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Introduce update_checkers() to simplify do_move()

Browse source 
No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2009-02-12 12:12:46 +01:00
parent 8365f8ac1e
commit 1d2247aea3
2 changed files with 41 additions and 38 deletions
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74
src/position.cpp
View file

@ -710,6 +710,22 @@ void Position::restore(const UndoInfo& u) {
// u.capture is restored in undo_move()
}
template<PieceType Piece>
inline void Position::update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates) {
if (Piece != KING && bit_is_set(piece_attacks<Piece>(ksq), to))
set_bit(pCheckersBB, to);
if (Piece != QUEEN && bit_is_set(dcCandidates, from))
{
if (Piece != ROOK)
(*pCheckersBB) |= (piece_attacks<ROOK>(ksq) & rooks_and_queens(side_to_move()));
if (Piece != BISHOP)
(*pCheckersBB) |= (piece_attacks<BISHOP>(ksq) & bishops_and_queens(side_to_move()));
}
}
/// Position::do_move() makes a move, and backs up all information necessary
/// to undo the move to an UndoInfo object. The move is assumed to be legal.
/// Pseudo-legal moves should be filtered out before this function is called.
@ -789,33 +805,34 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) {
if (piece == KING)
kingSquare[us] = to;
// If the move was a double pawn push, set the en passant square.
// This code is a bit ugly right now, and should be cleaned up later.
// FIXME
// Reset en passant square
if (epSquare != SQ_NONE)
{
key ^= zobEp[epSquare];
epSquare = SQ_NONE;
}
// If the moving piece was a pawn do some special extra work
if (piece == PAWN)
{
if (abs(int(to) - int(from)) == 16)
{
if( ( us == WHITE
&& (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK)))
|| ( us == BLACK
&& (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE))))
{
epSquare = Square((int(from) + int(to)) / 2);
key ^= zobEp[epSquare];
}
}
// Reset rule 50 draw counter
rule50 = 0;
// Update pawn hash key
pawnKey ^= zobrist[us][PAWN][from] ^ zobrist[us][PAWN][to];
// Set en passant square, only if moved pawn can be captured
if (abs(int(to) - int(from)) == 16)
{
if ( (us == WHITE && (pawn_attacks(WHITE, from + DELTA_N) & pawns(BLACK)))
|| (us == BLACK && (pawn_attacks(BLACK, from + DELTA_S) & pawns(WHITE))))
{
epSquare = Square((int(from) + int(to)) / 2);
key ^= zobEp[epSquare];
}
}
}
// Update piece lists
pieceList[us][piece][index[from]] = to;
index[to] = index[from];
@ -826,7 +843,7 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) {
castleRights &= castleRightsMask[to];
key ^= zobCastle[castleRights];
// Update checkers bitboard
// Update checkers bitboard, piece must be already moved
checkersBB = EmptyBoardBB;
Square ksq = king_square(them);
switch (piece)
@ -841,39 +858,23 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) {
break;
case KNIGHT:
if (bit_is_set(piece_attacks<KNIGHT>(ksq), to))
set_bit(&checkersBB, to);
if (bit_is_set(dcCandidates, from))
checkersBB |= ( (piece_attacks<ROOK>(ksq) & rooks_and_queens(us))
|(piece_attacks<BISHOP>(ksq) & bishops_and_queens(us)));
update_checkers<KNIGHT>(&checkersBB, ksq, from, to, dcCandidates);
break;
case BISHOP:
if (bit_is_set(piece_attacks<BISHOP>(ksq), to))
set_bit(&checkersBB, to);
if (bit_is_set(dcCandidates, from))
checkersBB |= (piece_attacks<ROOK>(ksq) & rooks_and_queens(us));
update_checkers<BISHOP>(&checkersBB, ksq, from, to, dcCandidates);
break;
case ROOK:
if (bit_is_set(piece_attacks<ROOK>(ksq), to))
set_bit(&checkersBB, to);
if (bit_is_set(dcCandidates, from))
checkersBB |= (piece_attacks<BISHOP>(ksq) & bishops_and_queens(us));
update_checkers<ROOK>(&checkersBB, ksq, from, to, dcCandidates);
break;
case QUEEN:
if (bit_is_set(piece_attacks<QUEEN>(ksq), to))
set_bit(&checkersBB, to);
update_checkers<QUEEN>(&checkersBB, ksq, from, to, dcCandidates);
break;
case KING:
if (bit_is_set(dcCandidates, from))
checkersBB |= ( (piece_attacks<ROOK>(ksq) & rooks_and_queens(us))
|(piece_attacks<BISHOP>(ksq) & bishops_and_queens(us)));
update_checkers<KING>(&checkersBB, ksq, from, to, dcCandidates);
break;
default:
@ -893,7 +894,6 @@ void Position::do_move(Move m, UndoInfo& u, Bitboard dcCandidates) {
assert(is_ok());
}
/// Position::do_capture_move() is a private method used to update captured
/// piece info. It is called from the main Position::do_move function.

5
src/position.h
View file

@ -86,8 +86,8 @@ struct UndoInfo {
Key key, pawnKey, materialKey;
int rule50;
Move lastMove;
PieceType capture;
Value mgValue, egValue;
PieceType capture;
};
@ -308,6 +308,9 @@ private:
void undo_ep_move(Move m);
void find_checkers();
template<PieceType Piece>
void update_checkers(Bitboard* pCheckersBB, Square ksq, Square from, Square to, Bitboard dcCandidates);
template<PieceType Piece, bool FindPinned>
Bitboard hidden_checks(Color c, Square ksq) const;