int i = 0; i < 16; i++) - zobCastle[i] = rk.rand(); + for (int cr = CASTLES_NONE; cr <= ALL_CASTLES; cr++) + { + Bitboard b = cr; + while (b) + { + Key k = zobCastle[1ULL << pop_1st_bit(&b)]; + zobCastle[cr] ^= k ? k : rk.rand(); + } + } zobSideToMove = rk.rand(); zobExclusion = rk.rand(); - 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 (Piece p = W_PAWN; p <= W_KING; p++) + { + Score ps = make_score(PieceValueMidgame[p], PieceValueEndgame[p]); - 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)]; + for (Square s = SQ_A1; s <= SQ_H8; s++) + { + pieceSquareTable[p][s] = ps + PSQT[p][s]; + pieceSquareTable[p+8][~s] = -pieceSquareTable[p][s]; + } + } } -/// Position::flip() flips position with the white and black sides reversed. This +/// Position::flip_me() flips position with the white and black sides reversed. This /// is only useful for debugging especially for finding evaluation symmetry bugs. -void Position::flip() { - - assert(is_ok()); +void Position::flip_me() { // Make a copy of current position before to start changing const Position pos(*this, threadID); @@ -1787,27 +1554,27 @@ void Position::flip() { // Board 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)); + put_piece(Piece(pos.piece_on(s) ^ 8), ~s); // Side to move - sideToMove = opposite_color(pos.side_to_move()); + sideToMove = ~pos.side_to_move(); // Castling rights if (pos.can_castle(WHITE_OO)) - set_castle(BLACK_OO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OO))); + set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OO)); if (pos.can_castle(WHITE_OOO)) - set_castle(BLACK_OOO, king_square(BLACK), flip_square(pos.castle_rook_square(WHITE_OOO))); + set_castle_right(BLACK, ~pos.castle_rook_square(WHITE_OOO)); if (pos.can_castle(BLACK_OO)) - set_castle(WHITE_OO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OO))); + set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OO)); if (pos.can_castle(BLACK_OOO)) - set_castle(WHITE_OOO, king_square(WHITE), flip_square(pos.castle_rook_square(BLACK_OOO))); + set_castle_right(WHITE, ~pos.castle_rook_square(BLACK_OOO)); // En passant square if (pos.st->epSquare != SQ_NONE) - st->epSquare = flip_square(pos.st->epSquare); + st->epSquare = ~pos.st->epSquare; // Checkers - find_checkers(); + st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); // Hash keys st->key = compute_key(); @@ -1821,14 +1588,14 @@ void Position::flip() { st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); - assert(is_ok()); + assert(pos_is_ok()); } -/// Position::is_ok() performs some consitency checks for the position object. +/// Position::pos_is_ok() performs some consitency checks for the position object. /// This is meant to be helpful when debugging. -bool Position::is_ok(int* failedStep) const { +bool Position::pos_is_ok(int* failedStep) const { // What features of the position should be verified? const bool debugAll = false; @@ -1849,16 +1616,16 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) *failedStep = 1; // Side to move OK? - if (side_to_move() != WHITE && side_to_move() != BLACK) + if (sideToMove != WHITE && sideToMove != BLACK) return false; // 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? @@ -1867,8 +1634,8 @@ bool Position::is_ok(int* failedStep) const { { int kingCount[2] = {0, 0}; for (Square s = SQ_A1; s <= SQ_H8; s++) - if (piece_type(piece_on(s)) == KING) - kingCount[piece_color(piece_on(s))]++; + if (type_of(piece_on(s)) == KING) + kingCount[color_of(piece_on(s))]++; if (kingCount[0] != 1 || kingCount[1] != 1) return false; @@ -1878,16 +1645,16 @@ bool Position::is_ok(int* failedStep) const { if (failedStep) (*failedStep)++; if (debugKingCapture) { - Color us = side_to_move(); - Color them = opposite_color(us); + Color us = sideToMove; + Color them = ~us; Square ksq = king_square(them); - if (attackers_to(ksq) & pieces_of_color(us)) + if (attackers_to(ksq) & pieces(us)) return false; } // 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? @@ -1895,12 +1662,12 @@ bool Position::is_ok(int* failedStep) const { if (debugBitboards) { // The intersection of the white and black pieces must be empty - if ((pieces_of_color(WHITE) & pieces_of_color(BLACK)) != EmptyBoardBB) + if (pieces(WHITE) & pieces(BLACK)) return false; // 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()) + if ((pieces(WHITE) | pieces(BLACK)) != pieces()) return false; // Separate piece type bitboards must have empty intersections @@ -1916,7 +1683,7 @@ bool Position::is_ok(int* failedStep) const { { // 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) + if (relative_rank(sideToMove, ep_square()) != RANK_6) return false; } @@ -1956,7 +1723,7 @@ bool Position::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)++; @@ -1965,10 +1732,10 @@ bool Position::is_ok(int* failedStep) const { 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)) + if (piece_on(piece_list(c, pt)[i]) != make_piece(c, pt)) return false; - if (index[piece_list(c, pt, i)] != i) + if (index[piece_list(c, pt)[i]] != i) return false; } @@ -1979,10 +1746,10 @@ bool Position::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) + if ( piece_on(castleRookSquare[f]) != rook + || castleRightsMask[castleRookSquare[f]] != f) return false; }