X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=0db293ccc7eb713901e139665578821a3b077a9f;hp=f22df724952a81d82cac66616c6921641b560d5e;hb=4dded4e72f9b9582db8adc9a478e9eda5841d8c5;hpb=9bffe811c44b88ba3b5dd0904539c8ca14257a35 diff --git a/src/movegen.cpp b/src/movegen.cpp index f22df724..0db293cc 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) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -23,12 +24,16 @@ #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 //// @@ -40,68 +45,51 @@ namespace { QUEEN_SIDE }; - static const bool CAPTURE = true; - static const bool NON_CAPTURE = false; - - // Function - bool castling_is_check(const Position&, CastlingSide); + enum MoveType { + CAPTURE, + NON_CAPTURE, + CHECK, + EVASION + }; - // Main templates + // Helper templates template MoveStack* generate_castle_moves(const Position&, MoveStack*); - template - MoveStack* generate_piece_checks(const Position&, MoveStack*, Color us, Bitboard, Square); + template + MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); - // Helper templates - template - MoveStack* do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist); + // Template generate_piece_moves (captures and non-captures) with specializations and overloads + template + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - template - MoveStack* do_generate_pawn_captures(const Position& pos, MoveStack* mlist); + template<> + MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - template - MoveStack* do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist); + template + inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { - // Template generate_pawn_checks() with specializations - template - MoveStack* do_generate_pawn_checks(const Position&, Bitboard, Square, MoveStack*); + assert(Piece == PAWN); + assert(Type == CAPTURE || Type == NON_CAPTURE || Type == EVASION); - template - inline MoveStack* generate_pawn_checks(const Position& p, MoveStack* m, Bitboard dc, Square ksq) { - return do_generate_pawn_checks(p, dc, ksq, m); - } - template<> - inline MoveStack* generate_pawn_checks(const Position& p, MoveStack* m, Bitboard dc, Square ksq) { - return do_generate_pawn_checks(p, dc, ksq, m); + return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) + : generate_pawn_moves(p, m, t, SQ_NONE)); } - // Template generate_piece_moves() with specializations - template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color us, Bitboard); - template<> - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target); - - template - inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us) { + // Templates for non-capture checks generation - assert(Piece == PAWN); - - if (Capture) - return (us == WHITE ? do_generate_pawn_captures(p, m) - : do_generate_pawn_captures(p, m)); - else - return (us == WHITE ? do_generate_pawn_noncaptures(p, m) - : do_generate_pawn_noncaptures(p, m)); - } + template + MoveStack* generate_discovered_checks(const Position&, MoveStack*, Square); - // Template generate_piece_blocking_evasions() with specializations template - MoveStack* generate_piece_blocking_evasions(const Position&, MoveStack*, Color us, Bitboard, Bitboard); + MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square); template<> - MoveStack* generate_piece_blocking_evasions(const Position& p, MoveStack* m, Color us, Bitboard np, Bitboard bs); + 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)); + } } @@ -110,402 +98,271 @@ 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)); - MoveStack* mlist_start = mlist; 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); - mlist = generate_piece_moves(pos, mlist, us, target); - return int(mlist - mlist_start); + 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(); - MoveStack* mlist_start = mlist; - mlist = generate_piece_moves(pos, mlist, us); + 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); - mlist = generate_castle_moves(pos, mlist); - return int(mlist - mlist_start); + return generate_castle_moves(pos, mlist); } -/// generate_checks() generates all pseudo-legal non-capturing, non-promoting -/// checks. It returns the number of generated moves. +/// generate_non_evasions() 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) { +MoveStack* generate_non_evasions(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); assert(!pos.is_check()); Color us = pos.side_to_move(); - Square ksq = pos.king_square(opposite_color(us)); - MoveStack* mlist_start = mlist; - - assert(pos.piece_on(ksq) == king_of_color(opposite_color(us))); - - // Pawn moves - if (us == WHITE) - mlist = generate_pawn_checks(pos, mlist, dc, ksq); - else - mlist = generate_pawn_checks(pos, mlist, dc, ksq); - - // Pieces moves - mlist = generate_piece_checks(pos, mlist, us, dc, ksq); - mlist = generate_piece_checks(pos, mlist, us, dc, ksq); - mlist = generate_piece_checks(pos, mlist, us, dc, ksq); - mlist = generate_piece_checks(pos, mlist, us, dc, ksq); - mlist = generate_piece_checks(pos, mlist, us, dc, ksq); - - // Castling moves that give check. Very rare but nice to have! - if ( pos.can_castle_queenside(us) - && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_D) - && castling_is_check(pos, QUEEN_SIDE)) - mlist = generate_castle_moves(pos, mlist); - - if ( pos.can_castle_kingside(us) - && (square_rank(ksq) == square_rank(pos.king_square(us)) || square_file(ksq) == FILE_F) - && castling_is_check(pos, KING_SIDE)) - mlist = generate_castle_moves(pos, mlist); - - return int(mlist - mlist_start); + Bitboard target = pos.pieces_of_color(opposite_color(us)); + + mlist = generate_piece_moves(pos, mlist, us, target); + mlist = generate_piece_moves(pos, mlist, us, pos.empty_squares()); + + target |= pos.empty_squares(); + + 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_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_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_evasions(const Position& pos, MoveStack* mlist) { +MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist) { assert(pos.is_ok()); - assert(pos.is_check()); + assert(!pos.is_check()); - Square from, to; + Bitboard b, dc; + Square from; Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - MoveStack* mlist_start = mlist; + Square ksq = pos.king_square(opposite_color(us)); - assert(pos.piece_on(ksq) == king_of_color(us)); + assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING)); - // The bitboard of occupied pieces without our king - Bitboard b2 = pos.occupied_squares(); - clear_bit(&b2, ksq); + // Discovered non-capture checks + b = dc = pos.discovered_check_candidates(us); - // Find squares attacked by slider checkers, we will - // remove them from king evasions set so to avoid a couple - // of cycles in the slow king evasions legality check loop. - Bitboard checkers = pos.checkers(); - Bitboard checkersAttacks = EmptyBoardBB; - Bitboard b = checkers & (pos.queens() | pos.bishops()); while (b) { - from = pop_1st_bit(&b); - checkersAttacks |= bishop_attacks_bb(from, b2); + 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; + } } - b = checkers & (pos.queens() | pos.rooks()); - while (b) - { - from = pop_1st_bit(&b); - checkersAttacks |= rook_attacks_bb(from, b2); - } + // 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 for king - Bitboard b1 = pos.piece_attacks(ksq) & ~pos.pieces_of_color(us) & ~checkersAttacks; - 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.piece_attacks(to) & pos.knights(them)) - || (pos.pawn_attacks(us, to) & pos.pawns(them)) - || (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.kings(them)))) - (*mlist++).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). - if (!(checkers & (checkers - 1))) // Only one bit set? - { - Square checksq = first_1(checkers); +/// 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. - assert(pos.color_of_piece_on(checksq) == them); +MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) { - // Find pinned pieces - Bitboard not_pinned = ~pos.pinned_pieces(us); + assert(pos.is_ok()); + assert(pos.is_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 = EmptyBoardBB; - // 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++).move = make_promotion_move(from, checksq, QUEEN); - (*mlist++).move = make_promotion_move(from, checksq, ROOK); - (*mlist++).move = make_promotion_move(from, checksq, BISHOP); - (*mlist++).move = make_promotion_move(from, checksq, KNIGHT); - } else - (*mlist++).move = make_move(from, checksq); - } + assert(pos.piece_on(ksq) == piece_of_color_and_type(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++).move = make_move(from, checksq); - } + assert(pos.color_of_piece_on(checksq) == opposite_color(us)); - // Blocking check evasions are possible only if the checking piece is - // a slider - if (checkers & pos.sliders()) + switch (pos.type_of_piece_on(checksq)) { - Bitboard blockSquares = squares_between(checksq, ksq); - - assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB); + 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 (squares_straight_aligned(checksq, ksq)) + sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from(checksq); + else + sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq); + default: + break; + } + } while (b); - // Pieces moves - mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); - mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); - mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); - mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); - mlist = generate_piece_blocking_evasions(pos, mlist, us, not_pinned, blockSquares); - } + // 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); - // 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); + // Generate evasions for other pieces only if not double check + if (checkersCnt > 1) + return mlist; - assert(b1 != EmptyBoardBB); + // Find squares where a blocking evasion or a capture of the + // checker piece is possible. + target = squares_between(checksq, ksq) | checkers; - 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++).move = make_ep_move(from, to); - } - } - } - return int(mlist - mlist_start); + 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_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. -int generate_legal_moves(const Position& pos, MoveStack* mlist) { +MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) { assert(pos.is_ok()); - if (pos.is_check()) - return generate_evasions(pos, mlist); + MoveStack *last, *cur = mlist; + Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); // 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()); + last = pos.is_check() ? generate_evasions(pos, mlist) + : generate_non_evasions(pos, mlist); + if (pseudoLegal) + return last; // Remove illegal moves from the list - for (int i = 0; i < n; i++) - if (!pos.pl_move_is_legal(mlist[i].move, pinned)) - mlist[i--].move = mlist[--n].move; + while (cur != last) + if (pos.pl_move_is_legal(cur->move, pinned)) + cur++; + else + cur->move = (--last)->move; - return n; + return last; } /// move_is_legal() takes a position and a (not necessarily pseudo-legal) -/// move and a pinned pieces bitboard as input, and tests whether -/// the move is legal. If the move is legal, the move itself is -/// returned. If not, the function returns false. This function must -/// only be used when the side to move is not in check. +/// move and tests whether the move is legal. This version is not very fast +/// and should be used only in non time-critical paths. + +bool move_is_legal(const Position& pos, const Move m) { + + MoveStack mlist[MOVES_MAX]; + MoveStack *cur, *last = generate_moves(pos, mlist, true); + + 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 false; +} + + +/// Fast version of move_is_legal() that takes a position a move and a +/// bitboard of pinned pieces as input, and tests whether the move is legal. 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_special(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 false; - Square to = move_to(m); - - // En passant moves - if (move_is_ep(m)) - { - // The piece must be a pawn and destination square must be the - // en passant square. - if ( type_of_piece(pc) != PAWN - || to != pos.ep_square()) - return false; - - assert(pos.square_is_empty(to)); - assert(pos.piece_on(to - pawn_push(us)) == pawn_of_color(them)); - - // The move is pseudo-legal, check if it is also legal - return pos.pl_move_is_legal(m, pinned); - } - - // Castling moves - if (move_is_short_castle(m)) - { - // The piece must be a king and side to move must still have - // the right to castle kingside. - if ( type_of_piece(pc) != KING - ||!pos.can_castle_kingside(us)) - return false; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_kr_square(us)); - assert(pos.piece_on(to) == 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; - } - - if (move_is_long_castle(m)) - { - // The piece must be a king and side to move must still have - // the right to castle kingside. - if ( type_of_piece(pc) != KING - ||!pos.can_castle_queenside(us)) - return false; - - assert(from == pos.king_square(us)); - assert(to == pos.initial_qr_square(us)); - assert(pos.piece_on(to) == 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; - } - - // Normal moves - // The destination square cannot be occupied by a friendly piece if (pos.color_of_piece_on(to) == us) return false; - // Proceed according to the type of the moving piece. + // Handle the special case of a pawn move if (type_of_piece(pc) == PAWN) { - // 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)) + // Move direction must be compatible with pawn color + int direction = to - from; + if ((us == WHITE) != (direction > 0)) + return false; + + // We have already handled promotion moves, so destination + // cannot be on the 8/1th rank. + if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1) return false; - // Proceed according to the square delta between the source and - // destionation squares. - switch (to - from) + // Proceed according to the square delta between the origin and + // destination squares. + switch (direction) { case DELTA_NW: case DELTA_NE: @@ -547,14 +404,12 @@ bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { default: return false; } - // The move is pseudo-legal, check if it is also legal - return pos.pl_move_is_legal(m, pinned); } + else if (!bit_is_set(pos.attacks_from(pc, from), to)) + return false; - // Luckly we can handle all the other pieces in one go - return ( pos.piece_attacks_square(from, to) - && pos.pl_move_is_legal(m, pinned) - && !move_promotion(m)); + // 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); } @@ -563,14 +418,17 @@ namespace { template MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - Square from; Bitboard b; + Square from; + const Square* ptr = pos.piece_list_begin(us, Piece); - for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++) + if (*ptr != SQ_NONE) { - from = pos.piece_list(us, Piece, i); - b = pos.piece_attacks(from) & target; - SERIALIZE_MOVES(b); + do { + from = *ptr; + b = pos.attacks_from(from) & target; + SERIALIZE_MOVES(b); + } while (*++ptr != SQ_NONE); } return mlist; } @@ -581,295 +439,218 @@ namespace { Bitboard b; Square from = pos.king_square(us); - b = pos.piece_attacks(from) & target; + b = pos.attacks_from(from) & target; SERIALIZE_MOVES(b); return mlist; } - template - MoveStack* generate_piece_blocking_evasions(const Position& pos, MoveStack* mlist, Color us, - Bitboard not_pinned, Bitboard blockSquares) { + template + inline Bitboard move_pawns(Bitboard p) { - Bitboard b = pos.pieces_of_color_and_type(us, Piece) & not_pinned; - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & blockSquares; - SERIALIZE_MOVES(bb); - } - return mlist; + 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; } - template<> - MoveStack* generate_piece_blocking_evasions(const Position& p, MoveStack* m, Color us, - Bitboard np, Bitboard bs) { - if (us == WHITE) - return do_generate_pawn_blocking_evasions(p, np, bs, m); - else - return do_generate_pawn_blocking_evasions(p, np, bs, m); - } + template + inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) { - template - MoveStack* do_generate_pawn_captures(const Position& pos, MoveStack* mlist) { + const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); + Bitboard b; Square to; - Bitboard pawns = pos.pawns(Us); - Bitboard enemyPieces = pos.pieces_of_color(Them); - // Captures in the a1-h8 (a8-h1 for black) direction - Bitboard b1 = (Us == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces; - - // Capturing promotions - Bitboard b2 = b1 & TRank8BB; - while (b2) - { - to = pop_1st_bit(&b2); - (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, QUEEN); - } + // 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; + } - // Capturing non-promotions - b2 = b1 & ~TRank8BB; - while (b2) - { - to = pop_1st_bit(&b2); - (*mlist++).move = make_move(to - TDELTA_NE, to); - } + template + inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) { - // Captures in the h1-a8 (h8-a1 for black) direction - b1 = (Us == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces; + const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); - // Capturing promotions - b2 = b1 & TRank8BB; - while (b2) - { - to = pop_1st_bit(&b2); - (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, QUEEN); - } + Bitboard b; + Square to; - // Capturing non-promotions - b2 = b1 & ~TRank8BB; - while (b2) - { - to = pop_1st_bit(&b2); - (*mlist++).move = make_move(to - TDELTA_NW, to); - } + // Promotions and under-promotions, both captures and non-captures + b = move_pawns(pawnsOn7) & target; - // Non-capturing promotions - b1 = (Us == WHITE ? pawns << 8 : pawns >> 8) & pos.empty_squares() & TRank8BB; - while (b1) - { - to = pop_1st_bit(&b1); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); - } + if (Delta != DELTA_N && Delta != DELTA_S) + b &= ~TFileABB; - // En passant captures - if (pos.ep_square() != SQ_NONE) + while (b) { - assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6); - assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3); + to = pop_1st_bit(&b); - b1 = pawns & pos.pawn_attacks(Them, pos.ep_square()); - assert(b1 != EmptyBoardBB); + if (Type == CAPTURE || Type == EVASION) + (*mlist++).move = make_promotion_move(to - Delta, to, QUEEN); - while (b1) + if (Type == NON_CAPTURE || Type == EVASION) { - to = pop_1st_bit(&b1); - (*mlist++).move = make_ep_move(to, pos.ep_square()); + (*mlist++).move = make_promotion_move(to - Delta, to, ROOK); + (*mlist++).move = make_promotion_move(to - Delta, to, BISHOP); + (*mlist++).move = make_promotion_move(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 == CHECK + && bit_is_set(pos.attacks_from(to), pos.king_square(opposite_color(Us)))) + (*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT); + else (void)pos; // Silence a warning under MSVC } return mlist; } - template - MoveStack* do_generate_pawn_noncaptures(const Position& pos, MoveStack* mlist) { + 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 SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); + const SquareDelta TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE); + const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW); - Bitboard pawns = pos.pawns(Us); - Bitboard enemyPieces = pos.pieces_of_color(Them); - Bitboard emptySquares = pos.empty_squares(); - Bitboard b1, b2; Square to; + Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares; + Bitboard pawns = pos.pieces(PAWN, Us); + Bitboard pawnsOn7 = pawns & TRank7BB; + Bitboard enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(Them)); - // Underpromotion captures in the a1-h8 (a8-h1 for black) direction - b1 = (Us == WHITE ? pawns << 9 : pawns >> 7) & ~FileABB & enemyPieces & TRank8BB; - while (b1) + // Pre-calculate pawn pushes before changing emptySquares definition + if (Type != CAPTURE) { - to = pop_1st_bit(&b1); - (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, ROOK); - (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TDELTA_NE, to, KNIGHT); + emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares()); + pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; } - // Underpromotion captures in the h1-a8 (h8-a1 for black) direction - b1 = (Us == WHITE ? pawns << 7 : pawns >> 9) & ~FileHBB & enemyPieces & TRank8BB; - while (b1) + if (Type == EVASION) { - to = pop_1st_bit(&b1); - (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, ROOK); - (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TDELTA_NW, to, KNIGHT); + emptySquares &= target; // Only blocking squares + enemyPieces &= target; // Capture only the checker piece } - // Single pawn pushes - b1 = (Us == WHITE ? pawns << 8 : pawns >> 8) & emptySquares; - b2 = b1 & TRank8BB; - while (b2) + // Promotions and underpromotions + if (pawnsOn7) { - to = pop_1st_bit(&b2); - (*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); + if (Type == CAPTURE) + emptySquares = pos.empty_squares(); + + pawns &= ~TRank7BB; + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, emptySquares); } - b2 = b1 & ~TRank8BB; - while (b2) + + // Standard captures + if (Type == CAPTURE || Type == EVASION) { - to = pop_1st_bit(&b2); - (*mlist++).move = make_move(to - TDELTA_N, to); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); } - // Double pawn pushes - b2 = (Us == WHITE ? (b1 & TRank3BB) << 8 : (b1 & TRank3BB) >> 8) & emptySquares; - while (b2) + // Single and double pawn pushes + if (Type != CAPTURE) { - to = pop_1st_bit(&b2); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + b1 = pawnPushes & emptySquares; + b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; + + if (Type == CHECK) + { + // Condider 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, -TDELTA_N); + SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); } - return mlist; - } + // En passant captures + if ((Type == CAPTURE || Type == EVASION) && pos.ep_square() != SQ_NONE) + { + assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6); + assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3); - template - MoveStack* do_generate_pawn_checks(const Position& pos, Bitboard dc, Square ksq, MoveStack* mlist) - { - // Find all friendly pawns not on the enemy king's file - Bitboard b1, b2, b3; - Bitboard empty = pos.empty_squares(); + // 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; - if (dc != EmptyBoardBB) - { - // 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. - b1 = pos.pawns(Us) & ~file_bb(ksq); - - // Discovered checks, single pawn pushes, no promotions - b2 = b3 = (Us == WHITE ? (b1 & dc) << 8 : (b1 & dc) >> 8) & empty & ~TRank8BB; - while (b3) - { - Square to = pop_1st_bit(&b3); - (*mlist++).move = make_move(to - TDELTA_N, to); - } + b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - // Discovered checks, double pawn pushes - b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) & empty; - while (b3) + assert(b1 != EmptyBoardBB); + + while (b1) { - Square to = pop_1st_bit(&b3); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + to = pop_1st_bit(&b1); + (*mlist++).move = make_ep_move(to, pos.ep_square()); } } + return mlist; + } - // Direct checks. These are possible only for pawns on neighboring files - // of the enemy king. - b1 = pos.pawns(Us) & neighboring_files_bb(ksq) & ~dc; + template + MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { - // 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++).move = make_move(to - TDELTA_N, to); - } + assert(Piece != QUEEN); - // Direct checks, double pawn pushes - b3 = (Us == WHITE ? (b2 & TRank3BB) << 8 : (b2 & TRank3BB) >> 8) - & empty - & pos.pawn_attacks(Them, ksq); - while (b3) + Bitboard b = pos.attacks_from(from) & pos.empty_squares(); + if (Piece == KING) { - Square to = pop_1st_bit(&b3); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + Square ksq = pos.king_square(opposite_color(pos.side_to_move())); + b &= ~QueenPseudoAttacks[ksq]; } + SERIALIZE_MOVES(b); return mlist; } template - MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us, + MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, Bitboard dc, Square ksq) { + assert(Piece != KING); - Bitboard target = pos.pieces_of_color_and_type(us, Piece); - - // Discovered checks - Bitboard b = target & dc; - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & pos.empty_squares(); - if (Piece == KING) - bb &= ~QueenPseudoAttacks[ksq]; - - SERIALIZE_MOVES(bb); - } + Bitboard checkSqs, b; + Square from; + const Square* ptr = pos.piece_list_begin(us, Piece); - // Direct checks - b = target & ~dc; - if (Piece == KING || !b) + if ((from = *ptr++) == SQ_NONE) return mlist; - Bitboard checkSqs = pos.piece_attacks(ksq) & pos.empty_squares(); - while (b) - { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.piece_attacks(from) & checkSqs; - SERIALIZE_MOVES(bb); - } - return mlist; - } - - template - MoveStack* do_generate_pawn_blocking_evasions(const Position& pos, Bitboard not_pinned, - Bitboard blockSquares, MoveStack* mlist) { - Square to; - - // Find non-pinned pawns - 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 { - to = pop_1st_bit(&b2); - - assert(pos.piece_on(to) == EMPTY); + if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) + || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs)) + || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) + continue; - if (square_rank(to) == TRANK_8) - { - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); - } else - (*mlist++).move = make_move(to - TDELTA_N, to); - } + if (dc && bit_is_set(dc, from)) + continue; - // Double pawn pushes - b2 = (Us == WHITE ? b1 << 8 : b1 >> 8) & pos.empty_squares() & TRank3BB; - b2 = (Us == WHITE ? b2 << 8 : b2 >> 8) & blockSquares;; - while (b2) - { - 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++).move = make_move(to - TDELTA_N - TDELTA_N, to); - } return mlist; } @@ -878,13 +659,13 @@ namespace { Color us = pos.side_to_move(); - if ( (Side == KING_SIDE && pos.can_castle_kingside(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)); 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); @@ -892,12 +673,12 @@ namespace { Square s; bool illegal = false; - assert(pos.piece_on(rsq) == rook_of_color(us)); + assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK)); // 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.square_is_attacked(s, them)) + ||(pos.attackers_to(s) & pos.pieces_of_color(them))) illegal = true; for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) @@ -906,8 +687,8 @@ namespace { if ( Side == QUEEN_SIDE && 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))) + && ( 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) @@ -915,17 +696,4 @@ namespace { } return mlist; } - - bool castling_is_check(const Position& pos, CastlingSide side) { - - // After castling opponent king is attacked by the castled rook? - File rookFile = (side == QUEEN_SIDE ? FILE_D : FILE_F); - Color us = pos.side_to_move(); - Square ksq = pos.king_square(us); - Bitboard occ = pos.occupied_squares(); - - clear_bit(&occ, ksq); // Remove our king from the board - Square rsq = make_square(rookFile, square_rank(ksq)); - return bit_is_set(rook_attacks_bb(rsq, occ), pos.king_square(opposite_color(us))); - } }