/*
- Glaurung, a UCI chess playing engine.
- Copyright (C) 2004-2008 Tord Romstad
+ Stockfish, a UCI chess playing engine derived from Glaurung 2.1
+ Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
+ Copyright (C) 2008 Marco Costalba
- Glaurung is free software: you can redistribute it and/or modify
+ Stockfish is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
- Glaurung is distributed in the hope that it will be useful,
+ Stockfish is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
#include <cassert>
#include <cmath>
+#include <cstring>
#include "tt.h"
TTEntry *tte, *replace;
tte = replace = first_entry(pos);
- for (int i = 0; i < 4; i++)
+ for (int i = 0; i < 4; i++, tte++)
{
- if (!(tte+i)->key()) // still empty
- {
- *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
- writes++;
- return;
- }
- if ((tte+i)->key() == pos.get_key()) // overwrite old
+ if (!tte->key() || tte->key() == pos.get_key()) // empty or overwrite old
{
if (m == MOVE_NONE)
- m = (tte+i)->move();
+ m = tte->move();
- *(tte+i) = TTEntry(pos.get_key(), v, type, d, m, generation);
+ *tte = TTEntry(pos.get_key(), v, type, d, m, generation);
return;
}
- if ( i == 0 // already is (replace == tte+i), common case
- || replace->generation() < (tte+i)->generation())
+ else if (i == 0) // replace would be a no-op in this common case
continue;
- if ( replace->generation() > (tte+i)->generation()
- || (tte+i)->depth() < replace->depth())
- replace = tte+i;
+ int c1 = (replace->generation() == generation ? 2 : 0);
+ int c2 = (tte->generation() == generation ? -2 : 0);
+ int c3 = (tte->depth() < replace->depth() ? 1 : 0);
+
+ if (c1 + c2 + c3 > 0)
+ replace = tte;
}
*replace = TTEntry(pos.get_key(), v, type, d, m, generation);
writes++;
TTEntry *tte = first_entry(pos);
- for (int i = 0; i < 4; i++)
+ for (int i = 0; i < 4; i++, tte++)
{
- tte += i;
if (tte->key() == pos.get_key())
return tte;
}