X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=4b36360c56ae7a13c67178e14d495b320897b531;hp=e7c78bb6e7b43cbf33f477aa635c304438a4dcf8;hb=7a68916ff992115d8013e7ce31850aec558d8ac5;hpb=b145e995592c95014a519e91845379d0f9f89ac6 diff --git a/src/movegen.cpp b/src/movegen.cpp index e7c78bb6..4b36360c 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,6 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) Copyright (C) 2008 Marco Costalba + Copyright (C) 2004-2008 Tord Romstad (Glaurung author) + Copyright (C) 2008-2009 Marco Costalba Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -23,8 +24,15 @@ #include +#include "bitcount.h" #include "movegen.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)) + +// 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); } //// //// Local definitions @@ -32,73 +40,56 @@ namespace { - // Function - int generate_castle_moves(const Position&, MoveStack*); + enum CastlingSide { + KING_SIDE, + QUEEN_SIDE + }; - // Template generate_pawn_captures() with specializations - template - int do_generate_pawn_captures(const Position& pos, MoveStack* mlist); + enum MoveType { + CAPTURE, + NON_CAPTURE, + CHECK, + EVASION + }; - template - inline int generate_pawn_captures(const Position& p, MoveStack* m) { - return do_generate_pawn_captures(p, m); - } - template<> - inline int generate_pawn_captures(const Position& p, MoveStack* m) { - return do_generate_pawn_captures(p, m); - } + // Helper templates + template + MoveStack* generate_castle_moves(const Position&, MoveStack*); - // Template generate_pawn_noncaptures() with specializations - template - int do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist); + template + MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); - template - inline int generate_pawn_noncaptures(const Position& p, MoveStack* m) { - return do_generate_pawn_noncaptures(p, m); - } - template<> - inline int generate_pawn_noncaptures(const Position& p, MoveStack* m) { - return do_generate_pawn_noncaptures(p, m); - } + // Template generate_piece_moves (captures and non-captures) with specializations and overloads + template + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - // Template generate_pawn_blocking_evasions() with specializations - template - int do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist); - template - inline int generate_pawn_blocking_evasions(const Position& p, Bitboard np, Bitboard bs, MoveStack* m) { - return do_generate_pawn_blocking_evasions(p, np, bs, m); - } template<> - inline int generate_pawn_blocking_evasions(const Position& p, Bitboard np, Bitboard bs, MoveStack* m) { - return do_generate_pawn_blocking_evasions(p, np, bs, m); - } + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - // Template generate_pawn_checks() with specializations - template - int do_generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*); + template + inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { - template - inline int generate_pawn_checks(const Position& p, Bitboard dc, Square ksq, MoveStack* m) { - return do_generate_pawn_checks(p, dc, ksq, m); - } - template<> - inline int generate_pawn_checks(const Position& p, Bitboard dc, Square ksq, MoveStack* m) { - return do_generate_pawn_checks(p, dc, ksq, m); + assert(Piece == PAWN); + assert(Type == CAPTURE || Type == NON_CAPTURE || Type == EVASION); + + return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) + : generate_pawn_moves(p, m, t, SQ_NONE)); } - // non-pawn templates - template - int generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard); - template<> - int generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target); + // Templates for non-capture checks generation - template - int generate_piece_checks(const Position&, Bitboard, Bitboard, Square, MoveStack*); - int generate_piece_checks_king(const Position&, Square, Bitboard, Square, MoveStack*); + template + MoveStack* generate_discovered_checks(const Position&, MoveStack*, Square); template - int generate_piece_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*); + MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square); + + template<> + inline MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { + + return (us == WHITE ? generate_pawn_moves(p, m, dc, ksq) + : generate_pawn_moves(p, m, dc, ksq)); + } } @@ -107,415 +98,249 @@ namespace { //// -/// generate_captures generates() all pseudo-legal captures and queen -/// promotions. The return value is the number of moves generated. +/// generate_captures() generates all pseudo-legal captures and queen +/// promotions. Returns a pointer to the end of the move list. -int generate_captures(const Position& pos, MoveStack* mlist) { +MoveStack* generate_captures(const Position& pos, MoveStack* mlist) { 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_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; + 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); + return generate_piece_moves(pos, mlist, us, target); } /// generate_noncaptures() generates all pseudo-legal non-captures and -/// underpromotions. The return value is the number of moves generated. +/// underpromotions. Returns a pointer to the end of the move list. -int generate_noncaptures(const Position& pos, MoveStack *mlist) { +MoveStack* generate_noncaptures(const Position& pos, MoveStack* mlist) { 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_pawn_noncaptures(pos, mlist); - else - n = generate_pawn_noncaptures(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); - n += generate_castle_moves(pos, mlist+n); - return 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); + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_castle_moves(pos, mlist); + return generate_castle_moves(pos, mlist); } -/// 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_non_capture_checks() generates all pseudo-legal non-captures and knight +/// underpromotions that give check. Returns a pointer to the end of the move list. -int generate_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { +MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(!pos.is_check()); - int n; + Bitboard b, dc; + Square from; 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))); - - dc = pos.discovered_check_candidates(us); - - // Pawn moves - if (us == WHITE) - n = generate_pawn_checks(pos, dc, ksq, mlist); - else - n = generate_pawn_checks(pos, dc, ksq, mlist); - - // Pieces moves - Bitboard b = pos.knights(us); - if (b) - n += generate_piece_checks(pos, b, dc, ksq, mlist+n); - - b = pos.bishops(us); - if (b) - n += generate_piece_checks(pos, b, dc, ksq, mlist+n); + assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING)); - b = pos.rooks(us); - if (b) - n += generate_piece_checks(pos, b, dc, ksq, mlist+n); + // Discovered non-capture checks + b = dc = pos.discovered_check_candidates(us); - b = pos.queens(us); - if (b) - n += generate_piece_checks(pos, b, dc, ksq, mlist+n); - - // Hopefully we always have a king ;-) - n += generate_piece_checks_king(pos, pos.king_square(us), dc, ksq, mlist+n); - - // TODO: Castling moves! + while (b) + { + from = pop_1st_bit(&b); + switch (pos.type_of_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; + } + } - return n; + // 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); } -/// 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 +/// generate_evasions() generates all pseudo-legal check evasions when +/// the side to move is in check. Returns a pointer to the end of the move list. -int generate_evasions(const Position& pos, MoveStack* mlist) { +MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(pos.is_check()); + Bitboard b, target; + Square from, checksq; + int checkersCnt = 0; Color us = pos.side_to_move(); - Color them = opposite_color(us); Square ksq = pos.king_square(us); - Square from, to; - int n = 0; - - 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); - - 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 (!( (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); - } - - // 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(); + Bitboard sliderAttacks = EmptyBoardBB; - if (!(checkers & (checkers - 1))) // Only one bit set? - { - Square checksq = first_1(checkers); - - assert(pos.color_of_piece_on(checksq) == them); - - // Find pinned pieces - Bitboard not_pinned = ~pos.pinned_pieces(us); + assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); + assert(checkers); - // Generate captures of the checking piece - - // 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); - } + // 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); - // 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; + assert(pos.color_of_piece_on(checksq) == opposite_color(us)); - while (b1) + switch (pos.type_of_piece_on(checksq)) { - from = pop_1st_bit(&b1); - mlist[n++].move = make_move(from, checksq); + case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break; + case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break; + case QUEEN: + // In case of a queen remove also squares attacked in the other direction to + // avoid possible illegal moves when queen and king are on adjacent squares. + if (direction_is_straight(checksq, ksq)) + sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from(checksq); + else + sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq); + default: + break; } + } while (b); + + // Generate evasions for king, capture and non capture moves + b = pos.attacks_from(ksq) & ~pos.pieces_of_color(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); +} - // 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. - if (us == WHITE) - n += generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist+n); - else - n += generate_pawn_blocking_evasions(pos, not_pinned, blockSquares, mlist+n); +/// 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. - // Pieces moves - b1 = pos.knights(us) & not_pinned; - if (b1) - n += generate_piece_blocking_evasions(pos, b1, blockSquares, mlist+n); +MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) { - b1 = pos.bishops(us) & not_pinned; - if (b1) - n += generate_piece_blocking_evasions(pos, b1, blockSquares, mlist+n); + assert(pos.is_ok()); - b1 = pos.rooks(us) & not_pinned; - if (b1) - n += generate_piece_blocking_evasions(pos, b1, blockSquares, mlist+n); + MoveStack *last, *cur = mlist; + Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - b1 = pos.queens(us) & not_pinned; - if (b1) - n += generate_piece_blocking_evasions(pos, b1, blockSquares, mlist+n); - } + // Generate pseudo-legal moves + if (pos.is_check()) + last = generate_evasions(pos, mlist); + else + last = generate_noncaptures(pos, generate_captures(pos, mlist)); - // 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); + if (pseudoLegal) + return last; - assert(b1 != EmptyBoardBB); + // Remove illegal moves from the list + while (cur != last) + if (pos.pl_move_is_legal(cur->move, pinned)) + cur++; + else + cur->move = (--last)->move; - 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; + return last; } -/// 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. +/// move_is_legal() takes a position and a (not necessarily pseudo-legal) +/// move and tests whether the move is legal. This version is not very fast +/// and should be used only in non time-critical paths. -int generate_legal_moves(const Position& pos, MoveStack* mlist) { +bool move_is_legal(const Position& pos, const Move m) { - assert(pos.is_ok()); + MoveStack mlist[256]; + MoveStack *cur, *last = generate_moves(pos, mlist, true); - if (pos.is_check()) - return generate_evasions(pos, mlist); - - // Generate pseudo-legal moves: - int n = generate_captures(pos, mlist); - n += generate_noncaptures(pos, mlist + n); - - 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; + for (cur = mlist; cur != last; cur++) + if (cur->move == m) + return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move())); - return n; + return false; } -/// 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. +/// 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. -Move generate_move_if_legal(const Position& pos, Move m, Bitboard pinned) { +bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { assert(pos.is_ok()); - assert(!pos.is_check()); assert(move_is_ok(m)); + assert(pinned == pos.pinned_pieces(pos.side_to_move())); 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); + // Use a slower but simpler function for uncommon cases + if (move_is_ep(m) || move_is_castle(m)) + return move_is_legal(pos, m); + // 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; - - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); - - // The move is pseudo-legal. If it is legal, return it. - return (pos.move_is_legal(m) ? m : MOVE_NONE); - } - - // 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); - } - - 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); - } - - // Normal moves + return false; // The destination square cannot be occupied by a friendly piece if (pos.color_of_piece_on(to) == us) - return MOVE_NONE; + 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) { - // 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) + // Move direction must be compatible with pawn color + int direction = to - from; + if ((us == WHITE) != (direction > 0)) + return false; + + // 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 origin and + // destination squares. + switch (direction) { case DELTA_NW: case DELTA_NE: @@ -524,14 +349,14 @@ Move generate_move_if_legal(const Position& pos, Move m, Bitboard pinned) { // 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; + return false; break; case DELTA_N: case DELTA_S: // Pawn push. The destination square must be empty. if (!pos.square_is_empty(to)) - return MOVE_NONE; + return false; break; case DELTA_NN: @@ -541,7 +366,7 @@ Move generate_move_if_legal(const Position& pos, Move m, Bitboard pinned) { if ( square_rank(to) != RANK_4 || !pos.square_is_empty(to) || !pos.square_is_empty(from + DELTA_N)) - return MOVE_NONE; + return false; break; case DELTA_SS: @@ -551,424 +376,318 @@ Move generate_move_if_legal(const Position& pos, Move m, Bitboard pinned) { if ( square_rank(to) != RANK_5 || !pos.square_is_empty(to) || !pos.square_is_empty(from + DELTA_S)) - return MOVE_NONE; + return false; break; default: - return MOVE_NONE; + return false; } - // The move is pseudo-legal. Return it if it is legal. - return (pos.move_is_legal(m) ? m : MOVE_NONE); + // The move is pseudo-legal, check if it is also legal + return pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned); } // 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); + return bit_is_set(pos.attacks_from(pc, from), to) + && (pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned)) + && !move_is_promotion(m); } namespace { template - int generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - Square from, to; Bitboard b; - int n = 0; + Square from; + const Square* ptr = pos.piece_list_begin(us, Piece); - for (int i = 0; i < pos.piece_count(us, Piece); i++) + while ((from = *ptr++) != SQ_NONE) { - from = pos.piece_list(us, Piece, i); - b = pos.piece_attacks(from) & target; - while (b) - { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); } - return n; + return mlist; } template<> - int generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { Bitboard b; - Square to, from = pos.king_square(us); - int n = 0; + Square from = pos.king_square(us); - b = pos.piece_attacks(from) & target; - while (b) - { - to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } - return n; + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); + return mlist; } - template - int generate_piece_blocking_evasions(const Position& pos, Bitboard b, - Bitboard blockSquares, MoveStack* mlist) { - int n = 0; - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & blockSquares; - while (bb) - { - Square to = pop_1st_bit(&bb); - mlist[n++].move = make_move(from, to); - } - } - return n; + template + inline Bitboard move_pawns(Bitboard p) { + + if (Direction == DELTA_N) + return Us == WHITE ? p << 8 : p >> 8; + else if (Direction == DELTA_NE) + return Us == WHITE ? p << 9 : p >> 7; + else if (Direction == DELTA_NW) + return Us == WHITE ? p << 7 : p >> 9; + else + return p; } + template + inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces) { - template - int do_generate_pawn_captures(const Position& pos, MoveStack* mlist) { + // Calculate our parametrized parameters at compile time + const Bitboard TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB); + const Bitboard TFileABB = (Diagonal == DELTA_NE ? FileABB : FileHBB); + const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE); + const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW); + const SquareDelta TTDELTA_NE = (Diagonal == DELTA_NE ? TDELTA_NE : TDELTA_NW); - Bitboard pawns = pos.pawns(Us); - Bitboard enemyPieces = pos.pieces_of_color(Them); - Square sq; - int n = 0; + Bitboard b1, b2; + Square to; - // Captures in the a1-h8 (a8-h1 for black) direction - Bitboard b1 = (Us == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces; + // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black) + b1 = move_pawns(pawns) & ~TFileABB & enemyPieces; - // Capturing promotions - Bitboard b2 = b1 & TRank8BB; - while (b2) + // Capturing promotions and under-promotions + if (b1 & TRank8BB) { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - TDELTA_NE, sq, QUEEN); + b2 = b1 & TRank8BB; + b1 &= ~TRank8BB; + while (b2) + { + to = pop_1st_bit(&b2); + + if (Type == CAPTURE || Type == EVASION) + (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN); + + if (Type == NON_CAPTURE || Type == EVASION) + { + (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, ROOK); + (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, BISHOP); + (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT); + } + + // This is the only possible under promotion that can give a check + // not already included in the queen-promotion. It is not sure that + // the promoted knight will give check, but it doesn't worth to verify. + if (Type == CHECK) + (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT); + } } - // Capturing non-promotions - b2 = b1 & ~TRank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - TDELTA_NE, sq); - } + // Serialize standard captures + if (Type == CAPTURE || Type == EVASION) + SERIALIZE_MOVES_D(b1, -TTDELTA_NE); - // Captures in the h1-a8 (h8-a1 for black) direction - b1 = (Us == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces; + return mlist; + } - // Capturing promotions - b2 = b1 & TRank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - TDELTA_NW, sq, QUEEN); - } + template + MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) { - // Capturing non-promotions - b2 = b1 & ~TRank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - TDELTA_NW, sq); - } + // Calculate our parametrized parameters at compile time + 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 SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); - // Non-capturing promotions - b1 = (Us == WHITE ? pawns << 8 : pawns >> 8) & pos.empty_squares() & TRank8BB; - while (b1) + Square to; + Bitboard b1, b2, enemyPieces, emptySquares; + Bitboard pawns = pos.pieces(PAWN, Us); + + // Standard captures and capturing promotions and underpromotions + if (Type == CAPTURE || Type == EVASION || (pawns & TRank7BB)) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - TDELTA_N, sq, QUEEN); + enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(opposite_color(Us))); + + if (Type == EVASION) + enemyPieces &= target; // Capture only the checker piece + + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); } - // En passant captures - if (pos.ep_square() != SQ_NONE) + // Non-capturing promotions and underpromotions + if (pawns & TRank7BB) { - assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6); - assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3); + b1 = move_pawns(pawns) & TRank8BB & pos.empty_squares(); - b1 = pawns & pos.pawn_attacks(Them, pos.ep_square()); - assert(b1 != EmptyBoardBB); + if (Type == EVASION) + b1 &= target; // Only blocking promotion pushes while (b1) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_ep_move(sq, pos.ep_square()); + to = pop_1st_bit(&b1); + + if (Type == CAPTURE || Type == EVASION) + (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); + + if (Type == NON_CAPTURE || Type == EVASION) + { + (*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); + } + + // This is the only possible under promotion that can give a check + // not already included in the queen-promotion. + if (Type == CHECK && bit_is_set(pos.attacks_from(to), pos.king_square(Them))) + (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); } } - return n; - } - template - int do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) { - - Bitboard pawns = pos.pawns(Us); - Bitboard enemyPieces = pos.pieces_of_color(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 = (Us == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces & TRank8BB; - while (b1) + // Standard pawn pushes and double pushes + if (Type != CAPTURE) { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - TDELTA_NE, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - TDELTA_NE, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - TDELTA_NE, sq, KNIGHT); - } + emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares()); - // Underpromotion captures in the h1-a8 (h8-a1 for black) direction - b1 = (Us == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces & TRank8BB; - while (b1) - { - sq = pop_1st_bit(&b1); - mlist[n++].move = make_promotion_move(sq - TDELTA_NW, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - TDELTA_NW, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - TDELTA_NW, sq, KNIGHT); - } - - // Single pawn pushes - b1 = (Us == WHITE ? pawns << 8 : pawns >> 8) & emptySquares; - b2 = b1 & TRank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_promotion_move(sq - TDELTA_N, sq, ROOK); - mlist[n++].move = make_promotion_move(sq - TDELTA_N, sq, BISHOP); - mlist[n++].move = make_promotion_move(sq - TDELTA_N, sq, KNIGHT); - } - b2 = b1 & ~TRank8BB; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - TDELTA_N, sq); - } + // Single and double pawn pushes + b1 = move_pawns(pawns) & emptySquares & ~TRank8BB; + b2 = move_pawns(b1 & TRank3BB) & emptySquares; - // Double pawn pushes - b2 = (Us == WHITE ? (b1 & TRank3BB) << 8 : (b1 & TRank3BB) >> 8) & emptySquares; - while (b2) - { - sq = pop_1st_bit(&b2); - mlist[n++].move = make_move(sq - TDELTA_N - TDELTA_N, sq); + // Filter out unwanted pushes according to the move type + if (Type == EVASION) + { + b1 &= target; + b2 &= target; + } + else if (Type == CHECK) + { + // Pawn moves which give direct cheks + b1 &= pos.attacks_from(ksq, Them); + b2 &= pos.attacks_from(ksq, Them); + + // 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 + { + Bitboard dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares & ~TRank8BB; + Bitboard dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } + } + SERIALIZE_MOVES_D(b1, -TDELTA_N); + SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); } - return n; - } - - template - int do_generate_pawn_checks(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(Us) & ~file_bb(ksq), b2, b3; - - // Discovered checks, single pawn pushes - b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & ~TRank8BB & empty; - while (b3) + // En passant captures + if ((Type == CAPTURE || Type == EVASION) && pos.ep_square() != SQ_NONE) { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - TDELTA_N, to); - } + assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6); + assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3); - // Discovered checks, double pawn pushes - b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty; - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - TDELTA_N - TDELTA_N, to); - } + // 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 == EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N)) + return mlist; - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king + b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - b1 &= (~dc & neighboring_files_bb(ksq)); // FIXME why ~dc ?? + assert(b1 != EmptyBoardBB); - // Direct checks, single pawn pushes - b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & empty; - b3 = b2 & pos.pawn_attacks(Them, ksq); - while (b3) - { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - TDELTA_N, to); + while (b1) + { + to = pop_1st_bit(&b1); + (*mlist++).move = make_ep_move(to, pos.ep_square()); + } } + return mlist; + } - // Direct checks, double pawn pushes - b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) - & empty - & pos.pawn_attacks(Them, ksq); + template + MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { - while (b3) + assert(Piece != QUEEN); + + Bitboard b = pos.attacks_from(from) & pos.empty_squares(); + if (Piece == KING) { - Square to = pop_1st_bit(&b3); - mlist[n++].move = make_move(to - TDELTA_N - TDELTA_N, to); + Square ksq = pos.king_square(opposite_color(pos.side_to_move())); + b &= ~QueenPseudoAttacks[ksq]; } - return n; + SERIALIZE_MOVES(b); + return mlist; } template - int generate_piece_checks(const Position& pos, Bitboard target, Bitboard dc, - Square ksq, MoveStack* mlist) { - // Discovered checks - int n = 0; - 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; - } + MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, + Bitboard dc, Square ksq) { + assert(Piece != KING); - int generate_piece_checks_king(const Position& pos, Square from, Bitboard dc, - Square ksq, MoveStack* mlist) { - int n = 0; - if (bit_is_set(dc, from)) - { - Bitboard b = pos.piece_attacks(from) - & pos.empty_squares() - & ~QueenPseudoAttacks[ksq]; - while (b) - { - Square to = pop_1st_bit(&b); - mlist[n++].move = make_move(from, to); - } - } - return n; - } + Bitboard checkSqs, b; + Square from; + const Square* ptr = pos.piece_list_begin(us, Piece); + if ((from = *ptr++) == SQ_NONE) + return mlist; - template - int do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist) { - // Find non-pinned pawns - int n = 0; - Bitboard b1 = pos.pawns(Us) & not_pinned; + checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); - // Single pawn pushes. We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - Bitboard b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & blockSquares; - while (b2) + do { - Square to = pop_1st_bit(&b2); + if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) + || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs)) + || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) + continue; - assert(pos.piece_on(to) == EMPTY); + if (dc && bit_is_set(dc, from)) + continue; - if (square_rank(to) == TRANK_8) - { - mlist[n++].move = make_promotion_move(to - TDELTA_N, to, QUEEN); - mlist[n++].move = make_promotion_move(to - TDELTA_N, to, ROOK); - mlist[n++].move = make_promotion_move(to - TDELTA_N, to, BISHOP); - mlist[n++].move = make_promotion_move(to - TDELTA_N, to, KNIGHT); - } else - mlist[n++].move = make_move(to - TDELTA_N, to); - } - - // Double pawn pushes - b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & pos.empty_squares() & TRank3BB; - b2 = (Us == WHITE ? b2 << 8 : b2 >> 8) & blockSquares;; - while (b2) - { - Square to = pop_1st_bit(&b2); + b = pos.attacks_from(from) & checkSqs; + SERIALIZE_MOVES(b); - assert(pos.piece_on(to) == EMPTY); - assert(Us != WHITE || square_rank(to) == RANK_4); - assert(Us != BLACK || square_rank(to) == RANK_5); + } while ((from = *ptr++) != SQ_NONE); - mlist[n++].move = make_move(to - TDELTA_N - TDELTA_N, to); - } - return n; + return mlist; } + template + MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) { - int generate_castle_moves(const Position& pos, MoveStack* mlist) { - - int n = 0; Color us = pos.side_to_move(); - if (pos.can_castle(us)) + if ( (Side == KING_SIDE && pos.can_castle_kingside(us)) + ||(Side == QUEEN_SIDE && pos.can_castle_queenside(us))) { Color them = opposite_color(us); Square ksq = pos.king_square(us); - assert(pos.piece_on(ksq) == king_of_color(us)); + assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); - 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)); + Square rsq = (Side == KING_SIDE ? pos.initial_kr_square(us) : pos.initial_qr_square(us)); + Square s1 = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); + Square s; + bool illegal = false; - 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.piece_on(rsq) == piece_of_color_and_type(us, ROOK)); - for (s = Min(rsq, f1); s <= Max(rsq, f1); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; + // It is a bit complicated to correctly handle Chess960 + for (s = Min(ksq, s1); s <= Max(ksq, s1); s++) + if ( (s != ksq && s != rsq && pos.square_is_occupied(s)) + ||(pos.attackers_to(s) & pos.pieces_of_color(them))) + illegal = true; - if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } + for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) + if (s != ksq && s != rsq && pos.square_is_occupied(s)) + illegal = true; - 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))) + if ( Side == QUEEN_SIDE + && square_file(rsq) == FILE_B + && ( pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, ROOK) + || pos.piece_on(relative_square(us, SQ_A1)) == piece_of_color_and_type(them, QUEEN))) illegal = true; if (!illegal) - mlist[n++].move = make_castle_move(ksq, rsq); - } + (*mlist++).move = make_castle_move(ksq, rsq); } - return n; + return mlist; } }