X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=271b98b74009eaf8f7e5e6601c5225c33a5be7f5;hp=a7042f9ef2b9c56a83cb987f30345eda5e0604d6;hb=481eda4ca0121cfa16f5a29f364ca30ee2852409;hpb=88c3670edf26d094678eeef3a2ed1eeffaf344d4

diff --git a/src/tt.cpp b/src/tt.cpp
index a7042f9e..271b98b7 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) 2008-2013 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
@@ -25,41 +25,33 @@
 
 TranspositionTable TT; // Our global transposition table
 
-TranspositionTable::TranspositionTable() {
-
-  size = generation = 0;
-  entries = NULL;
-}
-
-TranspositionTable::~TranspositionTable() {
-
-  delete [] entries;
-}
-
 
 /// TranspositionTable::set_size() sets the size of the transposition table,
-/// measured in megabytes. Transposition table consists of a power of 2 number of
-/// TTCluster and each cluster consists of ClusterSize number of TTEntries. Each
-/// non-empty entry contains information of exactly one position.
+/// measured in megabytes. Transposition table consists of a power of 2 number
+/// of clusters and each cluster consists of ClusterSize number of TTEntry.
 
 void TranspositionTable::set_size(size_t mbSize) {
 
-  size_t newSize = 1ULL << msb((mbSize << 20) / sizeof(TTCluster));
+  assert(msb((mbSize << 20) / sizeof(TTEntry)) < 32);
 
-  if (newSize == size)
+  uint32_t size = ClusterSize << msb((mbSize << 20) / sizeof(TTEntry[ClusterSize]));
+
+  if (hashMask == size - ClusterSize)
       return;
 
-  size = newSize;
-  delete [] entries;
-  entries = new (std::nothrow) TTCluster[size];
+  hashMask = size - ClusterSize;
+  free(mem);
+  mem = malloc(size * sizeof(TTEntry) + CACHE_LINE_SIZE - 1);
 
-  if (!entries)
+  if (!mem)
   {
       std::cerr << "Failed to allocate " << mbSize
                 << "MB for transposition table." << std::endl;
       exit(EXIT_FAILURE);
   }
 
+  // Align table start address to a cache line
+  for (char* c = (char*)mem; unsigned(table = (TTEntry*)(c)) % CACHE_LINE_SIZE; c++) {}
   clear(); // Operator new is not guaranteed to initialize memory to zero
 }
 
@@ -70,7 +62,7 @@ void TranspositionTable::set_size(size_t mbSize) {
 
 void TranspositionTable::clear() {
 
-  memset(entries, 0, size * sizeof(TTCluster));
+  memset(table, 0, (hashMask + ClusterSize) * sizeof(TTEntry));
 }
 
 
@@ -90,7 +82,7 @@ void TranspositionTable::store(const Key key, Value v, Bound t, Depth d, Move m,
 
   tte = replace = first_entry(key);
 
-  for (int i = 0; i < ClusterSize; i++, tte++)
+  for (unsigned i = 0; i < ClusterSize; i++, tte++)
   {
       if (!tte->key() || tte->key() == key32) // Empty or overwrite old
       {
@@ -123,19 +115,9 @@ TTEntry* TranspositionTable::probe(const Key key) const {
   TTEntry* tte = first_entry(key);
   uint32_t key32 = key >> 32;
 
-  for (int i = 0; i < ClusterSize; i++, tte++)
+  for (unsigned i = 0; i < ClusterSize; i++, tte++)
       if (tte->key() == key32)
           return tte;
 
   return NULL;
 }
-
-
-/// TranspositionTable::new_search() is called at the beginning of every new
-/// search. It increments the "generation" variable, which is used to
-/// distinguish transposition table entries from previous searches from
-/// entries from the current search.
-
-void TranspositionTable::new_search() {
-  generation++;
-}