X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=d915d92e43f545da1826e8408e148e952c90316a;hp=5f9525a6fbdbd3e37705ebddc6007c81747bdf24;hb=699bae632f283746a3eee15c0950fcdbca8a355e;hpb=c4d67d77c99b99c9ac387ab622773a320f8d5cc3

diff --git a/src/tt.h b/src/tt.h
index 5f9525a6..d915d92e 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -22,6 +22,8 @@
 #include "misc.h"
 #include "types.h"
 
+namespace Stockfish {
+
 /// TTEntry struct is the 10 bytes transposition table entry, defined as below:
 ///
 /// key        16 bit
@@ -72,9 +74,15 @@ class TranspositionTable {
 
   static_assert(sizeof(Cluster) == 32, "Unexpected Cluster size");
 
+  // Constants used to refresh the hash table periodically
+  static constexpr unsigned GENERATION_BITS  = 3;                                // nb of bits reserved for other things
+  static constexpr int      GENERATION_DELTA = (1 << GENERATION_BITS);           // increment for generation field
+  static constexpr int      GENERATION_CYCLE = 255 + (1 << GENERATION_BITS);     // cycle length
+  static constexpr int      GENERATION_MASK  = (0xFF << GENERATION_BITS) & 0xFF; // mask to pull out generation number
+
 public:
  ~TranspositionTable() { aligned_large_pages_free(table); }
-  void new_search() { generation8 += 8; } // Lower 3 bits are used by PV flag and Bound
+  void new_search() { generation8 += GENERATION_DELTA; } // Lower bits are used for other things
   TTEntry* probe(const Key key, bool& found) const;
   int hashfull() const;
   void resize(size_t mbSize);
@@ -94,4 +102,6 @@ private:
 
 extern TranspositionTable TT;
 
+} // namespace Stockfish
+
 #endif // #ifndef TT_H_INCLUDED