X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=9a6b902bb3efc8b66d2b08a52f63bbad7419a0d5;hp=afe561f55d623aacdc5f34270ba05014b321942a;hb=67338e6f322b8f8ec0d897815e16a87937efc9b0;hpb=aa94f2f4c28ffed69b647ccea3591903e74c4eb0 diff --git a/src/movegen.cpp b/src/movegen.cpp index afe561f5..1082ad01 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,926 +1,543 @@ /* - 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) 2008-2012 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 +#include "bitcount.h" #include "movegen.h" +#include "position.h" +// Simple macro to wrap a very common while loop, no facny, no flexibility, +// hardcoded list name 'mlist' and from square 'from'. +#define SERIALIZE_MOVES(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b)) -//// -//// Local definitions -//// +// Version used for pawns, where the 'from' square is given as a delta from the 'to' square +#define SERIALIZE_MOVES_D(b, d) while (b) { to = pop_1st_bit(&b); (*mlist++).move = make_move(to + (d), to); } namespace { - struct PawnParams { - Bitboard Rank3BB, Rank8BB; - Rank RANK_8; - SquareDelta DELTA_N, DELTA_NE, DELTA_NW; - Color us, them; + enum CastlingSide { + KING_SIDE, + QUEEN_SIDE }; - const PawnParams WhitePawnParams = { Rank3BB, Rank8BB, RANK_8, DELTA_N, DELTA_NE, DELTA_NW, WHITE, BLACK }; - const PawnParams BlackPawnParams = { Rank6BB, Rank1BB, RANK_1, DELTA_S, DELTA_SE, DELTA_SW, BLACK, WHITE }; - - int generate_castle_moves(const Position&, MoveStack*, Color); - template - int generate_pawn_captures(const Position&, MoveStack*); + template + MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us); - template - int generate_pawn_noncaptures(const Position&, MoveStack*); - - template - int generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*, int); + template + MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); - template - int generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*, int); + template + inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { - template - int generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); + assert(Pt != QUEEN && Pt != PAWN); - template - int generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*, int); + Bitboard b = pos.attacks_from(from) & pos.empty_squares(); - template - int generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*, int); + if (Pt == KING) + b &= ~QueenPseudoAttacks[pos.king_square(flip(pos.side_to_move()))]; + SERIALIZE_MOVES(b); + return mlist; + } - /// Templates with specializations are defined here to avoid lookup issues + template + inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, + Bitboard dc, Square ksq) { + assert(Pt != KING && Pt != PAWN); - template - int generate_piece_checks(const Position& pos, Bitboard target, Bitboard dc, - Square ksq, MoveStack* mlist, int n) { - // Discovered checks - Bitboard b = target & dc; - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & pos.empty_squares(); - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); - } - } - // Direct checks - b = target & ~dc; - Bitboard checkSqs = pos.piece_attacks(ksq) & pos.empty_squares(); - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & checkSqs; - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); - } - } - return n; - } + Bitboard checkSqs, b; + Square from; + const Square* pl = pos.piece_list(us, Pt); + + if ((from = *pl++) == SQ_NONE) + return mlist; + checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); - template<> // Special case the King - int generate_piece_checks(const Position& pos, Bitboard, Bitboard dc, - Square ksq, MoveStack* mlist, int n) { - if (bit_is_set(dc, ksq)) + do { - Bitboard bb = pos.piece_attacks(ksq) - & pos.empty_squares() - & ~QueenPseudoAttacks[ksq]; - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(ksq, to); - } - } - return n; - } -} + if ( (Pt == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) + || (Pt == ROOK && !(RookPseudoAttacks[from] & checkSqs)) + || (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) + continue; + if (dc && bit_is_set(dc, from)) + continue; -//// -//// Functions -//// + b = pos.attacks_from(from) & checkSqs; + SERIALIZE_MOVES(b); + } while ((from = *pl++) != SQ_NONE); -/// generate_captures generates() all pseudo-legal captures and queen -/// promotions. The return value is the number of moves generated. + return mlist; + } -int generate_captures(const Position& pos, MoveStack* mlist) { + template<> + FORCE_INLINE MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { - assert(pos.is_ok()); - assert(!pos.is_check()); + return (us == WHITE ? generate_pawn_moves(p, m, dc, ksq) + : generate_pawn_moves(p, m, dc, ksq)); + } - Color us = pos.side_to_move(); - Bitboard target = pos.pieces_of_color(opposite_color(us)); - int n; + template + FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { - if (us == WHITE) - n = generate_pawn_captures(pos, mlist); - else - n = generate_pawn_captures(pos, mlist); - - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - return n; -} + assert(Pt == PAWN); + assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION); + return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) + : generate_pawn_moves(p, m, t, SQ_NONE)); + } -/// generate_noncaptures() generates all pseudo-legal non-captures and -/// underpromotions. The return value is the number of moves generated. + template + FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { -int generate_noncaptures(const Position& pos, MoveStack *mlist) { + Bitboard b; + Square from; + const Square* pl = pos.piece_list(us, Pt); - assert(pos.is_ok()); - assert(!pos.is_check()); + if (*pl != SQ_NONE) + { + do { + from = *pl; + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); + } while (*++pl != SQ_NONE); + } + return mlist; + } - Color us = pos.side_to_move(); - Bitboard target = pos.empty_squares(); - int n; + template<> + FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - if (us == WHITE) - n = generate_pawn_noncaptures(pos, mlist); - else - n = generate_pawn_noncaptures(pos, mlist); + Bitboard b; + Square from = pos.king_square(us); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); - n += generate_piece_moves(pos, mlist+n, us, target); + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); + return mlist; + } - 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. +/// 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. -int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { +template +MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - assert(!pos.is_check()); + assert(!pos.in_check()); - int n; Color us = pos.side_to_move(); - Square ksq = pos.king_square(opposite_color(us)); - - assert(pos.piece_on(ksq) == king_of_color(opposite_color(us))); + Bitboard target; - dc = pos.discovered_check_candidates(us); - - // Pawn moves - if (us == WHITE) - n = generate_pawn_checks(pos, dc, ksq, mlist, 0); + if (Type == MV_CAPTURE || Type == MV_NON_EVASION) + target = pos.pieces(flip(us)); + else if (Type == MV_NON_CAPTURE) + target = pos.empty_squares(); else - n = generate_pawn_checks(pos, dc, ksq, mlist, 0); - - // Pieces moves - Bitboard b = pos.knights(us); - if (b) - n = generate_piece_checks(pos, b, dc, ksq, mlist, n); + assert(false); - b = pos.bishops(us); - if (b) - n = generate_piece_checks(pos, b, dc, ksq, mlist, n); + if (Type == MV_NON_EVASION) + { + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, pos.empty_squares()); + target |= pos.empty_squares(); + } + else + mlist = generate_piece_moves(pos, mlist, us, target); - b = pos.rooks(us); - if (b) - n = generate_piece_checks(pos, b, dc, ksq, mlist, n); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); - b = pos.queens(us); - if (b) - n = generate_piece_checks(pos, b, dc, ksq, mlist, n); + if (Type != MV_CAPTURE && pos.can_castle(us)) + { + if (pos.can_castle(us == WHITE ? WHITE_OO : BLACK_OO)) + mlist = generate_castle_moves(pos, mlist, us); - // Hopefully we always have a king ;-) - n = generate_piece_checks(pos, b, dc, pos.king_square(us), mlist, n); + if (pos.can_castle(us == WHITE ? WHITE_OOO : BLACK_OOO)) + mlist = generate_castle_moves(pos, mlist, us); + } - // TODO: Castling moves! - - return n; + return mlist; } +// Explicit template instantiations +template MoveStack* generate(const Position& pos, MoveStack* mlist); +template MoveStack* generate(const Position& pos, MoveStack* mlist); +template MoveStack* generate(const Position& pos, MoveStack* mlist); -/// 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) { +/// generate generates all pseudo-legal non-captures and knight +/// underpromotions that give check. Returns a pointer to the end of the move list. +template<> +MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - assert(pos.is_check()); + assert(!pos.in_check()); + Bitboard b, dc; + Square from; Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - Square from, to; - int n = 0; + Square ksq = pos.king_square(flip(us)); + + assert(pos.piece_on(ksq) == make_piece(flip(us), KING)); - assert(pos.piece_on(ksq) == king_of_color(us)); - - // Generate evasions for king - Bitboard b1 = pos.piece_attacks(ksq) & ~pos.pieces_of_color(us); - Bitboard b2 = pos.occupied_squares(); - clear_bit(&b2, ksq); + // Discovered non-capture checks + b = dc = pos.discovered_check_candidates(); - while (b1) + while (b) { - Square 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 (!( (bishop_attacks_bb(to, b2) & pos.bishops_and_queens(them)) - || (rook_attacks_bb(to, b2) & pos.rooks_and_queens(them)) - || (pos.piece_attacks(to) & pos.knights(them)) - || (pos.pawn_attacks(us, to) & pos.pawns(them)) - || (pos.piece_attacks(to) & pos.kings(them)))) - - mlist[n++].move = make_move(ksq, to); + from = pop_1st_bit(&b); + switch (type_of(pos.piece_on(from))) + { + case PAWN: /* Will be generated togheter with pawns direct checks */ break; + case KNIGHT: mlist = generate_discovered_checks(pos, mlist, from); break; + case BISHOP: mlist = generate_discovered_checks(pos, mlist, from); break; + case ROOK: mlist = generate_discovered_checks(pos, mlist, from); break; + case KING: mlist = generate_discovered_checks(pos, mlist, from); break; + default: assert(false); break; + } } - // 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). - Bitboard checkers = pos.checkers(); + // Direct non-capture checks + mlist = generate_direct_checks(pos, mlist, us, dc, ksq); + mlist = generate_direct_checks(pos, mlist, us, dc, ksq); + mlist = generate_direct_checks(pos, mlist, us, dc, ksq); + mlist = generate_direct_checks(pos, mlist, us, dc, ksq); + return generate_direct_checks(pos, mlist, us, dc, ksq); +} - if (!(checkers & (checkers - 1))) // Only one bit set? - { - Square checksq = first_1(checkers); - assert(pos.color_of_piece_on(checksq) == them); +/// 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<> +MoveStack* generate(const Position& pos, MoveStack* mlist) { - // Find pinned pieces - Bitboard not_pinned = ~pos.pinned_pieces(us); + assert(pos.in_check()); - // Generate captures of the checking piece + Bitboard b, target; + Square from, checksq; + int checkersCnt = 0; + Color us = pos.side_to_move(); + Square ksq = pos.king_square(us); + Bitboard checkers = pos.checkers(); + Bitboard sliderAttacks = 0; - // Pawn captures - b1 = pos.pawn_attacks(them, checksq) & pos.pawns(us) & not_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); - } + assert(pos.piece_on(ksq) == make_piece(us, KING)); + assert(checkers); - // Pieces captures - b1 = ( (pos.piece_attacks(checksq) & pos.knights(us)) - | (pos.piece_attacks(checksq) & pos.bishops_and_queens(us)) - | (pos.piece_attacks(checksq) & pos.rooks_and_queens(us)) ) & not_pinned; + // Find squares attacked by slider checkers, we will remove + // them from the king evasions set so to early skip known + // illegal moves and avoid an useless legality check later. + b = checkers; + do + { + checkersCnt++; + checksq = pop_1st_bit(&b); - while (b1) - { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); - } + assert(color_of(pos.piece_on(checksq)) == flip(us)); - // Blocking check evasions are possible only if the checking piece is - // a slider - if (checkers & pos.sliders()) + switch (type_of(pos.piece_on(checksq))) { - 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. - if (us == WHITE) - n = generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist, n); + case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break; + case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break; + case QUEEN: + // If queen and king are far we can safely remove all the squares attacked + // in the other direction becuase are not reachable by the king anyway. + if (squares_between(ksq, checksq) || (RookPseudoAttacks[checksq] & (1ULL << ksq))) + sliderAttacks |= QueenPseudoAttacks[checksq]; + + // Otherwise, if king and queen are adjacent and on a diagonal line, 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 - n = generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist, n); - - // Pieces moves - b1 = pos.knights(us) & not_pinned; - if (b1) - n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); + sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq); - b1 = pos.bishops(us) & not_pinned; - if (b1) - n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); - - b1 = pos.rooks(us) & not_pinned; - if (b1) - n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); - - b1 = pos.queens(us) & not_pinned; - if (b1) - n = generate_piece_blocking_evasions(pos, b1, blockSquares, mlist, n); - } - - // 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 &= not_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)) - ||(rook_attacks_bb(ksq, b2) & pos.rooks_and_queens(them)))) - - mlist[n++].move = make_ep_move(from, to); - } - } - } - return n; + default: + break; + } + } while (b); + + // Generate evasions for king, capture and non capture moves + b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; + from = ksq; + SERIALIZE_MOVES(b); + + // Generate evasions for other pieces only if not double check + if (checkersCnt > 1) + return mlist; + + // Find squares where a blocking evasion or a capture of the + // checker piece is possible. + target = squares_between(checksq, ksq) | checkers; + + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, target); + return generate_piece_moves(pos, mlist, us, target); } -/// 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 computes a complete list of legal moves in the current position -int generate_legal_moves(const Position& pos, MoveStack* mlist) { +template<> +MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); + MoveStack *last, *cur = mlist; + Bitboard pinned = pos.pinned_pieces(); - if (pos.is_check()) - return generate_evasions(pos, mlist); + last = pos.in_check() ? generate(pos, mlist) + : generate(pos, mlist); - // Generate pseudo-legal moves: - int n = generate_captures(pos, mlist); - n += generate_noncaptures(pos, mlist + n); + // Remove illegal moves from the list + while (cur != last) + if (!pos.pl_move_is_legal(cur->move, pinned)) + cur->move = (--last)->move; + else + cur++; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - - // 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; - - return n; + return last; } -/// 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. - -Move generate_move_if_legal(const Position &pos, Move m, Bitboard pinned) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - assert(move_is_ok(m)); - - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Piece pc = pos.piece_on(from); - - // 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; - - 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 MOVE_NONE; +namespace { - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); + template + inline Bitboard move_pawns(Bitboard p) { - // The move is pseudo-legal. If it is legal, return it. - return (pos.move_is_legal(m) ? m : MOVE_NONE); + return Delta == DELTA_N ? p << 8 : Delta == DELTA_S ? p >> 8 : + Delta == DELTA_NE ? p << 9 : Delta == DELTA_SE ? p >> 7 : + Delta == DELTA_NW ? p << 7 : Delta == DELTA_SW ? p >> 9 : p; } - // 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); - } + template + inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) { - 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); - } + const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); - // 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; + Bitboard b; + Square to; - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!pos.square_is_empty(to)) - return MOVE_NONE; - break; - - 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; - - 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; - - default: - return MOVE_NONE; - } - // The move is pseudo-legal. Return it if it is legal. - return (pos.move_is_legal(m) ? m : MOVE_NONE); + // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black) + b = move_pawns(pawns) & target & ~TFileABB; + SERIALIZE_MOVES_D(b, -Delta); + 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 + inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) { + const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); -namespace { + Bitboard b; + Square to; - template - int generate_piece_moves(const Position &pos, MoveStack *mlist, - Color side, Bitboard target) { - int n = 0; - for (int i = 0; i < pos.piece_count(side, Piece); i++) - { - Square from = pos.piece_list(side, Piece, i); - Bitboard b = pos.piece_attacks(from) & target; - while (b) - { - Square to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } - } - return n; - } + // Promotions and under-promotions, both captures and non-captures + b = move_pawns(pawnsOn7) & target; + if (Delta != DELTA_N && Delta != DELTA_S) + b &= ~TFileABB; - template - int generate_piece_blocking_evasions(const Position& pos, Bitboard b, - Bitboard blockSquares, MoveStack* mlist, int n) { while (b) { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & blockSquares; - while (bb) + to = pop_1st_bit(&b); + + if (Type == MV_CAPTURE || Type == MV_EVASION) + (*mlist++).move = make_promotion(to - Delta, to, QUEEN); + + if (Type == MV_NON_CAPTURE || Type == MV_EVASION) { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); + (*mlist++).move = make_promotion(to - Delta, to, ROOK); + (*mlist++).move = make_promotion(to - Delta, to, BISHOP); + (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); } + + // This is the only possible under promotion that can give a check + // not already included in the queen-promotion. + if ( Type == MV_CHECK + && bit_is_set(pos.attacks_from(to), pos.king_square(Delta > 0 ? BLACK : WHITE))) + (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); + else (void)pos; // Silence a warning under MSVC } - return n; + return mlist; } - - template - int generate_pawn_captures(const Position& pos, MoveStack* mlist) { - - static const PawnParams PP = (C == WHITE ? WhitePawnParams : BlackPawnParams); - - Bitboard pawns = pos.pawns(PP.us); - Bitboard enemyPieces = pos.pieces_of_color(PP.them); - Square sq; - int n = 0; - - // Captures in the a1-h8 (a8-h1 for black) direction - Bitboard b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces; - - // Capturing promotions - Bitboard b2 = b1 & PP.Rank8BB; - while (b2) + template + MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) { + + // Calculate 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 TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); + const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); + const Square UP = (Us == WHITE ? DELTA_N : DELTA_S); + const Square RIGHT_UP = (Us == WHITE ? DELTA_NE : DELTA_SW); + const Square LEFT_UP = (Us == WHITE ? DELTA_NW : DELTA_SE); + + Square to; + Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares; + Bitboard pawns = pos.pieces(PAWN, Us); + Bitboard pawnsOn7 = pawns & TRank7BB; + Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces(Them)); + + // Pre-calculate pawn pushes before changing emptySquares definition + if (Type != MV_CAPTURE) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NE, sq, QUEEN); + emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); + pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; } - // Capturing non-promotions - b2 = b1 & ~PP.Rank8BB; - while (b2) + if (Type == MV_EVASION) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - PP.DELTA_NE, sq); + emptySquares &= target; // Only blocking squares + enemyPieces &= target; // Capture only the checker piece } - // Captures in the h1-a8 (h8-a1 for black) direction - b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces; - - // Capturing promotions - b2 = b1 & PP.Rank8BB; - while (b2) + // Promotions and underpromotions + if (pawnsOn7) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NW, sq, QUEEN); - } + if (Type == MV_CAPTURE) + emptySquares = pos.empty_squares(); - // Capturing non-promotions - b2 = b1 & ~PP.Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - PP.DELTA_NW, sq); + pawns &= ~TRank7BB; + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, emptySquares); } - // Non-capturing promotions - b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & pos.empty_squares() & Rank8BB; - while (b1) + // Standard captures + if (Type == MV_CAPTURE || Type == MV_EVASION) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_N, sq, QUEEN); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); } - // En passant captures - if (pos.ep_square() != SQ_NONE) + // Single and double pawn pushes + if (Type != MV_CAPTURE) { - assert(PP.us != WHITE || square_rank(pos.ep_square()) == RANK_6); - assert(PP.us != BLACK || square_rank(pos.ep_square()) == RANK_3); - - b1 = pawns & pos.pawn_attacks(PP.them, pos.ep_square()); - assert(b1 != EmptyBoardBB); + b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares); + b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; - while (b1) + if (Type == MV_CHECK) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); + // Consider only pawn moves which give direct checks + b1 &= pos.attacks_from(ksq, Them); + b2 &= pos.attacks_from(ksq, Them); + + // Add 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 generate captures. + if (pawns & target) // For CHECK type target is dc bitboard + { + dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares; + dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } } + SERIALIZE_MOVES_D(b1, -UP); + SERIALIZE_MOVES_D(b2, -UP -UP); } - return n; - } - - - template - int generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) { - - static const PawnParams PP = (C == WHITE ? WhitePawnParams : BlackPawnParams); - - Bitboard pawns = pos.pawns(PP.us); - Bitboard enemyPieces = pos.pieces_of_color(PP.them); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; - Square sq; - int n = 0; - - // Underpromotion captures in the a1-h8 (a8-h1 for black) direction - b1 = (C == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces & PP.Rank8BB; - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NE, sq, KNIGHT); - } - - // Underpromotion captures in the h1-a8 (h8-a1 for black) direction - b1 = (C == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces & PP.Rank8BB; - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_NW, sq, KNIGHT); - } - - // Single pawn pushes - b1 = (C == WHITE ? pawns << 8 : pawns >> 8) & emptySquares; - b2 = b1 & PP.Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_N, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_N, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - PP.DELTA_N, sq, KNIGHT); - } - b2 = b1 & ~PP.Rank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - PP.DELTA_N, sq); - } - - // Double pawn pushes - b2 = (C == WHITE ? (b1 & PP.Rank3BB) << 8 : (b1 & PP.Rank3BB) >> 8) & emptySquares; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - PP.DELTA_N - PP.DELTA_N, sq); - } - return n; - } - - template - int generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist, int n) - { - static const PawnParams PP = (C == WHITE ? WhitePawnParams : BlackPawnParams); - - // 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. - 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 = (C == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & ~PP.Rank8BB & empty; - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - PP.DELTA_N, to); - } - - // Discovered checks, double pawn pushes - b3 = (C == WHITE ? (b2 & PP.Rank3BB) << 8 : (b2 & PP.Rank3BB) >> 8) & empty; - while (b3) + // En passant captures + if ((Type == MV_CAPTURE || Type == MV_EVASION) && pos.ep_square() != SQ_NONE) { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - PP.DELTA_N - PP.DELTA_N, to); - } + assert(Us != WHITE || rank_of(pos.ep_square()) == RANK_6); + assert(Us != BLACK || rank_of(pos.ep_square()) == RANK_3); - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king + // 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 == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP)) + return mlist; - b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ?? + b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - // Direct checks, single pawn pushes - b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & empty; - b3 = b2 & pos.pawn_attacks(PP.them, ksq); - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - PP.DELTA_N, to); - } + assert(b1); - // Direct checks, double pawn pushes - b3 = (C == WHITE ? (b2 & PP.Rank3BB) << 8 : (b2 & PP.Rank3BB) >> 8) - & empty - & pos.pawn_attacks(PP.them, ksq); - - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - PP.DELTA_N - PP.DELTA_N, to); + while (b1) + { + to = pop_1st_bit(&b1); + (*mlist++).move = make_enpassant(to, pos.ep_square()); + } } - return n; + return mlist; } - - template - int generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist, int n) { - - static const PawnParams PP = (C == WHITE ? WhitePawnParams : BlackPawnParams); - - // Find non-pinned pawns - Bitboard b1 = pos.pawns(PP.us) & not_pinned; - - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - Bitboard b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & blockSquares; - while (b2) + template + MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) { + + CastleRight f = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us); + Color them = flip(us); + + // After castling, the rook and king's final positions are exactly the same + // in Chess960 as they would be in standard chess. + Square kfrom = pos.king_square(us); + Square rfrom = pos.castle_rook_square(f); + Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); + + assert(!pos.in_check()); + assert(pos.piece_on(kfrom) == make_piece(us, KING)); + assert(pos.piece_on(rfrom) == make_piece(us, ROOK)); + + // Unimpeded rule: All the squares between the king's initial and final squares + // (including the final square), and all the squares between the rook's initial + // and final squares (including the final square), must be vacant except for + // the king and castling rook. + for (Square s = std::min(kfrom, kto); s <= std::max(kfrom, kto); s++) + if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + ||(pos.attackers_to(s) & pos.pieces(them))) + return mlist; + + for (Square s = std::min(rfrom, rto); s <= std::max(rfrom, rto); s++) + if (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + return mlist; + + // 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 (pos.is_chess960()) { - Square to = pop_1st_bit(&b2); - - assert(pos.piece_on(to) == EMPTY); - - if (square_rank(to) == PP.RANK_8) - { - mlist[n++].move = make_promotion_move(to - PP.DELTA_N, to, QUEEN); - mlist[n++].move = make_promotion_move(to - PP.DELTA_N, to, ROOK); - mlist[n++].move = make_promotion_move(to - PP.DELTA_N, to, BISHOP); - mlist[n++].move = make_promotion_move(to - PP.DELTA_N, to, KNIGHT); - } else - mlist[n++].move = make_move(to - PP.DELTA_N, to); + Bitboard occ = pos.occupied_squares(); + clear_bit(&occ, rfrom); + if (pos.attackers_to(kto, occ) & pos.pieces(them)) + return mlist; } - // Double pawn pushes - b2 = (C == WHITE ? b1 << 8 : b1 >> 8) & pos.empty_squares() & PP.Rank3BB; - b2 = (C == WHITE ? b2 << 8 : b2 >> 8) & blockSquares;; - while (b2) - { - Square to = pop_1st_bit(&b2); - - assert(pos.piece_on(to) == EMPTY); - assert(PP.us != WHITE || square_rank(to) == RANK_4); - assert(PP.us != BLACK || square_rank(to) == RANK_5); + (*mlist++).move = make_castle(kfrom, rfrom); - mlist[n++].move = make_move(to - PP.DELTA_N - PP.DELTA_N, to); - } - return n; + return mlist; } - - int generate_castle_moves(const Position &pos, MoveStack *mlist, Color us) { - - int n = 0; - - 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)); - - 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.piece_on(rsq) == rook_of_color(us)); - - 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; - - for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } - - if (pos.can_castle_queenside(us)) - { - 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); - } - } - return n; - } -} +} // namespace