X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=2979c104aac3020c3798996597b182174b03ad4b;hp=fa0d39de00db423202eab55e5d2e82d0f94ebd4a;hb=14cf27e6f65787a1f9c8e4759ae0fcc218f37d2d;hpb=c698362680d7d66801be100e20346bbbf4ec5c4f

diff --git a/src/tt.cpp b/src/tt.cpp
index fa0d39de..2979c104 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -1,7 +1,7 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
-  Copyright (C) 2008-2012 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2014 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -26,96 +26,73 @@
 TranspositionTable TT; // Our global transposition table
 
 
-/// TranspositionTable::set_size() sets the size of the transposition table,
+/// 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::set_size(size_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 = 1 << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
-
-  if (clusterMask == size - 1)
+  if (newClusterCount == clusterCount)
       return;
 
-  clusterMask = size - 1;
-  delete [] entries;
-  entries = new (std::nothrow) TTEntry[size * ClusterSize];
+  clusterCount = newClusterCount;
+
+  free(mem);
+  mem = calloc(clusterCount * sizeof(TTCluster) + CACHE_LINE_SIZE - 1, 1);
 
-  if (!entries)
+  if (!mem)
   {
       std::cerr << "Failed to allocate " << mbSize
                 << "MB for transposition table." << std::endl;
       exit(EXIT_FAILURE);
   }
 
-  clear(); // Operator new is not guaranteed to initialize memory to zero
+  table = (TTCluster*)((uintptr_t(mem) + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1));
 }
 
 
 /// TranspositionTable::clear() overwrites the entire transposition table
-/// with zeroes. It is called whenever the table is resized, or when the
+/// with zeros. It is called whenever the table is resized, or when the
 /// user asks the program to clear the table (from the UCI interface).
 
 void TranspositionTable::clear() {
 
-  memset(entries, 0, (clusterMask + 1) * sizeof(TTEntry[ClusterSize]));
+  std::memset(table, 0, clusterCount * sizeof(TTCluster));
 }
 
 
-/// TranspositionTable::store() writes a new entry containing position key and
-/// valuable information of current position. The lowest order bits of position
-/// key are used to decide on which cluster the position will be placed.
-/// When a new entry is written and there are no empty entries available in cluster,
-/// it replaces the least valuable of entries. A TTEntry t1 is considered to be
-/// more valuable than a TTEntry t2 if t1 is from the current search and t2 is from
-/// a previous search, or if the depth of t1 is bigger than the depth of t2.
-
-void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m, Value statV, Value kingD) {
+/// TranspositionTable::probe() looks up the current position in the
+/// transposition table. It returns true and a pointer to the TTEntry if
+/// the position is found. Otherwise, it returns false and a pointer to an empty or
+/// least valuable TTEntry to be replaced later. A TTEntry t1 is considered
+/// to be more valuable than a TTEntry t2 if t1 is from the current search and t2
+/// is from a previous search, or if the depth of t1 is bigger than the depth of t2.
 
-  int c1, c2, c3;
-  TTEntry *tte, *replace;
-  uint32_t key32 = key >> 32; // Use the high 32 bits as key inside the cluster
+TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
 
-  tte = replace = first_entry(key);
+  TTEntry* const tte = first_entry(key);
+  const uint16_t key16 = key >> 48;  // Use the high 16 bits as key inside the cluster
 
-  for (unsigned i = 0; i < ClusterSize; i++, tte++)
-  {
-      if (!tte->key() || tte->key() == key32) // Empty or overwrite old
+  for (unsigned i = 0; i < TTClusterSize; ++i)
+      if (!tte[i].key16 || tte[i].key16 == key16)
       {
-          // Preserve any existing ttMove
-          if (m == MOVE_NONE)
-              m = tte->move();
+          if (tte[i].key16)
+              tte[i].genBound8 = uint8_t(generation | tte[i].bound()); // Refresh
 
-          tte->save(key32, v, t, d, m, generation, statV, kingD);
-          return;
+          found = (bool)tte[i].key16;
+          return &tte[i];
       }
 
-      // Implement replace strategy
-      c1 = (replace->generation() == generation ?  2 : 0);
-      c2 = (tte->generation() == generation || tte->type() == BOUND_EXACT ? -2 : 0);
-      c3 = (tte->depth() < replace->depth() ?  1 : 0);
-
-      if (c1 + c2 + c3 > 0)
-          replace = tte;
-  }
-  replace->save(key32, v, t, d, m, generation, statV, kingD);
-}
-
-
-/// TranspositionTable::probe() looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL if
-/// position is not found.
-
-TTEntry* TranspositionTable::probe(const Key key) const {
-
-  TTEntry* tte = first_entry(key);
-  uint32_t key32 = key >> 32;
-
-  for (unsigned i = 0; i < ClusterSize; i++, tte++)
-      if (tte->key() == key32)
-          return tte;
+  // Find an entry to be replaced according to the replacement 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];
 
-  return NULL;
+  found = false;
+  return replace;
 }