X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=5095bb7455e6f36966d884ea297a8431b363183a;hp=e8e048c97bba3da53ade9210af2649d889c46a96;hb=ca3c1c5f3a5f011edd04af856cdd59bdaefe423d;hpb=822695d4d3a9336dc54bfabd0996e75865358ae2 diff --git a/src/movegen.cpp b/src/movegen.cpp index e8e048c9..5095bb74 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,8 +1,6 @@ /* Stockfish, a UCI chess playing engine derived from Glaurung 2.1 - Copyright (C) 2004-2008 Tord Romstad (Glaurung author) - Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad - Copyright (C) 2015-2017 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad + Copyright (C) 2004-2021 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 @@ -23,50 +21,12 @@ #include "movegen.h" #include "position.h" -namespace { - - template - ExtMove* generate_castling(const Position& pos, ExtMove* moveList, Color us) { - - static const bool KingSide = (Cr == WHITE_OO || Cr == BLACK_OO); - - if (pos.castling_impeded(Cr) || !pos.can_castle(Cr)) - return moveList; - - // After castling, the rook and king final positions are the same in Chess960 - // as they would be in standard chess. - Square kfrom = pos.square(us); - Square rfrom = pos.castling_rook_square(Cr); - Square kto = relative_square(us, KingSide ? SQ_G1 : SQ_C1); - Bitboard enemies = pos.pieces(~us); - - assert(!pos.checkers()); - - const Direction K = Chess960 ? kto > kfrom ? WEST : EAST - : KingSide ? WEST : EAST; - - for (Square s = kto; s != kfrom; s += K) - if (pos.attackers_to(s) & enemies) - return moveList; - - // 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 && (attacks_bb(kto, pos.pieces() ^ rfrom) & pos.pieces(~us, ROOK, QUEEN))) - return moveList; - - Move m = make(kfrom, rfrom); - - if (Checks && !pos.gives_check(m)) - return moveList; - - *moveList++ = m; - return moveList; - } +namespace Stockfish { +namespace { template - ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) { + ExtMove* make_promotions(ExtMove* moveList, Square to) { if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) *moveList++ = make(to - D, to, QUEEN); @@ -78,13 +38,6 @@ namespace { *moveList++ = make(to - D, to, KNIGHT); } - // Knight promotion is the only promotion that can give a direct check - // that's not already included in the queen promotion. - if (Type == QUIET_CHECKS && (PseudoAttacks[KNIGHT][to] & ksq)) - *moveList++ = make(to - D, to, KNIGHT); - else - (void)ksq; // Silence a warning under MSVC - return moveList; } @@ -92,29 +45,23 @@ namespace { template ExtMove* generate_pawn_moves(const Position& pos, ExtMove* moveList, Bitboard 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 Direction Up = (Us == WHITE ? NORTH : SOUTH); - const Direction Right = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); - const Direction Left = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); + 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 emptySquares; + const Bitboard emptySquares = ~pos.pieces(); + const Bitboard enemies = Type == EVASIONS ? pos.checkers() + : pos.pieces(Them); Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; - Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target: - Type == CAPTURES ? target : pos.pieces(Them)); - // Single and double pawn pushes, no promotions if (Type != CAPTURES) { - emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); - Bitboard b1 = shift(pawnsNotOn7) & emptySquares; Bitboard b2 = shift(b1 & TRank3BB) & emptySquares; @@ -126,98 +73,80 @@ namespace { if (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); - - 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 amongst the captures. - Bitboard dcCandidates = pos.discovered_check_candidates(); - if (pawnsNotOn7 & dcCandidates) - { - Bitboard dc1 = shift(pawnsNotOn7 & dcCandidates) & emptySquares & ~file_bb(ksq); - Bitboard dc2 = shift(dc1 & TRank3BB) & emptySquares; - - b1 |= dc1; - b2 |= dc2; - } + Bitboard dcCandidatePawns = pos.blockers_for_king(Them) & ~file_bb(ksq); + b1 &= pawn_attacks_bb(Them, ksq) | shift< Up>(dcCandidatePawns); + b2 &= pawn_attacks_bb(Them, ksq) | shift(dcCandidatePawns); } while (b1) { - Square to = pop_lsb(&b1); + Square to = pop_lsb(b1); *moveList++ = make_move(to - Up, to); } while (b2) { - Square to = pop_lsb(&b2); + Square to = pop_lsb(b2); *moveList++ = make_move(to - Up - Up, to); } } // Promotions and underpromotions - if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB))) + if (pawnsOn7) { - if (Type == CAPTURES) - emptySquares = ~pos.pieces(); + Bitboard b1 = shift(pawnsOn7) & enemies; + Bitboard b2 = shift(pawnsOn7) & enemies; + Bitboard b3 = shift(pawnsOn7) & emptySquares; if (Type == EVASIONS) - emptySquares &= target; - - Bitboard b1 = shift(pawnsOn7) & enemies; - Bitboard b2 = shift(pawnsOn7) & enemies; - Bitboard b3 = shift(pawnsOn7) & emptySquares; - - Square ksq = pos.square(Them); + b3 &= target; while (b1) - moveList = make_promotions(moveList, pop_lsb(&b1), ksq); + moveList = make_promotions(moveList, pop_lsb(b1)); while (b2) - moveList = make_promotions(moveList, pop_lsb(&b2), ksq); + moveList = make_promotions(moveList, pop_lsb(b2)); while (b3) - moveList = make_promotions(moveList, pop_lsb(&b3), ksq); + moveList = make_promotions(moveList, pop_lsb(b3)); } - // Standard and en-passant captures + // Standard and en passant captures if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) { - Bitboard b1 = shift(pawnsNotOn7) & enemies; - Bitboard b2 = shift(pawnsNotOn7) & enemies; + Bitboard b1 = shift(pawnsNotOn7) & enemies; + Bitboard b2 = shift(pawnsNotOn7) & enemies; while (b1) { - Square to = pop_lsb(&b1); - *moveList++ = make_move(to - Right, to); + Square to = pop_lsb(b1); + *moveList++ = make_move(to - UpRight, to); } while (b2) { - Square to = pop_lsb(&b2); - *moveList++ = make_move(to - Left, to); + Square to = pop_lsb(b2); + *moveList++ = make_move(to - UpLeft, to); } if (pos.ep_square() != SQ_NONE) { assert(rank_of(pos.ep_square()) == relative_rank(Us, RANK_6)); - // 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))) + // An en passant capture cannot resolve a discovered check + if (Type == EVASIONS && (target & (pos.ep_square() + Up))) return moveList; - b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); + b1 = pawnsNotOn7 & pawn_attacks_bb(Them, pos.ep_square()); assert(b1); while (b1) - *moveList++ = make(pop_lsb(&b1), pos.ep_square()); + *moveList++ = make(pop_lsb(b1), pos.ep_square()); } } @@ -225,33 +154,24 @@ namespace { } - template - ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Color us, - Bitboard target) { + template + ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard target) { - assert(Pt != KING && Pt != PAWN); + static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()"); - const Square* pl = pos.squares(us); + Bitboard bb = pos.pieces(Us, Pt); - for (Square from = *pl; from != SQ_NONE; from = *++pl) + while (bb) { - if (Checks) - { - if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) - && !(PseudoAttacks[Pt][from] & target & pos.check_squares(Pt))) - continue; - - if (pos.discovered_check_candidates() & from) - continue; - } - - Bitboard b = pos.attacks_from(from) & target; + Square from = pop_lsb(bb); + Bitboard b = attacks_bb(from, pos.pieces()) & target; - if (Checks) + // 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) - *moveList++ = make_move(from, pop_lsb(&b)); + *moveList++ = make_move(from, pop_lsb(b)); } return moveList; @@ -259,36 +179,42 @@ namespace { template - ExtMove* generate_all(const Position& pos, ExtMove* moveList, Bitboard target) { + ExtMove* generate_all(const Position& pos, ExtMove* moveList) { - const bool Checks = Type == QUIET_CHECKS; + static_assert(Type != LEGAL, "Unsupported type in generate_all()"); - moveList = generate_pawn_moves(pos, moveList, target); - moveList = generate_moves(pos, moveList, Us, target); - moveList = generate_moves(pos, moveList, Us, target); - moveList = generate_moves< ROOK, Checks>(pos, moveList, Us, target); - moveList = generate_moves< QUEEN, Checks>(pos, moveList, Us, target); + constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations + const Square ksq = pos.square(Us); + Bitboard target; - if (Type != QUIET_CHECKS && Type != EVASIONS) + // Skip generating non-king moves when in double check + if (Type != EVASIONS || !more_than_one(pos.checkers())) { - Square ksq = pos.square(Us); - Bitboard b = pos.attacks_from(ksq) & target; - while (b) - *moveList++ = make_move(ksq, pop_lsb(&b)); + 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); } - if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(Us)) + if (!Checks || pos.blockers_for_king(~Us) & ksq) { - if (pos.is_chess960()) - { - moveList = generate_castling::right, Checks, true>(pos, moveList, Us); - moveList = generate_castling::right, Checks, true>(pos, moveList, Us); - } - else - { - moveList = generate_castling::right, Checks, false>(pos, moveList, Us); - moveList = generate_castling::right, Checks, false>(pos, moveList, Us); - } + Bitboard b = attacks_bb(ksq) & (Type == EVASIONS ? ~pos.pieces(Us) : target); + if (Checks) + b &= ~attacks_bb(pos.square(~Us)); + + while (b) + *moveList++ = make_move(ksq, pop_lsb(b)); + + 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 moveList; @@ -297,120 +223,48 @@ namespace { } // namespace -/// 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. +/// Generates all pseudo-legal captures plus queen promotions +/// Generates all pseudo-legal non-captures and underpromotions +/// Generates all pseudo-legal check evasions when the side to move is in check +/// Generates all pseudo-legal non-captures giving check, except castling and promotions +/// Generates all pseudo-legal captures and non-captures /// -/// generate generates all pseudo-legal captures and -/// non-captures. Returns a pointer to the end of the move list. +/// Returns a pointer to the end of the move list. template ExtMove* generate(const Position& pos, ExtMove* moveList) { - assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); - assert(!pos.checkers()); + static_assert(Type != LEGAL, "Unsupported type in generate()"); + assert((Type == EVASIONS) == (bool)pos.checkers()); Color us = pos.side_to_move(); - Bitboard target = Type == CAPTURES ? pos.pieces(~us) - : Type == QUIETS ? ~pos.pieces() - : Type == NON_EVASIONS ? ~pos.pieces(us) : 0; - - return us == WHITE ? generate_all(pos, moveList, target) - : generate_all(pos, moveList, target); + return us == WHITE ? generate_all(pos, moveList) + : generate_all(pos, moveList); } // 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*); -/// generate generates all pseudo-legal non-captures and knight -/// underpromotions that give check. Returns a pointer to the end of the move list. -template<> -ExtMove* generate(const Position& pos, ExtMove* moveList) { - - assert(!pos.checkers()); - - Color us = pos.side_to_move(); - Bitboard dc = pos.discovered_check_candidates(); - - while (dc) - { - Square from = pop_lsb(&dc); - PieceType pt = type_of(pos.piece_on(from)); - - if (pt == PAWN) - continue; // Will be generated together with direct checks - - Bitboard b = pos.attacks_from(pt, from) & ~pos.pieces(); - - if (pt == KING) - b &= ~PseudoAttacks[QUEEN][pos.square(~us)]; - - while (b) - *moveList++ = make_move(from, pop_lsb(&b)); - } - - return us == WHITE ? generate_all(pos, moveList, ~pos.pieces()) - : generate_all(pos, moveList, ~pos.pieces()); -} - - -/// 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<> -ExtMove* generate(const Position& pos, ExtMove* moveList) { - - assert(pos.checkers()); - - Color us = pos.side_to_move(); - Square ksq = pos.square(us); - Bitboard sliderAttacks = 0; - Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN); - - // Find all the squares attacked by slider checkers. We will remove them from - // the king evasions in order to skip known illegal moves, which avoids any - // useless legality checks later on. - while (sliders) - { - Square checksq = pop_lsb(&sliders); - sliderAttacks |= LineBB[checksq][ksq] ^ checksq; - } - - // Generate evasions for king, capture and non capture moves - Bitboard b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; - while (b) - *moveList++ = make_move(ksq, pop_lsb(&b)); - - if (more_than_one(pos.checkers())) - return moveList; // Double check, only a king move can save the day - - // Generate blocking evasions or captures of the checking piece - Square checksq = lsb(pos.checkers()); - Bitboard target = between_bb(checksq, ksq) | checksq; - - return us == WHITE ? generate_all(pos, moveList, target) - : generate_all(pos, moveList, target); -} - - /// generate generates all the legal moves in the given position template<> ExtMove* generate(const Position& pos, ExtMove* moveList) { - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); - Square ksq = pos.square(pos.side_to_move()); + Color us = pos.side_to_move(); + Bitboard pinned = pos.blockers_for_king(us) & pos.pieces(us); + Square ksq = pos.square(us); ExtMove* cur = moveList; moveList = pos.checkers() ? generate(pos, moveList) : generate(pos, moveList); while (cur != moveList) - if ( (pinned || from_sq(*cur) == ksq || type_of(*cur) == ENPASSANT) + if ( ((pinned && pinned & from_sq(*cur)) || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT) && !pos.legal(*cur)) *cur = (--moveList)->move; else @@ -418,3 +272,5 @@ ExtMove* generate(const Position& pos, ExtMove* moveList) { return moveList; } + +} // namespace Stockfish