////
#include <cassert>
-#include <iostream>
+#include <cstring>
#include <fstream>
+#include <iostream>
#include "mersenne.h"
#include "movegen.h"
castleRightsMask[make_square(initialQRFile, RANK_8)] ^= BLACK_OOO;
find_checkers();
+ find_hidden_checks();
st->key = compute_key();
st->pawnKey = compute_pawn_key();
}
-/// 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<ROOK, true>(c, ksq, p1) | hidden_checks<BISHOP, true>(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);
-
- p = st->pinners[c];
- return st->pinned[c];
-}
-
-Bitboard Position::discovered_check_candidates(Color c) const {
-
- if (st->dcCandidates[c] != ~EmptyBoardBB)
- return st->dcCandidates[c];
-
- Bitboard dummy;
- Square ksq = king_square(opposite_color(c));
- st->dcCandidates[c] = hidden_checks<ROOK, false>(c, ksq, dummy) | hidden_checks<BISHOP, false>(c, ksq, dummy);
- return st->dcCandidates[c];
-}
-
/// 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.
+/// Note that checkersBB bitboard must be already updated.
template<PieceType Piece, bool FindPinned>
Bitboard Position::hidden_checks(Color c, Square ksq, Bitboard& pinners) 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.
st->checkersBB = attacks_to(king_square(us), opposite_color(us));
}
+/// Position:find_hidden_checks() computes the pinned, pinners and dcCandidates
+/// bitboards. There are two versions of this function. One takes a color and
+/// computes bitboards relative to that color only, the other computes both
+/// colors. Bitboard checkersBB must be already updated.
+
+void Position::find_hidden_checks(Color us, unsigned int types) {
+
+ Bitboard p1, p2;
+ Color them = opposite_color(us);
+ Square ksq = king_square(them);
+ if (types & Pinned)
+ {
+ st->pinned[them] = hidden_checks<ROOK, true>(them, ksq, p1) | hidden_checks<BISHOP, true>(them, ksq, p2);
+ st->pinners[them] = p1 | p2;
+ }
+ if (types & DcCandidates)
+ st->dcCandidates[us] = hidden_checks<ROOK, false>(us, ksq, p1) | hidden_checks<BISHOP, false>(us, ksq, p2);
+}
+
+void Position::find_hidden_checks() {
+
+ for (Color c = WHITE; c <= BLACK; c++)
+ find_hidden_checks(c, Pinned | DcCandidates);
+}
+
/// Position::pl_move_is_legal() tests whether a pseudo-legal move is legal
}
-/// 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<PieceType Piece>
inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from,
}
+/// Position::update_hidden_checks() udpates pinned, pinners and dcCandidates
+/// bitboards incrementally, given the move. It is called in do_move and is
+/// faster then find_hidden_checks().
+
+void Position::update_hidden_checks(Square from, Square to) {
+
+ Color us = sideToMove;
+ Color them = opposite_color(us);
+ Square ksq = king_square(opposite_color(us));
+
+ Bitboard moveSquares = EmptyBoardBB;
+ set_bit(&moveSquares, from);
+ set_bit(&moveSquares, to);
+
+ // Our moving piece could have been a possible pinner or hidden checker behind a dcCandidates?
+ bool checkerMoved = (st->dcCandidates[us] | st->pinners[them]) && (moveSquares & sliders());
+
+ // If we are moving from/to an opponent king attack direction and we was a possible hidden checker
+ // or there exsist some possible hidden checker on that line then recalculate the position
+ // otherwise skip because our dcCandidates and opponent pinned pieces are not changed.
+ if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerMoved || (rooks_and_queens(us) & RookPseudoAttacks[ksq]))
+ || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerMoved || (bishops_and_queens(us) & BishopPseudoAttacks[ksq])))
+ find_hidden_checks(us, Pinned | DcCandidates);
+
+ ksq = king_square(us);
+
+ if (ksq == to)
+ {
+ find_hidden_checks(them, Pinned | DcCandidates);
+ return;
+ }
+
+ // It is possible that we have captured an opponent hidden checker?
+ Bitboard checkerCaptured = st->capture && (st->dcCandidates[them] || bit_is_set(st->pinners[us], to));
+
+ // If we are moving from/to an our king attack direction and there was/is some possible
+ // opponent hidden checker then calculate the position otherwise skip because opponent
+ // dcCandidates and our pinned pieces are not changed.
+ if ( (moveSquares & RookPseudoAttacks[ksq]) && (checkerCaptured || (rooks_and_queens(them) & RookPseudoAttacks[ksq]))
+ || (moveSquares & BishopPseudoAttacks[ksq]) && (checkerCaptured || (bishops_and_queens(them) & BishopPseudoAttacks[ksq])))
+ {
+
+ // If we don't have opponent dc candidates and we are moving in the
+ // attack line then won't be dc candidates also after the move.
+ if ( st->dcCandidates[them]
+ || bit_is_set(RookPseudoAttacks[ksq], from)
+ || bit_is_set(BishopPseudoAttacks[ksq], from))
+
+ find_hidden_checks(them, Pinned | DcCandidates);
+ else
+ find_hidden_checks(them, Pinned);
+ }
+}
+
+
/// Position::do_move() makes a move, and saves all information necessary
/// to a StateInfo object. The move is assumed to be legal.
/// Pseudo-legal moves should be filtered out before this function is called.
assert(is_ok());
assert(move_is_ok(m));
- // Get now the current (pre-move) dc candidates that we will use
+ // Get now the current (before to move) dc candidates that we will use
// in update_checkers().
Bitboard oldDcCandidates = discovered_check_candidates(side_to_move());
- // 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.
+ // Copy some fields of old state to our new StateInfo object (except the
+ // captured piece, which is taken care of later) and switch state pointer
+ // to point to the new, ready to be updated, state.
newSt = *st;
newSt.capture = NO_PIECE_TYPE;
newSt.previous = st;
// 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->pinned[c] = st->dcCandidates[c] = ~EmptyBoardBB;
-
if (move_is_castle(m))
do_castle_move(m);
else if (move_promotion(m))
case KING: update_checkers<KING>(&st->checkersBB, ksq, from, to, oldDcCandidates); break;
default: assert(false); break;
}
+
+ update_hidden_checks(from, to);
}
// Finish
// Update checkers BB
st->checkersBB = attacks_to(king_square(them), us);
+
+ // Update hidden checks
+ find_hidden_checks();
}
// Update checkers BB
st->checkersBB = attacks_to(king_square(them), us);
+
+ // Update hidden checks
+ find_hidden_checks();
}
// Update checkers BB
st->checkersBB = attacks_to(king_square(them), us);
+
+ // Update hidden checks
+ find_hidden_checks();
}
/// 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.
Color us = (from != SQ_NONE ? color_of_piece_on(from) : opposite_color(color_of_piece_on(to)));
Color them = opposite_color(us);
+ // Initialize pinned and pinners bitboards
+ Bitboard pinned[2], pinners[2];
+ pinned[us] = pinned_pieces(us, pinners[us]);
+ pinned[them] = pinned_pieces(them, pinners[them]);
+
// Initialize pieces
Piece piece = piece_on(from);
Piece capture = piece_on(to);
| (pawn_attacks(WHITE, to) & pawns(BLACK))
| (pawn_attacks(BLACK, to) & pawns(WHITE));
+ // Remove our pinned pieces from attacks if the captured piece is not
+ // a pinner, otherwise we could remove a valid "capture the pinner" attack.
+ if (pinned[us] != EmptyBoardBB && !bit_is_set(pinners[us], to))
+ attackers &= ~pinned[us];
+
+ // Remove opponent pinned pieces from attacks if the moving piece is not
+ // a pinner, otherwise we could remove a piece that is no more pinned
+ // due to our pinner piece is moving away.
+ if (pinned[them] != EmptyBoardBB && !bit_is_set(pinners[them], from))
+ attackers &= ~pinned[them];
+
if (from != SQ_NONE)
break;
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++)
lastCapturingPieceValue = seeValues[pt];
c = opposite_color(c);
+ // Remove pinned pieces from attackers
+ if ( pinned[c] != EmptyBoardBB
+ && !bit_is_set(pinners[c], to)
+ && !(pinners[c] & attackers))
+ attackers &= ~pinned[c];
+
// Stop after a king capture
if (pt == KING && (attackers & pieces_of_color(c)))
{
}
+/// 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++)
{
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;
}
projects / stockfish / blobdiff