/*
- 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++;
/// TranspositionTable::retrieve looks up the current position in the
-/// transposition table, and extracts the value, value type, depth and
-/// best move if the position is found. The return value is true if
-/// the position is found, and false if it isn't.
+/// transposition table. Returns a pointer to the TTEntry or NULL
+/// if position is not found.
+
+const TTEntry* TranspositionTable::retrieve(const Position &pos) const {
-bool TranspositionTable::retrieve(const Position &pos, Value *value,
- Depth *d, Move *move,
- ValueType *type) const {
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())
- {
- *value = tte->value();
- *type = tte->type();
- *d = tte->depth();
- *move = tte->move();
- return true;
- }
+ return tte;
}
- *move = MOVE_NONE;
- return false;
+ return NULL;
}
void TranspositionTable::insert_pv(const Position &pos, Move pv[]) {
- UndoInfo u;
+ StateInfo st;
Position p(pos);
for (int i = 0; pv[i] != MOVE_NONE; i++)
{
store(p, VALUE_NONE, Depth(0), pv[i], VALUE_TYPE_NONE);
- p.do_move(pv[i], u);
+ p.do_move(pv[i], st);
}
}
TTEntry::TTEntry(Key k, Value v, ValueType t, Depth d, Move m,
int generation) :
key_ (k), data((m & 0x7FFFF) | (t << 20) | (generation << 23)),
- value_(v), depth_(int16_t(d)) {}
-
-
-/// Functions for extracting data from TTEntry objects.
-
-inline Key TTEntry::key() const {
- return key_;
-}
-
-inline Depth TTEntry::depth() const {
- return Depth(depth_);
-}
-
-inline Move TTEntry::move() const {
- return Move(data & 0x7FFFF);
-}
-
-inline Value TTEntry::value() const {
- return Value(value_);
-}
-
-inline ValueType TTEntry::type() const {
- return ValueType((data >> 20) & 3);
-}
-
-inline int TTEntry::generation() const {
- return (data >> 23);
-}
+ value_(int16_t(v)), depth_(int16_t(d)) {}