X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=21eff88c46898b46ca5e4fb86578f45bb895d8aa;hp=c07e6964fac76006c874ade7e2d3423b9fdd3862;hb=8df1cd10df0869f05916d1eb19e33b66127fcb86;hpb=91a76331ca27b40d63f0031fbd7b9e41ead354d4 diff --git a/src/position.cpp b/src/position.cpp index c07e6964..21eff88c 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -2,7 +2,7 @@ Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2018 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, 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 @@ -36,10 +36,6 @@ using std::string; -namespace PSQT { - extern Score psq[PIECE_NB][SQUARE_NB]; -} - namespace Zobrist { Key psq[PIECE_NB][SQUARE_NB]; @@ -130,13 +126,13 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { } -// Marcel van Kervink's cuckoo algorithm for fast detection of "upcoming repetition"/ -// "no progress" situations. Description of the algorithm in the following paper: +// Marcel van Kervinck's cuckoo algorithm for fast detection of "upcoming repetition" +// situations. Description of the algorithm in the following paper: // https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf // First and second hash functions for indexing the cuckoo tables -inline Key H1(Key h) { return h & 0x1fff; } -inline Key H2(Key h) { return (h >> 16) & 0x1fff; } +inline int H1(Key h) { return h & 0x1fff; } +inline int H2(Key h) { return (h >> 16) & 0x1fff; } // Cuckoo tables with Zobrist hashes of valid reversible moves, and the moves themselves Key cuckoo[8192]; @@ -172,6 +168,8 @@ void Position::init() { Zobrist::noPawns = rng.rand(); // Prepare the cuckoo tables + std::memset(cuckoo, 0, sizeof(cuckoo)); + std::memset(cuckooMove, 0, sizeof(cuckooMove)); int count = 0; for (Piece pc : Pieces) for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) @@ -180,12 +178,12 @@ void Position::init() { { Move move = make_move(s1, s2); Key key = Zobrist::psq[pc][s1] ^ Zobrist::psq[pc][s2] ^ Zobrist::side; - unsigned int i = H1(key); + int i = H1(key); while (true) { std::swap(cuckoo[i], key); std::swap(cuckooMove[i], move); - if (move == 0) // Arrived at empty slot ? + if (move == MOVE_NONE) // Arrived at empty slot? break; i = (i == H1(key)) ? H2(key) : H1(key); // Push victim to alternative slot } @@ -381,7 +379,6 @@ void Position::set_state(StateInfo* si) const { si->key = si->materialKey = 0; si->pawnKey = Zobrist::noPawns; si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO; - si->psq = SCORE_ZERO; si->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); set_check_info(si); @@ -391,7 +388,6 @@ void Position::set_state(StateInfo* si) const { Square s = pop_lsb(&b); Piece pc = piece_on(s); si->key ^= Zobrist::psq[pc][s]; - si->psq += PSQT::psq[pc][s]; } if (si->epSquare != SQ_NONE) @@ -469,18 +465,18 @@ const string Position::fen() const { ss << (sideToMove == WHITE ? " w " : " b "); if (can_castle(WHITE_OO)) - ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE | KING_SIDE))) : 'K'); + ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE_OO ))) : 'K'); if (can_castle(WHITE_OOO)) - ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE | QUEEN_SIDE))) : 'Q'); + ss << (chess960 ? char('A' + file_of(castling_rook_square(WHITE_OOO))) : 'Q'); if (can_castle(BLACK_OO)) - ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK | KING_SIDE))) : 'k'); + ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK_OO ))) : 'k'); if (can_castle(BLACK_OOO)) - ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK | QUEEN_SIDE))) : 'q'); + ss << (chess960 ? char('a' + file_of(castling_rook_square(BLACK_OOO))) : 'q'); - if (!can_castle(WHITE) && !can_castle(BLACK)) + if (!can_castle(ANY_CASTLING)) ss << '-'; ss << (ep_square() == SQ_NONE ? " - " : " " + UCI::square(ep_square()) + " ") @@ -544,6 +540,7 @@ bool Position::legal(Move m) const { Color us = sideToMove; Square from = from_sq(m); + Square to = to_sq(m); assert(color_of(moved_piece(m)) == us); assert(piece_on(square(us)) == make_piece(us, KING)); @@ -554,7 +551,6 @@ bool Position::legal(Move m) const { if (type_of(m) == ENPASSANT) { Square ksq = square(us); - Square to = to_sq(m); Square capsq = to - pawn_push(us); Bitboard occupied = (pieces() ^ from ^ capsq) | to; @@ -567,16 +563,35 @@ bool Position::legal(Move m) const { && !(attacks_bb(ksq, occupied) & pieces(~us, QUEEN, BISHOP)); } - // 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. + // Castling moves generation does not check if the castling path is clear of + // enemy attacks, it is delayed at a later time: now! + if (type_of(m) == CASTLING) + { + // After castling, the rook and king final positions are the same in + // Chess960 as they would be in standard chess. + to = relative_square(us, to > from ? SQ_G1 : SQ_C1); + Direction step = to > from ? WEST : EAST; + + for (Square s = to; s != from; s += step) + if (attackers_to(s) & pieces(~us)) + return false; + + // In case of Chess960, verify that when moving the castling rook we do + // not discover some hidden checker. + // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1. + return !chess960 + || !(attacks_bb(to, pieces() ^ to_sq(m)) & pieces(~us, ROOK, QUEEN)); + } + + // If the moving piece is a king, check whether the destination square is + // attacked by the opponent. if (type_of(piece_on(from)) == KING) - return type_of(m) == CASTLING || !(attackers_to(to_sq(m)) & pieces(~us)); + return !(attackers_to(to) & 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 !(blockers_for_king(us) & from) - || aligned(from, to_sq(m), square(us)); + || aligned(from, to, square(us)); } @@ -752,7 +767,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { Square rfrom, rto; do_castling(us, from, to, rfrom, rto); - st->psq += PSQT::psq[captured][rto] - PSQT::psq[captured][rfrom]; k ^= Zobrist::psq[captured][rfrom] ^ Zobrist::psq[captured][rto]; captured = NO_PIECE; } @@ -791,9 +805,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]]; prefetch(thisThread->materialTable[st->materialKey]); - // Update incremental scores - st->psq -= PSQT::psq[captured][capsq]; - // Reset rule 50 counter st->rule50 = 0; } @@ -847,9 +858,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { st->materialKey ^= Zobrist::psq[promotion][pieceCount[promotion]-1] ^ Zobrist::psq[pc][pieceCount[pc]]; - // Update incremental score - st->psq += PSQT::psq[promotion][to] - PSQT::psq[pc][to]; - // Update material st->nonPawnMaterial[us] += PieceValue[MG][promotion]; } @@ -862,9 +870,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { st->rule50 = 0; } - // Update incremental scores - st->psq += PSQT::psq[pc][to] - PSQT::psq[pc][from]; - // Set capture piece st->capturedPiece = captured; @@ -1148,12 +1153,12 @@ bool Position::has_repeated() const { StateInfo* stc = st; while (true) { - int i = 4, e = std::min(stc->rule50, stc->pliesFromNull); + int i = 4, end = std::min(stc->rule50, stc->pliesFromNull); - if (e < i) + if (end < i) return false; - StateInfo* stp = st->previous->previous; + StateInfo* stp = stc->previous->previous; do { stp = stp->previous->previous; @@ -1162,7 +1167,7 @@ bool Position::has_repeated() const { return true; i += 2; - } while (i <= e); + } while (i <= end); stc = stc->previous; } @@ -1174,7 +1179,7 @@ bool Position::has_repeated() const { bool Position::has_game_cycle(int ply) const { - unsigned int j; + int j; int end = std::min(st->rule50, st->pliesFromNull); @@ -1183,40 +1188,39 @@ bool Position::has_game_cycle(int ply) const { Key originalKey = st->key; StateInfo* stp = st->previous; - Key progressKey = stp->key ^ Zobrist::side; for (int i = 3; i <= end; i += 2) { - stp = stp->previous; - progressKey ^= stp->key ^ Zobrist::side; - stp = stp->previous; + stp = stp->previous->previous; - // "originalKey == " detects upcoming repetition, "progressKey == " detects no-progress - if ( originalKey == (progressKey ^ stp->key) - || progressKey == Zobrist::side) + Key moveKey = originalKey ^ stp->key; + if ( (j = H1(moveKey), cuckoo[j] == moveKey) + || (j = H2(moveKey), cuckoo[j] == moveKey)) { - Key moveKey = originalKey ^ stp->key; - if ( (j = H1(moveKey), cuckoo[j] == moveKey) - || (j = H2(moveKey), cuckoo[j] == moveKey)) + Move move = cuckooMove[j]; + Square s1 = from_sq(move); + Square s2 = to_sq(move); + + if (!(between_bb(s1, s2) & pieces())) { - Move m = Move(cuckooMove[j]); - if (!(between_bb(from_sq(m), to_sq(m)) & pieces())) - { - if (ply > i) - return true; + // In the cuckoo table, both moves Rc1c5 and Rc5c1 are stored in the same + // location. We select the legal one by reversing the move variable if necessary. + if (empty(s1)) + move = make_move(s2, s1); - // For repetitions before or at the root, require one more - StateInfo* next_stp = stp; - for (int k = i + 2; k <= end; k += 2) - { - next_stp = next_stp->previous->previous; - if (next_stp->key == stp->key) - return true; - } + if (ply > i) + return true; + + // For repetitions before or at the root, require one more + StateInfo* next_stp = stp; + for (int k = i + 2; k <= end; k += 2) + { + next_stp = next_stp->previous->previous; + if (next_stp->key == stp->key) + return true; } } } - progressKey ^= stp->key; } return false; }