X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fposition.cpp;h=21839d6abaf32e52e48d027e4a9b626864496fc3;hp=e2eeda85ac1e3c5d1f12728d530a840d1039b1a6;hb=68e711aac603388d38490521cf336b535aa10c91;hpb=8f59de48f559e477dc383d5b51a0b842986758d0 diff --git a/src/position.cpp b/src/position.cpp index e2eeda85..21839d6a 100644 --- a/src/position.cpp +++ b/src/position.cpp @@ -23,8 +23,9 @@ //// #include -#include +#include #include +#include #include "mersenne.h" #include "movegen.h" @@ -319,81 +320,40 @@ void Position::copy(const Position &pos) { } -/// Position:pinned_pieces() returns a bitboard of all pinned (against the -/// king) pieces for the given color. -Bitboard Position::pinned_pieces(Color c) const { - - if (st->pinned[c] != ~EmptyBoardBB) - return st->pinned[c]; - - Bitboard p1, p2; - Square ksq = king_square(c); - st->pinned[c] = hidden_checks(c, ksq, p1) | hidden_checks(c, ksq, p2); - st->pinners[c] = p1 | p2; - return st->pinned[c]; -} - -Bitboard Position::pinned_pieces(Color c, Bitboard& p) const { - - if (st->pinned[c] == ~EmptyBoardBB) - pinned_pieces(c); +/// Position:hidden_checkers<>() returns a bitboard of all pinned (against the +/// king) pieces for the given color and for the given pinner type. Or, when +/// template parameter FindPinned is false, the pieces of the given color +/// candidate for a discovery check against the enemy king. +/// Note that checkersBB bitboard must be already updated. - p = st->pinners[c]; - return st->pinned[c]; -} +template +Bitboard Position::hidden_checkers(Color c) const { -Bitboard Position::discovered_check_candidates(Color c) const { + Bitboard pinners, result = EmptyBoardBB; - if (st->dcCandidates[c] != ~EmptyBoardBB) - return st->dcCandidates[c]; + // Pinned pieces protect our king, dicovery checks attack + // the enemy king. + Square ksq = king_square(FindPinned ? c : opposite_color(c)); - Bitboard dummy; - Square ksq = king_square(opposite_color(c)); - st->dcCandidates[c] = hidden_checks(c, ksq, dummy) | hidden_checks(c, ksq, dummy); - return st->dcCandidates[c]; -} + // 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]); -/// Position:hidden_checks<>() returns a bitboard of all pinned (against the -/// king) pieces for the given color and for the given pinner type. Or, when -/// template parameter FindPinned is false, the pinned pieces of opposite color -/// that are, indeed, the pieces candidate for a discovery check. -template -Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) const { + if (FindPinned && pinners) + pinners &= ~st->checkersBB; - Square s; - Bitboard sliders, result = EmptyBoardBB; + while (pinners) + { + Square s = pop_1st_bit(&pinners); + Bitboard b = squares_between(s, ksq) & occupied_squares(); - if (Piece == ROOK) // Resolved at compile time - sliders = rooks_and_queens(FindPinned ? opposite_color(c) : c) & RookPseudoAttacks[ksq]; - else - sliders = bishops_and_queens(FindPinned ? opposite_color(c) : c) & BishopPseudoAttacks[ksq]; + assert(b); - if (sliders && (!FindPinned || (sliders & ~st->checkersBB))) - { - // King blockers are candidate pinned pieces - Bitboard candidate_pinned = piece_attacks(ksq) & pieces_of_color(c); - - // Pinners are sliders, not checkers, that give check when - // candidate pinned are removed. - pinners = (FindPinned ? sliders & ~st->checkersBB : sliders); - - if (Piece == ROOK) - pinners &= rook_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); - else - pinners &= bishop_attacks_bb(ksq, occupied_squares() ^ candidate_pinned); - - // Finally for each pinner find the corresponding pinned piece (if same color of king) - // or discovery checker (if opposite color) among the candidates. - Bitboard p = pinners; - while (p) - { - s = pop_1st_bit(&p); - result |= (squares_between(s, ksq) & candidate_pinned); - } + if ( !(b & (b - 1)) // Only one bit set? + && (b & pieces_of_color(c))) // Is an our piece? + result |= b; } - else - pinners = EmptyBoardBB; - return result; } @@ -466,7 +426,7 @@ bool Position::move_attacks_square(Move m, Square s) const { /// Position::find_checkers() computes the checkersBB bitboard, which -/// contains a nonzero bit for each checking piece (0, 1 or 2). It +/// contains a nonzero bit for each checking piece (0, 1 or 2). It /// currently works by calling Position::attacks_to, which is probably /// inefficient. Consider rewriting this function to use the last move /// played, like in non-bitboard versions of Glaurung. @@ -482,8 +442,14 @@ void Position::find_checkers() { bool Position::pl_move_is_legal(Move m) const { + return pl_move_is_legal(m, pinned_pieces(side_to_move())); +} + +bool Position::pl_move_is_legal(Move m, Bitboard pinned) const { + assert(is_ok()); assert(move_is_ok(m)); + assert(pinned == pinned_pieces(side_to_move())); // If we're in check, all pseudo-legal moves are legal, because our // check evasion generator only generates true legal moves. @@ -531,7 +497,7 @@ bool Position::pl_move_is_legal(Move m) const { // 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 ( !bit_is_set(pinned_pieces(us), from) + return ( !bit_is_set(pinned, from) || (direction_between_squares(from, ksq) == direction_between_squares(move_to(m), ksq))); } @@ -540,15 +506,21 @@ bool Position::pl_move_is_legal(Move m) const { bool Position::move_is_check(Move m) const { + Bitboard dc = discovered_check_candidates(side_to_move()); + return move_is_check(m, dc); +} + +bool Position::move_is_check(Move m, Bitboard dcCandidates) const { + assert(is_ok()); assert(move_is_ok(m)); + assert(dcCandidates == discovered_check_candidates(side_to_move())); Color us = side_to_move(); Color them = opposite_color(us); Square from = move_from(m); Square to = move_to(m); Square ksq = king_square(them); - Bitboard dcCandidates = discovered_check_candidates(us); assert(color_of_piece_on(from) == us); assert(piece_on(ksq) == piece_of_color_and_type(them, KING)); @@ -669,7 +641,8 @@ bool Position::move_is_capture(Move m) const { } -/// Position::update_checkers() is a private method to udpate chekers info +/// Position::update_checkers() udpates chekers info given the move. It is called +/// in do_move() and is faster then find_checkers(). template inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, @@ -695,18 +668,25 @@ inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square void Position::do_move(Move m, StateInfo& newSt) { + do_move(m, newSt, discovered_check_candidates(side_to_move())); +} + +void Position::do_move(Move m, StateInfo& newSt, Bitboard dcCandidates) { + assert(is_ok()); assert(move_is_ok(m)); - // Get now the current (pre-move) dc candidates that we will use - // in update_checkers(). - Bitboard oldDcCandidates = discovered_check_candidates(side_to_move()); + // Copy some fields of old state to our new StateInfo object except the + // ones which are recalculated from scratch anyway, then switch our state + // pointer to point to the new, ready to be updated, state. + struct ReducedStateInfo { + Key key, pawnKey, materialKey; + int castleRights, rule50; + Square epSquare; + Value mgValue, egValue; + }; - // Copy the old state to our new StateInfo object (except the - // captured piece, which is taken care of later. - // TODO do not copy pinners and checkersBB because are recalculated - // anyway. - newSt = *st; + memcpy(&newSt, st, sizeof(ReducedStateInfo)); newSt.capture = NO_PIECE_TYPE; newSt.previous = st; st = &newSt; @@ -719,10 +699,6 @@ void Position::do_move(Move m, StateInfo& newSt) { // case of non-reversible moves is taken care of later. st->rule50++; - // Reset pinned bitboard and its friends - for (Color c = WHITE; c <= BLACK; c++) - st->pinners[c] = st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB; - if (move_is_castle(m)) do_castle_move(m); else if (move_promotion(m)) @@ -812,12 +788,12 @@ void Position::do_move(Move m, StateInfo& newSt) { Square ksq = king_square(them); switch (piece) { - case PAWN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case KNIGHT: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case BISHOP: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case ROOK: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case QUEEN: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; - case KING: update_checkers(&st->checkersBB, ksq, from, to, oldDcCandidates); break; + case PAWN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KNIGHT: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case BISHOP: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case ROOK: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case QUEEN: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; + case KING: update_checkers(&(st->checkersBB), ksq, from, to, dcCandidates); break; default: assert(false); break; } } @@ -1199,7 +1175,7 @@ void Position::undo_move(Move m) { if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Replace the captured piece set_bit(&(byColorBB[them]), to); @@ -1348,7 +1324,7 @@ void Position::undo_promotion_move(Move m) { if (st->capture) { - assert(capture != KING); + assert(st->capture != KING); // Insert captured piece: set_bit(&(byColorBB[them]), to); @@ -1358,7 +1334,7 @@ void Position::undo_promotion_move(Move m) { // Update material. Because the move is a promotion move, we know // that the captured piece cannot be a pawn. - assert(capture != PAWN); + assert(st->capture != PAWN); npMaterial[them] += piece_value_midgame(st->capture); // Update piece list @@ -1389,7 +1365,7 @@ void Position::undo_ep_move(Move m) { Square to = move_to(m); Square capsq = (us == WHITE)? (to - DELTA_N) : (to - DELTA_S); - assert(to == ep_square()); + assert(to == st->previous->epSquare); assert(relative_rank(us, to) == RANK_6); assert(piece_on(to) == piece_of_color_and_type(us, PAWN)); assert(piece_on(from) == EMPTY); @@ -1490,7 +1466,7 @@ void Position::undo_null_move() { /// Position::see() is a static exchange evaluator: It tries to estimate the -/// material gain or loss resulting from a move. There are three versions of +/// material gain or loss resulting from a move. There are three versions of /// this function: One which takes a destination square as input, one takes a /// move, and one which takes a 'from' and a 'to' square. The function does /// not yet understand promotions captures. @@ -1596,7 +1572,7 @@ int Position::see(Square from, Square to) const { swapList[0] = seeValues[capture]; do { - // Locate the least valuable attacker for the side to move. The loop + // 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; !(attackers & pieces_of_color_and_type(c, pt)); pt++) @@ -1639,22 +1615,32 @@ int Position::see(Square from, Square to) const { } +/// Position::setStartState() copies the content of the argument +/// inside startState and makes st point to it. This is needed +/// when the st pointee could become stale, as example because +/// the caller is about to going out of scope. + +void Position::setStartState(const StateInfo& s) { + + startState = s; + st = &startState; +} + + /// Position::clear() erases the position object to a pristine state, with an /// empty board, white to move, and no castling rights. void Position::clear() { st = &startState; - st->previous = NULL; // We should never dereference this + memset(st, 0, sizeof(StateInfo)); + st->epSquare = SQ_NONE; + + memset(index, 0, sizeof(int) * 64); + memset(byColorBB, 0, sizeof(Bitboard) * 2); for (int i = 0; i < 64; i++) - { board[i] = EMPTY; - index[i] = 0; - } - - for (int i = 0; i < 2; i++) - byColorBB[i] = EmptyBoardBB; for (int i = 0; i < 7; i++) { @@ -1664,21 +1650,11 @@ void Position::clear() { pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE; } - st->checkersBB = EmptyBoardBB; - for (Color c = WHITE; c <= BLACK; c++) - st->pinners[c] = st->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB; - sideToMove = WHITE; gamePly = 0; initialKFile = FILE_E; initialKRFile = FILE_H; initialQRFile = FILE_A; - - st->lastMove = MOVE_NONE; - st->castleRights = NO_CASTLES; - st->epSquare = SQ_NONE; - st->rule50 = 0; - st->previous = NULL; }