X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=366d61f309ed9706b0bec3d3af5797b9b8fdf48f;hp=4a0075cb841845bff231bd8a8091404b16ea7b5e;hb=f7f09b91ea9e915c2c75582c7fffd760e454e99f;hpb=12461996a5bb6d4c07d4b7e464924eaaa406b01d diff --git a/src/position.cpp b/src/position.cpp index 4a0075cb..366d61f3 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -52,17 +52,29 @@ Key Position::zobCastle[16]; Key Position::zobMaterial[2][8][16]; Key Position::zobSideToMove; -Value Position::MgPieceSquareTable[16][64]; -Value Position::EgPieceSquareTable[16][64]; +Score Position::PieceSquareTable[16][64]; static bool RequestPending = false; -//// -//// Functions -//// /// Constructors +CheckInfo::CheckInfo(const Position& pos) { + + Color us = pos.side_to_move(); + Color them = opposite_color(us); + + ksq = pos.king_square(them); + dcCandidates = pos.discovered_check_candidates(us); + + 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; +} + Position::Position(const Position& pos) { copy(pos); } @@ -213,8 +225,7 @@ void Position::from_fen(const string& fen) { st->key = compute_key(); st->pawnKey = compute_pawn_key(); st->materialKey = compute_material_key(); - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); st->npMaterial[BLACK] = compute_non_pawn_material(BLACK); } @@ -458,19 +469,11 @@ void Position::find_checkers() { /// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal -bool Position::pl_move_is_legal(Move m) const { - - // If we're in check, all pseudo-legal moves are legal, because our - // check evasion generator only generates true legal moves. - return is_check() || pl_move_is_legal(m, pinned_pieces(side_to_move())); -} - 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_check()); // Castling moves are checked for legality during move generation. if (move_is_castle(m)) @@ -482,7 +485,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { assert(color_of_piece_on(from) == us); assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING)); - // En passant captures are a tricky special case. Because they are + // 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)) @@ -519,130 +522,127 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { } +/// Position::pl_move_is_evasion() tests whether a pseudo-legal move is a legal evasion + +bool Position::pl_move_is_evasion(Move m, Bitboard pinned) const +{ + assert(is_check()); + + Color us = side_to_move(); + Square from = move_from(m); + Square to = move_to(m); + + // King moves and en-passant captures are verified in pl_move_is_legal() + if (type_of_piece_on(from) == KING || move_is_ep(m)) + return pl_move_is_legal(m, pinned); + + Bitboard target = checkers(); + Square checksq = pop_1st_bit(&target); + + if (target) // double check ? + return false; + + // Our move must be a blocking evasion or a capture of the checking piece + target = squares_between(checksq, king_square(us)) | checkers(); + return bit_is_set(target, to) && pl_move_is_legal(m, pinned); +} + + /// Position::move_is_check() tests whether a pseudo-legal move is a check bool Position::move_is_check(Move m) const { - Bitboard dc = discovered_check_candidates(side_to_move()); - return move_is_check(m, dc); + return move_is_check(m, CheckInfo(*this)); } -bool Position::move_is_check(Move m, Bitboard dcCandidates) const { +bool Position::move_is_check(Move m, const CheckInfo& ci) const { assert(is_ok()); assert(move_is_ok(m)); - assert(dcCandidates == discovered_check_candidates(side_to_move())); + assert(ci.dcCandidates == discovered_check_candidates(side_to_move())); + assert(color_of_piece_on(move_from(m)) == side_to_move()); + assert(piece_on(ci.ksq) == piece_of_color_and_type(opposite_color(side_to_move()), KING)); - Color us = side_to_move(); - Color them = opposite_color(us); Square from = move_from(m); Square to = move_to(m); - Square ksq = king_square(them); + PieceType pt = type_of_piece_on(from); - assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == piece_of_color_and_type(them, KING)); + // Direct check ? + if (bit_is_set(ci.checkSq[pt], to)) + return true; - // Proceed according to the type of the moving piece - switch (type_of_piece_on(from)) + // Discovery check ? + if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) { - case PAWN: - - if (bit_is_set(attacks_from(ksq, them), to)) // Normal check? + // For pawn and king moves we need to verify also direction + if ( (pt != PAWN && pt != KING) + ||(direction_between_squares(from, ci.ksq) != direction_between_squares(to, ci.ksq))) return true; + } - if ( dcCandidates // Discovered check? - && bit_is_set(dcCandidates, from) - && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) - return true; + // Can we skip the ugly special cases ? + if (!move_is_special(m)) + return false; - if (move_is_promotion(m)) // Promotion with check? - { - Bitboard b = occupied_squares(); - clear_bit(&b, from); + Color us = side_to_move(); + Bitboard b = occupied_squares(); - switch (move_promotion_piece(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); - } - } - // 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. - else if (move_is_ep(m)) + // Promotion with check ? + if (move_is_promotion(m)) + { + clear_bit(&b, from); + + switch (move_promotion_piece(m)) { - Square capsq = make_square(square_file(to), square_rank(from)); - Bitboard b = occupied_squares(); - 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)); + case KNIGHT: + return bit_is_set(attacks_from(to), ci.ksq); + case BISHOP: + return bit_is_set(bishop_attacks_bb(to, b), ci.ksq); + case ROOK: + return bit_is_set(rook_attacks_bb(to, b), ci.ksq); + case QUEEN: + return bit_is_set(queen_attacks_bb(to, b), ci.ksq); + default: + assert(false); } - return false; + } - // Test discovered check and normal check according to piece type - case KNIGHT: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || bit_is_set(attacks_from(ksq), to); - - case BISHOP: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(ksq), to)); - - case ROOK: - return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)); - - case QUEEN: - // Discovered checks are impossible! - assert(!bit_is_set(dcCandidates, from)); - return ( (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)) - || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(ksq), to))); - - case KING: - // Discovered check? - if ( bit_is_set(dcCandidates, from) - && (direction_between_squares(from, ksq) != direction_between_squares(to, ksq))) - return true; + // 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)) + { + 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(ci.ksq, b) & pieces(ROOK, QUEEN, us)) + ||(bishop_attacks_bb(ci.ksq, b) & pieces(BISHOP, QUEEN, us)); + } - // Castling with check? - if (move_is_castle(m)) - { - Square kfrom, kto, rfrom, rto; - Bitboard b = occupied_squares(); - kfrom = from; - rfrom = to; + // Castling with check ? + if (move_is_castle(m)) + { + Square kfrom, kto, rfrom, rto; + kfrom = from; + rfrom = to; - 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); + 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); } - return false; - - default: // NO_PIECE_TYPE - break; + 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), ci.ksq); } - assert(false); + return false; } @@ -658,20 +658,18 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square const bool Rook = (Piece == QUEEN || Piece == ROOK); const bool Slider = Bishop || Rook; + assert(*pCheckersBB == EmptyBoardBB); + // Direct checks - if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) + if ( ( !Slider // try to early skip slide piece attacks + || (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) || (Rook && bit_is_set(RookPseudoAttacks[ksq], to))) - && bit_is_set(attacks_from(ksq), to)) // slow, try to early skip - set_bit(pCheckersBB, to); - - else if ( Piece != KING - && !Slider - && bit_is_set(Piece == PAWN ? attacks_from(ksq, opposite_color(sideToMove)) - : attacks_from(ksq), to)) - set_bit(pCheckersBB, to); - + && bit_is_set(Piece == PAWN ? attacks_from(ksq, opposite_color(sideToMove)) : attacks_from(ksq) , to)) + { + *pCheckersBB = SetMaskBB[to]; + } // Discovery checks - if (Piece != QUEEN && bit_is_set(dcCandidates, from)) + if (Piece != QUEEN && dcCandidates && bit_is_set(dcCandidates, from)) { if (Piece != ROOK) (*pCheckersBB) |= (attacks_from(ksq) & pieces(ROOK, QUEEN, side_to_move())); @@ -702,10 +700,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // 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 key, pawnKey, materialKey; + Key pawnKey, materialKey; int castleRights, rule50, pliesFromNull; Square epSquare; - Value mgValue, egValue; + Value value; Value npMaterial[2]; }; @@ -742,16 +740,15 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { Piece piece = piece_on(from); PieceType pt = type_of_piece(piece); + PieceType capture = ep ? PAWN : type_of_piece_on(to); assert(color_of_piece_on(from) == us); assert(color_of_piece_on(to) == them || square_is_empty(to)); assert(!(ep || pm) || piece == piece_of_color_and_type(us, PAWN)); assert(!pm || relative_rank(us, to) == RANK_8); - st->capture = ep ? PAWN : type_of_piece_on(to); - - if (st->capture) - do_capture_move(key, st->capture, them, to, ep); + if (capture) + do_capture_move(key, capture, them, to, ep); // Update hash key key ^= zobrist[us][pt][from] ^ zobrist[us][pt][to]; @@ -801,7 +798,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to]; // Set en passant square, only if moved pawn can be captured - if (abs(int(to) - int(from)) == 16) + if ((to ^ from) == 16) { if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) { @@ -812,8 +809,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { } // Update incremental scores - st->mgValue += pst_delta(piece, from, to); - st->egValue += pst_delta(piece, from, to); + st->value += pst_delta(piece, from, to); + + // Set capture piece + st->capture = capture; if (pm) // promotion ? { @@ -848,10 +847,8 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->pawnKey ^= zobrist[us][PAWN][to]; // Partially revert and update incremental scores - st->mgValue -= pst(us, PAWN, to); - st->mgValue += pst(us, promotion, to); - st->egValue -= pst(us, PAWN, to); - st->egValue += pst(us, promotion, to); + st->value -= pst(us, PAWN, to); + st->value += pst(us, promotion, to); // Update material st->npMaterial[us] += piece_value_midgame(promotion); @@ -881,9 +878,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Finish sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -919,8 +914,7 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ key ^= zobrist[them][capture][capsq]; // Update incremental scores - st->mgValue -= pst(them, capture, capsq); - st->egValue -= pst(them, capture, capsq); + st->value -= pst(them, capture, capsq); // If the captured piece was a pawn, update pawn hash key, // otherwise update non-pawn material. @@ -1017,10 +1011,8 @@ void Position::do_castle_move(Move m) { index[rto] = tmp; // Update incremental scores - st->mgValue += pst_delta(king, kfrom, kto); - st->egValue += pst_delta(king, kfrom, kto); - st->mgValue += pst_delta(rook, rfrom, rto); - st->egValue += pst_delta(rook, rfrom, rto); + 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]; @@ -1046,9 +1038,7 @@ void Position::do_castle_move(Move m) { // Finish sideToMove = opposite_color(sideToMove); - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + st->value += (sideToMove == WHITE ? TempoValue : -TempoValue); assert(is_ok()); } @@ -1240,8 +1230,7 @@ void Position::do_null_move(StateInfo& backupSt) { // a backup storage not as a new state to be used. backupSt.key = st->key; backupSt.epSquare = st->epSquare; - backupSt.mgValue = st->mgValue; - backupSt.egValue = st->egValue; + backupSt.value = st->value; backupSt.previous = st->previous; backupSt.pliesFromNull = st->pliesFromNull; st->previous = &backupSt; @@ -1261,10 +1250,8 @@ void Position::do_null_move(StateInfo& backupSt) { st->epSquare = SQ_NONE; st->rule50++; st->pliesFromNull = 0; + st->value += (sideToMove == WHITE) ? TempoValue : -TempoValue; gamePly++; - - st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; - st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; } @@ -1279,8 +1266,7 @@ void Position::undo_null_move() { StateInfo* backupSt = st->previous; st->key = backupSt->key; st->epSquare = backupSt->epSquare; - st->mgValue = backupSt->mgValue; - st->egValue = backupSt->egValue; + st->value = backupSt->value; st->previous = backupSt->previous; st->pliesFromNull = backupSt->pliesFromNull; @@ -1338,7 +1324,6 @@ int Position::see(Square from, Square to) const { Bitboard attackers, stmAttackers, b; - assert(!shortcut || from != SQ_NONE); assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1628,10 +1613,9 @@ Key Position::compute_material_key() const { /// game and the endgame. These functions are used to initialize the incremental /// scores when a new position is set up, and to verify that the scores are correctly /// updated by do_move and undo_move when the program is running in debug mode. -template -Value Position::compute_value() const { +Score Position::compute_value() const { - Value result = Value(0); + Score result = make_score(0, 0); Bitboard b; Square s; @@ -1643,12 +1627,11 @@ Value Position::compute_value() const { { s = pop_1st_bit(&b); assert(piece_on(s) == piece_of_color_and_type(c, pt)); - result += pst(c, pt, s); + result += pst(c, pt, s); } } - const Value TempoValue = (Phase == MidGame ? TempoValueMidgame : TempoValueEndgame); - result += (side_to_move() == WHITE)? TempoValue / 2 : -TempoValue / 2; + result += (side_to_move() == WHITE ? TempoValue / 2 : -TempoValue / 2); return result; } @@ -1706,8 +1689,7 @@ bool Position::is_draw() const { bool Position::is_mate() const { MoveStack moves[256]; - - return is_check() && (generate_evasions(*this, moves, pinned_pieces(sideToMove)) == moves); + return is_check() && (generate_moves(*this, moves, false) == moves); } @@ -1728,11 +1710,10 @@ bool Position::has_mate_threat(Color c) { MoveStack mlist[120]; bool result = false; - Bitboard dc = discovered_check_candidates(sideToMove); Bitboard pinned = pinned_pieces(sideToMove); // Generate pseudo-legal non-capture and capture check moves - MoveStack* last = generate_non_capture_checks(*this, mlist, dc); + MoveStack* last = generate_non_capture_checks(*this, mlist); last = generate_captures(*this, last); // Loop through the moves, and see if one of them is mate @@ -1799,16 +1780,12 @@ void Position::init_piece_square_tables() { for (Piece p = WP; p <= WK; p++) { i = (r == 0)? 0 : (genrand_int32() % (r*2) - r); - MgPieceSquareTable[p][s] = Value(MgPST[p][s] + i); - EgPieceSquareTable[p][s] = Value(EgPST[p][s] + i); + PieceSquareTable[p][s] = make_score(MgPST[p][s] + i, EgPST[p][s] + i); } for (Square s = SQ_A1; s <= SQ_H8; s++) for (Piece p = BP; p <= BK; p++) - { - MgPieceSquareTable[p][s] = -MgPieceSquareTable[p-8][flip_square(s)]; - EgPieceSquareTable[p][s] = -EgPieceSquareTable[p-8][flip_square(s)]; - } + PieceSquareTable[p][s] = -PieceSquareTable[p-8][flip_square(s)]; } @@ -1863,8 +1840,7 @@ void Position::flipped_copy(const Position& pos) { st->materialKey = compute_material_key(); // Incremental scores - st->mgValue = compute_value(); - st->egValue = compute_value(); + st->value = compute_value(); // Material st->npMaterial[WHITE] = compute_non_pawn_material(WHITE); @@ -1991,14 +1967,8 @@ bool Position::is_ok(int* failedStep) const { // Incremental eval OK? if (failedStep) (*failedStep)++; - if (debugIncrementalEval) - { - if (st->mgValue != compute_value()) - return false; - - if (st->egValue != compute_value()) - return false; - } + if (debugIncrementalEval && st->value != compute_value()) + return false; // Non-pawn material OK? if (failedStep) (*failedStep)++;