X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovegen.cpp;h=be16845095d43e04f317f33541f0b6a56761957a;hb=a0e2debe3f1d14f84984a9a2c1482dc41f695548;hp=e017d8fe2c596c4fd2cee565fce2bfec972c9f54;hpb=c4d67d77c99b99c9ac387ab622773a320f8d5cc3;p=stockfish diff --git a/src/movegen.cpp b/src/movegen.cpp index e017d8fe..be168450 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -21,6 +21,8 @@ #include "movegen.h" #include "position.h" +namespace Stockfish { + namespace { template @@ -56,19 +58,16 @@ namespace { constexpr Direction UpLeft = (Us == WHITE ? NORTH_WEST : SOUTH_EAST); const Square ksq = pos.square(Them); - Bitboard emptySquares; + const Bitboard emptySquares = Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces(); + const Bitboard enemies = Type == EVASIONS ? pos.checkers() + : Type == CAPTURES ? target : 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; @@ -80,33 +79,23 @@ 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. + 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); } } @@ -114,27 +103,24 @@ 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), ksq); while (b2) - moveList = make_promotions(moveList, pop_lsb(&b2), ksq); + moveList = make_promotions(moveList, pop_lsb(b2), ksq); while (b3) - moveList = make_promotions(moveList, pop_lsb(&b3), ksq); + 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) { Bitboard b1 = shift(pawnsNotOn7) & enemies; @@ -142,13 +128,13 @@ 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); } @@ -156,10 +142,8 @@ 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()); @@ -167,7 +151,7 @@ namespace { assert(b1); while (b1) - *moveList++ = make(pop_lsb(&b1), pos.ep_square()); + *moveList++ = make(pop_lsb(b1), pos.ep_square()); } } @@ -182,26 +166,17 @@ namespace { Bitboard bb = pos.pieces(Us, Pt); - while (bb) { - Square from = pop_lsb(&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; - } - + while (bb) + { + 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; @@ -210,30 +185,20 @@ 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) - { - 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()"); - } + if (Type == EVASIONS && more_than_one(pos.checkers())) + goto kingMoves; // Double check, only a king move can save the day + + 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); @@ -241,14 +206,17 @@ namespace { moveList = generate_moves(pos, moveList, target); moveList = generate_moves(pos, moveList, target); - if (Type != QUIET_CHECKS && Type != EVASIONS) +kingMoves: + 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)) + 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)); @@ -261,7 +229,9 @@ namespace { /// 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 non-captures and underpromotions (except checking knight) +/// Generates all pseudo-legal check evasions when the side to move is in check +/// Generates all pseudo-legal non-captures giving check, except castling /// Generates all pseudo-legal captures and non-captures /// /// Returns a pointer to the end of the move list. @@ -269,8 +239,8 @@ 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(); @@ -281,70 +251,11 @@ 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. -/// 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 |= line_bb(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<> @@ -358,7 +269,7 @@ 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 @@ -366,3 +277,5 @@ ExtMove* generate(const Position& pos, ExtMove* moveList) { return moveList; } + +} // namespace Stockfish