X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Ftt.h;h=2c989dacdcfdd399c9e010b114e19da1979af06a;hb=48b74142efa52f0da9d4e27f9bbcbe9520499524;hp=e778a3722a31188ec6f4e8cff2f5d29d231aaf60;hpb=cd4604b05c2d61928b26ab50c5864c36ef1d3785;p=stockfish

diff --git a/src/tt.h b/src/tt.h
index e778a372..2c989dac 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -72,7 +72,21 @@ private:
   int16_t depth_;
 };
 
-/// 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.
 
@@ -94,15 +108,17 @@ public:
 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;
 };
 
+extern TranspositionTable TT;
+
 #endif // !defined(TT_H_INCLUDED)