X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=c9d6a90d7d00c191db4080c63af14a9ea6ec4e68;hp=3848611ce9bb8b286f14f007bae58e9005bb572a;hb=0db374777e793f60bb897d078b3ab641613112ad;hpb=e82382703c96cfc480555e9db29d999e1f54a38f diff --git a/src/movegen.cpp b/src/movegen.cpp index 3848611c..c9d6a90d 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) 2008-2012 Marco Costalba, Joona Kiiski, 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 @@ -22,111 +21,42 @@ #include "movegen.h" #include "position.h" -/// 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 { - template - MoveStack* generate_castle(const Position& pos, MoveStack* mlist, Color us) { - - if (pos.castle_impeded(us, Side) || !pos.can_castle(make_castle_right(us, Side))) - return mlist; - - // 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(!pos.checkers()); - - const int K = Chess960 ? kto > kfrom ? -1 : 1 - : Side == KING_SIDE ? -1 : 1; - - for (Square s = kto; s != kfrom; s += (Square)K) - if (pos.attackers_to(s) & enemies) - return mlist; - - // 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; - - (*mlist++).move = make(kfrom, rfrom); - - if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) - mlist--; - - return mlist; - } - - - template - inline Bitboard move_pawns(Bitboard p) { - - 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; - } - - - template - inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, - Bitboard target, const CheckInfo* ci) { + template + ExtMove* make_promotions(ExtMove* moveList, Square to, Square ksq) { - Bitboard b = move_pawns(pawnsOn7) & target; - - while (b) + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) { - Square to = pop_lsb(&b); - - if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) - (*mlist++).move = make(to - Delta, to, QUEEN); - - 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); - } + *moveList++ = make(to - D, to, QUEEN); + if (attacks_bb(to) & ksq) + *moveList++ = make(to - D, to, KNIGHT); + } - // 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 + if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS) + { + *moveList++ = make(to - D, to, ROOK); + *moveList++ = make(to - D, to, BISHOP); + if (!(attacks_bb(to) & ksq)) + *moveList++ = make(to - D, to, KNIGHT); } - return mlist; + return moveList; } template - MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, - Bitboard target, const CheckInfo* ci) { + 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 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); + 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 b1, b2, dc1, dc2, emptySquares; + const Square ksq = pos.square(Them); + Bitboard emptySquares; Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; @@ -139,8 +69,8 @@ namespace { { emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); - b1 = move_pawns(pawnsNotOn7) & emptySquares; - b2 = move_pawns(b1 & TRank3BB) & emptySquares; + Bitboard b1 = shift(pawnsNotOn7) & emptySquares; + Bitboard b2 = shift(b1 & TRank3BB) & emptySquares; if (Type == EVASIONS) // Consider only blocking squares { @@ -150,29 +80,39 @@ namespace { if (Type == QUIET_CHECKS) { - b1 &= pos.attacks_from(ci->ksq, Them); - b2 &= pos.attacks_from(ci->ksq, Them); + b1 &= pawn_attacks_bb(Them, ksq); + b2 &= pawn_attacks_bb(Them, ksq); // 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) + // don't generate captures. Note that a possible discovered check + // promotion has been already generated amongst the captures. + Bitboard dcCandidateQuiets = pos.blockers_for_king(Them) & pawnsNotOn7; + if (dcCandidateQuiets) { - dc1 = move_pawns(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq); - dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + Bitboard dc1 = shift(dcCandidateQuiets) & emptySquares & ~file_bb(ksq); + Bitboard dc2 = shift(dc1 & TRank3BB) & emptySquares; b1 |= dc1; b2 |= dc2; } } - SERIALIZE_PAWNS(b1, UP); - SERIALIZE_PAWNS(b2, UP + UP); + while (b1) + { + Square to = pop_lsb(&b1); + *moveList++ = make_move(to - Up, to); + } + + while (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(); @@ -180,266 +120,245 @@ namespace { if (Type == EVASIONS) emptySquares &= target; - mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); - mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); - mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci); + Bitboard b1 = shift(pawnsOn7) & enemies; + Bitboard b2 = shift(pawnsOn7) & enemies; + Bitboard b3 = shift(pawnsOn7) & emptySquares; + + while (b1) + moveList = make_promotions(moveList, pop_lsb(&b1), ksq); + + while (b2) + moveList = make_promotions(moveList, pop_lsb(&b2), ksq); + + while (b3) + moveList = make_promotions(moveList, pop_lsb(&b3), ksq); } - // Standard and en-passant captures + // Standard and en passant captures if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) { - b1 = move_pawns(pawnsNotOn7) & enemies; - b2 = move_pawns(pawnsNotOn7) & enemies; + Bitboard b1 = shift(pawnsNotOn7) & enemies; + Bitboard b2 = shift(pawnsNotOn7) & enemies; - SERIALIZE_PAWNS(b1, RIGHT); - SERIALIZE_PAWNS(b2, LEFT); + while (b1) + { + Square to = pop_lsb(&b1); + *moveList++ = make_move(to - UpRight, to); + } + + while (b2) + { + 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))) - return mlist; + // 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) - (*mlist++).move = make(pop_lsb(&b1), pos.ep_square()); + *moveList++ = make(pop_lsb(&b1), pos.ep_square()); } } - return mlist; + return moveList; } - template FORCE_INLINE - MoveStack* generate_moves(const Position& pos, MoveStack* mlist, Color us, - Bitboard target, const CheckInfo* ci) { + template + ExtMove* generate_moves(const Position& pos, ExtMove* moveList, Bitboard piecesToMove, Bitboard target) { - assert(Pt != KING && Pt != PAWN); + static_assert(Pt != KING && Pt != PAWN, "Unsupported piece type in generate_moves()"); - const Square* pl = pos.piece_list(us, Pt); + Bitboard bb = piecesToMove & pos.pieces(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; + if (!bb) + return moveList; - if (ci->dcCandidates && (ci->dcCandidates & from)) - continue; - } + [[maybe_unused]] const Bitboard checkSquares = pos.check_squares(Pt); - Bitboard b = pos.attacks_from(from) & target; + while (bb) { + Square from = pop_lsb(&bb); - if (Checks) - b &= ci->checkSq[Pt]; + Bitboard b = attacks_bb(from, pos.pieces()) & target; + if constexpr (Checks) + b &= checkSquares; - SERIALIZE(b); + while (b) + *moveList++ = make_move(from, pop_lsb(&b)); } - return mlist; + return moveList; } - FORCE_INLINE MoveStack* generate_king_moves(const Position& pos, MoveStack* mlist, - Color us, Bitboard target) { - Square from = pos.king_square(us); - Bitboard b = pos.attacks_from(from) & target; - SERIALIZE(b); - return mlist; - } - - - template FORCE_INLINE - MoveStack* generate_all_moves(const Position& pos, MoveStack* mlist, Color us, - Bitboard target, const CheckInfo* ci = NULL) { + template + ExtMove* generate_all(const Position& pos, ExtMove* moveList) { - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target, ci) - : generate_pawn_moves(pos, mlist, target, ci)); + static_assert(Type != LEGAL, "Unsupported type in generate_all()"); - 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); + constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations + Bitboard target, piecesToMove = pos.pieces(Us); - if (Type != QUIET_CHECKS && Type != EVASIONS) - mlist = generate_king_moves(pos, mlist, us, target); + if(Type == QUIET_CHECKS) + piecesToMove &= ~pos.blockers_for_king(~Us); - if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us)) + switch (Type) { - if (pos.is_chess960()) - { - mlist = generate_castle(pos, mlist, us); - mlist = generate_castle(pos, mlist, us); - } - else + case CAPTURES: + target = pos.pieces(~Us); + break; + case QUIETS: + case QUIET_CHECKS: + target = ~pos.pieces(); + break; + case EVASIONS: { - mlist = generate_castle(pos, mlist, us); - mlist = generate_castle(pos, mlist, us); + Square checksq = lsb(pos.checkers()); + target = between_bb(pos.square(Us), checksq) | checksq; + break; } + case NON_EVASIONS: + target = ~pos.pieces(Us); + break; } - return mlist; - } + moveList = generate_pawn_moves(pos, moveList, target); + moveList = generate_moves(pos, moveList, piecesToMove, target); + moveList = generate_moves(pos, moveList, piecesToMove, target); + moveList = generate_moves< ROOK, Checks>(pos, moveList, piecesToMove, target); + moveList = generate_moves< QUEEN, Checks>(pos, moveList, piecesToMove, target); + if (Type != QUIET_CHECKS && Type != EVASIONS) + { + Square ksq = pos.square(Us); + Bitboard b = attacks_bb(ksq) & target; + while (b) + *moveList++ = make_move(ksq, pop_lsb(&b)); + + if ((Type != CAPTURES) && 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; + } } // 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 and checking knight promotions +/// Generates all pseudo-legal non-captures and underpromotions (except checking knight) +/// 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 -MoveStack* generate(const Position& pos, MoveStack* mlist) { +ExtMove* generate(const Position& pos, ExtMove* moveList) { - assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); + static_assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS, "Unsupported type in generate()"); assert(!pos.checkers()); Color us = pos.side_to_move(); - Bitboard target; - - if (Type == CAPTURES) - target = pos.pieces(~us); - - else if (Type == QUIETS) - target = ~pos.pieces(); - else if (Type == NON_EVASIONS) - target = ~pos.pieces(us); - - return generate_all_moves(pos, mlist, us, target); + return us == WHITE ? generate_all(pos, moveList) + : generate_all(pos, moveList); } // Explicit template instantiations -template MoveStack* generate(const Position&, MoveStack*); -template MoveStack* generate(const Position&, MoveStack*); -template MoveStack* generate(const Position&, MoveStack*); +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. +/// generate generates all pseudo-legal non-captures giving check, +/// except castling. Returns a pointer to the end of the move list. template<> -MoveStack* generate(const Position& pos, MoveStack* mlist) { +ExtMove* generate(const Position& pos, ExtMove* moveList) { assert(!pos.checkers()); Color us = pos.side_to_move(); - CheckInfo ci(pos); - Bitboard dc = ci.dcCandidates; + Bitboard dc = pos.blockers_for_king(~us) & pos.pieces(us) & ~pos.pieces(PAWN); while (dc) { Square from = pop_lsb(&dc); PieceType pt = type_of(pos.piece_on(from)); - if (pt == PAWN) - continue; // Will be generated togheter with direct checks - - Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces(); + Bitboard b = attacks_bb(pt, from, pos.pieces()) & ~pos.pieces(); if (pt == KING) - b &= ~PseudoAttacks[QUEEN][ci.ksq]; + b &= ~attacks_bb(pos.square(~us)); - SERIALIZE(b); + while (b) + *moveList++ = make_move(from, pop_lsb(&b)); } - return generate_all_moves(pos, mlist, us, ~pos.pieces(), &ci); + return us == WHITE ? generate_all(pos, moveList) + : generate_all(pos, moveList); } /// 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) { +ExtMove* generate(const Position& pos, ExtMove* moveList) { assert(pos.checkers()); - Square from, checksq; - int checkersCnt = 0; Color us = pos.side_to_move(); - Square ksq = pos.king_square(us); + Square ksq = pos.square(us); Bitboard sliderAttacks = 0; - Bitboard b = pos.checkers(); - - assert(pos.checkers()); + Bitboard sliders = pos.checkers() & ~pos.pieces(KNIGHT, PAWN); - // 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); - - assert(color_of(pos.piece_on(checksq)) == ~us); - - 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); - - default: - break; - } - } while (b); + // 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) + sliderAttacks |= line_bb(ksq, pop_lsb(&sliders)) & ~pos.checkers(); // Generate evasions for king, capture and non capture moves - b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; - from = ksq; - SERIALIZE(b); + Bitboard b = attacks_bb(ksq) & ~pos.pieces(us) & ~sliderAttacks; + while (b) + *moveList++ = make_move(ksq, pop_lsb(&b)); - if (checkersCnt > 1) - return mlist; // Double check, only a king move can save the day + 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 - Bitboard target = between_bb(checksq, ksq) | pos.checkers(); - - return generate_all_moves(pos, mlist, us, target); + return us == WHITE ? generate_all(pos, moveList) + : generate_all(pos, moveList); } /// generate generates all the legal moves in the given position template<> -MoveStack* generate(const Position& pos, MoveStack* mlist) { - - MoveStack *end, *cur = mlist; - Bitboard pinned = pos.pinned_pieces(); - Square ksq = pos.king_square(pos.side_to_move()); - - end = pos.checkers() ? 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; +ExtMove* generate(const Position& pos, ExtMove* moveList) { + + 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 && pinned & from_sq(*cur)) || from_sq(*cur) == ksq || type_of(*cur) == EN_PASSANT) + && !pos.legal(*cur)) + *cur = (--moveList)->move; else - cur++; + ++cur; - return end; + return moveList; }