diff --git a/src/movegen.cpp b/src/movegen.cpp index 8b0f20c7..d76441b3 100644 --- a/src/movegen.cpp +++ b/src/movegen.cpp @@ -99,29 +99,29 @@ namespace { template inline MoveStack* generate_pawn_captures(MoveStack* mlist, Bitboard pawns, Bitboard target) { - const Bitboard EdgeFileBB = ( Delta == DELTA_NE - || Delta == DELTA_SE ? FileABB : FileHBB); + const Bitboard TFileABB = ( Delta == DELTA_NE + || Delta == DELTA_SE ? FileABB : FileHBB); Bitboard b; Square to; - b = move_pawns(pawns) & target & ~EdgeFileBB; + b = move_pawns(pawns) & target & ~TFileABB; SERIALIZE_MOVES_D(b, -Delta); return mlist; } template - inline MoveStack* generate_promotions(const Position& pos, MoveStack* mlist, Bitboard pawnsOn7, Bitboard target) { + inline MoveStack* generate_promotions(MoveStack* mlist, Bitboard pawnsOn7, Bitboard target, Square ksq) { - const Bitboard EdgeFileBB = ( Delta == DELTA_NE - || Delta == DELTA_SE ? FileABB : FileHBB); + const Bitboard TFileABB = ( Delta == DELTA_NE + || Delta == DELTA_SE ? FileABB : FileHBB); Bitboard b; Square to; b = move_pawns(pawnsOn7) & target; if (Delta != DELTA_N && Delta != DELTA_S) - b &= ~EdgeFileBB; + b &= ~TFileABB; while (b) { @@ -137,16 +137,13 @@ namespace { (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); } - // Knight under promotion is the only one that can give a check not - // already included in the queen-promotion. - if (Type == MV_CHECK) - { - Square ksq = pos.king_square(Delta > 0 ? BLACK : WHITE); - if (bit_is_set(pos.attacks_from(to), ksq)) + // Knight-promotion is the only one that can give a check (direct or + // discovered) not already included in the queen-promotion. + if ( Type == MV_CHECK + && bit_is_set(StepAttacksBB[W_KNIGHT][to], ksq)) (*mlist++).move = make_promotion(to - Delta, to, KNIGHT); - } else - (void)pos; // Silence a warning under MSVC + (void)ksq; // Silence a warning under MSVC } return mlist; } @@ -155,32 +152,61 @@ namespace { template MoveStack* generate_pawn_moves(const Position& pos, MoveStack* mlist, Bitboard target, Square ksq) { - // Calculate 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 TRank7BB = (Us == WHITE ? Rank7BB : Rank2BB); - const Bitboard TRank3BB = (Us == WHITE ? Rank3BB : Rank6BB); - 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); + // Calculate 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 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); 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(Them)); + Bitboard b1, b2, dc1, dc2, emptySquares; - // Pre-calculate pawn pushes before changing emptySquares definition + Bitboard pawns = pos.pieces(PAWN, Us); + Bitboard pawnsOn7 = pawns & TRank7BB; + Bitboard pawnsNotOn7 = pawns & ~TRank7BB; + + Bitboard enemies = (Type == MV_EVASION ? pos.pieces(Them) & target: + Type == MV_CAPTURE ? target : pos.pieces(Them)); + + // Single and double pawn pushes, no promotions if (Type != MV_CAPTURE) { emptySquares = (Type == MV_NON_CAPTURE ? target : pos.empty_squares()); - pawnPushes = move_pawns(pawns & ~TRank7BB) & emptySquares; - } - if (Type == MV_EVASION) - { - emptySquares &= target; // Only blocking squares - enemyPieces &= target; // Capture only the checker piece + b1 = move_pawns(pawnsNotOn7) & emptySquares; + b2 = move_pawns(b1 & TRank3BB) & emptySquares; + + if (Type == MV_EVASION) + { + b1 &= target; // Consider only blocking squares + b2 &= target; + } + + if (Type == MV_CHECK) + { + // Consider only direct checks + b1 &= pos.attacks_from(ksq, Them); + b2 &= pos.attacks_from(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) // For CHECK type target is dc bitboard + { + dc1 = move_pawns(pawnsNotOn7 & target) & emptySquares & ~file_bb(ksq); + dc2 = move_pawns(dc1 & TRank3BB) & emptySquares; + + b1 |= dc1; + b2 |= dc2; + } + } + + SERIALIZE_MOVES_D(b1, -UP); + SERIALIZE_MOVES_D(b2, -UP -UP); } // Promotions and underpromotions @@ -189,70 +215,39 @@ namespace { if (Type == MV_CAPTURE) 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); + if (Type == MV_EVASION) + emptySquares &= target; + + mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); + mlist = generate_promotions(mlist, pawnsOn7, enemies, ksq); + mlist = generate_promotions(mlist, pawnsOn7, emptySquares, ksq); } - // Standard captures + // Standard and en-passant captures if (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) { - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - mlist = generate_pawn_captures(mlist, pawns, enemyPieces); - } + mlist = generate_pawn_captures(mlist, pawnsNotOn7, enemies); + mlist = generate_pawn_captures(mlist, pawnsNotOn7, enemies); - // Single and double pawn pushes - if (Type != MV_CAPTURE) - { - b1 = (Type != MV_EVASION ? pawnPushes : pawnPushes & emptySquares); - b2 = move_pawns(pawnPushes & TRank3BB) & emptySquares; - - if (Type == MV_CHECK) + if (pos.ep_square() != SQ_NONE) { - // Consider only pawn moves which give direct checks - b1 &= pos.attacks_from(ksq, Them); - b2 &= pos.attacks_from(ksq, Them); + assert(rank_of(pos.ep_square()) == (Us == WHITE ? RANK_6 : RANK_3)); - // Add pawn moves which gives 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. - 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; + // 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)) + return mlist; - b1 |= dc1; - b2 |= dc2; - } - } - SERIALIZE_MOVES_D(b1, -UP); - SERIALIZE_MOVES_D(b2, -UP -UP); - } + b1 = pawnsNotOn7 & pos.attacks_from(pos.ep_square(), Them); - // En passant captures - if ( (Type == MV_CAPTURE || Type == MV_EVASION || Type == MV_NON_EVASION) - && pos.ep_square() != SQ_NONE) - { - assert(Us != WHITE || rank_of(pos.ep_square()) == RANK_6); - assert(Us != BLACK || rank_of(pos.ep_square()) == RANK_3); + assert(b1); - // 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)) - return mlist; - - b1 = pawns & pos.attacks_from(pos.ep_square(), Them); - - assert(b1); - - while (b1) - { - to = pop_1st_bit(&b1); - (*mlist++).move = make_enpassant(to, pos.ep_square()); + while (b1) + (*mlist++).move = make_enpassant(pop_1st_bit(&b1), pos.ep_square()); } } + return mlist; }