X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=5095bb7455e6f36966d884ea297a8431b363183a;hb=2214fcecf7ae5d1d4165596bcd238b6e6bc909c1;hp=b57f41a9829ed3264293418feff27736dbe68eec;hpb=fd8e88427b1268bfddc0b2ab72f639f758b7be0b;p=stockfish diff --git a/src/movegen.cpp b/src/movegen.cpp index b57f41a9..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) 2015-2020 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 @@ -23,10 +21,12 @@ #include "movegen.h" #include "position.h" +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); @@ -38,13 +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 && (attacks_bb(to) & ksq)) - *moveList++ = make(to - D, to, KNIGHT); - else - (void)ksq; // Silence a warning under MSVC - return moveList; } @@ -59,20 +52,16 @@ namespace { constexpr Direction UpRight = (Us == WHITE ? NORTH_EAST : SOUTH_WEST); constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); - const Square ksq = pos.square(Them); - 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; @@ -84,33 +73,24 @@ namespace { if (Type == QUIET_CHECKS) { - 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 amongst the captures. - Bitboard dcCandidateQuiets = pos.blockers_for_king(Them) & pawnsNotOn7; - if (dcCandidateQuiets) - { - Bitboard dc1 = shift(dcCandidateQuiets) & emptySquares & ~file_bb(ksq); - Bitboard dc2 = shift(dc1 & TRank3BB) & emptySquares; - - b1 |= dc1; - b2 |= dc2; - } + // To make a quiet check, you either make a direct check by pushing a pawn + // or push a blocker pawn that is not on the same file as the enemy king. + // Discovered check promotion has been already generated amongst the captures. + Square ksq = pos.square(Them); + Bitboard dcCandidatePawns = pos.blockers_for_king(Them) & ~file_bb(ksq); + b1 &= pawn_attacks_bb(Them, ksq) | shift< 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); } } @@ -118,27 +98,24 @@ namespace { // Promotions and underpromotions if (pawnsOn7) { - if (Type == CAPTURES) - emptySquares = ~pos.pieces(); - - if (Type == EVASIONS) - emptySquares &= target; - Bitboard b1 = shift(pawnsOn7) & enemies; Bitboard b2 = shift(pawnsOn7) & enemies; Bitboard b3 = shift(pawnsOn7) & emptySquares; + if (Type == EVASIONS) + 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; @@ -146,13 +123,13 @@ namespace { while (b1) { - Square to = pop_lsb(&b1); + Square to = pop_lsb(b1); *moveList++ = make_move(to - UpRight, to); } while (b2) { - Square to = pop_lsb(&b2); + Square to = pop_lsb(b2); *moveList++ = make_move(to - UpLeft, to); } @@ -160,10 +137,8 @@ namespace { { 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 & pawn_attacks_bb(Them, pos.ep_square()); @@ -171,7 +146,7 @@ namespace { assert(b1); while (b1) - *moveList++ = make(pop_lsb(&b1), pos.ep_square()); + *moveList++ = make(pop_lsb(b1), pos.ep_square()); } } @@ -184,27 +159,19 @@ namespace { 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) - && !(attacks_bb(from) & target & pos.check_squares(Pt))) - continue; - - if (pos.blockers_for_king(~Us) & from) - continue; - } - + 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; @@ -213,46 +180,39 @@ namespace { template ExtMove* generate_all(const Position& pos, ExtMove* moveList) { - constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantations + + static_assert(Type != LEGAL, "Unsupported type in generate_all()"); + + constexpr bool Checks = Type == QUIET_CHECKS; // Reduce template instantiations + const Square ksq = pos.square(Us); Bitboard target; - switch (Type) + // Skip generating non-king moves when in double check + if (Type != EVASIONS || !more_than_one(pos.checkers())) { - case CAPTURES: - target = pos.pieces(~Us); - break; - case QUIETS: - case QUIET_CHECKS: - target = ~pos.pieces(); - break; - case EVASIONS: - { - Square checksq = lsb(pos.checkers()); - target = between_bb(pos.square(Us), checksq) | checksq; - break; - } - case NON_EVASIONS: - target = ~pos.pieces(Us); - break; - default: - static_assert(true, "Unsupported type in generate_all()"); + 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); } - 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 != QUIET_CHECKS && Type != EVASIONS) + if (!Checks || pos.blockers_for_king(~Us) & ksq) { - Square ksq = pos.square(Us); - Bitboard b = attacks_bb(ksq) & target; + 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)); + *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 ((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)); } @@ -263,8 +223,10 @@ namespace { } // namespace -/// Generates all pseudo-legal captures and queen promotions +/// 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 /// /// Returns a pointer to the end of the move list. @@ -272,8 +234,8 @@ namespace { template ExtMove* generate(const Position& pos, ExtMove* moveList) { - static_assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS, "Unsupported type in generate()"); - assert(!pos.checkers()); + static_assert(Type != LEGAL, "Unsupported type in generate()"); + assert((Type == EVASIONS) == (bool)pos.checkers()); Color us = pos.side_to_move(); @@ -284,70 +246,11 @@ ExtMove* generate(const Position& pos, ExtMove* 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.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)); - - Bitboard b = attacks_bb(pt, from, pos.pieces()) & ~pos.pieces(); - - if (pt == KING) - b &= ~attacks_bb(pos.square(~us)); - - while (b) - *moveList++ = make_move(from, pop_lsb(&b)); - } - - 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<> -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) - sliderAttacks |= LineBB[ksq][pop_lsb(&sliders)] & ~pos.checkers(); - - // Generate evasions for king, capture and non capture moves - Bitboard b = attacks_bb(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 - return us == WHITE ? generate_all(pos, moveList) - : generate_all(pos, moveList); -} - - /// generate generates all the legal moves in the given position template<> @@ -361,7 +264,7 @@ ExtMove* generate(const Position& pos, ExtMove* 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 @@ -369,3 +272,5 @@ ExtMove* generate(const Position& pos, ExtMove* moveList) { return moveList; } + +} // namespace Stockfish