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.
void undo_move(Move m);
void do_null_move(StateInfo& st);
void undo_null_move();
- Key hash_after_move(Move m) const;
// Static exchange evaluation
Value see(Move m) const;
// Accessing hash keys
Key key() const;
+ Key key_after(Move m) const;
Key exclusion_key() const;
Key pawn_key() const;
Key material_key() const;
}
}
- // Speculative prefetch
- prefetch((char*)TT.first_entry(pos.hash_after_move(move)));
+ // Speculative prefetch as early as possible
+ prefetch((char*)TT.first_entry(pos.key_after(move)));
// Check for legality just before making the move
if (!RootNode && !SpNode && !pos.legal(move, ci.pinned))
&& pos.see_sign(move) < VALUE_ZERO)
continue;
- // Speculative prefetch
- prefetch((char*)TT.first_entry(pos.hash_after_move(move)));
+ // Speculative prefetch as early as possible
+ prefetch((char*)TT.first_entry(pos.key_after(move)));
// Check for legality just before making the move
if (!pos.legal(move, ci.pinned))