#include "tt.h"
+/// This is the number of TTEntry slots for each position
+static const int ClusterSize = 5;
+
+
////
//// Functions
////
unsigned newSize = 1024;
- // We store a cluster of 4 TTEntry for each position and newSize is
- // the maximum number of storable positions
- while ((2 * newSize) * 4 * (sizeof(TTEntry)) <= (mbSize << 20))
+ // We store a cluster of ClusterSize number of TTEntry for each position
+ // and newSize is the maximum number of storable positions.
+ while ((2 * newSize) * ClusterSize * (sizeof(TTEntry)) <= (mbSize << 20))
newSize *= 2;
if (newSize != size)
{
size = newSize;
delete [] entries;
- entries = new TTEntry[size * 4];
+ entries = new TTEntry[size * ClusterSize];
if (!entries)
{
std::cerr << "Failed to allocate " << mbSize
void TranspositionTable::clear() {
- memset(entries, 0, size * 4 * sizeof(TTEntry));
+ memset(entries, 0, size * ClusterSize * sizeof(TTEntry));
}
void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m) {
TTEntry *tte, *replace;
+ uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key
tte = replace = first_entry(posKey);
- for (int i = 0; i < 4; i++, tte++)
+ for (int i = 0; i < ClusterSize; i++, tte++)
{
- if (!tte->key() || tte->key() == posKey) // empty or overwrite old
+ if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
{
// Do not overwrite when new type is VALUE_TYPE_EVAL
if (tte->key() && t == VALUE_TYPE_EVAL)
if (m == MOVE_NONE)
m = tte->move();
- *tte = TTEntry(posKey, v, t, d, m, generation);
+ *tte = TTEntry(posKey32, v, t, d, m, generation);
return;
}
else if (i == 0) // replace would be a no-op in this common case
if (c1 + c2 + c3 > 0)
replace = tte;
}
- *replace = TTEntry(posKey, v, t, d, m, generation);
+ *replace = TTEntry(posKey32, v, t, d, m, generation);
writes++;
}
TTEntry* TranspositionTable::retrieve(const Key posKey) const {
+ uint32_t posKey32 = posKey >> 32;
TTEntry *tte = first_entry(posKey);
- for (int i = 0; i < 4; i++, tte++)
- if (tte->key() == posKey)
+ for (int i = 0; i < ClusterSize; i++, tte++)
+ if (tte->key() == posKey32)
return tte;
return NULL;
/// TranspositionTable::first_entry returns a pointer to the first
-/// entry of a cluster given a position.
+/// entry of a cluster given a position. The low 32 bits of the key
+/// are used to get the index in the table.
inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
- return entries + (int(posKey & (size - 1)) << 2);
+ return entries + ((uint32_t(posKey) & (size - 1)) * ClusterSize);
}
/// TranspositionTable::new_search() is called at the beginning of every new
tte && tte->move() != MOVE_NONE && !stop;
tte = retrieve(p.get_key()), ply++)
{
- if (!move_is_legal(p, tte->move(), p.pinned_pieces(p.side_to_move())))
+ if (!move_is_legal(p, tte->move()))
break;
pv[ply] = tte->move();
p.do_move(pv[ply], st[ply]);
int TranspositionTable::full() const {
- double N = double(size) * 4.0;
+ double N = double(size) * ClusterSize;
return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
}