X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=7cbd157a75b5a008e6d0f92ae8bfc93f2fcf8366;hp=d821f0fad2e0ce56ccf6e03e6d22850b02ddb0b5;hb=d655147e8c;hpb=ae2f5f25cd8a6bc2762eefc032436052c0db679e diff --git a/src/movegen.cpp b/src/movegen.cpp index d821f0fa..7cbd157a 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,7 +1,7 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad + Copyright (C) 2008-2012 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 @@ -18,9 +18,12 @@ */ #include +#include #include "bitcount.h" #include "movegen.h" +#include "position.h" +#include "misc.h" // Simple macro to wrap a very common while loop, no facny, no flexibility, // hardcoded list name 'mlist' and from square 'from'. @@ -31,42 +34,234 @@ namespace { - enum CastlingSide { - KING_SIDE, - QUEEN_SIDE - }; + enum CastlingSide { KING_SIDE, QUEEN_SIDE }; - template - MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us); + template + MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) { - template - MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); + const CastleRight CR[] = { Side ? WHITE_OOO : WHITE_OO, + Side ? BLACK_OOO : BLACK_OO }; - template - inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { + if (!pos.can_castle(CR[us])) + return mlist; - assert(Pt != QUEEN); + // After castling, the rook and king final positions are the same in Chess960 + // as they would be in standard chess. + Square kfrom = pos.king_square(us); + Square rfrom = pos.castle_rook_square(CR[us]); + Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); + Bitboard enemies = pos.pieces(flip(us)); + + assert(!pos.in_check()); + assert(pos.piece_on(kfrom) == make_piece(us, KING)); + assert(pos.piece_on(rfrom) == make_piece(us, ROOK)); + + // Unimpeded rule: All the squares between the king's initial and final squares + // (including the final square), and all the squares between the rook's initial + // and final squares (including the final square), must be vacant except for + // the king and castling rook. + for (Square s = std::min(rfrom, rto), e = std::max(rfrom, rto); s <= e; s++) + if (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + return mlist; + + for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++) + if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + ||(pos.attackers_to(s) & enemies)) + return mlist; - Bitboard b = pos.attacks_from(from) & pos.empty_squares(); - if (Pt == KING) + // Because we generate only legal castling moves we need to verify that + // when moving the castling rook we do not discover some hidden checker. + // For instance an enemy queen in SQ_A1 when castling rook is in SQ_B1. + if (pos.is_chess960()) { - Square ksq = pos.king_square(opposite_color(pos.side_to_move())); - b &= ~QueenPseudoAttacks[ksq]; + Bitboard occ = pos.occupied_squares(); + clear_bit(&occ, rfrom); + if (pos.attackers_to(kto, occ) & enemies) + return mlist; } - SERIALIZE_MOVES(b); + + (*mlist++).move = make_castle(kfrom, rfrom); + + return mlist; + } + + + template + inline Bitboard move_pawns(Bitboard p) { + + 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 + inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) { + + const Bitboard TFileABB = ( Delta == DELTA_NE + || Delta == DELTA_SE ? FileABB : FileHBB); + Bitboard b; + Square to; + + b = move_pawns(pawns) & target & ~TFileABB; + SERIALIZE_MOVES_D(b, -Delta); + return mlist; + } + + + template + inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) { + + const Bitboard TFileABB = ( Delta == DELTA_NE + || Delta == DELTA_SE ? FileABB : FileHBB); + Bitboard b; + Square to; + + b = move_pawns(pawnsOn7) & target; + + if (Delta != DELTA_N && Delta != DELTA_S) + b &= ~TFileABB; + + while (b) + { + to = pop_1st_bit(&b); + + if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) + (*mlist++).move = make_promotion(to - Delta, to, QUEEN); + + if (Type == MV_NON_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) + { + (*mlist++).move = make_promotion(to - Delta, to, ROOK); + (*mlist++).move = make_promotion(to - Delta, to, BISHOP); + (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); + } + + // Knight-promotion is the only one that can give a check (direct or + // discovered) not already included in the queen-promotion. + if ( Type == MV_CHECK + && bit_is_set(StepAttacksBB[W_KNIGHT][to], ksq)) + (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); + else + (void)ksq; // Silence a warning under MSVC + } + return 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 Square UP = (Us == WHITE ? DELTA_N : DELTA_S); + const Square RIGHT = (Us == WHITE ? DELTA_NE : DELTA_SW); + const Square LEFT = (Us == WHITE ? DELTA_NW : DELTA_SE); + + Square to; + Bitboard b1, b2, dc1, dc2, emptySquares; + + Bitboard pawns = pos.pieces(PAWN, Us); + Bitboard pawnsOn7 = pawns & TRank7BB; + Bitboard pawnsNotOn7 = pawns & ~TRank7BB; + + Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target: + Type == MV_CAPTURE ? target : pos.pieces(Them)); + + // Single and double pawn pushes, no promotions + if (Type != MV_CAPTURE) + { + emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); + + b1 = move_pawns(pawnsNotOn7) & emptySquares; + b2 = move_pawns(b1 & TRank3BB) & emptySquares; + + if (Type == MV_EVASION) + { + b1 &= target; // Consider only blocking squares + b2 &= target; + } + + if (Type == MV_CHECK) + { + // Consider only direct checks + b1 &= pos.attacks_from(ksq, Them); + b2 &= pos.attacks_from(ksq, Them); + + // Add pawn pushes which give discovered check. This is possible only + // if the pawn is not on the same file as the enemy king, because we + // don't generate captures. Note that a possible discovery check + // promotion has been already generated among captures. + if (pawnsNotOn7 & target) // For CHECK type target is dc bitboard + { + dc1 = move_pawns(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq); + dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } + } + + SERIALIZE_MOVES_D(b1, -UP); + SERIALIZE_MOVES_D(b2, -UP -UP); + } + + // Promotions and underpromotions + if (pawnsOn7) + { + if (Type == MV_CAPTURE) + emptySquares = pos.empty_squares(); + + if (Type == MV_EVASION) + emptySquares &= target; + + mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ksq); + } + + // Standard and en-passant captures + if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) + { + mlist = generate_pawn_captures(mlist, pawnsNotOn7, enemies); + mlist = generate_pawn_captures(mlist, pawnsNotOn7, enemies); + + if (pos.ep_square() != SQ_NONE) + { + assert(rank_of(pos.ep_square()) == (Us == WHITE ? RANK_6 : RANK_3)); + + // An en passant capture can be an evasion only if the checking piece + // is the double pushed pawn and so is in the target. Otherwise this + // is a discovery check and we are forced to do otherwise. + if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP)) + return mlist; + + b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); + + assert(b1); + + while (b1) + (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square()); + } + } + return mlist; } + template inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, Bitboard dc, Square ksq) { - assert(Pt != KING); + assert(Pt != KING && Pt != PAWN); Bitboard checkSqs, b; Square from; - const Square* ptr = pos.piece_list_begin(us, Pt); + const Square* pl = pos.piece_list(us, Pt); - if ((from = *ptr++) == SQ_NONE) + if ((from = *pl++) == SQ_NONE) return mlist; checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); @@ -84,11 +279,12 @@ namespace { b = pos.attacks_from(from) & checkSqs; SERIALIZE_MOVES(b); - } while ((from = *ptr++) != SQ_NONE); + } while ((from = *pl++) != SQ_NONE); return mlist; } + template<> FORCE_INLINE MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { @@ -96,34 +292,35 @@ namespace { : generate_pawn_moves(p, m, dc, ksq)); } + template FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { assert(Pt == PAWN); - assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION); - return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) : generate_pawn_moves(p, m, t, SQ_NONE)); } + template FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { Bitboard b; Square from; - const Square* ptr = pos.piece_list_begin(us, Pt); + const Square* pl = pos.piece_list(us, Pt); - if (*ptr != SQ_NONE) + if (*pl != SQ_NONE) { do { - from = *ptr; + from = *pl; b = pos.attacks_from(from) & target; SERIALIZE_MOVES(b); - } while (*++ptr != SQ_NONE); + } while (*++pl != SQ_NONE); } return mlist; } + template<> FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { @@ -135,7 +332,7 @@ namespace { return mlist; } -} +} // namespace /// generate generates all pseudo-legal captures and queen @@ -150,41 +347,32 @@ namespace { template MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); + assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_NON_EVASION); assert(!pos.in_check()); Color us = pos.side_to_move(); Bitboard target; - if (Type == MV_CAPTURE || Type == MV_NON_EVASION) - target = pos.pieces_of_color(opposite_color(us)); + if (Type == MV_CAPTURE) + target = pos.pieces(flip(us)); + else if (Type == MV_NON_CAPTURE) target = pos.empty_squares(); - else - assert(false); - if (Type == MV_NON_EVASION) - { - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, pos.empty_squares()); - target |= pos.empty_squares(); - } - else - mlist = generate_piece_moves(pos, mlist, us, target); + else if (Type == MV_NON_EVASION) + target = pos.pieces(flip(us)) | 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_piece_moves(pos, mlist, us, target); - if (Type != MV_CAPTURE) + if (Type != MV_CAPTURE && pos.can_castle(us)) { - if (pos.can_castle_kingside(us)) - mlist = generate_castle_moves(pos, mlist, us); - - if (pos.can_castle_queenside(us)) - mlist = generate_castle_moves(pos, mlist, us); + mlist = generate_castle_moves(pos, mlist, us); + mlist = generate_castle_moves(pos, mlist, us); } return mlist; @@ -196,36 +384,38 @@ template MoveStack* generate(const Position& pos, MoveStack* mli template MoveStack* generate(const Position& pos, MoveStack* mlist); -/// generate_non_capture_checks() generates all pseudo-legal non-captures and knight +/// generate generates all pseudo-legal non-captures and knight /// underpromotions that give check. Returns a pointer to the end of the move list. template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); assert(!pos.in_check()); Bitboard b, dc; Square from; + PieceType pt; Color us = pos.side_to_move(); - Square ksq = pos.king_square(opposite_color(us)); + Square ksq = pos.king_square(flip(us)); - assert(pos.piece_on(ksq) == make_piece(opposite_color(us), KING)); + assert(pos.piece_on(ksq) == make_piece(flip(us), KING)); // Discovered non-capture checks - b = dc = pos.discovered_check_candidates(us); + b = dc = pos.discovered_check_candidates(); while (b) { from = pop_1st_bit(&b); - switch (piece_type(pos.piece_on(from))) - { - case PAWN: /* Will be generated togheter with pawns direct checks */ break; - case KNIGHT: mlist = generate_discovered_checks(pos, mlist, from); break; - case BISHOP: mlist = generate_discovered_checks(pos, mlist, from); break; - case ROOK: mlist = generate_discovered_checks(pos, mlist, from); break; - case KING: mlist = generate_discovered_checks(pos, mlist, from); break; - default: assert(false); break; - } + pt = type_of(pos.piece_on(from)); + + if (pt == PAWN) + continue; // Will be generated togheter with direct checks + + b = pos.attacks_from(Piece(pt), from) & pos.empty_squares(); + + if (pt == KING) + b &= ~QueenPseudoAttacks[ksq]; + + SERIALIZE_MOVES(b); } // Direct non-capture checks @@ -237,12 +427,11 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) } -/// 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. +/// generate generates all pseudo-legal check evasions when the side +/// to move is in check. Returns a pointer to the end of the move list. template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); assert(pos.in_check()); Bitboard b, target; @@ -251,7 +440,7 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { Color us = pos.side_to_move(); Square ksq = pos.king_square(us); Bitboard checkers = pos.checkers(); - Bitboard sliderAttacks = EmptyBoardBB; + Bitboard sliderAttacks = 0; assert(pos.piece_on(ksq) == make_piece(us, KING)); assert(checkers); @@ -265,9 +454,9 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { checkersCnt++; checksq = pop_1st_bit(&b); - assert(piece_color(pos.piece_on(checksq)) == opposite_color(us)); + assert(color_of(pos.piece_on(checksq)) == flip(us)); - switch (piece_type(pos.piece_on(checksq))) + switch (type_of(pos.piece_on(checksq))) { case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break; case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break; @@ -289,7 +478,7 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { } while (b); // Generate evasions for king, capture and non capture moves - b = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks; + b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; from = ksq; SERIALIZE_MOVES(b); @@ -314,10 +503,8 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - MoveStack *last, *cur = mlist; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + Bitboard pinned = pos.pinned_pieces(); last = pos.in_check() ? generate(pos, mlist) : generate(pos, mlist); @@ -331,209 +518,3 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { return last; } - - -namespace { - - template - inline Bitboard move_pawns(Bitboard p) { - - 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 - inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) { - - const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); - - Bitboard b; - Square to; - - // 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; - } - - template - inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) { - - const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); - - Bitboard b; - Square to; - - // Promotions and under-promotions, both captures and non-captures - b = move_pawns(pawnsOn7) & target; - - if (Delta != DELTA_N && Delta != DELTA_S) - b &= ~TFileABB; - - while (b) - { - to = pop_1st_bit(&b); - - if (Type == MV_CAPTURE || Type == MV_EVASION) - (*mlist++).move = make_promotion_move(to - Delta, to, QUEEN); - - if (Type == MV_NON_CAPTURE || Type == MV_EVASION) - { - (*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 == MV_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* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) { - - // Calculate our parametrized parameters at compile time, named - // according to the point of view of white side. - const Color Them = (Us == WHITE ? BLACK : WHITE); - const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); - const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - const Square TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); - const Square TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE); - const Square TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW); - - Square to; - Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares; - Bitboard pawns = pos.pieces(PAWN, Us); - Bitboard pawnsOn7 = pawns & TRank7BB; - Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces_of_color(Them)); - - // Pre-calculate pawn pushes before changing emptySquares definition - if (Type != MV_CAPTURE) - { - emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); - pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; - } - - if (Type == MV_EVASION) - { - emptySquares &= target; // Only blocking squares - enemyPieces &= target; // Capture only the checker piece - } - - // Promotions and underpromotions - if (pawnsOn7) - { - if (Type == MV_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); - } - - // Standard captures - if (Type == MV_CAPTURE || Type == MV_EVASION) - { - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - } - - // Single and double pawn pushes - if (Type != MV_CAPTURE) - { - b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares); - b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; - - if (Type == MV_CHECK) - { - // Consider only pawn moves which give direct checks - b1 &= pos.attacks_from(ksq, Them); - b2 &= pos.attacks_from(ksq, Them); - - // Add pawn moves which gives discovered check. This is possible only - // if the pawn is not on the same file as the enemy king, because we - // don't generate captures. - if (pawns & target) // For CHECK type target is dc bitboard - { - dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares; - dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; - - b1 |= dc1; - b2 |= dc2; - } - } - SERIALIZE_MOVES_D(b1, -TDELTA_N); - SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); - } - - // En passant captures - if ((Type == MV_CAPTURE || Type == MV_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); - - // An en passant capture can be an evasion only if the checking piece - // is the double pushed pawn and so is in the target. Otherwise this - // is a discovery check and we are forced to do otherwise. - if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N)) - return mlist; - - b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - - assert(b1 != EmptyBoardBB); - - while (b1) - { - to = pop_1st_bit(&b1); - (*mlist++).move = make_ep_move(to, pos.ep_square()); - } - } - return mlist; - } - - template - MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) { - - Color them = opposite_color(us); - Square ksq = pos.king_square(us); - - assert(pos.piece_on(ksq) == make_piece(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); - Square s2 = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); - Square s; - bool illegal = false; - - assert(pos.piece_on(rsq) == make_piece(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.attackers_to(s) & pos.pieces_of_color(them))) - illegal = true; - - 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)) == make_piece(them, ROOK) - || pos.piece_on(relative_square(us, SQ_A1)) == make_piece(them, QUEEN))) - illegal = true; - - if (!illegal) - (*mlist++).move = make_castle_move(ksq, rsq); - - return mlist; - } - -} // namespace