X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=cc1518a078de7d48064e93cbd23e8ad6b95b54be;hb=HEAD;hp=c4b43539bc280e9227cf4b772d8e53378dcebc65;hpb=0179a32cf5b22fdeeaf9a14aa88f49eb51f476ed;p=stockfish diff --git a/src/movegen.cpp b/src/movegen.cpp index c4b43539..7d6856bb 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,7 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2009 Marco Costalba + Copyright (C) 2004-2023 The Stockfish developers (see AUTHORS file) Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,821 +16,265 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - -#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)) +#include +#include -// 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); } +#include "bitboard.h" +#include "position.h" -//// -//// Local definitions -//// +namespace Stockfish { namespace { - enum CastlingSide { - KING_SIDE, - QUEEN_SIDE - }; - - enum MoveType { - CAPTURE, - NON_CAPTURE - }; - - // Functions - bool castling_is_check(const Position&, CastlingSide); - - // Helper templates - template - MoveStack* generate_castle_moves(const Position&, MoveStack*); - - template - MoveStack* generate_pawn_blocking_evasions(const Position&, Bitboard, Bitboard, MoveStack*); - - template - MoveStack* generate_pawn_captures(const Position&, MoveStack*); - - template - MoveStack* generate_pawn_captures_diagonal(MoveStack*, Bitboard, Bitboard, bool); - - template - MoveStack* generate_pawn_noncaptures(const Position&, MoveStack*, Bitboard = EmptyBoardBB, Square = SQ_NONE); - - 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 generate_piece_checks() with specializations - template - MoveStack* generate_piece_checks(const Position&, MoveStack*, Color, Bitboard, Square); - - template<> - inline MoveStack* generate_piece_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { - - return (us == WHITE ? generate_pawn_noncaptures(p, m, dc, ksq) - : generate_pawn_noncaptures(p, m, dc, ksq)); - } - - // Template generate_piece_moves() with specializations and overloads - template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - - template<> - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - - template - inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us) { - - assert(Piece == PAWN); - - if (Type == CAPTURE) - return (us == WHITE ? generate_pawn_captures(p, m) - : generate_pawn_captures(p, m)); - else - return (us == WHITE ? generate_pawn_noncaptures(p, m) - : generate_pawn_noncaptures(p, m)); - } - - template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard, Bitboard); - - template<> - inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, - Color us, Bitboard t, Bitboard pnd) { - - return (us == WHITE ? generate_pawn_blocking_evasions(p, pnd, t, m) - : generate_pawn_blocking_evasions(p, pnd, t, m)); - } -} - - -//// -//// Functions -//// - - -/// generate_captures() generates all pseudo-legal captures and queen -/// promotions. Returns a pointer to the end of the move list. - -MoveStack* generate_captures(const Position& pos, MoveStack* mlist) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - - Color us = pos.side_to_move(); - Bitboard target = pos.pieces_of_color(opposite_color(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); - return generate_piece_moves(pos, mlist, us, target); -} - - -/// generate_noncaptures() generates all pseudo-legal non-captures and -/// underpromotions. Returns a pointer to the end of the move list. - -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(); - - 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_castle_moves(pos, mlist); - return generate_castle_moves(pos, mlist); -} - - -/// generate_non_capture_checks() generates all pseudo-legal non-captures and -/// underpromotions that give check. Returns a pointer to the end of the move list. - -MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist, Bitboard dc) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - - Color us = pos.side_to_move(); - Square ksq = pos.king_square(opposite_color(us)); - - assert(pos.piece_on(ksq) == piece_of_color_and_type(opposite_color(us), KING)); - - // 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); - 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 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. Returns a pointer to the end of the move list. - -MoveStack* generate_evasions(const Position& pos, MoveStack* mlist, Bitboard pinned) { - - assert(pos.is_ok()); - assert(pos.is_check()); - - Square from, to; - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - Bitboard sliderAttacks = EmptyBoardBB; - Bitboard checkers = pos.checkers(); - - assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); - - // The bitboard of occupied pieces without our king - Bitboard b_noKing = pos.occupied_squares(); - clear_bit(&b_noKing, ksq); - - // Find squares attacked by slider checkers, we will remove - // them from the king evasions set so to avoid a couple - // of cycles in the slow king evasions legality check loop - // and to be able to use attackers_to(). - Bitboard b = checkers & pos.pieces(BISHOP, QUEEN); - while (b) - { - from = pop_1st_bit(&b); - sliderAttacks |= bishop_attacks_bb(from, b_noKing); - } - - b = checkers & pos.pieces(ROOK, QUEEN); - while (b) - { - from = pop_1st_bit(&b); - sliderAttacks |= rook_attacks_bb(from, b_noKing); - } - - // Generate evasions for king, capture and non capture moves - Bitboard enemy = pos.pieces_of_color(them); - Bitboard b1 = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks; - while (b1) - { - // Note that we can use attackers_to() only because we have already - // removed from b1 the squares attacked by slider checkers. - to = pop_1st_bit(&b1); - if (!(pos.attackers_to(to) & enemy)) - (*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); - - assert(pos.color_of_piece_on(checksq) == them); - - // Generate captures of the checking piece - - // Pawn captures - b1 = pos.attacks_from(checksq, them) & pos.pieces(PAWN, us) & ~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); - } - - // Pieces captures - b1 = ( (pos.attacks_from(checksq) & pos.pieces(KNIGHT, us)) - | (pos.attacks_from(checksq) & pos.pieces(BISHOP, QUEEN, us)) - | (pos.attacks_from(checksq) & pos.pieces(ROOK, QUEEN, us)) ) & ~pinned; - - while (b1) - { - from = pop_1st_bit(&b1); - (*mlist++).move = make_move(from, checksq); - } - - // Blocking check evasions are possible only if the checking piece is a slider - if (sliderAttacks) - { - Bitboard blockSquares = squares_between(checksq, ksq); - - assert((pos.occupied_squares() & blockSquares) == EmptyBoardBB); - - if (blockSquares) - { - mlist = generate_piece_moves(pos, mlist, us, blockSquares, pinned); - mlist = generate_piece_moves(pos, mlist, us, blockSquares, pinned); - mlist = generate_piece_moves(pos, mlist, us, blockSquares, pinned); - mlist = generate_piece_moves(pos, mlist, us, blockSquares, pinned); - mlist = generate_piece_moves(pos, mlist, us, blockSquares, pinned); - } - } - - // Finally, the 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.pieces(PAWN, them))) - { - to = pos.ep_square(); - b1 = pos.attacks_from(to, them) & pos.pieces(PAWN, us); - - // The checking pawn cannot be a discovered (bishop) check candidate - // otherwise we were in check also before last double push move. - assert(!bit_is_set(pos.discovered_check_candidates(them), checksq)); - assert(count_1s(b1) == 1 || count_1s(b1) == 2); - - b1 &= ~pinned; - while (b1) - { - from = pop_1st_bit(&b1); - // Move is always legal because checking pawn is not a discovered - // check candidate and our capturing pawn has been already tested - // against pinned pieces. - (*mlist++).move = make_ep_move(from, to); - } - } - } - return mlist; -} - - -/// generate_moves() computes a complete list of legal or pseudo-legal moves in -/// the current position. This function is not very fast, and should be used -/// only in non time-critical paths. - -MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) { - - assert(pos.is_ok()); - - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - - if (pos.is_check()) - return generate_evasions(pos, mlist, pinned); - - // Generate pseudo-legal moves - MoveStack* last = generate_captures(pos, mlist); - last = generate_noncaptures(pos, last); - if (pseudoLegal) - return last; - - // Remove illegal moves from the list - for (MoveStack* cur = mlist; cur != last; cur++) - if (!pos.pl_move_is_legal(cur->move, pinned)) - { - cur->move = (--last)->move; - cur--; - } - return last; -} +template +ExtMove* make_promotions(ExtMove* moveList, [[maybe_unused]] Square to) { + constexpr bool all = Type == EVASIONS || Type == NON_EVASIONS; -/// 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. + if constexpr (Type == CAPTURES || all) + *moveList++ = make(to - D, to, QUEEN); -bool move_is_legal(const Position& pos, const Move m) { - - MoveStack mlist[256]; - MoveStack* last = generate_moves(pos, mlist, true); - for (MoveStack* cur = mlist; cur != last; cur++) - if (cur->move == m) - return pos.pl_move_is_legal(m); - - return false; -} - - -/// Fast version of move_is_legal() that takes a position a move and a -/// bitboard of pinned pieces as input, and tests whether the move is legal. -/// This version must only be used when the side to move is not in check. - -bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - assert(move_is_ok(m)); - assert(pinned == pos.pinned_pieces(pos.side_to_move())); - - // Use a slower but simpler function for uncommon cases - if (move_is_ep(m) || move_is_castle(m)) - return move_is_legal(pos, m); - - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Square to = move_to(m); - Piece pc = pos.piece_on(from); - - // If the from square is not occupied by a piece belonging to the side to - // move, the move is obviously not legal. - if (color_of_piece(pc) != us) - return false; - - // The destination square cannot be occupied by a friendly piece - if (pos.color_of_piece_on(to) == us) - return false; - - // Handle the special case of a pawn move - if (type_of_piece(pc) == PAWN) - { - // 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 - // destionation squares. - switch (direction) - { - 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 false; - break; - - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!pos.square_is_empty(to)) - return false; - 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 false; - 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 false; - break; - - default: - return false; - } - // The move is pseudo-legal, check if it is also legal - return pos.pl_move_is_legal(m, pinned); - } - - // Luckly we can handle all the other pieces in one go - return ( bit_is_set(pos.attacks_from(pc, from), to) - && pos.pl_move_is_legal(m, pinned) - && !move_is_promotion(m)); -} - - -namespace { - - template - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - - Square from; - Bitboard b; - - for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++) + if constexpr ((Type == CAPTURES && Enemy) || (Type == QUIETS && !Enemy) || all) { - from = pos.piece_list(us, Piece, i); - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); + *moveList++ = make(to - D, to, ROOK); + *moveList++ = make(to - D, to, BISHOP); + *moveList++ = make(to - D, to, KNIGHT); } - return mlist; - } - template - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, - Color us, Bitboard target, Bitboard pinned) { - Square from; - Bitboard b; + return moveList; +} - for (int i = 0, e = pos.piece_count(us, Piece); i < e; i++) - { - from = pos.piece_list(us, Piece, i); - if (pinned && bit_is_set(pinned, from)) - continue; - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); - } - return mlist; - } +template +ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard target) { - template<> - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + constexpr Color Them = ~Us; + constexpr Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); + constexpr Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); + constexpr Direction Up = pawn_push(Us); + constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); + constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); - Bitboard b; - Square from = pos.king_square(us); + const Bitboard emptySquares = ~pos.pieces(); + const Bitboard enemies = Type == EVASIONS ? pos.checkers() : pos.pieces(Them); - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); - return mlist; - } + Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; + Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; - template - MoveStack* generate_pawn_captures_diagonal(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces, bool promotion) { + // Single and double pawn pushes, no promotions + if constexpr (Type != CAPTURES) + { + Bitboard b1 = shift(pawnsNotOn7) & emptySquares; + Bitboard b2 = shift(b1 & TRank3BB) & emptySquares; - // 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); + if constexpr (Type == EVASIONS) // Consider only blocking squares + { + b1 &= target; + b2 &= target; + } - Square to; + if constexpr (Type == QUIET_CHECKS) + { + // To make a quiet check, you either make a direct check by pushing a pawn + // or push a blocker pawn that is not on the same file as the enemy king. + // Discovered check promotion has been already generated amongst the captures. + Square ksq = pos.square(Them); + Bitboard dcCandidatePawns = pos.blockers_for_king(Them) & ~file_bb(ksq); + b1 &= pawn_attacks_bb(Them, ksq) | shift(dcCandidatePawns); + b2 &= pawn_attacks_bb(Them, ksq) | shift(dcCandidatePawns); + } - // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black) - Bitboard b1 = move_pawns(pawns) & ~TFileABB & enemyPieces; + while (b1) + { + Square to = pop_lsb(b1); + *moveList++ = make_move(to - Up, to); + } - // Capturing promotions - if (promotion) - { - Bitboard b2 = b1 & TRank8BB; - b1 &= ~TRank8BB; while (b2) { - to = pop_1st_bit(&b2); - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN); + Square to = pop_lsb(b2); + *moveList++ = make_move(to - Up - Up, to); } } - // Capturing non-promotions - SERIALIZE_MOVES_D(b1, -TTDELTA_NE); - return mlist; - } - - template - MoveStack* generate_pawn_captures(const Position& pos, MoveStack* mlist) { + // Promotions and underpromotions + if (pawnsOn7) + { + Bitboard b1 = shift(pawnsOn7) & enemies; + Bitboard b2 = shift(pawnsOn7) & enemies; + Bitboard b3 = shift(pawnsOn7) & emptySquares; - // 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 SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); + if constexpr (Type == EVASIONS) + b3 &= target; - Square to; - Bitboard pawns = pos.pieces(PAWN, Us); - Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us)); - bool possiblePromotion = (pawns & TRank7BB); + while (b1) + moveList = make_promotions(moveList, pop_lsb(b1)); - // Standard captures and capturing promotions in both directions - mlist = generate_pawn_captures_diagonal(mlist, pawns, enemyPieces, possiblePromotion); - mlist = generate_pawn_captures_diagonal(mlist, pawns, enemyPieces, possiblePromotion); + while (b2) + moveList = make_promotions(moveList, pop_lsb(b2)); - // Non-capturing promotions - if (possiblePromotion) - { - Bitboard b1 = move_pawns(pawns) & pos.empty_squares() & TRank8BB; - while (b1) - { - to = pop_1st_bit(&b1); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); - } + while (b3) + moveList = make_promotions(moveList, pop_lsb(b3)); } - // En passant captures - if (pos.ep_square() != SQ_NONE) + // Standard and en passant captures + if constexpr (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) { - assert(Us != WHITE || square_rank(pos.ep_square()) == RANK_6); - assert(Us != BLACK || square_rank(pos.ep_square()) == RANK_3); - - Bitboard b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - assert(b1 != EmptyBoardBB); + Bitboard b1 = shift(pawnsNotOn7) & enemies; + Bitboard b2 = shift(pawnsNotOn7) & enemies; while (b1) { - to = pop_1st_bit(&b1); - (*mlist++).move = make_ep_move(to, pos.ep_square()); + Square to = pop_lsb(b1); + *moveList++ = make_move(to - UpRight, to); } - } - return mlist; - } - - template - MoveStack* generate_pawn_noncaptures(const Position& pos, MoveStack* mlist, Bitboard dc, Square ksq) { - - // 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_NE = (Us == WHITE ? DELTA_NE : DELTA_SE); - const SquareDelta TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW); - const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); - - Bitboard b1, b2, dcPawns1, dcPawns2; - Square to; - Bitboard pawns = pos.pieces(PAWN, Us); - Bitboard emptySquares = pos.empty_squares(); - - if (pawns & TRank7BB) // There is some promotion candidate ? - { - // When generating checks consider under-promotion moves (both captures - // and non captures) only if can give a discovery check. - Bitboard pp = GenerateChecks ? pawns & dc : pawns; - Bitboard enemyPieces = pos.pieces_of_color(opposite_color(Us)); - // Underpromotion captures in the a1-h8 (a8-h1 for black) direction - b1 = move_pawns(pp) & ~FileABB & enemyPieces & TRank8BB; - while (b1) + while (b2) { - 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); + Square to = pop_lsb(b2); + *moveList++ = make_move(to - UpLeft, to); } - // Underpromotion captures in the h1-a8 (h8-a1 for black) direction - b1 = move_pawns(pp) & ~FileHBB & enemyPieces & TRank8BB; - while (b1) + if (pos.ep_square() != SQ_NONE) { - 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); - } + assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6)); - // Underpromotion pawn pushes - b1 = move_pawns(pp) & emptySquares & TRank8BB; - while (b1) - { - to = pop_1st_bit(&b1); - (*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); + // An en passant capture cannot resolve a discovered check + if (Type == EVASIONS && (target & (pos.ep_square() + Up))) + return moveList; + + b1 = pawnsNotOn7 & pawn_attacks_bb(Them, pos.ep_square()); + + assert(b1); + + while (b1) + *moveList++ = make(pop_lsb(b1), pos.ep_square()); } } - dcPawns1 = dcPawns2 = EmptyBoardBB; - if (GenerateChecks && (dc & pawns)) - { - // 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. - dcPawns1 = move_pawns(pawns & dc & ~file_bb(ksq)) & emptySquares & ~TRank8BB; - dcPawns2 = move_pawns(dcPawns1 & TRank3BB) & emptySquares; - } + return moveList; +} - // Single pawn pushes - b1 = move_pawns(pawns) & emptySquares & ~TRank8BB; - b2 = GenerateChecks ? (b1 & pos.attacks_from(ksq, Them)) | dcPawns1 : b1; - SERIALIZE_MOVES_D(b2, -TDELTA_N); - // Double pawn pushes - b1 = move_pawns(b1 & TRank3BB) & emptySquares; - b2 = GenerateChecks ? (b1 & pos.attacks_from(ksq, Them)) | dcPawns2 : b1; - SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); - return mlist; - } +template +ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard target) { - template - MoveStack* generate_piece_checks(const Position& pos, MoveStack* mlist, Color us, - Bitboard dc, Square ksq) { + static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()"); - Bitboard target = pos.pieces(Piece, us); + Bitboard bb = pos.pieces(Us, Pt); - // Discovered checks - Bitboard b = target & dc; - while (b) + while (bb) { - Square from = pop_1st_bit(&b); - Bitboard bb = pos.attacks_from(from) & pos.empty_squares(); - if (Piece == KING) - bb &= ~QueenPseudoAttacks[ksq]; - - SERIALIZE_MOVES(bb); - } + Square from = pop_lsb(bb); + Bitboard b = attacks_bb(from, pos.pieces()) & target; - // Direct checks - b = target & ~dc; - Bitboard checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); - if (Piece == KING || !checkSqs) - return mlist; + // To check, you either move freely a blocker or make a direct check. + if (Checks && (Pt == QUEEN || !(pos.blockers_for_king(~Us) & from))) + b &= pos.check_squares(Pt); - while (b) - { - Square from = pop_1st_bit(&b); - if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) - || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs)) - || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) - continue; - - Bitboard bb = pos.attacks_from(from) & checkSqs; - SERIALIZE_MOVES(bb); + while (b) + *moveList++ = make_move(from, pop_lsb(b)); } - return mlist; - } - template - MoveStack* generate_pawn_blocking_evasions(const Position& pos, Bitboard pinned, - Bitboard blockSquares, MoveStack* mlist) { - - // Calculate our parametrized parameters at compile time - const Rank TRANK_8 = (Us == WHITE ? RANK_8 : RANK_1); - const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - const SquareDelta TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); + return moveList; +} - Square to; - // Find non-pinned pawns and push them one square - Bitboard b1 = move_pawns(pos.pieces(PAWN, Us) & ~pinned); +template +ExtMove* generate_all(const Position& pos, ExtMove* moveList) { - // We don't have to AND with empty squares here, - // because the blocking squares will always be empty. - Bitboard b2 = b1 & blockSquares; - while (b2) - { - to = pop_1st_bit(&b2); + static_assert(Type != LEGAL, "Unsupported type in generate_all()"); - assert(pos.piece_on(to) == EMPTY); + constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations + const Square ksq = pos.square(Us); + Bitboard target; - 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); + // Skip generating non-king moves when in double check + if (Type != EVASIONS || !more_than_one(pos.checkers())) + { + target = Type == EVASIONS ? between_bb(ksq, lsb(pos.checkers())) + : Type == NON_EVASIONS ? ~pos.pieces(Us) + : Type == CAPTURES ? pos.pieces(~Us) + : ~pos.pieces(); // QUIETS || QUIET_CHECKS + + moveList = generate_pawn_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, target); } - // Double pawn pushes - b2 = b1 & pos.empty_squares() & TRank3BB; - b2 = move_pawns(b2) & blockSquares; - while (b2) + if (!Checks || pos.blockers_for_king(~Us) & ksq) { - to = pop_1st_bit(&b2); + Bitboard b = attacks_bb(ksq) & (Type == EVASIONS ? ~pos.pieces(Us) : target); + if (Checks) + b &= ~attacks_bb(pos.square(~Us)); - assert(pos.piece_on(to) == EMPTY); - assert(Us != WHITE || square_rank(to) == RANK_4); - assert(Us != BLACK || square_rank(to) == RANK_5); + while (b) + *moveList++ = make_move(ksq, pop_lsb(b)); - (*mlist++).move = make_move(to - TDELTA_N - TDELTA_N, to); + if ((Type == QUIETS || Type == NON_EVASIONS) && pos.can_castle(Us & ANY_CASTLING)) + for (CastlingRights cr : {Us & KING_SIDE, Us & QUEEN_SIDE}) + if (!pos.castling_impeded(cr) && pos.can_castle(cr)) + *moveList++ = make(ksq, pos.castling_rook_square(cr)); } - return mlist; - } - template - MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) { + return moveList; +} + +} // namespace - Color us = pos.side_to_move(); - 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); +// Generates all pseudo-legal captures plus queen promotions +// Generates all pseudo-legal non-captures and underpromotions +// Generates all pseudo-legal check evasions +// Generates all pseudo-legal captures and non-captures +// Generates all pseudo-legal non-captures giving check, +// except castling and promotions +// +// Returns a pointer to the end of the move list. +template +ExtMove* generate(const Position& pos, ExtMove* moveList) { - assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); + static_assert(Type != LEGAL, "Unsupported type in generate()"); + assert((Type == EVASIONS) == bool(pos.checkers())); - 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; + Color us = pos.side_to_move(); - assert(pos.piece_on(rsq) == piece_of_color_and_type(us, ROOK)); + return us == WHITE ? generate_all(pos, moveList) + : generate_all(pos, moveList); +} - // 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; +// Explicit template instantiations +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); +template ExtMove* generate(const Position&, ExtMove*); - for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; - 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; +// generate generates all the legal moves in the given position - if (!illegal) - (*mlist++).move = make_castle_move(ksq, rsq); - } - return mlist; - } +template<> +ExtMove* generate(const Position& pos, ExtMove* moveList) { - bool castling_is_check(const Position& pos, CastlingSide side) { + Color us = pos.side_to_move(); + Bitboard pinned = pos.blockers_for_king(us) & pos.pieces(us); + Square ksq = pos.square(us); + ExtMove* cur = moveList; - // 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(); + moveList = + pos.checkers() ? generate(pos, moveList) : generate(pos, moveList); + while (cur != moveList) + if (((pinned & from_sq(*cur)) || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT) + && !pos.legal(*cur)) + *cur = (--moveList)->move; + else + ++cur; - 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))); - } + return moveList; } + +} // namespace Stockfish