X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=1fe723aec461e20a303582484349b9696ca9c552;hp=fd2bf037acdb2f6968647b43e0b2c6ff7cd10431;hb=dddaeff7d8d4a0c255310d054a53066296e71004;hpb=e4fc957898a5e7d87060b6169b8397c0472a5d64 diff --git a/src/position.cpp b/src/position.cpp index fd2bf037..1fe723ae 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -340,8 +340,8 @@ Bitboard Position::hidden_checkers(Color c) const { // Pinners are sliders, not checkers, that give check when // candidate pinned is removed. - pinners = (rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]) - | (bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]); + pinners = (pieces(ROOK, QUEEN, FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]) + | (pieces(BISHOP, QUEEN, FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]); if (FindPinned && pinners) pinners &= ~st->checkersBB; @@ -379,36 +379,35 @@ Bitboard Position::discovered_check_candidates(Color c) const { return hidden_checkers(c); } -/// Position::attacks_to() computes a bitboard containing all pieces which +/// Position::attackers_to() computes a bitboard containing all pieces which /// attacks a given square. -Bitboard Position::attacks_to(Square s) const { +Bitboard Position::attackers_to(Square s) const { - return (pawn_attacks(BLACK, s) & pawns(WHITE)) - | (pawn_attacks(WHITE, s) & pawns(BLACK)) - | (piece_attacks(s) & pieces_of_type(KNIGHT)) - | (piece_attacks(s) & rooks_and_queens()) - | (piece_attacks(s) & bishops_and_queens()) - | (piece_attacks(s) & pieces_of_type(KING)); + return (attacks_from(s, BLACK) & pieces(PAWN, WHITE)) + | (attacks_from(s, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(s) & pieces(KNIGHT)) + | (attacks_from(s) & pieces(ROOK, QUEEN)) + | (attacks_from(s) & pieces(BISHOP, QUEEN)) + | (attacks_from(s) & pieces(KING)); } -/// Position::piece_attacks_square() tests whether the piece on square f -/// attacks square t. +/// Position::attacks_from() computes a bitboard of all attacks +/// of a given piece put in a given square. -bool Position::piece_attacks_square(Piece p, Square f, Square t) const { +Bitboard Position::attacks_from(Piece p, Square s) const { - assert(square_is_ok(f)); - assert(square_is_ok(t)); + assert(square_is_ok(s)); switch (p) { - case WP: return pawn_attacks_square(WHITE, f, t); - case BP: return pawn_attacks_square(BLACK, f, t); - case WN: case BN: return piece_attacks_square(f, t); - case WB: case BB: return piece_attacks_square(f, t); - case WR: case BR: return piece_attacks_square(f, t); - case WQ: case BQ: return piece_attacks_square(f, t); - case WK: case BK: return piece_attacks_square(f, t); + case WP: return attacks_from(s, WHITE); + case BP: return attacks_from(s, BLACK); + case WN: case BN: return attacks_from(s); + case WB: case BB: return attacks_from(s); + case WR: case BR: return attacks_from(s); + case WQ: case BQ: return attacks_from(s); + case WK: case BK: return attacks_from(s); default: break; } return false; @@ -427,7 +426,7 @@ bool Position::move_attacks_square(Move m, Square s) const { assert(square_is_occupied(f)); - if (piece_attacks_square(piece_on(f), t, s)) + if (bit_is_set(attacks_from(piece_on(f), t), s)) return true; // Move the piece and scan for X-ray attacks behind it @@ -435,25 +434,25 @@ bool Position::move_attacks_square(Move m, Square s) const { Color us = color_of_piece_on(f); clear_bit(&occ, f); set_bit(&occ, t); - Bitboard xray = ( (rook_attacks_bb(s, occ) & rooks_and_queens()) - |(bishop_attacks_bb(s, occ) & bishops_and_queens())) & pieces_of_color(us); + Bitboard xray = ( (rook_attacks_bb(s, occ) & pieces(ROOK, QUEEN)) + |(bishop_attacks_bb(s, occ) & pieces(BISHOP, QUEEN))) & pieces_of_color(us); // If we have attacks we need to verify that are caused by our move // and are not already existent ones. - return xray && (xray ^ (xray & piece_attacks(s))); + return xray && (xray ^ (xray & attacks_from(s))); } /// Position::find_checkers() computes the checkersBB bitboard, which /// contains a nonzero bit for each checking piece (0, 1 or 2). It -/// currently works by calling Position::attacks_to, which is probably +/// currently works by calling Position::attackers_to, which is probably /// inefficient. Consider rewriting this function to use the last move /// played, like in non-bitboard versions of Glaurung. void Position::find_checkers() { Color us = side_to_move(); - st->checkersBB = attacks_to(king_square(us), opposite_color(us)); + st->checkersBB = attackers_to(king_square(us)) & pieces_of_color(opposite_color(us)); } @@ -479,10 +478,9 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Color us = side_to_move(); Square from = move_from(m); - Square ksq = king_square(us); assert(color_of_piece_on(from) == us); - assert(piece_on(ksq) == piece_of_color_and_type(us, KING)); + assert(piece_on(king_square(us)) == piece_of_color_and_type(us, KING)); // En passant captures are a tricky special case. Because they are // rather uncommon, we do it simply by testing whether the king is attacked @@ -493,6 +491,7 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { Square to = move_to(m); Square capsq = make_square(square_file(to), square_rank(from)); Bitboard b = occupied_squares(); + Square ksq = king_square(us); assert(to == ep_square()); assert(piece_on(from) == piece_of_color_and_type(us, PAWN)); @@ -503,20 +502,20 @@ bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { clear_bit(&b, capsq); set_bit(&b, to); - return !(rook_attacks_bb(ksq, b) & rooks_and_queens(them)) - && !(bishop_attacks_bb(ksq, b) & bishops_and_queens(them)); + return !(rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, them)) + && !(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, them)); } // If the moving piece is a king, check whether the destination // square is attacked by the opponent. - if (from == ksq) - return !(square_is_attacked(move_to(m), opposite_color(us))); + if (type_of_piece_on(from) == KING) + return !(attackers_to(move_to(m)) & pieces_of_color(opposite_color(us))); // A non-king move is legal if and only if it is not pinned or it // is moving along the ray towards or away from the king. return ( !pinned || !bit_is_set(pinned, from) - || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); + || (direction_between_squares(from, king_square(us)) == direction_between_squares(move_to(m), king_square(us)))); } @@ -548,7 +547,7 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { { case PAWN: - if (bit_is_set(pawn_attacks(them, ksq), to)) // Normal check? + if (bit_is_set(attacks_from(ksq, them), to)) // Normal check? return true; if ( dcCandidates // Discovered check? @@ -564,7 +563,7 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { switch (move_promotion_piece(m)) { case KNIGHT: - return bit_is_set(piece_attacks(to), ksq); + return bit_is_set(attacks_from(to), ksq); case BISHOP: return bit_is_set(bishop_attacks_bb(to, b), ksq); case ROOK: @@ -586,29 +585,29 @@ bool Position::move_is_check(Move m, Bitboard dcCandidates) const { clear_bit(&b, from); clear_bit(&b, capsq); set_bit(&b, to); - return (rook_attacks_bb(ksq, b) & rooks_and_queens(us)) - ||(bishop_attacks_bb(ksq, b) & bishops_and_queens(us)); + return (rook_attacks_bb(ksq, b) & pieces(ROOK, QUEEN, us)) + ||(bishop_attacks_bb(ksq, b) & pieces(BISHOP, QUEEN, us)); } return false; // Test discovered check and normal check according to piece type case KNIGHT: return (dcCandidates && bit_is_set(dcCandidates, from)) - || bit_is_set(piece_attacks(ksq), to); + || bit_is_set(attacks_from(ksq), to); case BISHOP: return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks(ksq), to)); + || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(ksq), to)); case ROOK: return (dcCandidates && bit_is_set(dcCandidates, from)) - || (direction_is_straight(ksq, to) && bit_is_set(piece_attacks(ksq), to)); + || (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)); case QUEEN: // Discovered checks are impossible! assert(!bit_is_set(dcCandidates, from)); - return ( (direction_is_straight(ksq, to) && bit_is_set(piece_attacks(ksq), to)) - || (direction_is_diagonal(ksq, to) && bit_is_set(piece_attacks(ksq), to))); + return ( (direction_is_straight(ksq, to) && bit_is_set(attacks_from(ksq), to)) + || (direction_is_diagonal(ksq, to) && bit_is_set(attacks_from(ksq), to))); case KING: // Discovered check? @@ -662,22 +661,23 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square // Direct checks if ( ( (Bishop && bit_is_set(BishopPseudoAttacks[ksq], to)) || (Rook && bit_is_set(RookPseudoAttacks[ksq], to))) - && bit_is_set(piece_attacks(ksq), to)) // slow, try to early skip + && bit_is_set(attacks_from(ksq), to)) // slow, try to early skip set_bit(pCheckersBB, to); else if ( Piece != KING && !Slider - && bit_is_set(piece_attacks(ksq), to)) + && bit_is_set(Piece == PAWN ? attacks_from(ksq, opposite_color(sideToMove)) + : attacks_from(ksq), to)) set_bit(pCheckersBB, to); // Discovery checks if (Piece != QUEEN && bit_is_set(dcCandidates, from)) { if (Piece != ROOK) - (*pCheckersBB) |= (piece_attacks(ksq) & rooks_and_queens(side_to_move())); + (*pCheckersBB) |= (attacks_from(ksq) & pieces(ROOK, QUEEN, side_to_move())); if (Piece != BISHOP) - (*pCheckersBB) |= (piece_attacks(ksq) & bishops_and_queens(side_to_move())); + (*pCheckersBB) |= (attacks_from(ksq) & pieces(BISHOP, QUEEN, side_to_move())); } } @@ -703,7 +703,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // pointer to point to the new, ready to be updated, state. struct ReducedStateInfo { Key key, pawnKey, materialKey; - int castleRights, rule50; + int castleRights, rule50, pliesFromNull; Square epSquare; Value mgValue, egValue; Value npMaterial[2]; @@ -724,6 +724,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Increment the 50 moves rule draw counter. Resetting it to zero in the // case of non-reversible moves is taken care of later. st->rule50++; + st->pliesFromNull++; if (move_is_castle(m)) { @@ -784,10 +785,6 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { board[to] = board[from]; board[from] = EMPTY; - // If the moving piece was a king, update the king square - if (pt == KING) - kingSquare[us] = to; - // Update piece lists, note that index[from] is not updated and // becomes stale. This works as long as index[] is accessed just // by known occupied squares. @@ -806,7 +803,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Set en passant square, only if moved pawn can be captured if (abs(int(to) - int(from)) == 16) { - if (pawn_attacks(us, from + (us == WHITE ? DELTA_N : DELTA_S)) & pawns(them)) + if (attacks_from(from + (us == WHITE ? DELTA_N : DELTA_S), us) & pieces(PAWN, them)) { st->epSquare = Square((int(from) + int(to)) / 2); key ^= zobEp[st->epSquare]; @@ -829,6 +826,10 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { set_bit(&(byTypeBB[promotion]), to); board[to] = piece_of_color_and_type(us, promotion); + // Update material key + st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; + st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; + // Update piece counts pieceCount[us][PAWN]--; pieceCount[us][promotion]++; @@ -838,6 +839,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { Square lastPawnSquare = pieceList[us][PAWN][pieceCount[us][PAWN]]; index[lastPawnSquare] = index[to]; pieceList[us][PAWN][index[lastPawnSquare]] = lastPawnSquare; + pieceList[us][PAWN][pieceCount[us][PAWN]] = SQ_NONE; index[to] = pieceCount[us][promotion] - 1; pieceList[us][promotion][index[to]] = to; @@ -845,10 +847,6 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { key ^= zobrist[us][PAWN][to] ^ zobrist[us][promotion][to]; st->pawnKey ^= zobrist[us][PAWN][to]; - // Update material key - st->materialKey ^= zobMaterial[us][PAWN][pieceCount[us][PAWN]]; - st->materialKey ^= zobMaterial[us][promotion][pieceCount[us][promotion]+1]; - // Partially revert and update incremental scores st->mgValue -= pst(us, PAWN, to); st->mgValue += pst(us, promotion, to); @@ -864,7 +862,7 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { // Update checkers bitboard, piece must be already moved if (ep | pm) - st->checkersBB = attacks_to(king_square(them), us); + st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); else { st->checkersBB = EmptyBoardBB; @@ -886,6 +884,8 @@ void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + + assert(is_ok()); } @@ -918,16 +918,15 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ // Update hash key key ^= zobrist[them][capture][capsq]; - // If the captured piece was a pawn, update pawn hash key - if (capture == PAWN) - st->pawnKey ^= zobrist[them][PAWN][capsq]; - // Update incremental scores st->mgValue -= pst(them, capture, capsq); st->egValue -= pst(them, capture, capsq); - // Update material - if (capture != PAWN) + // If the captured piece was a pawn, update pawn hash key, + // otherwise update non-pawn material. + if (capture == PAWN) + st->pawnKey ^= zobrist[them][PAWN][capsq]; + else st->npMaterial[them] -= piece_value_midgame(capture); // Update material hash key @@ -937,9 +936,16 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ pieceCount[them][capture]--; // Update piece list, move the last piece at index[capsq] position + // + // WARNING: This is a not perfectly revresible operation. When we + // will reinsert the captured piece in undo_move() we will put it + // at the end of the list and not in its original place, it means + // index[] and pieceList[] are not guaranteed to be invariant to a + // do_move() + undo_move() sequence. Square lastPieceSquare = pieceList[them][capture][pieceCount[them][capture]]; index[lastPieceSquare] = index[capsq]; pieceList[them][capture][index[lastPieceSquare]] = lastPieceSquare; + pieceList[them][capture][pieceCount[them][capture]] = SQ_NONE; // Reset rule 50 counter st->rule50 = 0; @@ -953,7 +959,6 @@ void Position::do_capture_move(Bitboard& key, PieceType capture, Color them, Squ void Position::do_castle_move(Move m) { - assert(is_ok()); assert(move_is_ok(m)); assert(move_is_castle(m)); @@ -981,17 +986,22 @@ void Position::do_castle_move(Move m) { rto = relative_square(us, SQ_D1); } - // Move the pieces - Bitboard kmove_bb = make_move_bb(kfrom, kto); - do_move_bb(&(byColorBB[us]), kmove_bb); - do_move_bb(&(byTypeBB[KING]), kmove_bb); - do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares - - Bitboard rmove_bb = make_move_bb(rfrom, rto); - do_move_bb(&(byColorBB[us]), rmove_bb); - do_move_bb(&(byTypeBB[ROOK]), rmove_bb); - do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares - + // Remove pieces from source squares: + clear_bit(&(byColorBB[us]), kfrom); + clear_bit(&(byTypeBB[KING]), kfrom); + clear_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares + clear_bit(&(byColorBB[us]), rfrom); + clear_bit(&(byTypeBB[ROOK]), rfrom); + clear_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares + + // Put pieces on destination squares: + set_bit(&(byColorBB[us]), kto); + set_bit(&(byTypeBB[KING]), kto); + set_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares + set_bit(&(byColorBB[us]), rto); + set_bit(&(byTypeBB[ROOK]), rto); + set_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares + // Update board array Piece king = piece_of_color_and_type(us, KING); Piece rook = piece_of_color_and_type(us, ROOK); @@ -999,9 +1009,6 @@ void Position::do_castle_move(Move m) { board[kto] = king; board[rto] = rook; - // Update king square - kingSquare[us] = kto; - // Update piece lists pieceList[us][KING][index[kfrom]] = kto; pieceList[us][ROOK][index[rfrom]] = rto; @@ -1035,13 +1042,15 @@ void Position::do_castle_move(Move m) { st->rule50 = 0; // Update checkers BB - st->checkersBB = attacks_to(king_square(them), us); + st->checkersBB = attackers_to(king_square(them)) & pieces_of_color(us); // Finish sideToMove = opposite_color(sideToMove); st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; st->egValue += (sideToMove == WHITE)? TempoValueEndgame : -TempoValueEndgame; + + assert(is_ok()); } @@ -1098,10 +1107,12 @@ void Position::undo_move(Move m) { Square lastPromotionSquare = pieceList[us][promotion][pieceCount[us][promotion]]; index[lastPromotionSquare] = index[to]; pieceList[us][promotion][index[lastPromotionSquare]] = lastPromotionSquare; + pieceList[us][promotion][pieceCount[us][promotion]] = SQ_NONE; index[to] = pieceCount[us][PAWN] - 1; pieceList[us][PAWN][index[to]] = to; } + // Put the piece back at the source square Bitboard move_bb = make_move_bb(to, from); do_move_bb(&(byColorBB[us]), move_bb); @@ -1111,10 +1122,6 @@ void Position::undo_move(Move m) { board[from] = piece_of_color_and_type(us, pt); board[to] = EMPTY; - // If the moving piece was a king, update the king square - if (pt == KING) - kingSquare[us] = from; - // Update piece list index[from] = index[to]; pieceList[us][pt][index[from]] = from; @@ -1146,6 +1153,8 @@ void Position::undo_move(Move m) { // Finally point our state pointer back to the previous state st = st->previous; + + assert(is_ok()); } @@ -1181,26 +1190,28 @@ void Position::undo_castle_move(Move m) { assert(piece_on(kto) == piece_of_color_and_type(us, KING)); assert(piece_on(rto) == piece_of_color_and_type(us, ROOK)); - - // Put the pieces back at the source square - Bitboard kmove_bb = make_move_bb(kto, kfrom); - do_move_bb(&(byColorBB[us]), kmove_bb); - do_move_bb(&(byTypeBB[KING]), kmove_bb); - do_move_bb(&(byTypeBB[0]), kmove_bb); // HACK: byTypeBB[0] == occupied squares - - Bitboard rmove_bb = make_move_bb(rto, rfrom); - do_move_bb(&(byColorBB[us]), rmove_bb); - do_move_bb(&(byTypeBB[ROOK]), rmove_bb); - do_move_bb(&(byTypeBB[0]), rmove_bb); // HACK: byTypeBB[0] == occupied squares + + // Remove pieces from destination squares: + clear_bit(&(byColorBB[us]), kto); + clear_bit(&(byTypeBB[KING]), kto); + clear_bit(&(byTypeBB[0]), kto); // HACK: byTypeBB[0] == occupied squares + clear_bit(&(byColorBB[us]), rto); + clear_bit(&(byTypeBB[ROOK]), rto); + clear_bit(&(byTypeBB[0]), rto); // HACK: byTypeBB[0] == occupied squares + + // Put pieces on source squares: + set_bit(&(byColorBB[us]), kfrom); + set_bit(&(byTypeBB[KING]), kfrom); + set_bit(&(byTypeBB[0]), kfrom); // HACK: byTypeBB[0] == occupied squares + set_bit(&(byColorBB[us]), rfrom); + set_bit(&(byTypeBB[ROOK]), rfrom); + set_bit(&(byTypeBB[0]), rfrom); // HACK: byTypeBB[0] == occupied squares // Update board board[rto] = board[kto] = EMPTY; board[rfrom] = piece_of_color_and_type(us, ROOK); board[kfrom] = piece_of_color_and_type(us, KING); - // Update king square - kingSquare[us] = kfrom; - // Update piece lists pieceList[us][KING][index[kto]] = kfrom; pieceList[us][ROOK][index[rto]] = rfrom; @@ -1210,6 +1221,8 @@ void Position::undo_castle_move(Move m) { // Finally point our state pointer back to the previous state st = st->previous; + + assert(is_ok()); } @@ -1230,6 +1243,7 @@ void Position::do_null_move(StateInfo& backupSt) { backupSt.mgValue = st->mgValue; backupSt.egValue = st->egValue; backupSt.previous = st->previous; + backupSt.pliesFromNull = st->pliesFromNull; st->previous = &backupSt; // Save the current key to the history[] array, in order to be able to @@ -1246,6 +1260,7 @@ void Position::do_null_move(StateInfo& backupSt) { sideToMove = opposite_color(sideToMove); st->epSquare = SQ_NONE; st->rule50++; + st->pliesFromNull = 0; gamePly++; st->mgValue += (sideToMove == WHITE)? TempoValueMidgame : -TempoValueMidgame; @@ -1267,6 +1282,7 @@ void Position::undo_null_move() { st->mgValue = backupSt->mgValue; st->egValue = backupSt->egValue; st->previous = backupSt->previous; + st->pliesFromNull = backupSt->pliesFromNull; // Update the necessary information sideToMove = opposite_color(sideToMove); @@ -1284,13 +1300,13 @@ void Position::undo_null_move() { int Position::see(Square to) const { assert(square_is_ok(to)); - return see(SQ_NONE, to); + return see(SQ_NONE, to, false); } int Position::see(Move m) const { assert(move_is_ok(m)); - return see(move_from(m), move_to(m)); + return see(move_from(m), move_to(m), false); } int Position::see_sign(Move m) const { @@ -1306,10 +1322,10 @@ int Position::see_sign(Move m) const { && type_of_piece_on(from) != KING) return 1; - return see(from, to); + return see(from, to, true); } -int Position::see(Square from, Square to) const { +int Position::see(Square from, Square to, bool shortcut) const { // Material values static const int seeValues[18] = { @@ -1320,8 +1336,10 @@ int Position::see(Square from, Square to) const { 0, 0 }; - Bitboard attackers, stmAttackers, occ, b; + Bitboard attackers, stmAttackers, b; + int pieceDiff = 0; + assert(!shortcut || from != SQ_NONE); assert(square_is_ok(from) || from == SQ_NONE); assert(square_is_ok(to)); @@ -1332,10 +1350,27 @@ int Position::see(Square from, Square to) const { // Initialize pieces Piece piece = piece_on(from); Piece capture = piece_on(to); + Bitboard occ = occupied_squares(); - // Find all attackers to the destination square, with the moving piece - // removed, but possibly an X-ray attacker added behind it. - occ = occupied_squares(); + // King cannot be recaptured + if (type_of_piece(piece) == KING) + return seeValues[capture]; + + // If captured piece is defended by enemy pawns or knights then SEE is negative + // when captured piece value does not compensate the lost of capturing one. + if (shortcut) + { + pieceDiff = seeValues[piece] - seeValues[capture]; + + if ( pieceDiff > seeValues[PAWN] + &&(attacks_from(to, us) & pieces(PAWN, them))) + return -(pieceDiff - seeValues[PAWN] / 2); + + if ( pieceDiff > seeValues[KNIGHT] + && pieces(KNIGHT, them) + &&(pieces(KNIGHT, them) & attacks_from(to))) + return -(pieceDiff - seeValues[KNIGHT] / 2); + } // Handle en passant moves if (st->epSquare == to && type_of_piece_on(from) == PAWN) @@ -1352,13 +1387,15 @@ int Position::see(Square from, Square to) const { while (true) { + // Find all attackers to the destination square, with the moving piece + // removed, but possibly an X-ray attacker added behind it. clear_bit(&occ, from); - attackers = (rook_attacks_bb(to, occ) & rooks_and_queens()) - | (bishop_attacks_bb(to, occ) & bishops_and_queens()) - | (piece_attacks(to) & knights()) - | (piece_attacks(to) & kings()) - | (pawn_attacks(WHITE, to) & pawns(BLACK)) - | (pawn_attacks(BLACK, to) & pawns(WHITE)); + attackers = (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)) + | (attacks_from(to) & pieces(KNIGHT)) + | (attacks_from(to) & pieces(KING)) + | (attacks_from(to, WHITE) & pieces(PAWN, BLACK)) + | (attacks_from(to, BLACK) & pieces(PAWN, WHITE)); if (from != SQ_NONE) break; @@ -1369,11 +1406,12 @@ int Position::see(Square from, Square to) const { // Locate the least valuable attacker to the destination square // and use it to initialize from square. + stmAttackers = attackers & pieces_of_color(us); PieceType pt; - for (pt = PAWN; !(attackers & pieces_of_color_and_type(us, pt)); pt++) + for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) assert(pt < KING); - from = first_1(attackers & pieces_of_color_and_type(us, pt)); + from = first_1(stmAttackers & pieces(pt)); piece = piece_on(from); } @@ -1401,15 +1439,24 @@ int Position::see(Square from, Square to) const { // Locate the least valuable attacker for the side to move. The loop // below looks like it is potentially infinite, but it isn't. We know // that the side to move still has at least one attacker left. - for (pt = PAWN; !(stmAttackers & pieces_of_type(pt)); pt++) + for (pt = PAWN; !(stmAttackers & pieces(pt)); pt++) assert(pt < KING); + // If captured piece is defended by an enemy piece then SEE is negative + // if captured piece value does not compensate the lost of capturing one. + if (pieceDiff > seeValues[pt]) + { + assert(shortcut); + return -(pieceDiff - seeValues[pt] / 2); + } else + pieceDiff = 0; // Only first cycle + // Remove the attacker we just found from the 'attackers' bitboard, // and scan for new X-ray attacks behind the attacker. - b = stmAttackers & pieces_of_type(pt); + b = stmAttackers & pieces(pt); occ ^= (b & (~b + 1)); - attackers |= (rook_attacks_bb(to, occ) & rooks_and_queens()) - | (bishop_attacks_bb(to, occ) & bishops_and_queens()); + attackers |= (rook_attacks_bb(to, occ) & pieces(ROOK, QUEEN)) + | (bishop_attacks_bb(to, occ) & pieces(BISHOP, QUEEN)); attackers &= occ; @@ -1464,19 +1511,17 @@ void Position::clear() { memset(st, 0, sizeof(StateInfo)); st->epSquare = SQ_NONE; - memset(index, 0, sizeof(int) * 64); - memset(byColorBB, 0, sizeof(Bitboard) * 2); + memset(byColorBB, 0, sizeof(Bitboard) * 2); + memset(byTypeBB, 0, sizeof(Bitboard) * 8); + memset(pieceCount, 0, sizeof(int) * 2 * 8); + memset(index, 0, sizeof(int) * 64); for (int i = 0; i < 64; i++) board[i] = EMPTY; - for (int i = 0; i < 7; i++) - { - byTypeBB[i] = EmptyBoardBB; - pieceCount[0][i] = pieceCount[1][i] = 0; - for (int j = 0; j < 8; j++) + for (int i = 0; i < 8; i++) + for (int j = 0; j < 16; j++) pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; - } sideToMove = WHITE; gamePly = 0; @@ -1515,9 +1560,6 @@ void Position::put_piece(Piece p, Square s) { set_bit(&byTypeBB[0], s); // HACK: byTypeBB[0] contains all occupied squares. pieceCount[c][pt]++; - - if (pt == KING) - kingSquare[c] = s; } @@ -1577,7 +1619,7 @@ Key Position::compute_pawn_key() const { for (Color c = WHITE; c <= BLACK; c++) { - b = pawns(c); + b = pieces(PAWN, c); while(b) { s = pop_1st_bit(&b); @@ -1622,7 +1664,7 @@ Value Position::compute_value() const { for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) { - b = pieces_of_color_and_type(c, pt); + b = pieces(pt, c); while(b) { s = pop_1st_bit(&b); @@ -1648,7 +1690,7 @@ Value Position::compute_non_pawn_material(Color c) const { for (PieceType pt = KNIGHT; pt <= QUEEN; pt++) { - Bitboard b = pieces_of_color_and_type(c, pt); + Bitboard b = pieces(pt, c); while (b) { assert(piece_on(first_1(b)) == piece_of_color_and_type(c, pt)); @@ -1667,7 +1709,7 @@ Value Position::compute_non_pawn_material(Color c) const { bool Position::is_draw() const { // Draw by material? - if ( !pawns() + if ( !pieces(PAWN) && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMidgame)) return true; @@ -1676,7 +1718,7 @@ bool Position::is_draw() const { return true; // Draw by repetition? - for (int i = 2; i < Min(gamePly, st->rule50); i += 2) + for (int i = 2; i < Min(Min(gamePly, st->rule50), st->pliesFromNull); i += 2) if (history[gamePly - i] == st->key) return true; @@ -1691,7 +1733,7 @@ bool Position::is_mate() const { MoveStack moves[256]; - return is_check() && !generate_evasions(*this, moves, pinned_pieces(sideToMove)); + return is_check() && (generate_evasions(*this, moves, pinned_pieces(sideToMove)) == moves); } @@ -1711,20 +1753,18 @@ bool Position::has_mate_threat(Color c) { do_null_move(st1); MoveStack mlist[120]; - int count; bool result = false; Bitboard dc = discovered_check_candidates(sideToMove); Bitboard pinned = pinned_pieces(sideToMove); // Generate pseudo-legal non-capture and capture check moves - count = generate_non_capture_checks(*this, mlist, dc); - count += generate_captures(*this, mlist + count); + MoveStack* last = generate_non_capture_checks(*this, mlist, dc); + last = generate_captures(*this, last); // Loop through the moves, and see if one of them is mate - for (int i = 0; i < count; i++) + for (MoveStack* cur = mlist; cur != last; cur++) { - Move move = mlist[i].move; - + Move move = cur->move; if (!pl_move_is_legal(move, pinned)) continue; @@ -1921,7 +1961,7 @@ bool Position::is_ok(int* failedStep) const { Color us = side_to_move(); Color them = opposite_color(us); Square ksq = king_square(them); - if (square_is_attacked(ksq, us)) + if (attackers_to(ksq) & pieces_of_color(us)) return false; } @@ -1946,7 +1986,7 @@ bool Position::is_ok(int* failedStep) const { // Separate piece type bitboards must have empty intersections for (PieceType p1 = PAWN; p1 <= KING; p1++) for (PieceType p2 = PAWN; p2 <= KING; p2++) - if (p1 != p2 && (pieces_of_type(p1) & pieces_of_type(p2))) + if (p1 != p2 && (pieces(p1) & pieces(p2))) return false; } @@ -2002,7 +2042,7 @@ bool Position::is_ok(int* failedStep) const { if (debugPieceCounts) for (Color c = WHITE; c <= BLACK; c++) for (PieceType pt = PAWN; pt <= KING; pt++) - if (pieceCount[c][pt] != count_1s(pieces_of_color_and_type(c, pt))) + if (pieceCount[c][pt] != count_1s(pieces(pt, c))) return false; if (failedStep) (*failedStep)++;