Idea by Peter Oesterlund.
Implemented and tested by Joerg Oester
STC 3 threads
ELO: 3.19 +-2.1 (95%) LOS: 99.9%
Total: 40000 W: 7576 L: 7209 D: 25215
LTC
LLR: 2.96 (-2.94,2.94) [0.00,6.00]
Total: 22026 W: 3829 L: 3619 D: 14578
STC
LLR: 2.95 (-2.94,2.94) [-1.50,4.50]
Total: 7291 W: 1531 L: 1404 D: 4356
No functional change
Resolves #61
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::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;
}
}
+ // Speculative prefetch
+ prefetch((char*)TT.first_entry(pos.hash_after_move(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)));
+
// Check for legality just before making the move
if (!pos.legal(move, ci.pinned))
continue;