X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=e9e412749b51ec8493159b37a26d34d6337c0cc1;hb=21850536d54c3f142f1907e31ac0bfab8f4a8862;hp=8ec7124b1095c5517fd0252dcbb40723c65a522f;hpb=43ca5c926dfaf13d64d51c4085070209f4c5f452;p=stockfish diff --git a/src/movegen.cpp b/src/movegen.cpp index 8ec7124b..e9e41274 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -55,19 +55,19 @@ namespace { // Helper templates template - MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist); + MoveStack* generate_castle_moves(const Position&, MoveStack*); template MoveStack* generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*); template - MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist); + MoveStack* generate_pawn_captures(const Position&, MoveStack*); template - MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion); + MoveStack* generate_pawn_captures_diagonal(MoveStack*, Bitboard, Bitboard, bool); template - MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist, Bitboard dc = EmptyBoardBB, Square ksq = SQ_NONE); + MoveStack* generate_pawn_noncaptures(const Position&, MoveStack*, Bitboard = EmptyBoardBB, Square = SQ_NONE); template inline Bitboard move_pawns(Bitboard p) { @@ -95,7 +95,7 @@ namespace { // Template generate_piece_moves() with specializations and overloads template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard); + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); template<> MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); @@ -114,7 +114,7 @@ namespace { } template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard, Bitboard); + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard, Bitboard); template<> inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, @@ -131,7 +131,7 @@ namespace { //// -/// generate_captures generates() all pseudo-legal captures and queen +/// generate_captures() generates all pseudo-legal captures and queen /// promotions. Returns a pointer to the end of the move list. MoveStack* generate_captures(const Position& pos, MoveStack* mlist) { @@ -173,8 +173,8 @@ MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) { } -/// generate_non_capture_checks() generates all pseudo-legal non-capturing, -/// non-promoting checks. Returns a pointer to the end of the move list. +/// generate_non_capture_checks() generates all pseudo-legal non-captures and +/// underpromotions that give check. Returns a pointer to the end of the move list. MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { @@ -231,8 +231,8 @@ MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pin Bitboard b_noKing = pos.occupied_squares(); clear_bit(&b_noKing, ksq); - // Find squares attacked by slider checkers, we will - // remove them from king evasions set so to avoid a couple + // Find squares attacked by slider checkers, we will remove + // them from the king evasions set so to avoid a couple // of cycles in the slow king evasions legality check loop // and to be able to use attackers_to(). Bitboard b = checkers & pos.pieces(BISHOP, QUEEN); @@ -249,14 +249,14 @@ MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pin sliderAttacks |= rook_attacks_bb(from, b_noKing); } - // Generate evasions for king, both captures and non captures - Bitboard b1 = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks; + // Generate evasions for king, capture and non capture moves Bitboard enemy = pos.pieces_of_color(them); + Bitboard b1 = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks; while (b1) { + // Note that we can use attackers_to() only because we have already + // removed from b1 the squares attacked by slider checkers. to = pop_1st_bit(&b1); - // Note that we can use attackers_to() only because we - // have already removed slider checkers attacked squares. if (!(pos.attackers_to(to) & enemy)) (*mlist++).move = make_move(ksq, to); } @@ -345,13 +345,11 @@ MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pin } -/// generate_legal_moves() computes a complete list of legal moves in the -/// current position. This function is not very fast, and should be used -/// only in situations where performance is unimportant. It wouldn't be -/// very hard to write an efficient legal move generator, but for the moment -/// we don't need it. +/// generate_moves() computes a complete list of legal or pseudo-legal moves in +/// the current position. This function is not very fast, and should be used +/// only in non time-critical paths. -MoveStack* generate_legal_moves(const Position& pos, MoveStack* mlist) { +MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) { assert(pos.is_ok()); @@ -363,6 +361,8 @@ MoveStack* generate_legal_moves(const Position& pos, MoveStack* mlist) { // Generate pseudo-legal moves MoveStack* last = generate_captures(pos, mlist); last = generate_noncaptures(pos, last); + if (pseudoLegal) + return last; // Remove illegal moves from the list for (MoveStack* cur = mlist; cur != last; cur++) @@ -376,10 +376,24 @@ MoveStack* generate_legal_moves(const Position& pos, MoveStack* mlist) { /// move_is_legal() takes a position and a (not necessarily pseudo-legal) -/// move and a pinned pieces bitboard as input, and tests whether -/// the move is legal. If the move is legal, the move itself is -/// returned. If not, the function returns false. This function must -/// only be used when the side to move is not in check. +/// move and tests whether the move is legal. This version is not very fast +/// and should be used only in non time-critical paths. + +bool move_is_legal(const Position& pos, const Move m) { + + MoveStack mlist[256]; + MoveStack* last = generate_moves(pos, mlist, true); + for (MoveStack* cur = mlist; cur != last; cur++) + if (cur->move == m) + return pos.pl_move_is_legal(m); + + return false; +} + + +/// Fast version of move_is_legal() that takes a position a move and a +/// bitboard of pinned pieces as input, and tests whether the move is legal. +/// This version must only be used when the side to move is not in check. bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { @@ -388,8 +402,14 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { assert(move_is_ok(m)); assert(pinned == pos.pinned_pieces(pos.side_to_move())); + // Use a slower but simpler function for uncommon cases + if (move_is_ep(m) || move_is_castle(m)) + return move_is_legal(pos, m); + Color us = pos.side_to_move(); + Color them = opposite_color(us); Square from = move_from(m); + Square to = move_to(m); Piece pc = pos.piece_on(from); // If the from square is not occupied by a piece belonging to the side to @@ -397,100 +417,11 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { if (color_of_piece(pc) != us) return false; - Color them = opposite_color(us); - Square to = move_to(m); - - // En passant moves - if (move_is_ep(m)) - { - // The piece must be a pawn and destination square must be the - // en passant square. - if ( type_of_piece(pc) != PAWN - || to != pos.ep_square()) - return false; - - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == piece_of_color_and_type(them, PAWN)); - - // The move is pseudo-legal, check if it is also legal - return pos.pl_move_is_legal(m, pinned); - } - - // Castling moves - if (move_is_short_castle(m)) - { - // The piece must be a king and side to move must still have - // the right to castle kingside. - if ( type_of_piece(pc) != KING - ||!pos.can_castle_kingside(us)) - return false; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_kr_square(us)); - assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK)); - - Square g1 = relative_square(us, SQ_G1); - Square f1 = relative_square(us, SQ_F1); - Square s; - bool illegal = false; - - // Check if any of the squares between king and rook - // is occupied or under attack. - for (s = Min(from, g1); s <= Max(from, g1); s++) - if ( (s != from && s != to && !pos.square_is_empty(s)) - ||(pos.attackers_to(s) & pos.pieces_of_color(them))) - illegal = true; - - // Check if any of the squares between king and rook - // is occupied. - for (s = Min(to, f1); s <= Max(to, f1); s++) - if (s != from && s != to && !pos.square_is_empty(s)) - illegal = true; - - return !illegal; - } - - if (move_is_long_castle(m)) - { - // The piece must be a king and side to move must still have - // the right to castle kingside. - if ( type_of_piece(pc) != KING - ||!pos.can_castle_queenside(us)) - return false; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_qr_square(us)); - assert(pos.piece_on(to) == piece_of_color_and_type(us, ROOK)); - - Square c1 = relative_square(us, SQ_C1); - Square d1 = relative_square(us, SQ_D1); - Square s; - bool illegal = false; - - for (s = Min(from, c1); s <= Max(from, c1); s++) - if( (s != from && s != to && !pos.square_is_empty(s)) - ||(pos.attackers_to(s) & pos.pieces_of_color(them))) - illegal = true; - - for (s = Min(to, d1); s <= Max(to, d1); s++) - if(s != from && s != to && !pos.square_is_empty(s)) - illegal = true; - - if ( square_file(to) == FILE_B - && ( pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, ROOK) - || pos.piece_on(to + DELTA_W) == piece_of_color_and_type(them, QUEEN))) - illegal = true; - - return !illegal; - } - - // Normal moves - // The destination square cannot be occupied by a friendly piece if (pos.color_of_piece_on(to) == us) return false; - // Proceed according to the type of the moving piece. + // Handle the special case of a pawn move if (type_of_piece(pc) == PAWN) { // Move direction must be compatible with pawn color @@ -498,15 +429,14 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { if ((us == WHITE) != (direction > 0)) return false; - // If the destination square is on the 8/1th rank, the move must - // be a promotion. - if ( ( (square_rank(to) == RANK_8 && us == WHITE) - ||(square_rank(to) == RANK_1 && us != WHITE)) - && !move_is_promotion(m)) + // A pawn move is a promotion iff the destination square is + // on the 8/1th rank. + if (( (square_rank(to) == RANK_8 && us == WHITE) + ||(square_rank(to) == RANK_1 && us != WHITE)) != bool(move_is_promotion(m))) return false; - // Proceed according to the square delta between the source and - // destionation squares. + // Proceed according to the square delta between the origin and + // destination squares. switch (direction) { case DELTA_NW: @@ -560,30 +490,6 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { } -/// Another version of move_is_legal(), which takes only a position and a move -/// as input. This function does not require that the side to move is not in -/// check. It is not optimized for speed, and is only used for verifying move -/// legality when building a PV from the transposition table. - -bool move_is_legal(const Position& pos, const Move m) { - - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - if (!pos.is_check()) - return move_is_legal(pos, m, pinned); - else - { - Position p(pos); - MoveStack mlist[64]; - MoveStack* last = generate_evasions(p, mlist, pinned); - for (MoveStack* cur = mlist; cur != last; cur++) - if (cur->move == m) - return true; - - return false; - } -} - - namespace { template @@ -601,6 +507,17 @@ namespace { return mlist; } + template<> + MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + + Bitboard b; + Square from = pos.king_square(us); + + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); + return mlist; + } + template MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target, Bitboard pinned) { @@ -619,17 +536,6 @@ namespace { return mlist; } - template<> - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - - Bitboard b; - Square from = pos.king_square(us); - - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); - return mlist; - } - template MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion) { @@ -765,7 +671,7 @@ namespace { } dcPawns1 = dcPawns2 = EmptyBoardBB; - if (GenerateChecks && (dc & pawns)) + if (GenerateChecks && (pawns & dc)) { // Pawn moves which gives discovered check. This is possible only if the // pawn is not on the same file as the enemy king, because we don't @@ -792,8 +698,11 @@ namespace { Bitboard target = pos.pieces(Piece, us); - // Discovered checks + // Discovered non-capture checks Bitboard b = target & dc; + + assert(Piece != QUEEN || !b); + while (b) { Square from = pop_1st_bit(&b); @@ -804,7 +713,7 @@ namespace { SERIALIZE_MOVES(bb); } - // Direct checks + // Direct non-capture checks b = target & ~dc; Bitboard checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); if (Piece == KING || !checkSqs) @@ -829,47 +738,38 @@ namespace { Bitboard blockSquares, MoveStack* mlist) { // Calculate our parametrized parameters at compile time - const Rank TRANK_8 = (Us == WHITE ? RANK_8 : RANK_1); + const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB); + const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); + Bitboard b1, b2; Square to; + Bitboard pawns = pos.pieces(PAWN, Us) & ~pinned; + Bitboard emptySquares = pos.empty_squares(); - // Find non-pinned pawns and push them one square - Bitboard b1 = move_pawns(pos.pieces(PAWN, Us) & ~pinned); - - // We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - Bitboard b2 = b1 & blockSquares; - while (b2) + if (pawns & TRank7BB) // There is some promotion candidate ? { - to = pop_1st_bit(&b2); - - assert(pos.piece_on(to) == EMPTY); - - if (square_rank(to) == TRANK_8) + // Note that blockSquares are always empty + b1 = move_pawns(pawns) & blockSquares & TRank8BB; + while (b1) { + to = pop_1st_bit(&b1); (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK); (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP); (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); - } else - (*mlist++).move = make_move(to - TDELTA_N, to); + } } - // Double pawn pushes - b2 = b1 & pos.empty_squares() & TRank3BB; - b2 = move_pawns(b2) & blockSquares; - while (b2) - { - to = pop_1st_bit(&b2); - - assert(pos.piece_on(to) == EMPTY); - assert(Us != WHITE || square_rank(to) == RANK_4); - assert(Us != BLACK || square_rank(to) == RANK_5); + // Single pawn pushes + b1 = move_pawns(pawns) & emptySquares & ~TRank8BB; + b2 = b1 & blockSquares; + SERIALIZE_MOVES_D(b2, -TDELTA_N); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); - } + // Double pawn pushes. Note that blockSquares are always empty + b1 = move_pawns(b1 & TRank3BB) & blockSquares; + SERIALIZE_MOVES_D(b1, -TDELTA_N -TDELTA_N); return mlist; }