X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=90d0135a4d0dbe246aa38daa54b94d28820d5ad4;hp=0056ce384dfff017f45d164d442d746a62649943;hb=ad1f28bc1c1c5426fb8ab246f5d43ad57002b4d5;hpb=0fcda095df1caa860e8e3f3a714d5545ec9dc122 diff --git a/src/movegen.cpp b/src/movegen.cpp index 0056ce38..90d0135a 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -21,6 +21,7 @@ #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'. @@ -36,55 +37,56 @@ namespace { QUEEN_SIDE }; - template + template MoveStack* generate_castle_moves(const Position&, MoveStack*, Color us); - template + template MoveStack* generate_pawn_moves(const Position&, MoveStack*, Bitboard, Square); - template + template inline MoveStack* generate_discovered_checks(const Position& pos, MoveStack* mlist, Square from) { - assert(Piece != QUEEN); + assert(Pt != QUEEN); + assert(Pt != PAWN); + + Bitboard b = pos.attacks_from(from) & pos.empty_squares(); + + if (Pt == KING) + b &= ~QueenPseudoAttacks[pos.king_square(opposite_color(pos.side_to_move()))]; - 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; } - template + template inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, Color us, Bitboard dc, Square ksq) { - assert(Piece != KING); + assert(Pt != KING); + assert(Pt != PAWN); Bitboard checkSqs, b; Square from; - const Square* ptr = pos.piece_list_begin(us, Piece); + const Square* pl = pos.piece_list(us, Pt); - if ((from = *ptr++) == SQ_NONE) + if ((from = *pl++) == SQ_NONE) return mlist; - checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); + checkSqs = pos.attacks_from(ksq) & pos.empty_squares(); do { - if ( (Piece == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) - || (Piece == ROOK && !(RookPseudoAttacks[from] & checkSqs)) - || (Piece == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) + if ( (Pt == QUEEN && !(QueenPseudoAttacks[from] & checkSqs)) + || (Pt == ROOK && !(RookPseudoAttacks[from] & checkSqs)) + || (Pt == BISHOP && !(BishopPseudoAttacks[from] & checkSqs))) continue; if (dc && bit_is_set(dc, from)) continue; - b = pos.attacks_from(from) & checkSqs; + b = pos.attacks_from(from) & checkSqs; SERIALIZE_MOVES(b); - } while ((from = *ptr++) != SQ_NONE); + } while ((from = *pl++) != SQ_NONE); return mlist; } @@ -96,30 +98,30 @@ namespace { : generate_pawn_moves(p, m, dc, ksq)); } - template + template FORCE_INLINE MoveStack* generate_piece_moves(const Position& p, MoveStack* m, Color us, Bitboard t) { - assert(Piece == PAWN); + assert(Pt == PAWN); assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_EVASION); return (us == WHITE ? generate_pawn_moves(p, m, t, SQ_NONE) : generate_pawn_moves(p, m, t, SQ_NONE)); } - template + template FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { Bitboard b; Square from; - const Square* ptr = pos.piece_list_begin(us, Piece); + const Square* pl = pos.piece_list(us, Pt); - if (*ptr != SQ_NONE) + if (*pl != SQ_NONE) { do { - from = *ptr; - b = pos.attacks_from(from) & target; + from = *pl; + b = pos.attacks_from(from) & target; SERIALIZE_MOVES(b); - } while (*++ptr != SQ_NONE); + } while (*++pl != SQ_NONE); } return mlist; } @@ -137,10 +139,6 @@ namespace { } -//// -//// Functions -//// - /// generate generates all pseudo-legal captures and queen /// promotions. Returns a pointer to the end of the move list. @@ -154,14 +152,13 @@ namespace { template MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - assert(!pos.is_check()); + assert(!pos.in_check()); Color us = pos.side_to_move(); Bitboard target; if (Type == MV_CAPTURE || Type == MV_NON_EVASION) - target = pos.pieces_of_color(opposite_color(us)); + target = pos.pieces(opposite_color(us)); else if (Type == MV_NON_CAPTURE) target = pos.empty_squares(); else @@ -182,19 +179,19 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { mlist = generate_piece_moves(pos, mlist, us, target); mlist = generate_piece_moves(pos, mlist, us, target); - if (Type != MV_CAPTURE) + if (Type != MV_CAPTURE && pos.can_castle(us)) { - if (pos.can_castle_kingside(us)) + if (pos.can_castle(us == WHITE ? WHITE_OO : BLACK_OO)) mlist = generate_castle_moves(pos, mlist, us); - if (pos.can_castle_queenside(us)) + if (pos.can_castle(us == WHITE ? WHITE_OOO : BLACK_OOO)) mlist = generate_castle_moves(pos, mlist, us); } return mlist; } -// Explicit template instantiation +// Explicit template instantiations template MoveStack* generate(const Position& pos, MoveStack* mlist); template MoveStack* generate(const Position& pos, MoveStack* mlist); template MoveStack* generate(const Position& pos, MoveStack* mlist); @@ -205,8 +202,7 @@ template MoveStack* generate(const Position& pos, MoveStack* mli template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - assert(!pos.is_check()); + assert(!pos.in_check()); Bitboard b, dc; Square from; @@ -216,12 +212,12 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) assert(pos.piece_on(ksq) == make_piece(opposite_color(us), KING)); // Discovered non-capture checks - b = dc = pos.discovered_check_candidates(us); + b = dc = pos.discovered_check_candidates(); while (b) { from = pop_1st_bit(&b); - switch (pos.type_of_piece_on(from)) + switch (piece_type(pos.piece_on(from))) { case PAWN: /* Will be generated togheter with pawns direct checks */ break; case KNIGHT: mlist = generate_discovered_checks(pos, mlist, from); break; @@ -246,8 +242,7 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - assert(pos.is_check()); + assert(pos.in_check()); Bitboard b, target; Square from, checksq; @@ -269,26 +264,31 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { checkersCnt++; checksq = pop_1st_bit(&b); - assert(pos.color_of_piece_on(checksq) == opposite_color(us)); + assert(piece_color(pos.piece_on(checksq)) == opposite_color(us)); - switch (pos.type_of_piece_on(checksq)) + switch (piece_type(pos.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 (RookPseudoAttacks[checksq] & (1ULL << ksq)) - sliderAttacks |= RookPseudoAttacks[checksq] | pos.attacks_from(checksq); + // If queen and king are far we can safely remove all the squares attacked + // in the other direction becuase are not reachable by the king anyway. + if (squares_between(ksq, checksq) || (RookPseudoAttacks[checksq] & (1ULL << ksq))) + sliderAttacks |= QueenPseudoAttacks[checksq]; + + // Otherwise, if king and queen are adjacent and on a diagonal line, 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 |= BishopPseudoAttacks[checksq] | pos.attacks_from(checksq); + default: break; } } while (b); // Generate evasions for king, capture and non capture moves - b = pos.attacks_from(ksq) & ~pos.pieces_of_color(us) & ~sliderAttacks; + b = pos.attacks_from(ksq) & ~pos.pieces(us) & ~sliderAttacks; from = ksq; SERIALIZE_MOVES(b); @@ -308,148 +308,28 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { } -/// generate computes a complete list of legal -/// or pseudo-legal moves in the current position. -template<> -inline MoveStack* generate(const Position& pos, MoveStack* mlist) { - - assert(pos.is_ok()); - - return pos.is_check() ? generate(pos, mlist) - : generate(pos, mlist); -} +/// generate computes a complete list of legal moves in the current position template<> MoveStack* generate(const Position& pos, MoveStack* mlist) { - assert(pos.is_ok()); - MoveStack *last, *cur = mlist; - Bitboard pinned = pos.pinned_pieces(pos.side_to_move()); + Bitboard pinned = pos.pinned_pieces(); - last = generate(pos, mlist); + last = pos.in_check() ? generate(pos, mlist) + : generate(pos, mlist); // Remove illegal moves from the list while (cur != last) - if (pos.pl_move_is_legal(cur->move, pinned)) - cur++; - else + if (!pos.pl_move_is_legal(cur->move, pinned)) cur->move = (--last)->move; + else + cur++; return last; } -/// 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. - -bool move_is_legal(const Position& pos, const Move m) { - - MoveStack mlist[MOVES_MAX]; - MoveStack *cur, *last = generate(pos, mlist); - - for (cur = mlist; cur != last; cur++) - if (cur->move == m) - return pos.pl_move_is_legal(m, pos.pinned_pieces(pos.side_to_move())); - - return false; -} - - -/// 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. - -bool move_is_legal(const Position& pos, const Move m, Bitboard pinned) { - - assert(pos.is_ok()); - assert(pinned == pos.pinned_pieces(pos.side_to_move())); - - 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_special(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; - - // We have already handled promotion moves, so destination - // cannot be on the 8/1th rank. - if (square_rank(to) == RANK_8 || square_rank(to) == RANK_1) - 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; - - case DELTA_N: - case DELTA_S: - // Pawn push. The destination square must be empty. - if (!pos.square_is_empty(to)) - return false; - break; - - 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; - - default: - return false; - } - } - else if (!bit_is_set(pos.attacks_from(pc, from), to)) - 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); -} - - namespace { template @@ -474,7 +354,7 @@ namespace { return mlist; } - template + template inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) { const Bitboard TFileABB = (Delta == DELTA_NE || Delta == DELTA_SE ? FileABB : FileHBB); @@ -505,7 +385,7 @@ namespace { // This is the only possible under promotion that can give a check // not already included in the queen-promotion. if ( Type == MV_CHECK - && bit_is_set(pos.attacks_from(to), pos.king_square(opposite_color(Us)))) + && bit_is_set(pos.attacks_from(to), pos.king_square(Delta > 0 ? BLACK : WHITE))) (*mlist++).move = make_promotion_move(to - Delta, to, KNIGHT); else (void)pos; // Silence a warning under MSVC } @@ -520,21 +400,21 @@ namespace { const Color Them = (Us == WHITE ? BLACK : WHITE); const Bitboard TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - const Square TDELTA_N = (Us == WHITE ? DELTA_N : DELTA_S); - const Square TDELTA_NE = (Us == WHITE ? DELTA_NE : DELTA_SE); - const Square TDELTA_NW = (Us == WHITE ? DELTA_NW : DELTA_SW); + const Square UP = (Us == WHITE ? DELTA_N : DELTA_S); + const Square RIGHT_UP = (Us == WHITE ? DELTA_NE : DELTA_SW); + const Square LEFT_UP = (Us == WHITE ? DELTA_NW : DELTA_SE); Square to; Bitboard b1, b2, dc1, dc2, pawnPushes, emptySquares; Bitboard pawns = pos.pieces(PAWN, Us); Bitboard pawnsOn7 = pawns & TRank7BB; - Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces_of_color(Them)); + Bitboard enemyPieces = (Type == MV_CAPTURE ? target : pos.pieces(Them)); // Pre-calculate pawn pushes before changing emptySquares definition if (Type != MV_CAPTURE) { emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); - pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; + pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; } if (Type == MV_EVASION) @@ -550,23 +430,23 @@ namespace { emptySquares = pos.empty_squares(); pawns &= ~TRank7BB; - mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); - mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); - mlist = generate_promotions(pos, mlist, pawnsOn7, emptySquares); + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, enemyPieces); + mlist = generate_promotions(pos, mlist, pawnsOn7, emptySquares); } // Standard captures if (Type == MV_CAPTURE || Type == MV_EVASION) { - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); + mlist = generate_pawn_captures(mlist, pawns, enemyPieces); } // Single and double pawn pushes if (Type != MV_CAPTURE) { - b1 = pawnPushes & emptySquares; - b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; + b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares); + b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; if (Type == MV_CHECK) { @@ -579,15 +459,15 @@ namespace { // don't generate captures. if (pawns & target) // For CHECK type target is dc bitboard { - dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares; - dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + dc1 = move_pawns(pawns & target & ~file_bb(ksq)) & emptySquares; + dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; b1 |= dc1; b2 |= dc2; } } - SERIALIZE_MOVES_D(b1, -TDELTA_N); - SERIALIZE_MOVES_D(b2, -TDELTA_N -TDELTA_N); + SERIALIZE_MOVES_D(b1, -UP); + SERIALIZE_MOVES_D(b2, -UP -UP); } // En passant captures @@ -599,7 +479,7 @@ namespace { // 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 == MV_EVASION && !bit_is_set(target, pos.ep_square() - TDELTA_N)) + if (Type == MV_EVASION && !bit_is_set(target, pos.ep_square() - UP)) return mlist; b1 = pawns & pos.attacks_from(pos.ep_square(), Them); @@ -618,37 +498,45 @@ namespace { template MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) { + CastleRight f = CastleRight((Side == KING_SIDE ? WHITE_OO : WHITE_OOO) << us); Color them = opposite_color(us); - Square ksq = pos.king_square(us); - - assert(pos.piece_on(ksq) == make_piece(us, KING)); - 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) == make_piece(us, ROOK)); - - // 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; + // After castling, the rook and king's final positions are exactly the same + // in Chess960 as they would be in standard chess. + Square kfrom = pos.king_square(us); + Square rfrom = pos.castle_rook_square(f); + Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); + Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); + + assert(!pos.in_check()); + assert(pos.piece_on(kfrom) == make_piece(us, KING)); + assert(pos.piece_on(rfrom) == make_piece(us, ROOK)); + + // Unimpeded rule: All the squares between the king's initial and final squares + // (including the final square), and all the squares between the rook's initial + // and final squares (including the final square), must be vacant except for + // the king and castling rook. + for (Square s = Min(kfrom, kto); s <= Max(kfrom, kto); s++) + if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + ||(pos.attackers_to(s) & pos.pieces(them))) + return mlist; - for (s = Min(rsq, s2); s <= Max(rsq, s2); s++) - if (s != ksq && s != rsq && pos.square_is_occupied(s)) - illegal = true; + for (Square s = Min(rfrom, rto); s <= Max(rfrom, rto); s++) + if (s != kfrom && s != rfrom && !pos.square_is_empty(s)) + return mlist; - if ( Side == QUEEN_SIDE - && square_file(rsq) == FILE_B - && ( pos.piece_on(relative_square(us, SQ_A1)) == make_piece(them, ROOK) - || pos.piece_on(relative_square(us, SQ_A1)) == make_piece(them, QUEEN))) - illegal = true; + // 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 (pos.is_chess960()) + { + Bitboard occ = pos.occupied_squares(); + clear_bit(&occ, rfrom); + if (pos.attackers_to(kto, occ) & pos.pieces(them)) + return mlist; + } - if (!illegal) - (*mlist++).move = make_castle_move(ksq, rsq); + (*mlist++).move = make_castle_move(kfrom, rfrom); return mlist; }