X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fmovegen.cpp;h=a0c06aa8dc6404f1c4b4df109a7fefa6ae0ef67f;hp=caf2bfe675b77edc05e54e4ba16d0cdd97ffd4b5;hb=99e547f4cb190e462d0c582b731a0fcf25ce1545;hpb=972dec454c6da25879bcaeae4392907d3ad577e0 diff --git a/src/movegen.cpp b/src/movegen.cpp index caf2bfe6..a0c06aa8 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -1,7 +1,7 @@ /* 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) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad Stockfish is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -17,7 +17,6 @@ along with this program. If not, see . */ -#include #include #include "movegen.h" @@ -25,192 +24,163 @@ /// 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_1st_bit(&b)) +#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_1st_bit(&b); \ - (*mlist++).move = make_move(to + (d), to); } +#define SERIALIZE_PAWNS(b, d) while (b) { Square to = pop_lsb(&b); \ + (*mlist++).move = make_move(to - (d), to); } namespace { - enum CastlingSide { KING_SIDE, QUEEN_SIDE }; + template + ExtMove* generate_castle(const Position& pos, ExtMove* mlist, Color us) { - template - MoveStack* generate_castle_moves(const Position& pos, MoveStack* mlist, Color us) { - - const CastleRight CR[] = { Side ? WHITE_OOO : WHITE_OO, - Side ? BLACK_OOO : BLACK_OO }; - - if (!pos.can_castle(CR[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(CR[us]); + Square rfrom = pos.castle_rook_square(us, Side); Square kto = relative_square(us, Side == KING_SIDE ? SQ_G1 : SQ_C1); - Square rto = relative_square(us, Side == KING_SIDE ? SQ_F1 : SQ_D1); Bitboard enemies = pos.pieces(~us); - assert(!pos.in_check()); - assert(pos.piece_on(kfrom) == make_piece(us, KING)); - assert(pos.piece_on(rfrom) == make_piece(us, ROOK)); + assert(!pos.checkers()); - // 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 = std::min(rfrom, rto), e = std::max(rfrom, rto); s <= e; s++) - if (s != kfrom && s != rfrom && !pos.square_is_empty(s)) - return mlist; + const int K = Chess960 ? kto > kfrom ? -1 : 1 + : Side == KING_SIDE ? -1 : 1; - for (Square s = std::min(kfrom, kto), e = std::max(kfrom, kto); s <= e; s++) - if ( (s != kfrom && s != rfrom && !pos.square_is_empty(s)) - ||(pos.attackers_to(s) & enemies)) + 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 (pos.is_chess960()) - { - Bitboard occ = pos.occupied_squares(); - clear_bit(&occ, rfrom); - if (pos.attackers_to(kto, occ) & enemies) - return mlist; - } + if (Chess960 && (pos.attackers_to(kto, pos.pieces() ^ rfrom) & enemies)) + return mlist; - (*mlist++).move = make_castle(kfrom, rfrom); + (*mlist++).move = make(kfrom, rfrom); - if (OnlyChecks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) + if (Checks && !pos.move_gives_check((mlist - 1)->move, CheckInfo(pos))) mlist--; return mlist; } - template - inline Bitboard move_pawns(Bitboard p) { + template + inline ExtMove* generate_promotions(ExtMove* mlist, Bitboard pawnsOn7, + Bitboard target, const CheckInfo* ci) { - 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 : p; - } - - - template - inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) { - - Bitboard b = move_pawns(pawnsOn7) & target; + Bitboard b = shift_bb(pawnsOn7) & target; while (b) { - Square to = pop_1st_bit(&b); + Square to = pop_lsb(&b); - if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) - (*mlist++).move = make_promotion(to - Delta, to, QUEEN); + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) + (*mlist++).move = make(to - Delta, to, QUEEN); - if (Type == MV_NON_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) + if (Type == QUIETS || Type == EVASIONS || Type == NON_EVASIONS) { - (*mlist++).move = make_promotion(to - Delta, to, ROOK); - (*mlist++).move = make_promotion(to - Delta, to, BISHOP); - (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); + (*mlist++).move = make(to - Delta, to, ROOK); + (*mlist++).move = make(to - Delta, to, BISHOP); + (*mlist++).move = make(to - Delta, to, KNIGHT); } - // Knight-promotion is the only one that can give a check (direct or - // discovered) not already included in the queen-promotion. - if (Type == MV_NON_CAPTURE_CHECK && bit_is_set(StepAttacksBB[W_KNIGHT][to], ksq)) - (*mlist++).move = make_promotion(to - Delta, 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)ksq; // Silence a warning under MSVC + (void)ci; // Silence a warning under MSVC } return mlist; } - template - MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq = SQ_NONE) { + template + ExtMove* generate_pawn_moves(const Position& pos, ExtMove* mlist, + Bitboard target, const CheckInfo* ci) { - // Calculate our parametrized parameters at compile time, named according to + // 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); + 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); Bitboard b1, b2, dc1, dc2, emptySquares; - Bitboard pawnsOn7 = pos.pieces(PAWN, Us) & TRank7BB; - Bitboard pawnsNotOn7 = pos.pieces(PAWN, Us) & ~TRank7BB; + Bitboard pawnsOn7 = pos.pieces(Us, PAWN) & TRank7BB; + Bitboard pawnsNotOn7 = pos.pieces(Us, PAWN) & ~TRank7BB; - Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target: - Type == MV_CAPTURE ? target : pos.pieces(Them)); + Bitboard enemies = (Type == EVASIONS ? pos.pieces(Them) & target: + Type == CAPTURES ? target : pos.pieces(Them)); // Single and double pawn pushes, no promotions - if (Type != MV_CAPTURE) + if (Type != CAPTURES) { - emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); + emptySquares = (Type == QUIETS || Type == QUIET_CHECKS ? target : ~pos.pieces()); - b1 = move_pawns(pawnsNotOn7) & emptySquares; - b2 = move_pawns(b1 & TRank3BB) & emptySquares; + b1 = shift_bb(pawnsNotOn7) & emptySquares; + b2 = shift_bb(b1 & TRank3BB) & emptySquares; - if (Type == MV_EVASION) // Consider only blocking squares + if (Type == EVASIONS) // Consider only blocking squares { b1 &= target; b2 &= target; } - if (Type == MV_NON_CAPTURE_CHECK) + if (Type == QUIET_CHECKS) { - b1 &= pos.attacks_from(ksq, Them); - b2 &= pos.attacks_from(ksq, Them); + b1 &= pos.attacks_from(ci->ksq, Them); + b2 &= pos.attacks_from(ci->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 among captures. - if (pawnsNotOn7 & target) // Target is dc bitboard + if (pawnsNotOn7 & ci->dcCandidates) { - dc1 = move_pawns(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq); - dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + dc1 = shift_bb(pawnsNotOn7 & ci->dcCandidates) & emptySquares & ~file_bb(ci->ksq); + dc2 = shift_bb(dc1 & TRank3BB) & emptySquares; b1 |= dc1; b2 |= dc2; } } - SERIALIZE_PAWNS(b1, -UP); - SERIALIZE_PAWNS(b2, -UP -UP); + SERIALIZE_PAWNS(b1, Up); + SERIALIZE_PAWNS(b2, Up + Up); } // Promotions and underpromotions - if (pawnsOn7 && (Type != MV_EVASION || (target & TRank8BB))) + if (pawnsOn7 && (Type != EVASIONS || (target & TRank8BB))) { - if (Type == MV_CAPTURE) - emptySquares = pos.empty_squares(); + if (Type == CAPTURES) + emptySquares = ~pos.pieces(); - if (Type == MV_EVASION) + if (Type == EVASIONS) emptySquares &= target; - mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); - mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); - mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ksq); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ci); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ci); } // Standard and en-passant captures - if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) + if (Type == CAPTURES || Type == EVASIONS || Type == NON_EVASIONS) { - b1 = move_pawns(pawnsNotOn7) & enemies; - b2 = move_pawns(pawnsNotOn7) & enemies; + b1 = shift_bb(pawnsNotOn7) & enemies; + b2 = shift_bb(pawnsNotOn7) & enemies; - SERIALIZE_PAWNS(b1, -RIGHT); - SERIALIZE_PAWNS(b2, -LEFT); + SERIALIZE_PAWNS(b1, Right); + SERIALIZE_PAWNS(b2, Left); if (pos.ep_square() != SQ_NONE) { @@ -219,7 +189,7 @@ 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() - UP)) + if (Type == EVASIONS && !(target & (pos.ep_square() - Up))) return mlist; b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); @@ -227,7 +197,7 @@ namespace { assert(b1); while (b1) - (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square()); + (*mlist++).move = make(pop_lsb(&b1), pos.ep_square()); } } @@ -235,140 +205,129 @@ namespace { } - template - inline MoveStack* generate_direct_checks(const Position& pos, MoveStack* mlist, - Color us, const CheckInfo& ci) { + template FORCE_INLINE + ExtMove* generate_moves(const Position& pos, ExtMove* mlist, Color us, + Bitboard target, const CheckInfo* ci) { + assert(Pt != KING && Pt != PAWN); - Square from; - const Square* pl = pos.piece_list(us, Pt); + const Square* pl = pos.list(us); - if ((from = *pl++) == SQ_NONE) - return mlist; + 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; - Bitboard checkSqs = ci.checkSq[Pt] & pos.empty_squares(); + if (ci->dcCandidates && (ci->dcCandidates & from)) + continue; + } - do - { - if ( (Pt == BISHOP || Pt == ROOK || Pt == QUEEN) - && !(PseudoAttacks[Pt][from] & checkSqs)) - continue; + Bitboard b = pos.attacks_from(from) & target; - if (ci.dcCandidates && bit_is_set(ci.dcCandidates, from)) - continue; + if (Checks) + b &= ci->checkSq[Pt]; - Bitboard b = pos.attacks_from(from) & checkSqs; SERIALIZE(b); - - } while ((from = *pl++) != SQ_NONE); + } return mlist; } - template - FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + template FORCE_INLINE + ExtMove* generate_all(const Position& pos, ExtMove* mlist, Color us, + Bitboard target, const CheckInfo* ci = NULL) { - Bitboard b; - Square from; - const Square* pl = pos.piece_list(us, Pt); + const bool Checks = Type == QUIET_CHECKS; - if (*pl != SQ_NONE) - { - do { - from = *pl; - b = pos.attacks_from(from) & target; - SERIALIZE(b); - } while (*++pl != SQ_NONE); - } + mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target, ci) + : generate_pawn_moves(pos, mlist, target, ci)); - return mlist; - } + 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); + if (Type != QUIET_CHECKS && Type != EVASIONS) + { + Square from = pos.king_square(us); + Bitboard b = pos.attacks_from(from) & target; + SERIALIZE(b); + } - template<> - FORCE_INLINE MoveStack* generate_piece_moves(const Position& pos, MoveStack* mlist, Color us, Bitboard target) { + if (Type != CAPTURES && Type != EVASIONS && pos.can_castle(us)) + { + if (pos.is_chess960()) + { + mlist = generate_castle(pos, mlist, us); + mlist = generate_castle(pos, mlist, us); + } + else + { + mlist = generate_castle(pos, mlist, us); + mlist = generate_castle(pos, mlist, us); + } + } - Square from = pos.king_square(us); - Bitboard b = pos.attacks_from(from) & target; - SERIALIZE(b); return mlist; } + } // namespace -/// generate generates all pseudo-legal captures and queen +/// 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 +/// generate generates all pseudo-legal non-captures and /// underpromotions. Returns a pointer to the end of the move list. /// -/// generate generates all pseudo-legal captures and +/// generate generates all pseudo-legal captures and /// non-captures. Returns a pointer to the end of the move list. -template -MoveStack* generate(const Position& pos, MoveStack* mlist) { +template +ExtMove* generate(const Position& pos, ExtMove* mlist) { - assert(Type == MV_CAPTURE || Type == MV_NON_CAPTURE || Type == MV_NON_EVASION); - assert(!pos.in_check()); + assert(Type == CAPTURES || Type == QUIETS || Type == NON_EVASIONS); + assert(!pos.checkers()); Color us = pos.side_to_move(); - Bitboard target; - - if (Type == MV_CAPTURE) - target = pos.pieces(~us); - - else if (Type == MV_NON_CAPTURE) - target = pos.empty_squares(); - - else if (Type == MV_NON_EVASION) - target = pos.pieces(~us) | pos.empty_squares(); - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target) - : generate_pawn_moves(pos, mlist, target)); + Bitboard target = Type == CAPTURES ? pos.pieces(~us) + : Type == QUIETS ? ~pos.pieces() + : Type == NON_EVASIONS ? ~pos.pieces(us) : 0; - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - - if (Type != MV_CAPTURE && pos.can_castle(us)) - { - mlist = generate_castle_moves(pos, mlist, us); - mlist = generate_castle_moves(pos, mlist, us); - } - - return mlist; + return generate_all(pos, mlist, us, target); } // 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); +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 +/// generate generates all pseudo-legal non-captures and knight /// underpromotions that give 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* mlist) { - assert(!pos.in_check()); + assert(!pos.checkers()); - Color us = pos.side_to_move(); CheckInfo ci(pos); Bitboard dc = ci.dcCandidates; while (dc) { - Square from = pop_1st_bit(&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.empty_squares(); + Bitboard b = pos.attacks_from(Piece(pt), from) & ~pos.pieces(); if (pt == KING) b &= ~PseudoAttacks[QUEEN][ci.ksq]; @@ -376,48 +335,32 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) SERIALIZE(b); } - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, ci.dcCandidates, ci.ksq) - : generate_pawn_moves(pos, mlist, ci.dcCandidates, ci.ksq)); - - mlist = generate_direct_checks(pos, mlist, us, ci); - mlist = generate_direct_checks(pos, mlist, us, ci); - mlist = generate_direct_checks(pos, mlist, us, ci); - mlist = generate_direct_checks(pos, mlist, us, ci); - - if (pos.can_castle(us)) - { - mlist = generate_castle_moves(pos, mlist, us); - mlist = generate_castle_moves(pos, mlist, us); - } - - return mlist; + return generate_all(pos, mlist, pos.side_to_move(), ~pos.pieces(), &ci); } -/// generate generates all pseudo-legal check evasions when the side +/// 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* mlist) { - assert(pos.in_check()); + assert(pos.checkers()); - Bitboard b, target; Square from, checksq; int checkersCnt = 0; Color us = pos.side_to_move(); Square ksq = pos.king_square(us); Bitboard sliderAttacks = 0; - Bitboard checkers = pos.checkers(); + Bitboard b = pos.checkers(); - assert(checkers); + assert(pos.checkers()); // 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. - b = checkers; do { checkersCnt++; - checksq = pop_1st_bit(&b); + checksq = pop_lsb(&b); assert(color_of(pos.piece_on(checksq)) == ~us); @@ -429,7 +372,7 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { // 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 (squares_between(ksq, checksq) || !bit_is_set(PseudoAttacks[BISHOP][checksq], ksq)) + 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 @@ -448,38 +391,33 @@ MoveStack* generate(const Position& pos, MoveStack* mlist) { from = ksq; SERIALIZE(b); - // Generate evasions for other pieces only if not under a double check if (checkersCnt > 1) - return mlist; - - // Blocking evasions or captures of the checking piece - target = squares_between(checksq, ksq) | checkers; + return mlist; // Double check, only a king move can save the day - mlist = (us == WHITE ? generate_pawn_moves(pos, mlist, target) - : generate_pawn_moves(pos, mlist, target)); + // Generate blocking evasions or captures of the checking piece + Bitboard target = between_bb(checksq, ksq) | pos.checkers(); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - mlist = generate_piece_moves(pos, mlist, us, target); - return generate_piece_moves(pos, mlist, us, target); + return generate_all(pos, mlist, us, target); } -/// generate generates all the legal moves in the given position +/// generate generates all the legal moves in the given position template<> -MoveStack* generate(const Position& pos, MoveStack* mlist) { +ExtMove* generate(const Position& pos, ExtMove* mlist) { - MoveStack *last, *cur = mlist; + ExtMove *end, *cur = mlist; Bitboard pinned = pos.pinned_pieces(); - - last = pos.in_check() ? generate(pos, mlist) - : generate(pos, mlist); - while (cur != last) - if (!pos.pl_move_is_legal(cur->move, pinned)) - cur->move = (--last)->move; + 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; else cur++; - return last; + return end; }