X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=be848cf1a6acb370e1ddf262b4f79762ba187f56;hp=ea3255cc3c8c91e7f309f360f12a119f3707c747;hb=55bd27b8f08a151128d7065fa2819aa3e9605299;hpb=d9dc9dbd65263f8644afcc1fc632e9201ad20c70 diff --git a/src/movegen.cpp b/src/movegen.cpp index ea3255cc..be848cf1 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 @@ -17,707 +17,429 @@ along with this program. If not, see . */ - -//// -//// Includes -//// - #include -#include "bitcount.h" #include "movegen.h" +#include "position.h" -// Simple macro to wrap a very common while loop, no facny, no flexibility, -// hardcoded list name 'mlist' and from square 'from'. -#define SERIALIZE_MOVES(b) while (b) (*mlist++).move = make_move(from, pop_1st_bit(&b)) - -// 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 -//// +/// Simple macro to wrap a very common while loop, no facny, no flexibility, +/// hardcoded names 'mlist' and 'from'. +#define SERIALIZE(b) while (b) (*mlist++).move = make_move(from, pop_lsb(&b)) +/// Version used for pawns, where the 'from' square is given as a delta from the 'to' square +#define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_lsb(&b); \ + (*mlist++).move = make_move(to - (d), to); } namespace { - enum CastlingSide { - KING_SIDE, - QUEEN_SIDE - }; - - enum MoveType { - CAPTURE, - NON_CAPTURE, - CHECK, - EVASION - }; - - // Helper templates - template - MoveStack* generate_castle_moves(const Position&, MoveStack*); - - template - MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); + template + MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) { - // Template generate_piece_moves (captures and non-captures) with specializations and overloads - template - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); - - template<> - MoveStack* generate_piece_moves(const Position&, MoveStack*, Color, Bitboard); + if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side))) + return mlist; - template - inline MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { + // 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(us, Side); + Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Bitboard enemies = pos.pieces(~us); - assert(Piece == PAWN); - assert(Type == CAPTURE || Type == NON_CAPTURE || Type == EVASION); + assert(!pos.in_check()); - return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) - : generate_pawn_moves(p, m, t, SQ_NONE)); - } + const int K = Chess960 ? kto > kfrom ? -1 : 1 + : Side == KING_SIDE ? -1 : 1; - // Templates for non-capture checks generation + for (Square s = kto; s != kfrom; s += (Square)K) + if (pos.attackers_to(s) & enemies) + return mlist; - template - MoveStack* generate_discovered_checks(const Position&, MoveStack*, Square); + // 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 (Chess960 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies)) + return mlist; - template - MoveStack* generate_direct_checks(const Position&, MoveStack*, Color, Bitboard, Square); + (*mlist++).move = make(kfrom, rfrom); - template<> - inline MoveStack* generate_direct_checks(const Position& p, MoveStack* m, Color us, Bitboard dc, Square ksq) { + if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) + mlist--; - return (us == WHITE ? generate_pawn_moves(p, m, dc, ksq) - : generate_pawn_moves(p, m, dc, ksq)); + return mlist; } -} - - -//// -//// 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, target); - 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, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_castle_moves(pos, mlist); - return generate_castle_moves(pos, mlist); -} - - -/// generate_non_evasions() generates all pseudo-legal captures and -/// non-captures. Returns a pointer to the end of the move list. - -MoveStack* generate_non_evasions(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, 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_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. - -MoveStack* generate_non_capture_checks(const Position& pos, MoveStack* mlist) { - - assert(pos.is_ok()); - assert(!pos.is_check()); - - Bitboard b, dc; - Square from; - 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)); - - // Discovered non-capture checks - b = dc = pos.discovered_check_candidates(us); + template + inline Bitboard move_pawns(Bitboard p) { - while (b) - { - from = pop_1st_bit(&b); - switch (pos.type_of_piece_on(from)) - { - case PAWN: /* Will be generated togheter with pawns direct checks */ break; - case KNIGHT: mlist = generate_discovered_checks(pos, mlist, from); break; - case BISHOP: mlist = generate_discovered_checks(pos, mlist, from); break; - case ROOK: mlist = generate_discovered_checks(pos, mlist, from); break; - case KING: mlist = generate_discovered_checks(pos, mlist, from); break; - default: assert(false); break; - } + return Delta == DELTA_N ? p << 8 + : Delta == DELTA_S ? p >> 8 + : Delta == DELTA_NE ? (p & ~FileHBB) << 9 + : Delta == DELTA_SE ? (p & ~FileHBB) >> 7 + : Delta == DELTA_NW ? (p & ~FileABB) << 7 + : Delta == DELTA_SW ? (p & ~FileABB) >> 9 : 0; } - // Direct non-capture checks - mlist = generate_direct_checks(pos, mlist, us, dc, ksq); - mlist = generate_direct_checks(pos, mlist, us, dc, ksq); - mlist = generate_direct_checks(pos, mlist, us, dc, ksq); - mlist = generate_direct_checks(pos, mlist, us, dc, ksq); - return generate_direct_checks(pos, mlist, us, dc, ksq); -} - - -/// generate_evasions() generates all pseudo-legal check evasions when -/// the side to move is in check. Returns a pointer to the end of the move list. -MoveStack* generate_evasions(const Position& pos, MoveStack* mlist) { + template + inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, + Bitboard target, const CheckInfo* ci) { - assert(pos.is_ok()); - assert(pos.is_check()); + Bitboard b = move_pawns(pawnsOn7) & target; - 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; - - assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); - assert(checkers); + while (b) + { + Square to = pop_lsb(&b); - // 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); + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + (*mlist++).move = make(to - Delta, to, QUEEN); - assert(pos.color_of_piece_on(checksq) == opposite_color(us)); + if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS) + { + (*mlist++).move = make(to - Delta, to, ROOK); + (*mlist++).move = make(to - Delta, to, BISHOP); + (*mlist++).move = make(to - Delta, to, KNIGHT); + } - switch (pos.type_of_piece_on(checksq)) - { - case BISHOP: sliderAttacks |= BishopPseudoAttacks[checksq]; break; - case ROOK: sliderAttacks |= RookPseudoAttacks[checksq]; break; - case QUEEN: - // In case of a queen remove also squares attacked in the other direction to - // avoid possible illegal moves when queen and king are on adjacent squares. - if (direction_is_straight(checksq, ksq)) - sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from(checksq); - else - sliderAttacks |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq); - default: - break; - } - } while (b); + // Knight-promotion is the only one that can give a direct check not + // already included in the queen-promotion. + if (Type == QUIET_CHECKS && (StepAttacksBB[W_KNIGHT][to] & ci->ksq)) + (*mlist++).move = make(to - Delta, to, KNIGHT); + else + (void)ci; // Silence a warning under MSVC + } - // 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); + return mlist; + } - // Generate evasions for other pieces only if not double check - if (checkersCnt > 1) - return mlist; - // Find squares where a blocking evasion or a capture of the - // checker piece is possible. - target = squares_between(checksq, ksq) | checkers; + template + MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, + Bitboard target, const CheckInfo* ci) { - 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); -} + // Compute 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 TRank8BB = (Us == WHITE ? Rank8BB : Rank1BB); + 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); + Bitboard b1, b2, dc1, dc2, emptySquares; -/// 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. + Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; + Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; -MoveStack* generate_moves(const Position& pos, MoveStack* mlist, bool pseudoLegal) { + Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target: + Type == CAPTURES ? target : pos.pieces(Them)); - assert(pos.is_ok()); + // Single and double pawn pushes, no promotions + if (Type != CAPTURES) + { + emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); - MoveStack *last, *cur = mlist; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + b1 = move_pawns(pawnsNotOn7) & emptySquares; + b2 = move_pawns(b1 & TRank3BB) & emptySquares; - // Generate pseudo-legal moves - last = pos.is_check() ? generate_evasions(pos, mlist) - : generate_non_evasions(pos, mlist); - if (pseudoLegal) - return last; + if (Type == EVASIONS) // Consider only blocking squares + { + b1 &= target; + b2 &= target; + } - // Remove illegal moves from the list - while (cur != last) - if (pos.pl_move_is_legal(cur->move, pinned)) - cur++; - else - cur->move = (--last)->move; + if (Type == QUIET_CHECKS) + { + b1 &= pos.attacks_from(ci->ksq, Them); + b2 &= pos.attacks_from(ci->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 & ci->dcCandidates) + { + dc1 = move_pawns(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq); + dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; - return last; -} + b1 |= dc1; + b2 |= dc2; + } + } + SERIALIZE_PAWNS(b1, UP); + SERIALIZE_PAWNS(b2, UP + UP); + } -/// 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. + // Promotions and underpromotions + if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB))) + { + if (Type == CAPTURES) + emptySquares = ~pos.pieces(); -bool move_is_legal(const Position& pos, const Move m) { + if (Type == EVASIONS) + emptySquares &= target; - MoveStack mlist[256]; - MoveStack *cur, *last = generate_moves(pos, mlist, true); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci); + } - for (cur = mlist; cur != last; cur++) - if (cur->move == m) - return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move())); + // Standard and en-passant captures + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + { + b1 = move_pawns(pawnsNotOn7) & enemies; + b2 = move_pawns(pawnsNotOn7) & enemies; - return false; -} + SERIALIZE_PAWNS(b1, RIGHT); + SERIALIZE_PAWNS(b2, LEFT); + if (pos.ep_square() != SQ_NONE) + { + assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6)); -/// 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. + // 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 == EVASIONS && !(target & (pos.ep_square() - UP))) + return mlist; -bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { + b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); - assert(pos.is_ok()); - assert(move_is_ok(m)); - assert(pinned == pos.pinned_pieces(pos.side_to_move())); + assert(b1); - Color us = pos.side_to_move(); - Color them = opposite_color(us); - Square from = move_from(m); - Square to = move_to(m); - Piece pc = pos.piece_on(from); - - // Use a slower but simpler function for uncommon cases - if (move_is_ep(m) || move_is_castle(m)) - return move_is_legal(pos, m); - - // If the from square is not occupied by a piece belonging to the side to - // move, the move is obviously not legal. - if (color_of_piece(pc) != us) - return 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; - - // The promotion piece, if any, must be valid - if (move_promotion_piece(m) > QUEEN || move_promotion_piece(m) == PAWN) - return false; - - // Proceed according to the square delta between the origin and - // destination 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; + while (b1) + (*mlist++).move = make(pop_lsb(&b1), pos.ep_square()); + } + } - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!pos.square_is_empty(to)) - return false; - break; + return mlist; + } - 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; + template FORCE_INLINE + MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us, + Bitboard target, const CheckInfo* ci) { - default: - return false; - } - // 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); - } + assert(Pt != KING && Pt != PAWN); - // Luckly we can handle all the other pieces in one go - return bit_is_set(pos.attacks_from(pc, from), to) - && (pos.is_check() ? pos.pl_move_is_evasion(m, pinned) : pos.pl_move_is_legal(m, pinned)) - && !move_is_promotion(m); -} + const Square* pl = pos.piece_list(us, Pt); + for (Square from = *pl; from != SQ_NONE; from = *++pl) + { + if (Checks) + { + if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) + && !(PseudoAttacks[Pt][from] & target & ci->checkSq[Pt])) + continue; -namespace { + if (ci->dcCandidates && (ci->dcCandidates & from)) + continue; + } - template - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + Bitboard b = pos.attacks_from(from) & target; - Bitboard b; - Square from; - const Square* ptr = pos.piece_list_begin(us, Piece); + if (Checks) + b &= ci->checkSq[Pt]; - if (*ptr != SQ_NONE) - { - do { - from = *ptr; - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); - } while (*++ptr != SQ_NONE); + SERIALIZE(b); } + return mlist; } - template<> - MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { - Bitboard b; + FORCE_INLINE MoveStack* generate_king_moves(const Position& pos, MoveStack* mlist, + Color us, Bitboard target) { Square from = pos.king_square(us); - - b = pos.attacks_from(from) & target; - SERIALIZE_MOVES(b); + Bitboard b = pos.attacks_from(from) & target; + SERIALIZE(b); return mlist; } - template - inline Bitboard move_pawns(Bitboard p) { - - if (Direction == DELTA_N) - return Us == WHITE ? p << 8 : p >> 8; - else if (Direction == DELTA_NE) - return Us == WHITE ? p << 9 : p >> 7; - else if (Direction == DELTA_NW) - return Us == WHITE ? p << 7 : p >> 9; - else - return p; - } - template - inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard enemyPieces) { + template FORCE_INLINE + MoveStack* generate_all_moves(const Position& pos, MoveStack* mlist, Color us, + Bitboard target, const CheckInfo* ci = NULL) { - // 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); + mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target, ci) + : generate_pawn_moves(pos, mlist, target, ci)); - Bitboard b1, b2; - Square to; + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); + mlist = generate_moves(pos, mlist, us, target, ci); - // Captures in the a1-h8 (a8-h1 for black) diagonal or in the h1-a8 (h8-a1 for black) - b1 = move_pawns(pawns) & ~TFileABB & enemyPieces; + if (Type != QUIET_CHECKS && Type != EVASIONS) + mlist = generate_king_moves(pos, mlist, us, target); - // Capturing promotions and under-promotions - if (b1 & TRank8BB) + if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us)) { - b2 = b1 & TRank8BB; - b1 &= ~TRank8BB; - while (b2) + if (pos.is_chess960()) { - to = pop_1st_bit(&b2); - - if (Type == CAPTURE || Type == EVASION) - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, QUEEN); - - if (Type == NON_CAPTURE || Type == EVASION) - { - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, ROOK); - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT); - } - - // This is the only possible under promotion that can give a check - // not already included in the queen-promotion. It is not sure that - // the promoted knight will give check, but it doesn't worth to verify. - if (Type == CHECK) - (*mlist++).move = make_promotion_move(to - TTDELTA_NE, to, KNIGHT); + mlist = generate_castle(pos, mlist, us); + mlist = generate_castle(pos, mlist, us); + } + else + { + mlist = generate_castle(pos, mlist, us); + mlist = generate_castle(pos, mlist, us); } } - // Serialize standard captures - if (Type == CAPTURE || Type == EVASION) - SERIALIZE_MOVES_D(b1, -TTDELTA_NE); - return mlist; } - template - MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, 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_N = (Us == WHITE ? DELTA_N : DELTA_S); +} // namespace - Square to; - Bitboard b1, b2, enemyPieces, emptySquares; - Bitboard pawns = pos.pieces(PAWN, Us); - // Standard captures and capturing promotions and underpromotions - if (Type == CAPTURE || Type == EVASION || (pawns & TRank7BB)) - { - enemyPieces = (Type == CAPTURE ? target : pos.pieces_of_color(opposite_color(Us))); +/// generate generates all pseudo-legal captures and queen +/// promotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal non-captures and +/// underpromotions. Returns a pointer to the end of the move list. +/// +/// generate generates all pseudo-legal captures and +/// non-captures. Returns a pointer to the end of the move list. - if (Type == EVASION) - enemyPieces &= target; // Capture only the checker piece +template +MoveStack* generate(const Position& pos, MoveStack* mlist) { - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - } + assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); + assert(!pos.in_check()); - // Non-capturing promotions and underpromotions - if (pawns & TRank7BB) - { - b1 = move_pawns(pawns) & TRank8BB & pos.empty_squares(); + Color us = pos.side_to_move(); + Bitboard target; - if (Type == EVASION) - b1 &= target; // Only blocking promotion pushes + if (Type == CAPTURES) + target = pos.pieces(~us); - while (b1) - { - to = pop_1st_bit(&b1); + else if (Type == QUIETS) + target = ~pos.pieces(); - if (Type == CAPTURE || Type == EVASION) - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, QUEEN); + else if (Type == NON_EVASIONS) + target = ~pos.pieces(us); - if (Type == NON_CAPTURE || Type == EVASION) - { - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, ROOK); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, BISHOP); - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); - } + return generate_all_moves(pos, mlist, us, target); +} - // This is the only possible under promotion that can give a check - // not already included in the queen-promotion. - if (Type == CHECK && bit_is_set(pos.attacks_from(to), pos.king_square(Them))) - (*mlist++).move = make_promotion_move(to - TDELTA_N, to, KNIGHT); - } - } +// Explicit template instantiations +template MoveStack* generate(const Position&, MoveStack*); +template MoveStack* generate(const Position&, MoveStack*); +template MoveStack* generate(const Position&, MoveStack*); - // Standard pawn pushes and double pushes - if (Type != CAPTURE) - { - emptySquares = (Type == NON_CAPTURE ? target : pos.empty_squares()); - // Single and double pawn pushes - b1 = move_pawns(pawns) & emptySquares & ~TRank8BB; - b2 = move_pawns(b1 & TRank3BB) & emptySquares; +/// 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) { - // Filter out unwanted pushes according to the move type - if (Type == EVASION) - { - b1 &= target; - b2 &= target; - } - else if (Type == CHECK) - { - // Pawn moves which give direct cheks - b1 &= pos.attacks_from(ksq, Them); - b2 &= pos.attacks_from(ksq, Them); - - // Pawn moves which gives discovered check. This is possible only if - // the pawn is not on the same file as the enemy king, because we - // don't generate captures. - if (pawns & target) // For CHECK type target is dc bitboard - { - Bitboard dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares & ~TRank8BB; - Bitboard dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + assert(!pos.in_check()); - b1 |= dc1; - b2 |= dc2; - } - } - SERIALIZE_MOVES_D(b1, -TDELTA_N); - SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); - } + Color us = pos.side_to_move(); + CheckInfo ci(pos); + Bitboard dc = ci.dcCandidates; - // 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); + while (dc) + { + Square from = pop_lsb(&dc); + PieceType pt = type_of(pos.piece_on(from)); - // 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 (pt == PAWN) + continue; // Will be generated togheter with direct checks - b1 = pawns & pos.attacks_from(pos.ep_square(), Them); + Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces(); - assert(b1 != EmptyBoardBB); + if (pt == KING) + b &= ~PseudoAttacks[QUEEN][ci.ksq]; - while (b1) - { - to = pop_1st_bit(&b1); - (*mlist++).move = make_ep_move(to, pos.ep_square()); - } - } - return mlist; + SERIALIZE(b); } - template - MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { - - assert(Piece != QUEEN); - - Bitboard b = pos.attacks_from(from) & pos.empty_squares(); - if (Piece == KING) - { - Square ksq = pos.king_square(opposite_color(pos.side_to_move())); - b &= ~QueenPseudoAttacks[ksq]; - } - SERIALIZE_MOVES(b); - return mlist; - } + return generate_all_moves(pos, mlist, us, ~pos.pieces(), &ci); +} - template - MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, - Bitboard dc, Square ksq) { - assert(Piece != KING); - Bitboard checkSqs, b; - Square from; - const Square* ptr = pos.piece_list_begin(us, Piece); +/// 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) { - if ((from = *ptr++) == SQ_NONE) - return mlist; + assert(pos.in_check()); - checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); + Square from, checksq; + int checkersCnt = 0; + Color us = pos.side_to_move(); + Square ksq = pos.king_square(us); + Bitboard sliderAttacks = 0; + Bitboard b = pos.checkers(); - do - { - if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) - || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs)) - || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) - continue; + assert(pos.checkers()); - if (dc && bit_is_set(dc, from)) - continue; + // Find squares attacked by slider checkers, we will remove them from the king + // evasions so to skip known illegal moves avoiding useless legality check later. + do + { + checkersCnt++; + checksq = pop_lsb(&b); - b = pos.attacks_from(from) & checkSqs; - SERIALIZE_MOVES(b); + assert(color_of(pos.piece_on(checksq)) == ~us); - } while ((from = *ptr++) != SQ_NONE); + switch (type_of(pos.piece_on(checksq))) + { + case BISHOP: sliderAttacks |= PseudoAttacks[BISHOP][checksq]; break; + case ROOK: sliderAttacks |= PseudoAttacks[ROOK][checksq]; break; + case QUEEN: + // If queen and king are far or not on a diagonal line we can safely + // remove all the squares attacked in the other direction becuase are + // not reachable by the king anyway. + if (between_bb(ksq, checksq) || !(PseudoAttacks[BISHOP][checksq] & ksq)) + sliderAttacks |= PseudoAttacks[QUEEN][checksq]; + + // Otherwise we need to use real rook attacks to check if king is safe + // to move in the other direction. For example: king in B2, queen in A1 + // a knight in B1, and we can safely move to C1. + else + sliderAttacks |= PseudoAttacks[BISHOP][checksq] | pos.attacks_from(checksq); - return mlist; - } + default: + break; + } + } while (b); - template - MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist) { + // Generate evasions for king, capture and non capture moves + b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; + from = ksq; + SERIALIZE(b); - Color us = pos.side_to_move(); + if (checkersCnt > 1) + return mlist; // Double check, only a king move can save the day - 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); + // Generate blocking evasions or captures of the checking piece + Bitboard target = between_bb(checksq, ksq) | pos.checkers(); - assert(pos.piece_on(ksq) == piece_of_color_and_type(us, KING)); + return generate_all_moves(pos, mlist, us, target); +} - 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) == piece_of_color_and_type(us, ROOK)); +/// generate generates all the legal moves in the given position - // 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; +template<> +MoveStack* generate(const Position& pos, MoveStack* mlist) { - for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; + MoveStack *end, *cur = mlist; + Bitboard pinned = pos.pinned_pieces(); + Square ksq = pos.king_square(pos.side_to_move()); - 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; + end = pos.in_check() ? generate(pos, mlist) + : generate(pos, mlist); + while (cur != end) + if ( (pinned || from_sq(cur->move) == ksq || type_of(cur->move) == ENPASSANT) + && !pos.pl_move_is_legal(cur->move, pinned)) + cur->move = (--end)->move; + else + cur++; - if (!illegal) - (*mlist++).move = make_castle_move(ksq, rsq); - } - return mlist; - } + return end; }