X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=fab5e46182f924118c63fe797ea9e8bb87b921a0;hp=f363fa5af1133ea9c749d85b044fa7b2e1b6ea5f;hb=49e110c52b19f5c99954d4797b8e991b0b60007c;hpb=34a515f20b0d8fa467af776c78b572cdafe819b1 diff --git a/src/movegen.cpp b/src/movegen.cpp index f363fa5a..fab5e461 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,1038 +1,423 @@ /* - Glaurung, a UCI chess playing engine. - Copyright (C) 2004-2008 Tord Romstad + Stockfish, a UCI chess playing engine derived from Glaurung 2.1 + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad - Glaurung is free software: you can redistribute it and/or modify + Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. - - Glaurung is distributed in the hope that it will be useful, + + Stockfish is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. - + You should have received a copy of the GNU General Public License along with this program. If not, see . */ - -//// -//// Includes -//// - #include #include "movegen.h" +#include "position.h" +/// Simple macro to wrap a very common while loop, no facny, no flexibility, +/// hardcoded names 'mlist' and 'from'. +#define SERIALIZE(b) while (b) (mlist++)->move = make_move(from, pop_lsb(&b)) -//// -//// Local definitions -//// - +/// Version used for pawns, where the 'from' square is given as a delta from the 'to' square +#define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_lsb(&b); \ + (mlist++)->move = make_move(to - (d), to); } namespace { - - int generate_white_pawn_captures(const Position&, MoveStack*); - int generate_black_pawn_captures(const Position&, MoveStack*); - int generate_white_pawn_noncaptures(const Position&, MoveStack*); - int generate_black_pawn_noncaptures(const Position&, MoveStack*); - int generate_piece_moves(PieceType, const Position&, MoveStack*, Color side, Bitboard t); - int generate_castle_moves(const Position&, MoveStack*, Color us); - - int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target, - Bitboard dc, Square ksq, MoveStack* mlist); - - inline Bitboard next_row_white(Bitboard b) { return b << 8; } - inline Bitboard next_row_black(Bitboard b) { return b >> 8; } - - struct PawnOffsets { - - Bitboard Rank3BB; - Bitboard Rank8BB; - SquareDelta DELTA_N; - Color them; - Bitboard (*next_row_fn)(Bitboard b); - }; - const PawnOffsets WhitePawnOffsets = { Rank3BB, Rank8BB, DELTA_N, BLACK, &next_row_white }; - const PawnOffsets BlackPawnOffsets = { Rank6BB, Rank1BB, DELTA_S, WHITE, &next_row_black }; - - int generate_pawn_checks(const PawnOffsets& ofs, const Position& pos, Bitboard dc, - Square ksq, MoveStack* mlist); -} - -//// -//// Functions -//// + template + ExtMove* generate_castle(const Position& pos, ExtMove* mlist, Color us) { + if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side))) + return mlist; -/// generate_captures generates() all pseudo-legal captures and queen -/// promotions. The return value is the number of moves generated. + // After castling, the rook and king final positions are the same in Chess960 + // as they would be in standard chess. + Square kfrom = pos.king_square(us); + Square rfrom = pos.castle_rook_square(us, Side); + Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Bitboard enemies = pos.pieces(~us); -int generate_captures(const Position& pos, MoveStack* mlist) { + assert(!pos.checkers()); - assert(pos.is_ok()); - assert(!pos.is_check()); - - Color us = pos.side_to_move(); - Bitboard target = pos.pieces_of_color(opposite_color(us)); - int n; - - if (us == WHITE) - n = generate_white_pawn_captures(pos, mlist); - else - n = generate_black_pawn_captures(pos, mlist); - - for (PieceType pce = KNIGHT; pce <= KING; pce++) - n += generate_piece_moves(pce, pos, mlist+n, us, target); - - return n; -} + const int K = Chess960 ? kto > kfrom ? -1 : 1 + : Side == KING_SIDE ? -1 : 1; + for (Square s = kto; s != kfrom; s += (Square)K) + if (pos.attackers_to(s) & enemies) + return mlist; -/// generate_noncaptures() generates all pseudo-legal non-captures and -/// underpromotions. The return value is the number of moves generated. + // Because we generate only legal castling moves we need to 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. + if (Chess960 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies)) + return mlist; -int generate_noncaptures(const Position& pos, MoveStack *mlist) { + (mlist++)->move = make(kfrom, rfrom); - assert(pos.is_ok()); - assert(!pos.is_check()); - - Color us = pos.side_to_move(); - Bitboard target = pos.empty_squares(); - int n; - - if (us == WHITE) - n = generate_white_pawn_noncaptures(pos, mlist); - else - n = generate_black_pawn_noncaptures(pos, mlist); - - for (PieceType pce = KNIGHT; pce <= KING; pce++) - n += generate_piece_moves(pce, pos, mlist+n, us, target); - - n += generate_castle_moves(pos, mlist+n, us); - return n; -} - - -/// generate_checks() generates all pseudo-legal non-capturing, non-promoting -/// checks, except castling moves (will add this later). It returns the -/// number of generated moves. - -int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - - Color us = pos.side_to_move(); - Square ksq = pos.king_square(opposite_color(us)); - int n = 0; + if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) + mlist--; - assert(pos.piece_on(ksq) == king_of_color(opposite_color(us))); - - dc = pos.discovered_check_candidates(us); - - // Pawn moves - if (us == WHITE) - n += generate_pawn_checks(WhitePawnOffsets, pos, dc, ksq, mlist); - else - n += generate_pawn_checks(BlackPawnOffsets, pos, dc, ksq, mlist); - - // Pieces moves - Bitboard b = pos.knights(us); - if (b) - n += generate_piece_checks(KNIGHT, pos, b, dc, ksq, mlist); - - b = pos.bishops(us); - if (b) - n += generate_piece_checks(BISHOP, pos, b, dc, ksq, mlist); - - b = pos.rooks(us); - if (b) - n += generate_piece_checks(ROOK, pos, b, dc, ksq, mlist); - - b = pos.queens(us); - if (b) - n += generate_piece_checks(QUEEN, pos, b, dc, ksq, mlist); - - // King moves - Square from = pos.king_square(us); - if (bit_is_set(dc, from)) - { - b = pos.king_attacks(from) & pos.empty_squares() & ~QueenPseudoAttacks[ksq]; - while (b) - { - Square to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } - } - - // TODO: Castling moves! - - return n; -} - - -/// generate_evasions() generates all check evasions when the side to move is -/// in check. Unlike the other move generation functions, this one generates -/// only legal moves. It returns the number of generated moves. This -/// function is very ugly, and needs cleaning up some time later. FIXME - -int generate_evasions(const Position &pos, MoveStack *mlist) { - - assert(pos.is_ok()); - assert(pos.is_check()); - - Color us, them; - Bitboard checkers = pos.checkers(); - Bitboard pinned, b1, b2; - Square ksq, from, to; - int n = 0; - - us = pos.side_to_move(); - them = opposite_color(us); - - ksq = pos.king_square(us); - assert(pos.piece_on(ksq) == king_of_color(us)); - - // Generate evasions for king: - b1 = pos.king_attacks(ksq) & ~pos.pieces_of_color(us); - b2 = pos.occupied_squares(); - clear_bit(&b2, ksq); - while(b1) { - to = pop_1st_bit(&b1); - - // Make sure to is not attacked by the other side. This is a bit ugly, - // because we can't use Position::square_is_attacked. Instead we use - // the low-level bishop_attacks_bb and rook_attacks_bb with the bitboard - // b2 (the occupied squares with the king removed) in order to test whether - // the king will remain in check on the destination square. - if(((pos.pawn_attacks(us, to) & pos.pawns(them)) == EmptyBoardBB) && - ((pos.knight_attacks(to) & pos.knights(them)) == EmptyBoardBB) && - ((pos.king_attacks(to) & pos.kings(them)) == EmptyBoardBB) && - ((bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them)) - == EmptyBoardBB) && - ((rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) == EmptyBoardBB)) - mlist[n++].move = make_move(ksq, to); + return mlist; } - // Generate evasions for other pieces only if not double check. We use a - // simple bit twiddling hack here rather than calling count_1s in order to - // save some time (we know that pos.checkers() has at most two nonzero bits). - if(!(checkers & (checkers - 1))) { - Square checksq = first_1(checkers); - assert(pos.color_of_piece_on(checksq) == them); - - // Find pinned pieces: - pinned = pos.pinned_pieces(us); - - // Generate captures of the checking piece: - - // Pawn captures: - b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - if(relative_rank(us, checksq) == RANK_8) { - mlist[n++].move = make_promotion_move(from, checksq, QUEEN); - mlist[n++].move = make_promotion_move(from, checksq, ROOK); - mlist[n++].move = make_promotion_move(from, checksq, BISHOP); - mlist[n++].move = make_promotion_move(from, checksq, KNIGHT); - } - else - mlist[n++].move = make_move(from, checksq); - } + template + inline ExtMove* generate_promotions(ExtMove* mlist, Bitboard pawnsOn7, + Bitboard target, const CheckInfo* ci) { - // Knight captures: - b1 = pos.knight_attacks(checksq) & pos.knights(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + Bitboard b = shift_bb(pawnsOn7) & target; - // Bishop and queen captures: - b1 = pos.bishop_attacks(checksq) & pos.bishops_and_queens(us) - & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + while (b) + { + Square to = pop_lsb(&b); - // Rook and queen captures: - b1 = pos.rook_attacks(checksq) & pos.rooks_and_queens(us) - & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + (mlist++)->move = make(to - Delta, to, QUEEN); - // Blocking check evasions are possible only if the checking piece is - // a slider: - if(checkers & pos.sliders()) { - Bitboard blockSquares = squares_between(checksq, ksq); - assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB); - - // Pawn moves. Because a blocking evasion can never be a capture, we - // only generate pawn pushes. As so often, the code for pawns is a bit - // ugly, and uses separate clauses for white and black pawns. :-( - if(us == WHITE) { - // Find non-pinned pawns: - b1 = pos.pawns(WHITE) & ~pinned; - - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - b2 = (b1 << 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - if(square_rank(to) == RANK_8) { - mlist[n++].move = make_promotion_move(to - DELTA_N, to, QUEEN); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, ROOK); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, BISHOP); - mlist[n++].move = make_promotion_move(to - DELTA_N, to, KNIGHT); - } - else - mlist[n++].move = make_move(to - DELTA_N, to); - } - // Double pawn pushes. - b2 = (((b1 << 8) & pos.empty_squares() & Rank3BB) << 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - assert(square_rank(to) == RANK_4); - mlist[n++].move = make_move(to - DELTA_N - DELTA_N, to); - } - } - else { // (us == BLACK) - // Find non-pinned pawns: - b1 = pos.pawns(BLACK) & ~pinned; - - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - b2 = (b1 >> 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - if(square_rank(to) == RANK_1) { - mlist[n++].move = make_promotion_move(to - DELTA_S, to, QUEEN); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, ROOK); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, BISHOP); - mlist[n++].move = make_promotion_move(to - DELTA_S, to, KNIGHT); - } - else - mlist[n++].move = make_move(to - DELTA_S, to); - } - // Double pawn pushes. - b2 = (((b1 >> 8) & pos.empty_squares() & Rank6BB) >> 8) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - assert(pos.piece_on(to) == EMPTY); - assert(square_rank(to) == RANK_5); - mlist[n++].move = make_move(to - DELTA_S - DELTA_S, to); + if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS) + { + (mlist++)->move = make(to - Delta, to, ROOK); + (mlist++)->move = make(to - Delta, to, BISHOP); + (mlist++)->move = make(to - Delta, to, KNIGHT); } - } - // Knight moves - b1 = pos.knights(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.knight_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Bishop moves - b1 = pos.bishops(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.bishop_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Rook moves - b1 = pos.rooks(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.rook_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } - - // Queen moves - b1 = pos.queens(us) & ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - b2 = pos.queen_attacks(from) & blockSquares; - while(b2) { - to = pop_1st_bit(&b2); - mlist[n++].move = make_move(from, to); - } - } + // Knight-promotion is the only one that can give a direct check not + // already included in the queen-promotion. + if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ci->ksq)) + (mlist++)->move = make(to - Delta, to, KNIGHT); + else + (void)ci; // Silence a warning under MSVC } - // Finally, the ugly special case of en passant captures. An en passant - // capture can only be a check evasion if the check is not a discovered - // check. If pos.ep_square() is set, the last move made must have been - // a double pawn push. If, furthermore, the checking piece is a pawn, - // an en passant check evasion may be possible. - if(pos.ep_square() != SQ_NONE && (checkers & pos.pawns(them))) { - to = pos.ep_square(); - b1 = pos.pawn_attacks(them, to) & pos.pawns(us); - assert(b1 != EmptyBoardBB); - b1 &= ~pinned; - while(b1) { - from = pop_1st_bit(&b1); - - // Before generating the move, we have to make sure it is legal. - // This is somewhat tricky, because the two disappearing pawns may - // cause new "discovered checks". We test this by removing the - // two relevant bits from the occupied squares bitboard, and using - // the low-level bitboard functions for bishop and rook attacks. - b2 = pos.occupied_squares(); - clear_bit(&b2, from); - clear_bit(&b2, checksq); - if(((bishop_attacks_bb(ksq, b2) & pos.bishops_and_queens(them)) - == EmptyBoardBB) && - ((rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them)) - == EmptyBoardBB)) - mlist[n++].move = make_ep_move(from, to); - } - } + return mlist; } - return n; -} - - -/// 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. - -int generate_legal_moves(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); + template + ExtMove* generate_pawn_moves(const Position& pos, ExtMove* mlist, + Bitboard target, const CheckInfo* ci) { - if (pos.is_check()) - return generate_evasions(pos, mlist); + // Compute our parametrized parameters at compile time, named according to + // the point of view of white side. + const Color Them = (Us == WHITE ? BLACK : WHITE); + const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB); + const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); + const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); + const Square Up = (Us == WHITE ? DELTA_N : DELTA_S); + const Square Right = (Us == WHITE ? DELTA_NE : DELTA_SW); + const Square Left = (Us == WHITE ? DELTA_NW : DELTA_SE); - // Generate pseudo-legal moves: - int n = generate_captures(pos, mlist); - n += generate_noncaptures(pos, mlist + n); + Bitboard b1, b2, dc1, dc2, emptySquares; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; + Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; - // Remove illegal moves from the list: - for (int i = 0; i < n; i++) - if (!pos.move_is_legal(mlist[i].move, pinned)) - mlist[i--].move = mlist[--n].move; + Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target: + Type == CAPTURES ? target : pos.pieces(Them)); - return n; -} - - -/// generate_move_if_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 MOVE_NONE. This function must -/// only be used when the side to move is not in check. + // Single and double pawn pushes, no promotions + if (Type != CAPTURES) + { + emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); -Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) { + b1 = shift_bb(pawnsNotOn7) & emptySquares; + b2 = shift_bb(b1 & TRank3BB) & emptySquares; - assert(pos.is_ok()); - assert(!pos.is_check()); - assert(move_is_ok(m)); + if (Type == EVASIONS) // Consider only blocking squares + { + b1 &= target; + b2 &= target; + } - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Piece pc = pos.piece_on(from); + if (Type == QUIET_CHECKS) + { + b1 &= pos.attacks_from(ci->ksq, Them); + b2 &= pos.attacks_from(ci->ksq, Them); + + // Add pawn pushes which give discovered check. This is possible only + // if the pawn is not on the same file as the enemy king, because we + // don't generate captures. Note that a possible discovery check + // promotion has been already generated among captures. + if (pawnsNotOn7 & ci->dcCandidates) + { + dc1 = shift_bb(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq); + dc2 = shift_bb(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } + } - // If the from square is not occupied by a piece belonging to the side to - // move, the move is obviously not legal. - if (color_of_piece(pc) != us) - return MOVE_NONE; + SERIALIZE_PAWNS(b1, Up); + SERIALIZE_PAWNS(b2, Up + Up); + } - Square to = move_to(m); + // Promotions and underpromotions + if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB))) + { + if (Type == CAPTURES) + emptySquares = ~pos.pieces(); - // 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 MOVE_NONE; + if (Type == EVASIONS) + emptySquares &= target; - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci); + } - // The move is pseudo-legal. If it is legal, return it. - return (pos.move_is_legal(m) ? m : MOVE_NONE); - } + // Standard and en-passant captures + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + { + b1 = shift_bb(pawnsNotOn7) & enemies; + b2 = shift_bb(pawnsNotOn7) & enemies; - // 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 MOVE_NONE; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_kr_square(us)); - assert(pos.piece_on(to) == rook_of_color(us)); - - 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.square_is_attacked(s, 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 ? m : MOVE_NONE); - } + SERIALIZE_PAWNS(b1, Right); + SERIALIZE_PAWNS(b2, Left); - 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 MOVE_NONE; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_qr_square(us)); - assert(pos.piece_on(to) == rook_of_color(us)); - - 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.square_is_attacked(s, 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) == rook_of_color(them) - || pos.piece_on(to + DELTA_W) == queen_of_color(them))) - illegal = true; - - return (!illegal ? m : MOVE_NONE); - } + if (pos.ep_square() != SQ_NONE) + { + assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6)); - // Normal moves - - // The destination square cannot be occupied by a friendly piece - if (pos.color_of_piece_on(to) == us) - return MOVE_NONE; - - // Proceed according to the type of the moving piece. - if (type_of_piece(pc) == PAWN) - { - // 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_promotion(m)) - return MOVE_NONE; - - // Proceed according to the square delta between the source and - // destionation squares. - switch (to - from) - { - case DELTA_NW: - case DELTA_NE: - case DELTA_SW: - case DELTA_SE: - // Capture. The destination square must be occupied by an enemy - // piece (en passant captures was handled earlier). - if (pos.color_of_piece_on(to) != them) - return MOVE_NONE; - break; + // An en passant capture can be an evasion only if the checking piece + // is the double pushed pawn and so is in the target. Otherwise this + // is a discovery check and we are forced to do otherwise. + if (Type == EVASIONS && !(target & (pos.ep_square() - Up))) + return mlist; - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!pos.square_is_empty(to)) - return MOVE_NONE; - break; + b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); - case DELTA_NN: - // Double white pawn push. The destination square must be on the fourth - // rank, and both the destination square and the square between the - // source and destination squares must be empty. - if ( square_rank(to) != RANK_4 - || !pos.square_is_empty(to) - || !pos.square_is_empty(from + DELTA_N)) - return MOVE_NONE; - break; + assert(b1); - case DELTA_SS: - // Double black pawn push. The destination square must be on the fifth - // rank, and both the destination square and the square between the - // source and destination squares must be empty. - if ( square_rank(to) != RANK_5 - || !pos.square_is_empty(to) - || !pos.square_is_empty(from + DELTA_S)) - return MOVE_NONE; - break; + while (b1) + (mlist++)->move = make(pop_lsb(&b1), pos.ep_square()); + } + } - default: - return MOVE_NONE; - } - // The move is pseudo-legal. Return it if it is legal. - return (pos.move_is_legal(m) ? m : MOVE_NONE); + return mlist; } - // Luckly we can handle all the other pieces in one go - return ( pos.piece_attacks_square(from, to) - && pos.move_is_legal(m) - && !move_promotion(m) ? m : MOVE_NONE); -} + template FORCE_INLINE + ExtMove* generate_moves(const Position& pos, ExtMove* mlist, Color us, + Bitboard target, const CheckInfo* ci) { -namespace { + assert(Pt != KING && Pt != PAWN); - int generate_white_pawn_captures(const Position &pos, MoveStack *mlist) { + const Square* pl = pos.list(us); - Bitboard pawns = pos.pawns(WHITE); - Bitboard enemyPieces = pos.pieces_of_color(BLACK); - Square sq; - int n = 0; - - // Captures in the a1-h8 direction - Bitboard b1 = (pawns << 9) & ~FileABB & enemyPieces; - - // Capturing promotions - Bitboard b2 = b1 & Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, QUEEN); - } - - // Capturing non-promotions - b2 = b1 & ~Rank8BB; - while (b2) + for (Square from = *pl; from != SQ_NONE; from = *++pl) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_NE, sq); - } + if (Checks) + { + if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) + && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt])) + continue; - // Captures in the h1-a8 direction - b1 = (pawns << 7) & ~FileHBB & enemyPieces; + if (unlikely(ci->dcCandidates) && (ci->dcCandidates & from)) + continue; + } - // Capturing promotions - b2 = b1 & Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, QUEEN); - } + Bitboard b = pos.attacks_from(from) & target; - // Capturing non-promotions - b2 = b1 & ~Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_NW, sq); - } + if (Checks) + b &= ci->checkSq[Pt]; - // Non-capturing promotions - b1 = (pawns << 8) & pos.empty_squares() & Rank8BB; - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, QUEEN); + SERIALIZE(b); } - // En passant captures - if (pos.ep_square() != SQ_NONE) - { - assert(square_rank(pos.ep_square()) == RANK_6); - b1 = pawns & pos.black_pawn_attacks(pos.ep_square()); - assert(b1 != EmptyBoardBB); - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); - } - } - return n; + return mlist; } - int generate_black_pawn_captures(const Position &pos, MoveStack *mlist) { + template FORCE_INLINE + ExtMove* generate_all(const Position& pos, ExtMove* mlist, Bitboard target, + const CheckInfo* ci = NULL) { - Bitboard pawns = pos.pawns(BLACK); - Bitboard enemyPieces = pos.pieces_of_color(WHITE); - Square sq; - int n = 0; + const bool Checks = Type == QUIET_CHECKS; - // Captures in the a8-h1 direction - Bitboard b1 = (pawns >> 7) & ~FileABB & enemyPieces; + mlist = generate_pawn_moves(pos, mlist, target, ci); + mlist = generate_moves(pos, mlist, Us, target, ci); + mlist = generate_moves(pos, mlist, Us, target, ci); + mlist = generate_moves< ROOK, Checks>(pos, mlist, Us, target, ci); + mlist = generate_moves< QUEEN, Checks>(pos, mlist, Us, target, ci); - // Capturing promotions - Bitboard b2 = b1 & Rank1BB; - while (b2) + if (Type != QUIET_CHECKS && Type != EVASIONS) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, QUEEN); + Square from = pos.king_square(Us); + Bitboard b = pos.attacks_from(from) & target; + SERIALIZE(b); } - // Capturing non-promotions - b2 = b1 & ~Rank1BB; - while (b2) + if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(Us)) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_SE, sq); - } - - // Captures in the h8-a1 direction - b1 = (pawns >> 9) & ~FileHBB & enemyPieces; - - // Capturing promotions - b2 = b1 & Rank1BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, QUEEN); - } - - // Capturing Non-promotions - b2 = b1 & ~Rank1BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_SW, sq); - } - - // Non-capturing promotions - b1 = (pawns >> 8) & pos.empty_squares() & Rank1BB; - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, QUEEN); - } - - // En passant captures - if (pos.ep_square() != SQ_NONE) - { - assert(square_rank(pos.ep_square()) == RANK_3); - b1 = pawns & pos.white_pawn_attacks(pos.ep_square()); - assert(b1 != EmptyBoardBB); - while (b1) + if (pos.is_chess960()) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); + mlist = generate_castle< KING_SIDE, Checks, true>(pos, mlist, Us); + mlist = generate_castle(pos, mlist, Us); + } + else + { + mlist = generate_castle< KING_SIDE, Checks, false>(pos, mlist, Us); + mlist = generate_castle(pos, mlist, Us); } } - return n; + + return mlist; } - int generate_white_pawn_noncaptures(const Position &pos, MoveStack *mlist) { +} // namespace - Bitboard pawns = pos.pawns(WHITE); - Bitboard enemyPieces = pos.pieces_of_color(BLACK); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; - Square sq; - int n = 0; - // Underpromotion captures in the a1-h8 direction: - b1 = (pawns << 9) & ~FileABB & enemyPieces & Rank8BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_NE, sq, KNIGHT); - } +/// generate generates all pseudo-legal captures and queen +/// promotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal non-captures and +/// underpromotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal captures and +/// non-captures. Returns a pointer to the end of the move list. - // Underpromotion captures in the h1-a8 direction: - b1 = (pawns << 7) & ~FileHBB & enemyPieces & Rank8BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_NW, sq, KNIGHT); - } +template +ExtMove* generate(const Position& pos, ExtMove* mlist) { - // Single pawn pushes: - b1 = (pawns << 8) & emptySquares; - b2 = b1 & Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_N, sq, KNIGHT); - } - b2 = b1 & ~Rank8BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_N, sq); - } + assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); + assert(!pos.checkers()); - // Double pawn pushes: - b2 = ((b1 & Rank3BB) << 8) & emptySquares; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_N - DELTA_N, sq); - } + Color us = pos.side_to_move(); - return n; - } + Bitboard target = Type == CAPTURES ? pos.pieces(~us) + : Type == QUIETS ? ~pos.pieces() + : Type == NON_EVASIONS ? ~pos.pieces(us) : 0; + return us == WHITE ? generate_all(pos, mlist, target) + : generate_all(pos, mlist, target); +} - int generate_black_pawn_noncaptures(const Position &pos, MoveStack *mlist) { - Bitboard pawns = pos.pawns(BLACK); - Bitboard enemyPieces = pos.pieces_of_color(WHITE); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; - Square sq; - int n = 0; - - // Underpromotion captures in the a8-h1 direction: - b1 = (pawns >> 7) & ~FileABB & enemyPieces & Rank1BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_SE, sq, KNIGHT); - } +// Explicit template instantiations +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); - // Underpromotion captures in the h8-a1 direction: - b1 = (pawns >> 9) & ~FileHBB & enemyPieces & Rank1BB; - while(b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_SW, sq, KNIGHT); - } - // Single pawn pushes: - b1 = (pawns >> 8) & emptySquares; - b2 = b1 & Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - DELTA_S, sq, KNIGHT); - } - b2 = b1 & ~Rank1BB; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_S, sq); - } - - // Double pawn pushes: - b2 = ((b1 & Rank6BB) >> 8) & emptySquares; - while(b2) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - DELTA_S - DELTA_S, sq); - } +/// generate generates all pseudo-legal non-captures and knight +/// underpromotions that give check. Returns a pointer to the end of the move list. +template<> +ExtMove* generate(const Position& pos, ExtMove* mlist) { - return n; - } + assert(!pos.checkers()); + Color us = pos.side_to_move(); + CheckInfo ci(pos); + Bitboard dc = ci.dcCandidates; - int generate_piece_moves(PieceType piece, const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { + while (dc) + { + Square from = pop_lsb(&dc); + PieceType pt = type_of(pos.piece_on(from)); - const Piece_attacks_fn mem_fn = piece_attacks_fn[piece]; - Square from, to; - Bitboard b; - int n = 0; + if (pt == PAWN) + continue; // Will be generated togheter with direct checks - for (int i = 0; i < pos.piece_count(side, piece); i++) - { - from = pos.piece_list(side, piece, i); - b = (pos.*mem_fn)(from) & target; - while (b) - { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } - } - return n; - } + Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces(); + if (pt == KING) + b &= ~PseudoAttacks[QUEEN][ci.ksq]; - int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { + SERIALIZE(b); + } - int n = 0; + return us == WHITE ? generate_all(pos, mlist, ~pos.pieces(), &ci) + : generate_all(pos, mlist, ~pos.pieces(), &ci); +} - if (pos.can_castle(us)) - { - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - assert(pos.piece_on(ksq) == king_of_color(us)); +/// generate generates all pseudo-legal check evasions when the side +/// to move is in check. Returns a pointer to the end of the move list. +template<> +ExtMove* generate(const Position& pos, ExtMove* mlist) { - if (pos.can_castle_kingside(us)) - { - Square rsq = pos.initial_kr_square(us); - Square g1 = relative_square(us, SQ_G1); - Square f1 = relative_square(us, SQ_F1); - Square s; - bool illegal = false; + assert(pos.checkers()); - assert(pos.piece_on(rsq) == rook_of_color(us)); + int checkersCnt = 0; + Color us = pos.side_to_move(); + Square ksq = pos.king_square(us), from = ksq /* For SERIALIZE */, checksq; + Bitboard sliderAttacks = 0; + Bitboard b = pos.checkers(); - for (s = Min(ksq, g1); s <= Max(ksq, g1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; + assert(pos.checkers()); - for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; + // Find squares attacked by slider checkers, we will remove them from the king + // evasions so to skip known illegal moves avoiding useless legality check later. + do + { + checkersCnt++; + checksq = pop_lsb(&b); - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } + assert(color_of(pos.piece_on(checksq)) == ~us); - if (pos.can_castle_queenside(us)) + switch (type_of(pos.piece_on(checksq))) { - Square rsq = pos.initial_qr_square(us); - Square c1 = relative_square(us, SQ_C1); - Square d1 = relative_square(us, SQ_D1); - Square s; - bool illegal = false; - - assert(pos.piece_on(rsq) == rook_of_color(us)); - - for (s = Min(ksq, c1); s <= Max(ksq, c1); s++) - if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) - || pos.square_is_attacked(s, them)) - illegal = true; - - for (s = Min(rsq, d1); s <= Max(rsq, d1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - - if ( square_file(rsq) == FILE_B - && ( pos.piece_on(relative_square(us, SQ_A1)) == rook_of_color(them) - || pos.piece_on(relative_square(us, SQ_A1)) == queen_of_color(them))) - illegal = true; - - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); + case BISHOP: sliderAttacks |= PseudoAttacks[BISHOP][checksq]; break; + case ROOK: sliderAttacks |= PseudoAttacks[ROOK][checksq]; break; + case QUEEN: + // If queen and king are far or not on a diagonal line we can safely + // remove all the squares attacked in the other direction becuase are + // not reachable by the king anyway. + if (between_bb(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq)) + sliderAttacks |= PseudoAttacks[QUEEN][checksq]; + + // Otherwise we need to use real rook attacks to check if king is safe + // to move in the other direction. For example: king in B2, queen in A1 + // a knight in B1, and we can safely move to C1. + else + sliderAttacks |= PseudoAttacks[BISHOP][checksq] | pos.attacks_from(checksq); + + default: + break; } - } - return n; - } + } while (b); - int generate_piece_checks(PieceType pce, const Position& pos, Bitboard target, - Bitboard dc, Square ksq, MoveStack* mlist) { + // Generate evasions for king, capture and non capture moves + b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; + SERIALIZE(b); - const Piece_attacks_fn mem_fn = piece_attacks_fn[pce]; - int n = 0; + if (checkersCnt > 1) + return mlist; // Double check, only a king move can save the day - // Discovered checks - Bitboard b = target & dc; - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = (pos.*mem_fn)(from) & pos.empty_squares(); - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); - } - } + // Generate blocking evasions or captures of the checking piece + Bitboard target = between_bb(checksq, ksq) | checksq; - // Direct checks - b = target & ~dc; - Bitboard checkSqs = (pos.*mem_fn)(ksq) & pos.empty_squares(); - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = (pos.*mem_fn)(from) & checkSqs; - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); - } - } - return n; - } + return us == WHITE ? generate_all(pos, mlist, target) + : generate_all(pos, mlist, target); +} - int generate_pawn_checks(const PawnOffsets& ofs, const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist) - { - // Pawn moves which give discovered check. This is possible only if the - // pawn is not on the same file as the enemy king, because we don't - // generate captures. - int n = 0; - Bitboard empty = pos.empty_squares(); - - // Find all friendly pawns not on the enemy king's file - Bitboard b1 = pos.pawns(pos.side_to_move()) & ~file_bb(ksq), b2, b3; - - // Discovered checks, single pawn pushes - b2 = b3 = (ofs.next_row_fn)(b1 & dc) & ~ofs.Rank8BB & empty; - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - ofs.DELTA_N, to); - } - // Discovered checks, double pawn pushes - b3 = (ofs.next_row_fn)(b2 & ofs.Rank3BB) & empty; - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to); - } +/// generate generates all the legal moves in the given position - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king +template<> +ExtMove* generate(const Position& pos, ExtMove* mlist) { - b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ?? + ExtMove *end, *cur = mlist; + Bitboard pinned = pos.pinned_pieces(); + Square ksq = pos.king_square(pos.side_to_move()); - // Direct checks, single pawn pushes - b2 = (ofs.next_row_fn)(b1) & empty; - b3 = b2 & pos.pawn_attacks(ofs.them, ksq); - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - ofs.DELTA_N, to); - } + end = pos.checkers() ? generate(pos, mlist) + : generate(pos, mlist); + while (cur != end) + if ( (pinned || from_sq(cur->move) == ksq || type_of(cur->move) == ENPASSANT) + && !pos.pl_move_is_legal(cur->move, pinned)) + cur->move = (--end)->move; + else + cur++; - // Direct checks, double pawn pushes - b3 = (ofs.next_row_fn)(b2 & ofs.Rank3BB) & empty & pos.pawn_attacks(ofs.them, ksq); - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - ofs.DELTA_N - ofs.DELTA_N, to); - } - return n; - } + return end; }