#include <xmmintrin.h>
#endif
-// This is the number of TTEntry slots for each position
-static const int ClusterSize = 4;
-
// The main transposition table
TranspositionTable TT;
// 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))
+ while ((2 * newSize) * sizeof(TTCluster) <= (mbSize << 20))
newSize *= 2;
if (newSize != size)
{
size = newSize;
delete [] entries;
- entries = new TTEntry[size * ClusterSize];
+ entries = new TTCluster[size];
if (!entries)
{
std::cerr << "Failed to allocate " << mbSize
void TranspositionTable::clear() {
- memset(entries, 0, size * ClusterSize * sizeof(TTEntry));
+ memset(entries, 0, size * sizeof(TTCluster));
}
inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
- return entries + ((uint32_t(posKey) & (size - 1)) * ClusterSize);
+ return entries[uint32_t(posKey) & (size - 1)].data;
}
uint32_t data;
int16_t value_;
int16_t depth_;
- uint32_t pad_to_16_bytes;
};
-/// The transposition table class. This is basically just a huge array
+
+/// This is the number of TTEntry slots for each position
+const int ClusterSize = 5;
+
+/// Each group of ClusterSize number of TTEntry form a TTCluster
+/// that is indexed by a single position key. Cluster is padded
+/// to a cache line size so to guarantee always aligned accesses.
+
+struct TTCluster {
+ TTEntry data[ClusterSize];
+ char cache_line_padding[64 - sizeof(TTEntry[ClusterSize])];
+};
+
+
+/// The transposition table class. This is basically just a huge array
/// containing TTEntry objects, and a few methods for writing new entries
/// and reading new ones.
private:
inline TTEntry* first_entry(const Key posKey) const;
- // Be sure 'writes' is at least one cacheline away
+ // Be sure 'writes' is at least one cache line away
// from read only variables.
unsigned char pad_before[64 - sizeof(unsigned)];
unsigned writes; // heavy SMP read/write access here
unsigned char pad_after[64];
unsigned size;
- TTEntry* entries;
+ TTCluster* entries;
uint8_t generation;
};