X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fposition.cpp;h=af274d3f2c64183e61eaa163a121112082b8ede1;hb=5930c0defbe01576315d7d081447f94a01daf337;hp=17b165b9afb6f9a4115afc03d0762e98076993b4;hpb=7ffae17f85709e49672a0e98e136b66aea067b2c;p=stockfish diff --git a/src/position.cpp b/src/position.cpp index 17b165b9..af274d3f 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -1,6 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2021 The Stockfish developers (see AUTHORS file) + Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file) 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 // For std::memset, std::memcmp #include #include +#include #include "bitboard.h" #include "misc.h" @@ -46,7 +47,7 @@ namespace Zobrist { namespace { -const string PieceToChar(" PNBRQK pnbrqk"); +constexpr std::string_view PieceToChar(" PNBRQK pnbrqk"); constexpr Piece Pieces[] = { W_PAWN, W_KNIGHT, W_BISHOP, W_ROOK, W_QUEEN, W_KING, B_PAWN, B_KNIGHT, B_BISHOP, B_ROOK, B_QUEEN, B_KING }; @@ -73,13 +74,13 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { << std::setfill(' ') << std::dec << "\nCheckers: "; for (Bitboard b = pos.checkers(); b; ) - os << UCI::square(pop_lsb(&b)) << " "; + os << UCI::square(pop_lsb(b)) << " "; if ( int(Tablebases::MaxCardinality) >= popcount(pos.pieces()) && !pos.can_castle(ANY_CASTLING)) { StateInfo st; - ASSERT_ALIGNED(&st, Eval::NNUE::kCacheLineSize); + ASSERT_ALIGNED(&st, Eval::NNUE::CacheLineSize); Position p; p.set(pos.fen(), pos.is_chess960(), &st, pos.this_thread()); @@ -96,7 +97,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { // 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 +// http://web.archive.org/web/20201107002606/https://marcelk.net/2013-04-06/paper/upcoming-rep-v2.pdf // First and second hash functions for indexing the cuckoo tables inline int H1(Key h) { return h & 0x1fff; } @@ -129,7 +130,7 @@ void Position::init() { // Prepare the cuckoo tables std::memset(cuckoo, 0, sizeof(cuckoo)); std::memset(cuckooMove, 0, sizeof(cuckooMove)); - int count = 0; + [[maybe_unused]] int count = 0; for (Piece pc : Pieces) for (Square s1 = SQ_A1; s1 <= SQ_H8; ++s1) for (Square s2 = Square(s1 + 1); s2 <= SQ_H8; ++s2) @@ -251,8 +252,6 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th set_castling_right(c, rsq); } - set_state(st); - // 4. En passant square. // Ignore if square is invalid or not on side to move relative rank 6. bool enpassant = false; @@ -266,24 +265,12 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th // a) side to move have a pawn threatening epSquare // b) there is an enemy pawn in front of epSquare // c) there is no piece on epSquare or behind epSquare - // d) enemy pawn didn't block a check of its own color by moving forward enpassant = pawn_attacks_bb(~sideToMove, st->epSquare) & pieces(sideToMove, PAWN) && (pieces(~sideToMove, PAWN) & (st->epSquare + pawn_push(~sideToMove))) - && !(pieces() & (st->epSquare | (st->epSquare + pawn_push(sideToMove)))) - && ( file_of(square(sideToMove)) == file_of(st->epSquare) - || !(blockers_for_king(sideToMove) & (st->epSquare + pawn_push(~sideToMove)))); + && !(pieces() & (st->epSquare | (st->epSquare + pawn_push(sideToMove)))); } - // It's necessary for st->previous to be intialized in this way because legality check relies on its existence - if (enpassant) { - st->previous = new StateInfo(); - remove_piece(st->epSquare - pawn_push(sideToMove)); - st->previous->checkersBB = attackers_to(square(~sideToMove)) & pieces(sideToMove); - st->previous->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE), st->previous->pinners[BLACK]); - st->previous->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK), st->previous->pinners[WHITE]); - put_piece(make_piece(~sideToMove, PAWN), st->epSquare - pawn_push(sideToMove)); - } - else + if (!enpassant) st->epSquare = SQ_NONE; // 5-6. Halfmove clock and fullmove number @@ -295,8 +282,7 @@ Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Th chess960 = isChess960; thisThread = th; - st->accumulator.state[WHITE] = Eval::NNUE::INIT; - st->accumulator.state[BLACK] = Eval::NNUE::INIT; + set_state(); assert(pos_is_ok()); @@ -320,67 +306,66 @@ void Position::set_castling_right(Color c, Square rfrom) { Square kto = relative_square(c, cr & KING_SIDE ? SQ_G1 : SQ_C1); Square rto = relative_square(c, cr & KING_SIDE ? SQ_F1 : SQ_D1); - castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto) | rto | kto) + castlingPath[cr] = (between_bb(rfrom, rto) | between_bb(kfrom, kto)) & ~(kfrom | rfrom); } /// Position::set_check_info() sets king attacks to detect if a move gives check -void Position::set_check_info(StateInfo* si) const { +void Position::set_check_info() const { - si->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE), si->pinners[BLACK]); - si->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK), si->pinners[WHITE]); + st->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE), st->pinners[BLACK]); + st->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK), st->pinners[WHITE]); Square ksq = square(~sideToMove); - si->checkSquares[PAWN] = pawn_attacks_bb(~sideToMove, ksq); - si->checkSquares[KNIGHT] = attacks_bb(ksq); - si->checkSquares[BISHOP] = attacks_bb(ksq, pieces()); - si->checkSquares[ROOK] = attacks_bb(ksq, pieces()); - si->checkSquares[QUEEN] = si->checkSquares[BISHOP] | si->checkSquares[ROOK]; - si->checkSquares[KING] = 0; + st->checkSquares[PAWN] = pawn_attacks_bb(~sideToMove, ksq); + st->checkSquares[KNIGHT] = attacks_bb(ksq); + st->checkSquares[BISHOP] = attacks_bb(ksq, pieces()); + st->checkSquares[ROOK] = attacks_bb(ksq, pieces()); + st->checkSquares[QUEEN] = st->checkSquares[BISHOP] | st->checkSquares[ROOK]; + st->checkSquares[KING] = 0; } /// Position::set_state() computes the hash keys of the position, and other /// data that once computed is updated incrementally as moves are made. -/// The function is only used when a new position is set up, and to verify -/// the correctness of the StateInfo data when running in debug mode. +/// The function is only used when a new position is set up -void Position::set_state(StateInfo* si) const { +void Position::set_state() const { - si->key = si->materialKey = 0; - si->pawnKey = Zobrist::noPawns; - si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO; - si->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); + st->key = st->materialKey = 0; + st->pawnKey = Zobrist::noPawns; + st->nonPawnMaterial[WHITE] = st->nonPawnMaterial[BLACK] = VALUE_ZERO; + st->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); - set_check_info(si); + set_check_info(); for (Bitboard b = pieces(); b; ) { - Square s = pop_lsb(&b); + Square s = pop_lsb(b); Piece pc = piece_on(s); - si->key ^= Zobrist::psq[pc][s]; + st->key ^= Zobrist::psq[pc][s]; if (type_of(pc) == PAWN) - si->pawnKey ^= Zobrist::psq[pc][s]; + st->pawnKey ^= Zobrist::psq[pc][s]; else if (type_of(pc) != KING) - si->nonPawnMaterial[color_of(pc)] += PieceValue[MG][pc]; + st->nonPawnMaterial[color_of(pc)] += PieceValue[MG][pc]; } - if (si->epSquare != SQ_NONE) - si->key ^= Zobrist::enpassant[file_of(si->epSquare)]; + if (st->epSquare != SQ_NONE) + st->key ^= Zobrist::enpassant[file_of(st->epSquare)]; if (sideToMove == BLACK) - si->key ^= Zobrist::side; + st->key ^= Zobrist::side; - si->key ^= Zobrist::castling[si->castlingRights]; + st->key ^= Zobrist::castling[st->castlingRights]; for (Piece pc : Pieces) for (int cnt = 0; cnt < pieceCount[pc]; ++cnt) - si->materialKey ^= Zobrist::psq[pc][cnt]; + st->materialKey ^= Zobrist::psq[pc][cnt]; } @@ -476,7 +461,7 @@ Bitboard Position::slider_blockers(Bitboard sliders, Square s, Bitboard& pinners while (snipers) { - Square sniperSq = pop_lsb(&snipers); + Square sniperSq = pop_lsb(snipers); Bitboard b = between_bb(s, sniperSq) & occupancy; if (b && !more_than_one(b)) @@ -517,11 +502,23 @@ bool Position::legal(Move m) const { assert(color_of(moved_piece(m)) == us); assert(piece_on(square(us)) == make_piece(us, KING)); - // st->previous->blockersForKing consider capsq as empty. - // If pinned, it has to move along the king ray. + // 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 (type_of(m) == EN_PASSANT) - return !(st->previous->blockersForKing[sideToMove] & from) - || aligned(from, to, square(us)); + { + Square ksq = square(us); + Square capsq = to - pawn_push(us); + Bitboard occupied = (pieces() ^ from ^ capsq) | to; + + assert(to == ep_square()); + assert(moved_piece(m) == make_piece(us, PAWN)); + assert(piece_on(capsq) == make_piece(~us, PAWN)); + assert(piece_on(to) == NO_PIECE); + + return !(attacks_bb< ROOK>(ksq, occupied) & pieces(~us, QUEEN, ROOK)) + && !(attacks_bb(ksq, occupied) & pieces(~us, QUEEN, BISHOP)); + } // Castling moves generation does not check if the castling path is clear of // enemy attacks, it is delayed at a later time: now! @@ -544,7 +541,7 @@ bool Position::legal(Move m) const { // 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 !(attackers_to(to) & pieces(~us)); + return !(attackers_to(to, pieces() ^ from) & 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. @@ -571,8 +568,7 @@ bool Position::pseudo_legal(const Move m) const { : MoveList(*this).contains(m); // Is not a promotion, so promotion piece must be empty - if (promotion_type(m) - KNIGHT != NO_PIECE_TYPE) - return false; + assert(promotion_type(m) - KNIGHT == NO_PIECE_TYPE); // If the 'from' square is not occupied by a piece belonging to the side to // move, the move is obviously not legal. @@ -613,8 +609,8 @@ bool Position::pseudo_legal(const Move m) const { if (more_than_one(checkers())) return false; - // Our move must be a blocking evasion or a capture of the checking piece - if (!((between_bb(lsb(checkers()), square(us)) | checkers()) & to)) + // Our move must be a blocking interposition or a capture of the checking piece + if (!(between_bb(square(us), lsb(checkers())) & to)) return false; } // In case of king moves under check we have to remove king so as to catch @@ -654,15 +650,18 @@ bool Position::gives_check(Move m) const { case PROMOTION: return attacks_bb(promotion_type(m), to, pieces() ^ from) & square(~sideToMove); - // The double-pushed pawn blocked a check? En Passant will remove the blocker. - // The only discovery check that wasn't handle is through capsq and fromsq - // So the King must be in the same rank as fromsq to consider this possibility. - // st->previous->blockersForKing consider capsq as empty. + // En passant capture with check? We have already handled the case + // of direct checks and ordinary discovered check, so the only case we + // need to handle is the unusual case of a discovered check through + // the captured pawn. case EN_PASSANT: - return st->previous->checkersBB - || ( rank_of(square(~sideToMove)) == rank_of(from) - && st->previous->blockersForKing[~sideToMove] & from); + { + Square capsq = make_square(file_of(to), rank_of(from)); + Bitboard b = (pieces() ^ from ^ capsq) | to; + return (attacks_bb< ROOK>(square(~sideToMove), b) & pieces(sideToMove, QUEEN, ROOK)) + | (attacks_bb(square(~sideToMove), b) & pieces(sideToMove, QUEEN, BISHOP)); + } default: //CASTLING { // Castling is encoded as 'king captures the rook' @@ -702,8 +701,8 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { ++st->pliesFromNull; // Used by NNUE - st->accumulator.state[WHITE] = Eval::NNUE::EMPTY; - st->accumulator.state[BLACK] = Eval::NNUE::EMPTY; + st->accumulator.computed[WHITE] = false; + st->accumulator.computed[BLACK] = false; auto& dp = st->dirtyPiece; dp.dirty_num = 1; @@ -765,9 +764,6 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { // Update board and piece lists remove_piece(capsq); - if (type_of(m) == EN_PASSANT) - board[capsq] = NO_PIECE; - // Update material hash key and prefetch access to materialTable k ^= Zobrist::psq[captured][capsq]; st->materialKey ^= Zobrist::psq[captured][pieceCount[captured]]; @@ -868,7 +864,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { sideToMove = ~sideToMove; // Update king attacks used for fast check detection - set_check_info(st); + set_check_info(); // Calculate the repetition info. It is the ply distance from the previous // occurrence of the same position, negative in the 3-fold case, or zero @@ -988,7 +984,7 @@ void Position::do_castling(Color us, Square from, Square& to, Square& rfrom, Squ } -/// Position::do(undo)_null_move() is used to do(undo) a "null move": it flips +/// Position::do_null_move() is used to do a "null move": it flips /// the side to move without executing any move on the board. void Position::do_null_move(StateInfo& newSt) { @@ -1003,8 +999,8 @@ void Position::do_null_move(StateInfo& newSt) { st->dirtyPiece.dirty_num = 0; st->dirtyPiece.piece[0] = NO_PIECE; // Avoid checks in UpdateAccumulator() - st->accumulator.state[WHITE] = Eval::NNUE::EMPTY; - st->accumulator.state[BLACK] = Eval::NNUE::EMPTY; + st->accumulator.computed[WHITE] = false; + st->accumulator.computed[BLACK] = false; if (st->epSquare != SQ_NONE) { @@ -1013,20 +1009,23 @@ void Position::do_null_move(StateInfo& newSt) { } st->key ^= Zobrist::side; + ++st->rule50; prefetch(TT.first_entry(key())); - ++st->rule50; st->pliesFromNull = 0; sideToMove = ~sideToMove; - set_check_info(st); + set_check_info(); st->repetition = 0; assert(pos_is_ok()); } + +/// Position::undo_null_move() must be used to undo a "null move" + void Position::undo_null_move() { assert(!checkers()); @@ -1051,7 +1050,10 @@ Key Position::key_after(Move m) const { if (captured) k ^= Zobrist::psq[captured][to]; - return k ^ Zobrist::psq[pc][to] ^ Zobrist::psq[pc][from]; + k ^= Zobrist::psq[pc][to] ^ Zobrist::psq[pc][from]; + + return (captured || type_of(pc) == PAWN) + ? k : adjust_key50(k); } @@ -1077,8 +1079,9 @@ bool Position::see_ge(Move m, Value threshold) const { if (swap <= 0) return true; - Bitboard occupied = pieces() ^ from ^ to; - Color stm = color_of(piece_on(from)); + assert(color_of(piece_on(from)) == sideToMove); + Bitboard occupied = pieces() ^ from ^ to; // xoring to is important for pinned piece logic + Color stm = sideToMove; Bitboard attackers = attackers_to(to, occupied); Bitboard stmAttackers, bb; int res = 1; @@ -1092,13 +1095,15 @@ bool Position::see_ge(Move m, Value threshold) const { if (!(stmAttackers = attackers & pieces(stm))) break; - // Don't allow pinned pieces to attack (except the king) as long as - // there are pinners on their original square. + // Don't allow pinned pieces to attack as long as there are + // pinners on their original square. if (pinners(~stm) & occupied) + { stmAttackers &= ~blockers_for_king(stm); - if (!stmAttackers) - break; + if (!stmAttackers) + break; + } res ^= 1; @@ -1108,8 +1113,8 @@ bool Position::see_ge(Move m, Value threshold) const { { if ((swap = PawnValueMg - swap) < res) break; + occupied ^= least_significant_square_bb(bb); - occupied ^= lsb(bb); attackers |= attacks_bb(to, occupied) & pieces(BISHOP, QUEEN); } @@ -1117,16 +1122,15 @@ bool Position::see_ge(Move m, Value threshold) const { { if ((swap = KnightValueMg - swap) < res) break; - - occupied ^= lsb(bb); + occupied ^= least_significant_square_bb(bb); } else if ((bb = stmAttackers & pieces(BISHOP))) { if ((swap = BishopValueMg - swap) < res) break; + occupied ^= least_significant_square_bb(bb); - occupied ^= lsb(bb); attackers |= attacks_bb(to, occupied) & pieces(BISHOP, QUEEN); } @@ -1134,8 +1138,8 @@ bool Position::see_ge(Move m, Value threshold) const { { if ((swap = RookValueMg - swap) < res) break; + occupied ^= least_significant_square_bb(bb); - occupied ^= lsb(bb); attackers |= attacks_bb(to, occupied) & pieces(ROOK, QUEEN); } @@ -1143,8 +1147,8 @@ bool Position::see_ge(Move m, Value threshold) const { { if ((swap = QueenValueMg - swap) < res) break; + occupied ^= least_significant_square_bb(bb); - occupied ^= lsb(bb); attackers |= (attacks_bb(to, occupied) & pieces(BISHOP, QUEEN)) | (attacks_bb(to, occupied) & pieces(ROOK , QUEEN)); } @@ -1218,7 +1222,7 @@ bool Position::has_game_cycle(int ply) const { Square s1 = from_sq(move); Square s2 = to_sq(move); - if (!(between_bb(s1, s2) & pieces())) + if (!((between_bb(s1, s2) ^ s2) & pieces())) { if (ply > i) return true; @@ -1314,12 +1318,6 @@ bool Position::pos_is_ok() const { if (p1 != p2 && (pieces(p1) & pieces(p2))) assert(0 && "pos_is_ok: Bitboards"); - StateInfo si = *st; - ASSERT_ALIGNED(&si, Eval::NNUE::kCacheLineSize); - - set_state(&si); - if (std::memcmp(&si, st, sizeof(StateInfo))) - assert(0 && "pos_is_ok: State"); for (Piece pc : Pieces) if ( pieceCount[pc] != popcount(pieces(color_of(pc), type_of(pc)))