X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.cpp;h=bc26606721413eb90ecae8923c7d4238960892d2;hp=501d016fd70461995a1554852dd8c70766ec52a9;hb=605b3aedd5b2cc530db417fc8bb57cc45200cca1;hpb=ed2754227a53c38f2570dc92b731c83cf4e0e434

diff --git a/src/tt.cpp b/src/tt.cpp
index 501d016f..bc266067 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -23,11 +23,7 @@
 ////
 
 #include <cassert>
-#include <cmath>
 #include <cstring>
-#if !defined(NO_PREFETCH)
-#  include <xmmintrin.h>
-#endif
 
 #include "movegen.h"
 #include "tt.h"
@@ -41,7 +37,7 @@ TranspositionTable TT;
 
 TranspositionTable::TranspositionTable() {
 
-  size = writes = 0;
+  size = 0;
   entries = 0;
   generation = 0;
 }
@@ -75,7 +71,6 @@ void TranspositionTable::set_size(size_t mbSize) {
                     << " MB for transposition table." << std::endl;
           Application::exit_with_failure();
       }
-      clear();
   }
 }
 
@@ -91,16 +86,6 @@ void TranspositionTable::clear() {
 }
 
 
-/// TranspositionTable::first_entry returns a pointer to the first
-/// entry of a cluster given a position. The low 32 bits of the key
-/// are used to get the index in the table.
-
-inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
-
-  return entries[uint32_t(posKey) & (size - 1)].data;
-}
-
-
 /// TranspositionTable::store writes a new entry containing a position,
 /// a value, a value type, a search depth, and a best move to the
 /// transposition table. Transposition table is organized in clusters of
@@ -113,6 +98,7 @@ inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
 
 void TranspositionTable::store(const Key posKey, Value v, ValueType 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
 
@@ -128,18 +114,18 @@ void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d,
           tte->save(posKey32, v, t, d, m, generation, statV, kingD);
           return;
       }
-      else if (i == 0)  // replace would be a no-op in this common case
+
+      if (i == 0)  // replace would be a no-op in this common case
           continue;
 
-      int c1 = (replace->generation() == generation ?  2 : 0);
-      int c2 = (tte->generation() == generation ? -2 : 0);
-      int c3 = (tte->depth() < replace->depth() ?  1 : 0);
+      c1 = (replace->generation() == generation ?  2 : 0);
+      c2 = (tte->generation() == generation ? -2 : 0);
+      c3 = (tte->depth() < replace->depth() ?  1 : 0);
 
       if (c1 + c2 + c3 > 0)
           replace = tte;
   }
   replace->save(posKey32, v, t, d, m, generation, statV, kingD);
-  writes++;
 }
 
 
@@ -160,40 +146,13 @@ TTEntry* TranspositionTable::retrieve(const Key posKey) const {
 }
 
 
-/// TranspositionTable::prefetch looks up the current position in the
-/// transposition table and load it in L1/L2 cache. This is a non
-/// blocking function and do not stalls the CPU waiting for data
-/// 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(NO_PREFETCH)
-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
-   // Intel compiler. Both MSVC and gcc seems not affected.
-   __asm__ ("");
-#endif
-
-   char const* addr = (char*)first_entry(posKey);
-  _mm_prefetch(addr, _MM_HINT_T2);
-  _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
 /// distinguish transposition table entries from previous searches from
 /// entries from the current search.
 
 void TranspositionTable::new_search() {
-
   generation++;
-  writes = 0;
 }
 
 
@@ -217,24 +176,24 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 }
 
 
-/// TranspositionTable::extract_pv() extends a PV by adding moves from the
-/// transposition table at the end. This should ensure that the PV is almost
-/// always at least two plies long, which is important, because otherwise we
-/// 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.
+/// TranspositionTable::extract_pv() builds a PV by adding moves from the
+/// transposition table. We consider also failing high nodes and not only
+/// VALUE_TYPE_EXACT nodes. This allow to always have a ponder move even
+/// when we fail high at root and also a long PV to print that is important
+/// for position analysis.
 
-void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PLY_MAX) {
+void TranspositionTable::extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX) {
 
   const TTEntry* tte;
   StateInfo st;
   Position p(pos, pos.thread());
   int ply = 0;
 
-  // Update position to the end of current PV
-  while (pv[ply] != MOVE_NONE)
-      p.do_move(pv[ply++], st);
+  assert(bestMove != MOVE_NONE);
+
+  pv[ply] = bestMove;
+  p.do_move(pv[ply++], st);
 
-  // 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())
@@ -246,14 +205,3 @@ void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PL
   }
   pv[ply] = MOVE_NONE;
 }
-
-
-/// TranspositionTable::full() returns the permill of all transposition table
-/// entries which have received at least one write during the current search.
-/// It is used to display the "info hashfull ..." information in UCI.
-
-int TranspositionTable::full() const {
-
-  double N = double(size) * ClusterSize;
-  return int(1000 * (1 - exp(writes * log(1.0 - 1.0/N))));
-}