st->castlingRights &= ~cr;
}
- // Prefetch TT access as soon as we know the new hash key
- prefetch((char*)TT.first_entry(k));
-
// Move the piece. The tricky Chess960 castling is handled earlier
if (type_of(m) != CASTLING)
move_piece(from, to, us, pt);
sideToMove = ~sideToMove;
}
-// Position::hash_after_move() updates the hash key needed for the speculative prefetch.
-// It doesn't recognize special moves like castling, en-passant and promotions.
-Key Position::hash_after_move(Move m) const {
-
- int from = from_sq(m);
- int to = to_sq(m);
- Piece p = board[from];
- Piece capP = board[to];
- Key ret = st->key ^ Zobrist::side;
- if (capP != NO_PIECE)
- ret ^= Zobrist::psq[color_of(capP)][type_of(capP)][to];
- ret ^= Zobrist::psq[color_of(p)][type_of(p)][to];
- ret ^= Zobrist::psq[color_of(p)][type_of(p)][from];
- return ret;
+
+/// Position::key_after() computes the new hash key after the given moven. Needed
+/// for speculative prefetch. It doesn't recognize special moves like castling,
+/// en-passant and promotions.
+
+Key Position::key_after(Move m) const {
+
+ Color us = sideToMove;
+ Square from = from_sq(m);
+ Square to = to_sq(m);
+ PieceType pt = type_of(piece_on(from));
+ PieceType captured = type_of(piece_on(to));
+ Key k = st->key ^ Zobrist::side;
+
+ if (captured)
+ k ^= Zobrist::psq[~us][captured][to];
+
+ return k ^ Zobrist::psq[us][pt][to] ^ Zobrist::psq[us][pt][from];
}
+
/// Position::see() is a static exchange evaluator: It tries to estimate the
/// material gain or loss resulting from a move.