X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=5b2efabec3181399592b564bbbaddf1758a4b064;hp=9db41b784918388f31b9f4d5a3385c043d2ae4f8;hb=805afcbf3d5db39c85b759232cfb99ab0a250311;hpb=be509525336b65419e708678abe4e16efb5f6f4d diff --git a/src/position.cpp b/src/position.cpp index 9db41b78..5b2efabe 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -2,6 +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) 2015-2016 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 @@ -23,21 +24,16 @@ #include #include -#include "bitcount.h" +#include "bitboard.h" #include "misc.h" #include "movegen.h" #include "position.h" -#include "psqtab.h" #include "thread.h" #include "tt.h" #include "uci.h" using std::string; -Value PieceValue[PHASE_NB][PIECE_NB] = { -{ VALUE_ZERO, PawnValueMg, KnightValueMg, BishopValueMg, RookValueMg, QueenValueMg }, -{ VALUE_ZERO, PawnValueEg, KnightValueEg, BishopValueEg, RookValueEg, QueenValueEg } }; - namespace Zobrist { Key psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; @@ -52,14 +48,13 @@ Key Position::exclusion_key() const { return st->key ^ Zobrist::exclusion; } namespace { const string PieceToChar(" PNBRQK pnbrqk"); -Score psq[COLOR_NB][PIECE_TYPE_NB][SQUARE_NB]; // min_attacker() is a helper function used by see() to locate the least // valuable attacker for the side to move, remove the attacker we just found // from the bitboards and scan for new X-ray attacks behind it. -template FORCE_INLINE -PieceType min_attacker(const Bitboard* bb, const Square& to, const Bitboard& stmAttackers, +template +PieceType min_attacker(const Bitboard* bb, Square to, Bitboard stmAttackers, Bitboard& occupied, Bitboard& attackers) { Bitboard b = stmAttackers & bb[Pt]; @@ -78,33 +73,14 @@ PieceType min_attacker(const Bitboard* bb, const Square& to, const Bitboard& stm return (PieceType)Pt; } -template<> FORCE_INLINE -PieceType min_attacker(const Bitboard*, const Square&, const Bitboard&, Bitboard&, Bitboard&) { +template<> +PieceType min_attacker(const Bitboard*, Square, Bitboard, Bitboard&, Bitboard&) { return KING; // No need to update bitboards: it is the last cycle } } // namespace -/// CheckInfo c'tor - -CheckInfo::CheckInfo(const Position& pos) { - - Color them = ~pos.side_to_move(); - ksq = pos.king_square(them); - - pinned = pos.pinned_pieces(pos.side_to_move()); - 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] = 0; -} - - /// operator<<(Position) returns an ASCII representation of the position std::ostream& operator<<(std::ostream& os, const Position& pos) { @@ -120,7 +96,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { } os << "\nFen: " << pos.fen() << "\nKey: " << std::hex << std::uppercase - << std::setfill('0') << std::setw(16) << pos.st->key << std::dec << "\nCheckers: "; + << std::setfill('0') << std::setw(16) << pos.key() << std::dec << "\nCheckers: "; for (Bitboard b = pos.checkers(); b; ) os << UCI::square(pop_lsb(&b)) << " "; @@ -130,10 +106,7 @@ std::ostream& operator<<(std::ostream& os, const Position& pos) { /// Position::init() initializes at startup the various arrays used to compute -/// hash keys and the piece square tables. The latter is a two-step operation: -/// Firstly, the white halves of the tables are copied from PSQT[] tables. -/// Secondly, the black halves of the tables are initialized by flipping and -/// changing the sign of the white scores. +/// hash keys. void Position::init() { @@ -149,6 +122,7 @@ void Position::init() { for (int cr = NO_CASTLING; cr <= ANY_CASTLING; ++cr) { + Zobrist::castling[cr] = 0; Bitboard b = cr; while (b) { @@ -159,51 +133,6 @@ void Position::init() { Zobrist::side = rng.rand(); Zobrist::exclusion = rng.rand(); - - for (PieceType pt = PAWN; pt <= KING; ++pt) - { - PieceValue[MG][make_piece(BLACK, pt)] = PieceValue[MG][pt]; - PieceValue[EG][make_piece(BLACK, pt)] = PieceValue[EG][pt]; - - Score v = make_score(PieceValue[MG][pt], PieceValue[EG][pt]); - - for (Square s = SQ_A1; s <= SQ_H8; ++s) - { - psq[WHITE][pt][ s] = (v + PSQT[pt][s]); - psq[BLACK][pt][~s] = -(v + PSQT[pt][s]); - } - } -} - - -/// Position::operator=() creates a copy of 'pos' but detaching the state pointer -/// from the source to be self-consistent and not depending on any external data. - -Position& Position::operator=(const Position& pos) { - - std::memcpy(this, &pos, sizeof(Position)); - std::memcpy(&startState, st, sizeof(StateInfo)); - st = &startState; - nodes = 0; - - assert(pos_is_ok()); - - return *this; -} - - -/// Position::clear() erases the position object to a pristine state, with an -/// empty board, white to move, and no castling rights. - -void Position::clear() { - - std::memset(this, 0, sizeof(Position)); - startState.epSquare = SQ_NONE; - st = &startState; - - for (int i = 0; i < PIECE_TYPE_NB; ++i) - for (int j = 0; j < 16; ++j) - pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE; } @@ -211,7 +140,7 @@ void Position::clear() { /// 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::set(const string& fenStr, bool isChess960, Thread* th) { +Position& Position::set(const string& fenStr, bool isChess960, StateInfo* si, Thread* th) { /* A FEN string defines a particular position using only the ASCII character set. @@ -251,7 +180,11 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { Square sq = SQ_A8; std::istringstream ss(fenStr); - clear(); + std::memset(this, 0, sizeof(Position)); + std::memset(si, 0, sizeof(StateInfo)); + std::fill_n(&pieceList[0][0][0], sizeof(pieceList) / sizeof(Square), SQ_NONE); + st = si; + ss >> std::noskipws; // 1. Piece placement @@ -284,14 +217,15 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { { Square rsq; Color c = islower(token) ? BLACK : WHITE; + Piece rook = make_piece(c, ROOK); token = char(toupper(token)); if (token == 'K') - for (rsq = relative_square(c, SQ_H1); type_of(piece_on(rsq)) != ROOK; --rsq) {} + for (rsq = relative_square(c, SQ_H1); piece_on(rsq) != rook; --rsq) {} else if (token == 'Q') - for (rsq = relative_square(c, SQ_A1); type_of(piece_on(rsq)) != ROOK; ++rsq) {} + for (rsq = relative_square(c, SQ_A1); piece_on(rsq) != rook; ++rsq) {} else if (token >= 'A' && token <= 'H') rsq = make_square(File(token - 'A'), relative_rank(c, RANK_1)); @@ -311,6 +245,8 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { if (!(attackers_to(st->epSquare) & pieces(sideToMove, PAWN))) st->epSquare = SQ_NONE; } + else + st->epSquare = SQ_NONE; // 5-6. Halfmove clock and fullmove number ss >> std::skipws >> st->rule50 >> gamePly; @@ -324,6 +260,8 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { set_state(st); assert(pos_is_ok()); + + return *this; } @@ -332,7 +270,7 @@ void Position::set(const string& fenStr, bool isChess960, Thread* th) { void Position::set_castling_right(Color c, Square rfrom) { - Square kfrom = king_square(c); + Square kfrom = square(c); CastlingSide cs = kfrom < rfrom ? KING_SIDE : QUEEN_SIDE; CastlingRight cr = (c | cs); @@ -354,6 +292,24 @@ void Position::set_castling_right(Color c, Square rfrom) { } +/// Position::set_check_info() sets king attacks to detect if a move gives check + +void Position::set_check_info(CheckInfo* ci) const { + + ci->blockersForKing[WHITE] = slider_blockers(pieces(BLACK), square(WHITE)); + ci->blockersForKing[BLACK] = slider_blockers(pieces(WHITE), square(BLACK)); + + Square ksq = ci->ksq = square(~sideToMove); + + ci->checkSquares[PAWN] = attacks_from(ksq, ~sideToMove); + ci->checkSquares[KNIGHT] = attacks_from(ksq); + ci->checkSquares[BISHOP] = attacks_from(ksq); + ci->checkSquares[ROOK] = attacks_from(ksq); + ci->checkSquares[QUEEN] = ci->checkSquares[BISHOP] | ci->checkSquares[ROOK]; + ci->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 @@ -364,15 +320,16 @@ void Position::set_state(StateInfo* si) const { si->key = si->pawnKey = si->materialKey = 0; si->nonPawnMaterial[WHITE] = si->nonPawnMaterial[BLACK] = VALUE_ZERO; si->psq = SCORE_ZERO; + si->checkersBB = attackers_to(square(sideToMove)) & pieces(~sideToMove); - si->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove); + set_check_info(&si->ci); for (Bitboard b = pieces(); b; ) { Square s = pop_lsb(&b); Piece pc = piece_on(s); si->key ^= Zobrist::psq[color_of(pc)][type_of(pc)][s]; - si->psq += psq[color_of(pc)][type_of(pc)][s]; + si->psq += PSQT::psq[color_of(pc)][type_of(pc)][s]; } if (si->epSquare != SQ_NONE) @@ -463,28 +420,27 @@ Phase Position::game_phase() const { } -/// Position::check_blockers() returns a bitboard of all the pieces with color -/// 'c' that are blocking check on the king with color 'kingColor'. A piece -/// blocks a check if removing that piece from the board would result in a -/// position where the king is in check. A check blocking piece can be either a -/// pinned or a discovered check piece, according if its color 'c' is the same -/// or the opposite of 'kingColor'. +/// Position::slider_blockers() returns a bitboard of all the pieces (both colors) that +/// are blocking attacks on the square 's' from 'sliders'. A piece blocks a slider +/// if removing that piece from the board would result in a position where square 's' +/// is attacked. For example, a king-attack blocking piece can be either a pinned or +/// a discovered check piece, according if its color is the opposite or the same of +/// the color of the slider. -Bitboard Position::check_blockers(Color c, Color kingColor) const { +Bitboard Position::slider_blockers(Bitboard sliders, Square s) const { Bitboard b, pinners, result = 0; - Square ksq = king_square(kingColor); - // Pinners are sliders that give check when a pinned piece is removed - pinners = ( (pieces( ROOK, QUEEN) & PseudoAttacks[ROOK ][ksq]) - | (pieces(BISHOP, QUEEN) & PseudoAttacks[BISHOP][ksq])) & pieces(~kingColor); + // Pinners are sliders that attack 's' when a pinned piece is removed + pinners = ( (PseudoAttacks[ROOK ][s] & pieces(QUEEN, ROOK)) + | (PseudoAttacks[BISHOP][s] & pieces(QUEEN, BISHOP))) & sliders; while (pinners) { - b = between_bb(ksq, pop_lsb(&pinners)) & pieces(); + b = between_bb(s, pop_lsb(&pinners)) & pieces(); if (!more_than_one(b)) - result |= b & pieces(c); + result |= b; } return result; } @@ -506,23 +462,22 @@ Bitboard Position::attackers_to(Square s, Bitboard occupied) const { /// Position::legal() tests whether a pseudo-legal move is legal -bool Position::legal(Move m, Bitboard pinned) const { +bool Position::legal(Move m) const { assert(is_ok(m)); - assert(pinned == pinned_pieces(sideToMove)); Color us = sideToMove; Square from = from_sq(m); assert(color_of(moved_piece(m)) == us); - assert(piece_on(king_square(us)) == make_piece(us, KING)); + assert(piece_on(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 (type_of(m) == ENPASSANT) { - Square ksq = king_square(us); + Square ksq = square(us); Square to = to_sq(m); Square capsq = to - pawn_push(us); Bitboard occupied = (pieces() ^ from ^ capsq) | to; @@ -544,9 +499,8 @@ bool Position::legal(Move m, Bitboard pinned) const { // 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 - || !(pinned & from) - || aligned(from, to_sq(m), king_square(us)); + return !(pinned_pieces(us) & from) + || aligned(from, to_sq(m), square(us)); } @@ -609,7 +563,7 @@ bool Position::pseudo_legal(const Move m) const { return false; // Our move must be a blocking evasion or a capture of the checking piece - if (!((between_bb(lsb(checkers()), king_square(us)) | checkers()) & to)) + if (!((between_bb(lsb(checkers()), square(us)) | checkers()) & to)) return false; } // In case of king moves under check we have to remove king so as to catch @@ -624,23 +578,21 @@ bool Position::pseudo_legal(const Move m) const { /// Position::gives_check() tests whether a pseudo-legal move gives a check -bool Position::gives_check(Move m, const CheckInfo& ci) const { +bool Position::gives_check(Move m) const { assert(is_ok(m)); - assert(ci.dcCandidates == discovered_check_candidates()); assert(color_of(moved_piece(m)) == sideToMove); Square from = from_sq(m); Square to = to_sq(m); // Is there a direct check? - if (ci.checkSq[type_of(piece_on(from))] & to) + if (st->ci.checkSquares[type_of(piece_on(from))] & to) return true; // Is there a discovered check? - if ( ci.dcCandidates - && (ci.dcCandidates & from) - && !aligned(from, to, ci.ksq)) + if ( (discovered_check_candidates() & from) + && !aligned(from, to, st->ci.ksq)) return true; switch (type_of(m)) @@ -649,7 +601,7 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { return false; case PROMOTION: - return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & ci.ksq; + return attacks_bb(Piece(promotion_type(m)), to, pieces() ^ from) & st->ci.ksq; // En passant capture with check? We have already handled the case // of direct checks and ordinary discovered check, so the only case we @@ -660,8 +612,8 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { Square capsq = make_square(file_of(to), rank_of(from)); Bitboard b = (pieces() ^ from ^ capsq) | to; - return (attacks_bb< ROOK>(ci.ksq, b) & pieces(sideToMove, QUEEN, ROOK)) - | (attacks_bb(ci.ksq, b) & pieces(sideToMove, QUEEN, BISHOP)); + return (attacks_bb< ROOK>(st->ci.ksq, b) & pieces(sideToMove, QUEEN, ROOK)) + | (attacks_bb(st->ci.ksq, b) & pieces(sideToMove, QUEEN, BISHOP)); } case CASTLING: { @@ -670,8 +622,8 @@ bool Position::gives_check(Move m, const CheckInfo& ci) const { Square kto = relative_square(sideToMove, rfrom > kfrom ? SQ_G1 : SQ_C1); Square rto = relative_square(sideToMove, rfrom > kfrom ? SQ_F1 : SQ_D1); - return (PseudoAttacks[ROOK][rto] & ci.ksq) - && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & ci.ksq); + return (PseudoAttacks[ROOK][rto] & st->ci.ksq) + && (attacks_bb(rto, (pieces() ^ kfrom ^ rfrom) | rto | kto) & st->ci.ksq); } default: assert(false); @@ -724,7 +676,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { do_castling(us, from, to, rfrom, rto); captured = NO_PIECE_TYPE; - st->psq += psq[us][ROOK][rto] - psq[us][ROOK][rfrom]; + st->psq += PSQT::psq[us][ROOK][rto] - PSQT::psq[us][ROOK][rfrom]; k ^= Zobrist::psq[us][ROOK][rfrom] ^ Zobrist::psq[us][ROOK][rto]; } @@ -763,7 +715,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { prefetch(thisThread->materialTable[st->materialKey]); // Update incremental scores - st->psq -= psq[them][captured][capsq]; + st->psq -= PSQT::psq[them][captured][capsq]; // Reset rule 50 counter st->rule50 = 0; @@ -819,7 +771,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { ^ Zobrist::psq[us][PAWN][pieceCount[us][PAWN]]; // Update incremental score - st->psq += psq[us][promotion][to] - psq[us][PAWN][to]; + st->psq += PSQT::psq[us][promotion][to] - PSQT::psq[us][PAWN][to]; // Update material st->nonPawnMaterial[us] += PieceValue[MG][promotion]; @@ -834,7 +786,7 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { } // Update incremental scores - st->psq += psq[us][pt][to] - psq[us][pt][from]; + st->psq += PSQT::psq[us][pt][to] - PSQT::psq[us][pt][from]; // Set capture piece st->capturedType = captured; @@ -843,10 +795,13 @@ void Position::do_move(Move m, StateInfo& newSt, bool givesCheck) { st->key = k; // Calculate checkers bitboard (if move gives check) - st->checkersBB = givesCheck ? attackers_to(king_square(them)) & pieces(us) : 0; + st->checkersBB = givesCheck ? attackers_to(square(them)) & pieces(us) : 0; sideToMove = ~sideToMove; + // Update CheckInfo + set_check_info(&st->ci); + assert(pos_is_ok()); } @@ -960,6 +915,8 @@ void Position::do_null_move(StateInfo& newSt) { sideToMove = ~sideToMove; + set_check_info(&st->ci); + assert(pos_is_ok()); } @@ -1078,8 +1035,8 @@ Value Position::see(Move m) const { } -/// Position::is_draw() tests whether the position is drawn by material, 50 moves -/// rule or repetition. It does not detect stalemates. +/// Position::is_draw() tests whether the position is drawn by 50-move rule +/// or by repetition. It does not detect stalemates. bool Position::is_draw() const { @@ -1128,7 +1085,7 @@ void Position::flip() { std::getline(ss, token); // Half and full moves f += token; - set(f, is_chess960(), this_thread()); + set(f, is_chess960(), st, this_thread()); assert(pos_is_ok()); } @@ -1150,8 +1107,8 @@ bool Position::pos_is_ok(int* failedStep) const { if (step == Default) if ( (sideToMove != WHITE && sideToMove != BLACK) - || piece_on(king_square(WHITE)) != W_KING - || piece_on(king_square(BLACK)) != B_KING + || piece_on(square(WHITE)) != W_KING + || piece_on(square(BLACK)) != B_KING || ( ep_square() != SQ_NONE && relative_rank(sideToMove, ep_square()) != RANK_6)) return false; @@ -1159,7 +1116,7 @@ bool Position::pos_is_ok(int* failedStep) const { if (step == King) if ( std::count(board, board + SQUARE_NB, W_KING) != 1 || std::count(board, board + SQUARE_NB, B_KING) != 1 - || attackers_to(king_square(~sideToMove)) & pieces(sideToMove)) + || attackers_to(square(~sideToMove)) & pieces(sideToMove)) return false; if (step == Bitboards) @@ -1186,7 +1143,7 @@ bool Position::pos_is_ok(int* failedStep) const { for (Color c = WHITE; c <= BLACK; ++c) for (PieceType pt = PAWN; pt <= KING; ++pt) { - if (pieceCount[c][pt] != popcount(pieces(c, pt))) + if (pieceCount[c][pt] != popcount(pieces(c, pt))) return false; for (int i = 0; i < pieceCount[c][pt]; ++i) @@ -1204,7 +1161,7 @@ bool Position::pos_is_ok(int* failedStep) const { if ( piece_on(castlingRookSquare[c | s]) != make_piece(c, ROOK) || castlingRightsMask[castlingRookSquare[c | s]] != (c | s) - ||(castlingRightsMask[king_square(c)] & (c | s)) != (c | s)) + ||(castlingRightsMask[square(c)] & (c | s)) != (c | s)) return false; } }