Rename ValueType to Bound

[stockfish] / src / tt.cpp

diff --git a/src/tt.cpp b/src/tt.cpp
index 20ac1608e2fee1eb0e1338c3dbbe940275cc9f36..09a74d2d5936273b1a97d25358dd7c45ae63e5f4 100644 (file)
--- 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) 2008-2010 Marco Costalba, Joona Kiiski, Tord Romstad
+  Copyright (C) 2008-2012 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
@@ -17,29 +17,17 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-
-////
-//// Includes
-////
-
-#include <cassert>
 #include <cstring>
 #include <iostream>
 
 #include "tt.h"
 
-// The main transposition table
-TranspositionTable TT;
-
-////
-//// Functions
-////
+TranspositionTable TT; // Our global transposition table
 
 TranspositionTable::TranspositionTable() {
 
-  size = 0;
-  entries = 0;
-  generation = 0;
+  size = generation = 0;
+  entries = NULL;
 }
 
 TranspositionTable::~TranspositionTable() {
@@ -48,7 +36,7 @@ TranspositionTable::~TranspositionTable() {
 }
 
 
-/// TranspositionTable::set_size sets the size of the transposition table,
+/// TranspositionTable::set_size() sets the size of the transposition table,
 /// measured in megabytes.
 
 void TranspositionTable::set_size(size_t mbSize) {
@@ -62,26 +50,25 @@ void TranspositionTable::set_size(size_t mbSize) {
   while (2ULL * newSize * sizeof(TTCluster) <= (mbSize << 20))
       newSize *= 2;
 
-  if (newSize != size)
+  if (newSize == size)
+      return;
+
+  size = newSize;
+  delete [] entries;
+  entries = new (std::nothrow) TTCluster[size];
+  if (!entries)
   {
-      size = newSize;
-      delete [] entries;
-      entries = new (std::nothrow) TTCluster[size];
-      if (!entries)
-      {
-          std::cerr << "Failed to allocate " << mbSize
-                    << " MB for transposition table." << std::endl;
-          exit(EXIT_FAILURE);
-      }
-      clear();
+      std::cerr << "Failed to allocate " << mbSize
+                << "MB for transposition table." << std::endl;
+      exit(EXIT_FAILURE);
   }
+  clear();
 }
 
 
-/// TranspositionTable::clear overwrites the entire transposition table
+/// TranspositionTable::clear() overwrites the entire transposition table
 /// with zeroes. It is called whenever the table is resized, or when the
 /// user asks the program to clear the table (from the UCI interface).
-/// Perhaps we should also clear it when the "ucinewgame" command is received?
 
 void TranspositionTable::clear() {
 
@@ -89,26 +76,25 @@ void TranspositionTable::clear() {
 }
 
 
-/// 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.
+/// 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.
+/// 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 posKey, Value v, ValueType t, Depth d, Move m, Value statV, Value kingD) {
+void TranspositionTable::store(const Key posKey, Value v, Bound t, Depth d, Move m, Value statV, Value kingD) {
 
   int c1, c2, c3;
   TTEntry *tte, *replace;
-  uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key
+  uint32_t posKey32 = posKey >> 32; // Use the high 32 bits as key inside the cluster
 
   tte = replace = first_entry(posKey);
+
   for (int i = 0; i < ClusterSize; i++, tte++)
   {
-      if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
+      if (!tte->key() || tte->key() == posKey32) // Empty or overwrite old
       {
           // Preserve any existing ttMove
           if (m == MOVE_NONE)
@@ -118,11 +104,9 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
           return;
       }
 
-      if (i == 0)  // Replacing first entry is default and already set before entering for-loop
-          continue;
-
+      // Implement replace strategy
       c1 = (replace->generation() == generation ?  2 : 0);
-      c2 = (tte->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)
@@ -132,11 +116,11 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
 }
 
 
-/// TranspositionTable::retrieve looks up the current position in the
-/// transposition table. Returns a pointer to the TTEntry or NULL
-/// if position is not found.
+/// 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::retrieve(const Key posKey) const {
+TTEntry* TranspositionTable::probe(const Key posKey) const {
 
   uint32_t posKey32 = posKey >> 32;
   TTEntry* tte = first_entry(posKey);