Reverse the logic used to detect prefetch

[stockfish] / src / tt.cpp

diff --git a/src/tt.cpp b/src/tt.cpp
index 5e1dfe1788e8432e44b511e8fce8df25d19aa8f2..e8a316c96b7ae5831cb32737ec0df38eb72300b8 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) 2008-2009 Marco Costalba
+  Copyright (C) 2008-2010 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
@@ -25,7 +25,9 @@
 #include <cassert>
 #include <cmath>
 #include <cstring>
-#include <xmmintrin.h>
+#if defined(__i386__) || defined(_M_IX86) || defined(_X86_)
+#  include <xmmintrin.h>
+#endif
 
 #include "movegen.h"
 #include "tt.h"
@@ -53,11 +55,9 @@ TranspositionTable::~TranspositionTable() {
 /// TranspositionTable::set_size sets the size of the transposition table,
 /// measured in megabytes.
 
-void TranspositionTable::set_size(unsigned mbSize) {
-
-  assert(mbSize >= 4 && mbSize <= 4096);
+void TranspositionTable::set_size(size_t mbSize) {
 
-  unsigned newSize = 1024;
+  size_t newSize = 1024;
 
   // We store a cluster of ClusterSize number of TTEntry for each position
   // and newSize is the maximum number of storable positions.
@@ -121,10 +121,7 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
   {
       if (!tte->key() || tte->key() == posKey32) // empty or overwrite old
       {
-          // Do not overwrite when new type is VALUE_TYPE_EV_LO
-          if (tte->key() && t == VALUE_TYPE_EV_LO)
-              return;
-
+          // Preserve any exsisting ttMove
           if (m == MOVE_NONE)
               m = tte->move();
 
@@ -169,11 +166,14 @@ TTEntry* TranspositionTable::retrieve(const Key posKey) const {
 /// to be loaded from RAM, that can be very slow. When we will
 /// subsequently call retrieve() the TT data will be already
 /// quickly accessible in L1/L2 CPU cache.
+#if !(defined(__i386__) || defined(_M_IX86) || defined(_X86_))
+void TranspositionTable::prefetch(const Key) const {}
+#else
 
 void TranspositionTable::prefetch(const Key posKey) const {
 
 #if defined(__INTEL_COMPILER) || defined(__ICL)
-   // This hack prevents prefetches to be optimized away by the
+   // This hack prevents prefetches to be optimized away by
    // Intel compiler. Both MSVC and gcc seems not affected.
    __asm__ ("");
 #endif
@@ -183,6 +183,7 @@ void TranspositionTable::prefetch(const Key posKey) const {
   _mm_prefetch(addr+64, _MM_HINT_T2); // 64 bytes ahead
 }
 
+#endif
 
 /// TranspositionTable::new_search() is called at the beginning of every new
 /// search. It increments the "generation" variable, which is used to
@@ -208,7 +209,9 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 
   for (int i = 0; pv[i] != MOVE_NONE; i++)
   {
-      store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
+      TTEntry *tte = retrieve(p.get_key());
+      if (!tte || tte->move() != pv[i])
+          store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
       p.do_move(pv[i], st);
   }
 }
@@ -220,7 +223,7 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 /// will often get single-move PVs when the search stops while failing high,
 /// and a single-move PV means that we don't have a ponder move.
 
-void TranspositionTable::extract_pv(const Position& pos, Move pv[], int pvSize) {
+void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PLY_MAX) {
 
   const TTEntry* tte;
   StateInfo st;
@@ -231,12 +234,12 @@ void TranspositionTable::extract_pv(const Position& pos, Move pv[], int pvSize)
   while (pv[ply] != MOVE_NONE)
       p.do_move(pv[ply++], st);
 
-  // Try to add moves from TT until possible
+  // Try to add moves from TT while possible
   while (   (tte = retrieve(p.get_key())) != NULL
          && tte->move() != MOVE_NONE
          && move_is_legal(p, tte->move())
          && (!p.is_draw() || ply < 2)
-         && ply < pvSize)
+         && ply < PLY_MAX)
   {
       pv[ply] = tte->move();
       p.do_move(pv[ply++], st);