/// TranspositionTable::resize() sets the size of the transposition table,
/// measured in megabytes. Transposition table consists of a power of 2 number
-/// of clusters and each cluster consists of ClusterSize number of TTEntry.
+/// of clusters and each cluster consists of TTClusterSize number of TTEntry.
-void TranspositionTable::resize(uint64_t mbSize) {
+void TranspositionTable::resize(size_t mbSize) {
- assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
+ size_t newClusterCount = size_t(1) << msb((mbSize * 1024 * 1024) / sizeof(TTCluster));
- uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
-
- if (hashMask == size - ClusterSize)
+ if (newClusterCount == clusterCount)
return;
- hashMask = size - ClusterSize;
+ clusterCount = newClusterCount;
+
free(mem);
- mem = calloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1, 1);
+ mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
if (!mem)
{
exit(EXIT_FAILURE);
}
- table = (TTEntry*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
+ table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
}
void TranspositionTable::clear() {
- std::memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
+ std::memset(table, 0, clusterCount * sizeof(TTCluster));
}
const TTEntry* TranspositionTable::probe(const Key key) const {
- TTEntry* tte = first_entry(key);
- uint32_t key32 = key >> 32;
+ TTEntry* const tte = first_entry(key);
+ const uint16_t key16 = key >> 48;
- for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
- if (tte->key32 == key32)
+ for (unsigned i = 0; i < TTClusterSize; ++i)
+ if (tte[i].key16 == key16)
{
- tte->generation8 = generation; // Refresh
- return tte;
+ tte[i].genBound8 = generation | (uint8_t)tte[i].bound(); // Refresh
+ return &tte[i];
}
return NULL;
void TranspositionTable::store(const Key key, Value v, Bound b, Depth d, Move m, Value statV) {
- int c1, c2, c3;
- TTEntry *tte, *replace;
- uint32_t key32 = key >> 32; // Use the high 32 bits as key inside the cluster
+ TTEntry* const tte = first_entry(key);
+ const uint16_t key16 = key >> 48; // Use the high 16 bits as key inside the cluster
- tte = replace = first_entry(key);
-
- for (unsigned i = 0; i < ClusterSize; ++i, ++tte)
+ for (unsigned i = 0; i < TTClusterSize; ++i)
{
- if (!tte->key32 || tte->key32 == key32) // Empty or overwrite old
+ if (!tte[i].key16 || tte[i].key16 == key16) // Empty or overwrite old
{
- if (!m)
- m = tte->move(); // Preserve any existing ttMove
-
- replace = tte;
- break;
+ // Save preserving any existing ttMove
+ tte[i].save(key16, v, b, d, m ? m : tte[i].move(), generation, statV);
+ return;
}
+ }
- // Implement replace strategy
- c1 = (replace->generation8 == generation ? 2 : 0);
- c2 = (tte->generation8 == generation || tte->bound() == BOUND_EXACT ? -2 : 0);
- c3 = (tte->depth16 < replace->depth16 ? 1 : 0);
-
- if (c1 + c2 + c3 > 0)
- replace = tte;
+ // Implement replace strategy
+ TTEntry* replace = tte;
+ for (unsigned i = 1; i < TTClusterSize; ++i)
+ {
+ if ( (( tte[i].genBound8 & 0xFC) == generation || tte[i].bound() == BOUND_EXACT)
+ - ((replace->genBound8 & 0xFC) == generation)
+ - (tte[i].depth8 < replace->depth8) < 0)
+ replace = &tte[i];
}
- replace->save(key32, v, b, d, m, generation, statV);
+ replace->save(key16, v, b, d, m, generation, statV);
}