Introduce ThreadsManager class

Main aim of this patch is to consolidate all the thread related stuff
behind a single class interface so to avoid messing with global flags
and having thread code scattered among non-thread related stuff.

Another advantage is that now access to thread's variables is
more controlled, in particular we can differentiate between
read and write accesses by the mean of different interfaces, it
is so simpler to understand how a function is related to threads.

Lastly this rewrite is the base for future code consolidations and
semplifications that are easier now that we have only one thread's
access point.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/search.cpp b/src/search.cpp
index 4654256065bd54612ff03e1c2a6778e65a7f169c..857aaff87ea9fd1d0812fcd2519f560ab1adf4fd 100644 (file)
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -53,23 +53,62 @@ namespace {
 
   /// Types
 
 
   /// Types
 

-  // The BetaCounterType class is used to order moves at ply one.
-  // Apart for the first one that has its score, following moves
-  // normally have score -VALUE_INFINITE, so are ordered according
-  // to the number of beta cutoffs occurred under their subtree during
-  // the last iteration. The counters are per thread variables to avoid
-  // concurrent accessing under SMP case.
-
-  struct BetaCounterType {
-
-    BetaCounterType();
-    void clear();
-    void add(Color us, Depth d, int threadID);
-    void read(Color us, int64_t& our, int64_t& their);
+
+  // ThreadsManager class is used to handle all the threads related stuff in search,
+  // init, starting, parking and, the most important, launching a slave thread at a
+  // split point are what this class does. All the access to shared thread data is
+  // done through this class, so that we avoid using global variables instead.
+
+  class ThreadsManager {
+    /* As long as the single ThreadsManager object is defined as a global we don't
+       need to explicitly initialize to zero its data members because variables with
+       static storage duration are automatically set to zero before enter main()
+    */
+  public:
+    void init_threads();
+    void exit_threads();
+
+    int active_threads() const { return ActiveThreads; }
+    void set_active_threads(int newActiveThreads) { ActiveThreads = newActiveThreads; }
+    void set_stop_request(int threadID) { threads[threadID].stop = true; }
+    void incrementNodeCounter(int threadID) { threads[threadID].nodes++; }
+    void incrementBetaCounter(Color us, Depth d, int threadID) { threads[threadID].betaCutOffs[us] += unsigned(d); }
+    void print_current_line(SearchStack ss[], int ply, int threadID);
+
+    void resetNodeCounters();
+    void resetBetaCounters();
+    int64_t nodes_searched() const;
+    void get_beta_counters(Color us, int64_t& our, int64_t& their) const;
+    bool idle_thread_exists(int master) const;
+    bool thread_is_available(int slave, int master) const;
+    bool thread_should_stop(int threadID);
+    void wake_sleeping_threads();
+    void put_threads_to_sleep();
+    void idle_loop(int threadID, SplitPoint* waitSp);
+    bool split(const Position& pos, SearchStack* ss, int ply, Value* alpha, Value* beta, Value* bestValue,
+               const Value futilityValue, Depth depth, int* moves, MovePicker* mp, int master, bool pvNode);
+
+  private:
+    friend void poll();
+
+    int ActiveThreads;
+    bool AllThreadsShouldExit, AllThreadsShouldSleep;
+    Thread threads[THREAD_MAX];
+    SplitPoint SplitPointStack[THREAD_MAX][ACTIVE_SPLIT_POINTS_MAX];
+
+    Lock MPLock, IOLock;
+
+#if !defined(_MSC_VER)
+    pthread_cond_t WaitCond;
+    pthread_mutex_t WaitLock;
+#else
+    HANDLE SitIdleEvent[THREAD_MAX];
+#endif
+

   };
 
 
   };
 
 

-  // The RootMove class is used for moves at the root at the tree. For each
+  // RootMove struct is used for moves at the root at the tree. For each

   // root move, we store a score, a node count, and a PV (really a refutation
   // in the case of moves which fail low).
 
   // root move, we store a score, a node count, and a PV (really a refutation
   // in the case of moves which fail low).
 


@@ -184,7 +223,6 @@ namespace {
 
   // Iteration counters
   int Iteration;
 
   // Iteration counters
   int Iteration;

-  BetaCounterType BetaCounter;

 
   // Scores and number of times the best move changed for each iteration
   Value ValueByIteration[PLY_MAX_PLUS_2];
 
   // Scores and number of times the best move changed for each iteration
   Value ValueByIteration[PLY_MAX_PLUS_2];


@@ -213,21 +251,9 @@ namespace {
   std::ofstream LogFile;
 
   // MP related variables
   std::ofstream LogFile;
 
   // MP related variables

-  int ActiveThreads = 1;

   Depth MinimumSplitDepth;
   int MaxThreadsPerSplitPoint;
   Depth MinimumSplitDepth;
   int MaxThreadsPerSplitPoint;

-  Thread Threads[THREAD_MAX];
-  Lock MPLock;
-  Lock IOLock;
-  bool AllThreadsShouldExit, AllThreadsShouldSleep;
-  SplitPoint SplitPointStack[THREAD_MAX][ACTIVE_SPLIT_POINTS_MAX];
-
-#if !defined(_MSC_VER)
-  pthread_cond_t WaitCond;
-  pthread_mutex_t WaitLock;
-#else
-  HANDLE SitIdleEvent[THREAD_MAX];
-#endif
+  ThreadsManager TM;

 
   // Node counters, used only by thread[0] but try to keep in different
   // cache lines (64 bytes each) from the heavy SMP read accessed variables.
 
   // Node counters, used only by thread[0] but try to keep in different
   // cache lines (64 bytes each) from the heavy SMP read accessed variables.


@@ -265,23 +291,9 @@ namespace {
   int nps();
   void poll();
   void ponderhit();
   int nps();
   void poll();
   void ponderhit();

-  void print_current_line(SearchStack ss[], int ply, int threadID);

   void wait_for_stop_or_ponderhit();
   void init_ss_array(SearchStack ss[]);
 
   void wait_for_stop_or_ponderhit();
   void init_ss_array(SearchStack ss[]);
 

-  void idle_loop(int threadID, SplitPoint* waitSp);
-  void init_split_point_stack();
-  void destroy_split_point_stack();
-  bool thread_should_stop(int threadID);
-  bool thread_is_available(int slave, int master);
-  bool idle_thread_exists(int master);
-  bool split(const Position& pos, SearchStack* ss, int ply,
-             Value *alpha, Value *beta, Value *bestValue,
-             const Value futilityValue, Depth depth, int *moves,
-             MovePicker *mp, int master, bool pvNode);
-  void wake_sleeping_threads();
-  void put_threads_to_sleep();
-

 #if !defined(_MSC_VER)
   void *init_thread(void *threadID);
 #else
 #if !defined(_MSC_VER)
   void *init_thread(void *threadID);
 #else


@@ -295,6 +307,13 @@ namespace {
 //// Functions
 ////
 
 //// Functions
 ////
 

+/// init_threads(), exit_threads() and nodes_searched() are helpers to
+/// give accessibility to some TM methods from outside of current file.
+
+void init_threads() { TM.init_threads(); }
+void exit_threads() { TM.exit_threads(); }
+int64_t nodes_searched() { return TM.nodes_searched(); }
+

 
 /// perft() is our utility to verify move generation is bug free. All the legal
 /// moves up to given depth are generated and counted and the sum returned.
 
 /// perft() is our utility to verify move generation is bug free. All the legal
 /// moves up to given depth are generated and counted and the sum returned.


@@ -365,10 +384,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
       }
   }
 
       }
   }
 

-  for (int i = 0; i < THREAD_MAX; i++)
-  {
-      Threads[i].nodes = 0ULL;
-  }
+  TM.resetNodeCounters();

 
   if (button_was_pressed("New Game"))
       loseOnTime = false; // Reset at the beginning of a new game
 
   if (button_was_pressed("New Game"))
       loseOnTime = false; // Reset at the beginning of a new game


@@ -414,10 +430,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
 
   // Set the number of active threads
   int newActiveThreads = get_option_value_int("Threads");
 
   // Set the number of active threads
   int newActiveThreads = get_option_value_int("Threads");

-  if (newActiveThreads != ActiveThreads)
+  if (newActiveThreads != TM.active_threads())

   {
   {

-      ActiveThreads = newActiveThreads;
-      init_eval(ActiveThreads);
+      TM.set_active_threads(newActiveThreads);
+      init_eval(TM.active_threads());

       // HACK: init_eval() destroys the static castleRightsMask[] array in the
       // Position class. The below line repairs the damage.
       Position p(pos.to_fen());
       // HACK: init_eval() destroys the static castleRightsMask[] array in the
       // Position class. The below line repairs the damage.
       Position p(pos.to_fen());


@@ -425,10 +441,10 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   }
 
   // Wake up sleeping threads
   }
 
   // Wake up sleeping threads

-  wake_sleeping_threads();
+  TM.wake_sleeping_threads();

 
 

-  for (int i = 1; i < ActiveThreads; i++)
-      assert(thread_is_available(i, 0));
+  for (int i = 1; i < TM.active_threads(); i++)
+      assert(TM.thread_is_available(i, 0));

 
   // Set thinking time
   int myTime = time[side_to_move];
 
   // Set thinking time
   int myTime = time[side_to_move];


@@ -522,7 +538,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   if (UseLogFile)
       LogFile.close();
 
   if (UseLogFile)
       LogFile.close();
 

-  put_threads_to_sleep();
+  TM.put_threads_to_sleep();

 
   return !Quit;
 }
 
   return !Quit;
 }


@@ -555,95 +571,6 @@ void init_search() {
 }
 
 
 }
 
 

-/// init_threads() is called during startup. It launches all helper threads,
-/// and initializes the split point stack and the global locks and condition
-/// objects.
-
-void init_threads() {
-
-  volatile int i;
-  bool ok;
-
-#if !defined(_MSC_VER)
-  pthread_t pthread[1];
-#endif
-
-  // Initialize global locks
-  lock_init(&MPLock, NULL);
-  lock_init(&IOLock, NULL);
-
-  init_split_point_stack();
-
-#if !defined(_MSC_VER)
-  pthread_mutex_init(&WaitLock, NULL);
-  pthread_cond_init(&WaitCond, NULL);
-#else
-  for (i = 0; i < THREAD_MAX; i++)
-      SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
-#endif
-
-  // Will be set just before program exits to properly end the threads
-  AllThreadsShouldExit = false;
-
-  // Threads will be put to sleep as soon as created
-  AllThreadsShouldSleep = true;
-
-  // All threads except the main thread should be initialized to idle state
-  for (i = 1; i < THREAD_MAX; i++)
-      Threads[i].idle = true;
-
-  // Launch the helper threads
-  for (i = 1; i < THREAD_MAX; i++)
-  {
-#if !defined(_MSC_VER)
-      ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
-#else
-      DWORD iID[1];
-      ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL);
-#endif
-
-      if (!ok)
-      {
-          cout << "Failed to create thread number " << i << endl;
-          Application::exit_with_failure();
-      }
-
-      // Wait until the thread has finished launching and is gone to sleep
-      while (!Threads[i].running || !Threads[i].sleeping);
-  }
-}
-
-
-/// exit_threads() is called when the program exits. It makes all the
-/// helper threads exit cleanly.
-
-void exit_threads() {
-
-  ActiveThreads = THREAD_MAX;  // HACK
-  AllThreadsShouldSleep = true;  // HACK
-  wake_sleeping_threads();
-  AllThreadsShouldExit = true;
-  for (int i = 1; i < THREAD_MAX; i++)
-  {
-      Threads[i].stop = true;
-      while (Threads[i].running);
-  }
-  destroy_split_point_stack();
-}
-
-
-/// nodes_searched() returns the total number of nodes searched so far in
-/// the current search.
-
-int64_t nodes_searched() {
-
-  int64_t result = 0ULL;
-  for (int i = 0; i < ActiveThreads; i++)
-      result += Threads[i].nodes;
-  return result;
-}
-
-

 // SearchStack::init() initializes a search stack. Used at the beginning of a
 // new search from the root.
 void SearchStack::init(int ply) {
 // SearchStack::init() initializes a search stack. Used at the beginning of a
 // new search from the root.
 void SearchStack::init(int ply) {


@@ -690,7 +617,7 @@ namespace {
     cout << "info depth " << 1 << "\ninfo depth " << 1
          << " score " << value_to_string(rml.get_move_score(0))
          << " time " << current_search_time()
     cout << "info depth " << 1 << "\ninfo depth " << 1
          << " score " << value_to_string(rml.get_move_score(0))
          << " time " << current_search_time()

-         << " nodes " << nodes_searched()
+         << " nodes " << TM.nodes_searched()

          << " nps " << nps()
          << " pv " << rml.get_move(0) << "\n";
 
          << " nps " << nps()
          << " pv " << rml.get_move(0) << "\n";
 


@@ -773,7 +700,7 @@ namespace {
                 stopSearch = true;
 
             // Stop search early if one move seems to be much better than the rest
                 stopSearch = true;
 
             // Stop search early if one move seems to be much better than the rest

-            int64_t nodes = nodes_searched();
+            int64_t nodes = TM.nodes_searched();

             if (   Iteration >= 8
                 && EasyMove == ss[0].pv[0]
                 && (  (   rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
             if (   Iteration >= 8
                 && EasyMove == ss[0].pv[0]
                 && (  (   rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100


@@ -814,7 +741,7 @@ namespace {
         wait_for_stop_or_ponderhit();
     else
         // Print final search statistics
         wait_for_stop_or_ponderhit();
     else
         // Print final search statistics

-        cout << "info nodes " << nodes_searched()
+        cout << "info nodes " << TM.nodes_searched()

              << " nps " << nps()
              << " time " << current_search_time()
              << " hashfull " << TT.full() << endl;
              << " nps " << nps()
              << " time " << current_search_time()
              << " hashfull " << TT.full() << endl;


@@ -839,7 +766,7 @@ namespace {
         if (dbg_show_hit_rate)
             dbg_print_hit_rate(LogFile);
 
         if (dbg_show_hit_rate)
             dbg_print_hit_rate(LogFile);
 

-        LogFile << "\nNodes: " << nodes_searched()
+        LogFile << "\nNodes: " << TM.nodes_searched()

                 << "\nNodes/second: " << nps()
                 << "\nBest move: " << move_to_san(p, ss[0].pv[0]);
 
                 << "\nNodes/second: " << nps()
                 << "\nBest move: " << move_to_san(p, ss[0].pv[0]);
 


@@ -890,10 +817,10 @@ namespace {
             RootMoveNumber = i + 1;
 
             // Save the current node count before the move is searched
             RootMoveNumber = i + 1;
 
             // Save the current node count before the move is searched

-            nodes = nodes_searched();
+            nodes = TM.nodes_searched();

 
             // Reset beta cut-off counters
 
             // Reset beta cut-off counters

-            BetaCounter.clear();
+            TM.resetBetaCounters();

 
             // Pick the next root move, and print the move and the move number to
             // the standard output.
 
             // Pick the next root move, and print the move and the move number to
             // the standard output.


@@ -974,7 +901,7 @@ namespace {
                      << ((value >= beta) ? " lowerbound" :
                         ((value <= alpha)? " upperbound" : ""))
                      << " time "  << current_search_time()
                      << ((value >= beta) ? " lowerbound" :
                         ((value <= alpha)? " upperbound" : ""))
                      << " time "  << current_search_time()

-                     << " nodes " << nodes_searched()
+                     << " nodes " << TM.nodes_searched()

                      << " nps "   << nps()
                      << " pv ";
 
                      << " nps "   << nps()
                      << " pv ";
 


@@ -989,7 +916,7 @@ namespace {
                                     : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
 
                     LogFile << pretty_pv(pos, current_search_time(), Iteration,
                                     : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
 
                     LogFile << pretty_pv(pos, current_search_time(), Iteration,

-                                         nodes_searched(), value, type, ss[0].pv) << endl;
+                                         TM.nodes_searched(), value, type, ss[0].pv) << endl;

                 }
 
                 // Prepare for a research after a fail high, each time with a wider window
                 }
 
                 // Prepare for a research after a fail high, each time with a wider window


@@ -1009,9 +936,9 @@ namespace {
             // Remember beta-cutoff and searched nodes counts for this move. The
             // info is used to sort the root moves at the next iteration.
             int64_t our, their;
             // Remember beta-cutoff and searched nodes counts for this move. The
             // info is used to sort the root moves at the next iteration.
             int64_t our, their;

-            BetaCounter.read(pos.side_to_move(), our, their);
+            TM.get_beta_counters(pos.side_to_move(), our, their);

             rml.set_beta_counters(i, our, their);
             rml.set_beta_counters(i, our, their);

-            rml.set_move_nodes(i, nodes_searched() - nodes);
+            rml.set_move_nodes(i, TM.nodes_searched() - nodes);

 
             assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
 
 
             assert(value >= -VALUE_INFINITE && value <= VALUE_INFINITE);
 


@@ -1041,7 +968,7 @@ namespace {
                          << ((value >= beta) ? " lowerbound" :
                             ((value <= alpha)? " upperbound" : ""))
                          << " time "  << current_search_time()
                          << ((value >= beta) ? " lowerbound" :
                             ((value <= alpha)? " upperbound" : ""))
                          << " time "  << current_search_time()

-                         << " nodes " << nodes_searched()
+                         << " nodes " << TM.nodes_searched()

                          << " nps "   << nps()
                          << " pv ";
 
                          << " nps "   << nps()
                          << " pv ";
 


@@ -1056,7 +983,7 @@ namespace {
                                         : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
 
                         LogFile << pretty_pv(pos, current_search_time(), Iteration,
                                         : (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
 
                         LogFile << pretty_pv(pos, current_search_time(), Iteration,

-                                             nodes_searched(), value, type, ss[0].pv) << endl;
+                                             TM.nodes_searched(), value, type, ss[0].pv) << endl;

                     }
                     if (value > alpha)
                         alpha = value;
                     }
                     if (value > alpha)
                         alpha = value;


@@ -1070,7 +997,7 @@ namespace {
                              << " score " << value_to_string(rml.get_move_score(j))
                              << " depth " << ((j <= i)? Iteration : Iteration - 1)
                              << " time " << current_search_time()
                              << " score " << value_to_string(rml.get_move_score(j))
                              << " depth " << ((j <= i)? Iteration : Iteration - 1)
                              << " time " << current_search_time()

-                             << " nodes " << nodes_searched()
+                             << " nodes " << TM.nodes_searched()

                              << " nps " << nps()
                              << " pv ";
 
                              << " nps " << nps()
                              << " pv ";
 


@@ -1114,7 +1041,7 @@ namespace {
     assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
     assert(beta > alpha && beta <= VALUE_INFINITE);
     assert(ply >= 0 && ply < PLY_MAX);
     assert(alpha >= -VALUE_INFINITE && alpha <= VALUE_INFINITE);
     assert(beta > alpha && beta <= VALUE_INFINITE);
     assert(ply >= 0 && ply < PLY_MAX);

-    assert(threadID >= 0 && threadID < ActiveThreads);
+    assert(threadID >= 0 && threadID < TM.active_threads());

 
     Move movesSearched[256];
     StateInfo st;
 
     Move movesSearched[256];
     StateInfo st;


@@ -1134,7 +1061,7 @@ namespace {
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()

-    if (AbortSearch || thread_should_stop(threadID))
+    if (AbortSearch || TM.thread_should_stop(threadID))

         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)
         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)


@@ -1189,7 +1116,7 @@ namespace {
     // occurs.
     while (   alpha < beta
            && (move = mp.get_next_move()) != MOVE_NONE
     // occurs.
     while (   alpha < beta
            && (move = mp.get_next_move()) != MOVE_NONE

-           && !thread_should_stop(threadID))
+           && !TM.thread_should_stop(threadID))

     {
       assert(move_is_ok(move));
 
     {
       assert(move_is_ok(move));
 


@@ -1277,15 +1204,15 @@ namespace {
       }
 
       // Split?
       }
 
       // Split?

-      if (   ActiveThreads > 1
+      if (   TM.active_threads() > 1

           && bestValue < beta
           && depth >= MinimumSplitDepth
           && Iteration <= 99
           && bestValue < beta
           && depth >= MinimumSplitDepth
           && Iteration <= 99

-          && idle_thread_exists(threadID)
+          && TM.idle_thread_exists(threadID)

           && !AbortSearch
           && !AbortSearch

-          && !thread_should_stop(threadID)
-          && split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE,
-                   depth, &moveCount, &mp, threadID, true))
+          && !TM.thread_should_stop(threadID)
+          && TM.split(pos, ss, ply, &alpha, &beta, &bestValue, VALUE_NONE,
+                      depth, &moveCount, &mp, threadID, true))

           break;
     }
 
           break;
     }
 


@@ -1296,7 +1223,7 @@ namespace {
 
     // If the search is not aborted, update the transposition table,
     // history counters, and killer moves.
 
     // If the search is not aborted, update the transposition table,
     // history counters, and killer moves.

-    if (AbortSearch || thread_should_stop(threadID))
+    if (AbortSearch || TM.thread_should_stop(threadID))

         return bestValue;
 
     if (bestValue <= oldAlpha)
         return bestValue;
 
     if (bestValue <= oldAlpha)


@@ -1304,7 +1231,7 @@ namespace {
 
     else if (bestValue >= beta)
     {
 
     else if (bestValue >= beta)
     {

-        BetaCounter.add(pos.side_to_move(), depth, threadID);
+        TM.incrementBetaCounter(pos.side_to_move(), depth, threadID);

         move = ss[ply].pv[ply];
         if (!pos.move_is_capture_or_promotion(move))
         {
         move = ss[ply].pv[ply];
         if (!pos.move_is_capture_or_promotion(move))
         {


@@ -1327,7 +1254,7 @@ namespace {
 
     assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
     assert(ply >= 0 && ply < PLY_MAX);
 
     assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
     assert(ply >= 0 && ply < PLY_MAX);

-    assert(threadID >= 0 && threadID < ActiveThreads);
+    assert(threadID >= 0 && threadID < TM.active_threads());

 
     Move movesSearched[256];
     EvalInfo ei;
 
     Move movesSearched[256];
     EvalInfo ei;


@@ -1349,7 +1276,7 @@ namespace {
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()

-    if (AbortSearch || thread_should_stop(threadID))
+    if (AbortSearch || TM.thread_should_stop(threadID))

         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)
         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)


@@ -1482,7 +1409,7 @@ namespace {
     // Loop through all legal moves until no moves remain or a beta cutoff occurs
     while (   bestValue < beta
            && (move = mp.get_next_move()) != MOVE_NONE
     // Loop through all legal moves until no moves remain or a beta cutoff occurs
     while (   bestValue < beta
            && (move = mp.get_next_move()) != MOVE_NONE

-           && !thread_should_stop(threadID))
+           && !TM.thread_should_stop(threadID))

     {
       assert(move_is_ok(move));
 
     {
       assert(move_is_ok(move));
 


@@ -1591,15 +1518,15 @@ namespace {
       }
 
       // Split?
       }
 
       // Split?

-      if (   ActiveThreads > 1
+      if (   TM.active_threads() > 1

           && bestValue < beta
           && depth >= MinimumSplitDepth
           && Iteration <= 99
           && bestValue < beta
           && depth >= MinimumSplitDepth
           && Iteration <= 99

-          && idle_thread_exists(threadID)
+          && TM.idle_thread_exists(threadID)

           && !AbortSearch
           && !AbortSearch

-          && !thread_should_stop(threadID)
-          && split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
-                   depth, &moveCount, &mp, threadID, false))
+          && !TM.thread_should_stop(threadID)
+          && TM.split(pos, ss, ply, &beta, &beta, &bestValue, futilityValue, //FIXME: SMP & futilityValue
+                      depth, &moveCount, &mp, threadID, false))

           break;
     }
 
           break;
     }
 


@@ -1610,14 +1537,14 @@ namespace {
 
     // If the search is not aborted, update the transposition table,
     // history counters, and killer moves.
 
     // If the search is not aborted, update the transposition table,
     // history counters, and killer moves.

-    if (AbortSearch || thread_should_stop(threadID))
+    if (AbortSearch || TM.thread_should_stop(threadID))

         return bestValue;
 
     if (bestValue < beta)
         TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
     else
     {
         return bestValue;
 
     if (bestValue < beta)
         TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
     else
     {

-        BetaCounter.add(pos.side_to_move(), depth, threadID);
+        TM.incrementBetaCounter(pos.side_to_move(), depth, threadID);

         move = ss[ply].pv[ply];
         TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
         if (!pos.move_is_capture_or_promotion(move))
         move = ss[ply].pv[ply];
         TT.store(posKey, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, move);
         if (!pos.move_is_capture_or_promotion(move))


@@ -1645,7 +1572,7 @@ namespace {
     assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
     assert(depth <= 0);
     assert(ply >= 0 && ply < PLY_MAX);
     assert(beta >= -VALUE_INFINITE && beta <= VALUE_INFINITE);
     assert(depth <= 0);
     assert(ply >= 0 && ply < PLY_MAX);

-    assert(threadID >= 0 && threadID < ActiveThreads);
+    assert(threadID >= 0 && threadID < TM.active_threads());

 
     EvalInfo ei;
     StateInfo st;
 
     EvalInfo ei;
     StateInfo st;


@@ -1662,7 +1589,7 @@ namespace {
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()
     init_node(ss, ply, threadID);
 
     // After init_node() that calls poll()

-    if (AbortSearch || thread_should_stop(threadID))
+    if (AbortSearch || TM.thread_should_stop(threadID))

         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)
         return Value(0);
 
     if (pos.is_draw() || ply >= PLY_MAX - 1)


@@ -1834,8 +1761,8 @@ namespace {
 
   void sp_search(SplitPoint* sp, int threadID) {
 
 
   void sp_search(SplitPoint* sp, int threadID) {
 

-    assert(threadID >= 0 && threadID < ActiveThreads);
-    assert(ActiveThreads > 1);
+    assert(threadID >= 0 && threadID < TM.active_threads());
+    assert(TM.active_threads() > 1);

 
     Position pos(*sp->pos);
     CheckInfo ci(pos);
 
     Position pos(*sp->pos);
     CheckInfo ci(pos);


@@ -1849,7 +1776,7 @@ namespace {
 
     while (    lock_grab_bool(&(sp->lock))
            &&  sp->bestValue < sp->beta
 
     while (    lock_grab_bool(&(sp->lock))
            &&  sp->bestValue < sp->beta

-           && !thread_should_stop(threadID)
+           && !TM.thread_should_stop(threadID)

            && (move = sp->mp->get_next_move()) != MOVE_NONE)
     {
       moveCount = ++sp->moves;
            && (move = sp->mp->get_next_move()) != MOVE_NONE)
     {
       moveCount = ++sp->moves;


@@ -1924,7 +1851,7 @@ namespace {
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 

-      if (thread_should_stop(threadID))
+      if (TM.thread_should_stop(threadID))

       {
           lock_grab(&(sp->lock));
           break;
       {
           lock_grab(&(sp->lock));
           break;


@@ -1934,15 +1861,15 @@ namespace {
       if (value > sp->bestValue) // Less then 2% of cases
       {
           lock_grab(&(sp->lock));
       if (value > sp->bestValue) // Less then 2% of cases
       {
           lock_grab(&(sp->lock));

-          if (value > sp->bestValue && !thread_should_stop(threadID))
+          if (value > sp->bestValue && !TM.thread_should_stop(threadID))

           {
               sp->bestValue = value;
               if (sp->bestValue >= sp->beta)
               {
                   sp_update_pv(sp->parentSstack, ss, sp->ply);
           {
               sp->bestValue = value;
               if (sp->bestValue >= sp->beta)
               {
                   sp_update_pv(sp->parentSstack, ss, sp->ply);

-                  for (int i = 0; i < ActiveThreads; i++)
+                  for (int i = 0; i < TM.active_threads(); i++)

                       if (i != threadID && (i == sp->master || sp->slaves[i]))
                       if (i != threadID && (i == sp->master || sp->slaves[i]))

-                          Threads[i].stop = true;
+                          TM.set_stop_request(i);

 
                   sp->finished = true;
               }
 
                   sp->finished = true;
               }


@@ -1955,10 +1882,10 @@ namespace {
 
     // If this is the master thread and we have been asked to stop because of
     // a beta cutoff higher up in the tree, stop all slave threads.
 
     // If this is the master thread and we have been asked to stop because of
     // a beta cutoff higher up in the tree, stop all slave threads.

-    if (sp->master == threadID && thread_should_stop(threadID))
-        for (int i = 0; i < ActiveThreads; i++)
+    if (sp->master == threadID && TM.thread_should_stop(threadID))
+        for (int i = 0; i < TM.active_threads(); i++)

             if (sp->slaves[i])
             if (sp->slaves[i])

-                Threads[i].stop = true;
+                TM.set_stop_request(i);

 
     sp->cpus--;
     sp->slaves[threadID] = 0;
 
     sp->cpus--;
     sp->slaves[threadID] = 0;


@@ -1977,8 +1904,8 @@ namespace {
 
   void sp_search_pv(SplitPoint* sp, int threadID) {
 
 
   void sp_search_pv(SplitPoint* sp, int threadID) {
 

-    assert(threadID >= 0 && threadID < ActiveThreads);
-    assert(ActiveThreads > 1);
+    assert(threadID >= 0 && threadID < TM.active_threads());
+    assert(TM.active_threads() > 1);

 
     Position pos(*sp->pos);
     CheckInfo ci(pos);
 
     Position pos(*sp->pos);
     CheckInfo ci(pos);


@@ -1989,7 +1916,7 @@ namespace {
 
     while (    lock_grab_bool(&(sp->lock))
            &&  sp->alpha < sp->beta
 
     while (    lock_grab_bool(&(sp->lock))
            &&  sp->alpha < sp->beta

-           && !thread_should_stop(threadID)
+           && !TM.thread_should_stop(threadID)

            && (move = sp->mp->get_next_move()) != MOVE_NONE)
     {
       moveCount = ++sp->moves;
            && (move = sp->mp->get_next_move()) != MOVE_NONE)
     {
       moveCount = ++sp->moves;


@@ -2043,14 +1970,14 @@ namespace {
               if (localAlpha < sp->beta)
                   value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID);
               else
               if (localAlpha < sp->beta)
                   value = -search_pv(pos, ss, -sp->beta, -localAlpha, newDepth, sp->ply+1, threadID);
               else

-                  assert(thread_should_stop(threadID));
+                  assert(TM.thread_should_stop(threadID));

         }
       }
       pos.undo_move(move);
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 
         }
       }
       pos.undo_move(move);
 
       assert(value > -VALUE_INFINITE && value < VALUE_INFINITE);
 

-      if (thread_should_stop(threadID))
+      if (TM.thread_should_stop(threadID))

       {
           lock_grab(&(sp->lock));
           break;
       {
           lock_grab(&(sp->lock));
           break;


@@ -2060,7 +1987,7 @@ namespace {
       if (value > sp->bestValue) // Less then 2% of cases
       {
           lock_grab(&(sp->lock));
       if (value > sp->bestValue) // Less then 2% of cases
       {
           lock_grab(&(sp->lock));

-          if (value > sp->bestValue && !thread_should_stop(threadID))
+          if (value > sp->bestValue && !TM.thread_should_stop(threadID))

           {
               sp->bestValue = value;
               if (value > sp->alpha)
           {
               sp->bestValue = value;
               if (value > sp->alpha)


@@ -2068,9 +1995,9 @@ namespace {
                   // Ask threads to stop before to modify sp->alpha
                   if (value >= sp->beta)
                   {
                   // Ask threads to stop before to modify sp->alpha
                   if (value >= sp->beta)
                   {

-                      for (int i = 0; i < ActiveThreads; i++)
+                      for (int i = 0; i < TM.active_threads(); i++)

                           if (i != threadID && (i == sp->master || sp->slaves[i]))
                           if (i != threadID && (i == sp->master || sp->slaves[i]))

-                              Threads[i].stop = true;
+                              TM.set_stop_request(i);

 
                       sp->finished = true;
                   }
 
                       sp->finished = true;
                   }


@@ -2090,10 +2017,10 @@ namespace {
 
     // If this is the master thread and we have been asked to stop because of
     // a beta cutoff higher up in the tree, stop all slave threads.
 
     // If this is the master thread and we have been asked to stop because of
     // a beta cutoff higher up in the tree, stop all slave threads.

-    if (sp->master == threadID && thread_should_stop(threadID))
-        for (int i = 0; i < ActiveThreads; i++)
+    if (sp->master == threadID && TM.thread_should_stop(threadID))
+        for (int i = 0; i < TM.active_threads(); i++)

             if (sp->slaves[i])
             if (sp->slaves[i])

-                Threads[i].stop = true;
+                TM.set_stop_request(i);

 
     sp->cpus--;
     sp->slaves[threadID] = 0;
 
     sp->cpus--;
     sp->slaves[threadID] = 0;


@@ -2101,124 +2028,6 @@ namespace {
     lock_release(&(sp->lock));
   }
 
     lock_release(&(sp->lock));
   }
 

-  /// The BetaCounterType class
-
-  BetaCounterType::BetaCounterType() { clear(); }
-
-  void BetaCounterType::clear() {
-
-    for (int i = 0; i < THREAD_MAX; i++)
-        Threads[i].betaCutOffs[WHITE] = Threads[i].betaCutOffs[BLACK] = 0ULL;
-  }
-
-  void BetaCounterType::add(Color us, Depth d, int threadID) {
-
-    // Weighted count based on depth
-    Threads[threadID].betaCutOffs[us] += unsigned(d);
-  }
-
-  void BetaCounterType::read(Color us, int64_t& our, int64_t& their) {
-
-    our = their = 0UL;
-    for (int i = 0; i < THREAD_MAX; i++)
-    {
-        our += Threads[i].betaCutOffs[us];
-        their += Threads[i].betaCutOffs[opposite_color(us)];
-    }
-  }
-
-
-  /// The RootMoveList class
-
-  // RootMoveList c'tor
-
-  RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) {
-
-    SearchStack ss[PLY_MAX_PLUS_2];
-    MoveStack mlist[MaxRootMoves];
-    StateInfo st;
-    bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
-
-    // Generate all legal moves
-    MoveStack* last = generate_moves(pos, mlist);
-
-    // Add each move to the moves[] array
-    for (MoveStack* cur = mlist; cur != last; cur++)
-    {
-        bool includeMove = includeAllMoves;
-
-        for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
-            includeMove = (searchMoves[k] == cur->move);
-
-        if (!includeMove)
-            continue;
-
-        // Find a quick score for the move
-        init_ss_array(ss);
-        pos.do_move(cur->move, st);
-        moves[count].move = cur->move;
-        moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
-        moves[count].pv[0] = cur->move;
-        moves[count].pv[1] = MOVE_NONE;
-        pos.undo_move(cur->move);
-        count++;
-    }
-    sort();
-  }
-
-
-  // RootMoveList simple methods definitions
-
-  void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) {
-
-    moves[moveNum].nodes = nodes;
-    moves[moveNum].cumulativeNodes += nodes;
-  }
-
-  void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) {
-
-    moves[moveNum].ourBeta = our;
-    moves[moveNum].theirBeta = their;
-  }
-
-  void RootMoveList::set_move_pv(int moveNum, const Move pv[]) {
-
-    int j;
-
-    for (j = 0; pv[j] != MOVE_NONE; j++)
-        moves[moveNum].pv[j] = pv[j];
-
-    moves[moveNum].pv[j] = MOVE_NONE;
-  }
-
-
-  // RootMoveList::sort() sorts the root move list at the beginning of a new
-  // iteration.
-
-  void RootMoveList::sort() {
-
-    sort_multipv(count - 1); // Sort all items
-  }
-
-
-  // RootMoveList::sort_multipv() sorts the first few moves in the root move
-  // list by their scores and depths. It is used to order the different PVs
-  // correctly in MultiPV mode.
-
-  void RootMoveList::sort_multipv(int n) {
-
-    int i,j;
-
-    for (i = 1; i <= n; i++)
-    {
-        RootMove rm = moves[i];
-        for (j = i; j > 0 && moves[j - 1] < rm; j--)
-            moves[j] = moves[j - 1];
-
-        moves[j] = rm;
-    }
-  }
-

 
   // init_node() is called at the beginning of all the search functions
   // (search(), search_pv(), qsearch(), and so on) and initializes the
 
   // init_node() is called at the beginning of all the search functions
   // (search(), search_pv(), qsearch(), and so on) and initializes the


@@ -2229,9 +2038,9 @@ namespace {
   void init_node(SearchStack ss[], int ply, int threadID) {
 
     assert(ply >= 0 && ply < PLY_MAX);
   void init_node(SearchStack ss[], int ply, int threadID) {
 
     assert(ply >= 0 && ply < PLY_MAX);

-    assert(threadID >= 0 && threadID < ActiveThreads);
+    assert(threadID >= 0 && threadID < TM.active_threads());

 
 

-    Threads[threadID].nodes++;
+    TM.incrementNodeCounter(threadID);

 
     if (threadID == 0)
     {
 
     if (threadID == 0)
     {


@@ -2244,9 +2053,7 @@ namespace {
     }
     ss[ply].init(ply);
     ss[ply + 2].initKillers();
     }
     ss[ply].init(ply);
     ss[ply + 2].initKillers();

-
-    if (Threads[threadID].printCurrentLine)
-        print_current_line(ss, ply, threadID);
+    TM.print_current_line(ss, ply, threadID);

   }
 
 
   }
 
 


@@ -2596,7 +2403,7 @@ namespace {
   int nps() {
 
     int t = current_search_time();
   int nps() {
 
     int t = current_search_time();

-    return (t > 0 ? int((nodes_searched() * 1000) / t) : 0);
+    return (t > 0 ? int((TM.nodes_searched() * 1000) / t) : 0);

   }
 
 
   }
 
 


@@ -2646,7 +2453,7 @@ namespace {
     else if (t - lastInfoTime >= 1000)
     {
         lastInfoTime = t;
     else if (t - lastInfoTime >= 1000)
     {
         lastInfoTime = t;

-        lock_grab(&IOLock);
+        lock_grab(&TM.IOLock);

 
         if (dbg_show_mean)
             dbg_print_mean();
 
         if (dbg_show_mean)
             dbg_print_mean();


@@ -2654,13 +2461,13 @@ namespace {
         if (dbg_show_hit_rate)
             dbg_print_hit_rate();
 
         if (dbg_show_hit_rate)
             dbg_print_hit_rate();
 

-        cout << "info nodes " << nodes_searched() << " nps " << nps()
+        cout << "info nodes " << TM.nodes_searched() << " nps " << nps()

              << " time " << t << " hashfull " << TT.full() << endl;
 
              << " time " << t << " hashfull " << TT.full() << endl;
 

-        lock_release(&IOLock);
+        lock_release(&TM.IOLock);

 
         if (ShowCurrentLine)
 
         if (ShowCurrentLine)

-            Threads[0].printCurrentLine = true;
+            TM.threads[0].printCurrentLineRequest = true;

     }
 
     // Should we stop the search?
     }
 
     // Should we stop the search?


@@ -2676,7 +2483,7 @@ namespace {
 
     if (   (Iteration >= 3 && UseTimeManagement && noMoreTime)
         || (ExactMaxTime && t >= ExactMaxTime)
 
     if (   (Iteration >= 3 && UseTimeManagement && noMoreTime)
         || (ExactMaxTime && t >= ExactMaxTime)

-        || (Iteration >= 3 && MaxNodes && nodes_searched() >= MaxNodes))
+        || (Iteration >= 3 && MaxNodes && TM.nodes_searched() >= MaxNodes))

         AbortSearch = true;
   }
 
         AbortSearch = true;
   }
 


@@ -2702,30 +2509,6 @@ namespace {
   }
 
 
   }
 
 

-  // print_current_line() prints the current line of search for a given
-  // thread. Called when the UCI option UCI_ShowCurrLine is 'true'.
-
-  void print_current_line(SearchStack ss[], int ply, int threadID) {
-
-    assert(ply >= 0 && ply < PLY_MAX);
-    assert(threadID >= 0 && threadID < ActiveThreads);
-
-    if (!Threads[threadID].idle)
-    {
-        lock_grab(&IOLock);
-        cout << "info currline " << (threadID + 1);
-        for (int p = 0; p < ply; p++)
-            cout << " " << ss[p].currentMove;
-
-        cout << endl;
-        lock_release(&IOLock);
-    }
-    Threads[threadID].printCurrentLine = false;
-    if (threadID + 1 < ActiveThreads)
-        Threads[threadID + 1].printCurrentLine = true;
-  }
-
-

   // init_ss_array() does a fast reset of the first entries of a SearchStack array
 
   void init_ss_array(SearchStack ss[]) {
   // init_ss_array() does a fast reset of the first entries of a SearchStack array
 
   void init_ss_array(SearchStack ss[]) {


@@ -2765,15 +2548,77 @@ namespace {
   }
 
 
   }
 
 

+  // init_thread() is the function which is called when a new thread is
+  // launched. It simply calls the idle_loop() function with the supplied
+  // threadID. There are two versions of this function; one for POSIX
+  // threads and one for Windows threads.
+
+#if !defined(_MSC_VER)
+
+  void* init_thread(void *threadID) {
+
+    TM.idle_loop(*(int*)threadID, NULL);
+    return NULL;
+  }
+
+#else
+
+  DWORD WINAPI init_thread(LPVOID threadID) {
+
+    TM.idle_loop(*(int*)threadID, NULL);
+    return NULL;
+  }
+
+#endif
+
+
+  /// The ThreadsManager class
+
+  // resetNodeCounters(), resetBetaCounters(), searched_nodes() and
+  // get_beta_counters() are getters/setters for the per thread
+  // counters used to sort the moves at root.
+
+  void ThreadsManager::resetNodeCounters() {
+
+    for (int i = 0; i < THREAD_MAX; i++)
+        threads[i].nodes = 0ULL;
+  }
+
+  void ThreadsManager::resetBetaCounters() {
+
+    for (int i = 0; i < THREAD_MAX; i++)
+        threads[i].betaCutOffs[WHITE] = threads[i].betaCutOffs[BLACK] = 0ULL;
+  }
+
+  int64_t ThreadsManager::nodes_searched() const {
+
+    int64_t result = 0ULL;
+    for (int i = 0; i < ActiveThreads; i++)
+        result += threads[i].nodes;
+
+    return result;
+  }
+
+  void ThreadsManager::get_beta_counters(Color us, int64_t& our, int64_t& their) const {
+
+    our = their = 0UL;
+    for (int i = 0; i < THREAD_MAX; i++)
+    {
+        our += threads[i].betaCutOffs[us];
+        their += threads[i].betaCutOffs[opposite_color(us)];
+    }
+  }
+
+

   // idle_loop() is where the threads are parked when they have no work to do.
   // The parameter "waitSp", if non-NULL, is a pointer to an active SplitPoint
   // object for which the current thread is the master.
 
   // idle_loop() is where the threads are parked when they have no work to do.
   // The parameter "waitSp", if non-NULL, is a pointer to an active SplitPoint
   // object for which the current thread is the master.
 

-  void idle_loop(int threadID, SplitPoint* waitSp) {
+  void ThreadsManager::idle_loop(int threadID, SplitPoint* waitSp) {

 
     assert(threadID >= 0 && threadID < THREAD_MAX);
 
 
     assert(threadID >= 0 && threadID < THREAD_MAX);
 

-    Threads[threadID].running = true;
+    threads[threadID].running = true;

 
     while (!AllThreadsShouldExit || threadID == 0)
     {
 
     while (!AllThreadsShouldExit || threadID == 0)
     {


@@ -2784,7 +2629,7 @@ namespace {
                && (AllThreadsShouldSleep || threadID >= ActiveThreads))
         {
 
                && (AllThreadsShouldSleep || threadID >= ActiveThreads))
         {
 

-            Threads[threadID].sleeping = true;
+            threads[threadID].sleeping = true;

 
 #if !defined(_MSC_VER)
             pthread_mutex_lock(&WaitLock);
 
 #if !defined(_MSC_VER)
             pthread_mutex_lock(&WaitLock);


@@ -2799,51 +2644,115 @@ namespace {
 
         // Out of the while loop to avoid races in case thread is woken up but
         // while condition still holds true so that is put to sleep again.
 
         // Out of the while loop to avoid races in case thread is woken up but
         // while condition still holds true so that is put to sleep again.

-        Threads[threadID].sleeping = false;
+        threads[threadID].sleeping = false;

 
 

-      // If this thread has been assigned work, launch a search
-      if (Threads[threadID].workIsWaiting)
-      {
-          assert(!Threads[threadID].idle);
+        // If this thread has been assigned work, launch a search
+        if (threads[threadID].workIsWaiting)
+        {
+            assert(!threads[threadID].idle);

 
 

-          Threads[threadID].workIsWaiting = false;
-          if (Threads[threadID].splitPoint->pvNode)
-              sp_search_pv(Threads[threadID].splitPoint, threadID);
-          else
-              sp_search(Threads[threadID].splitPoint, threadID);
+            threads[threadID].workIsWaiting = false;
+            if (threads[threadID].splitPoint->pvNode)
+                sp_search_pv(threads[threadID].splitPoint, threadID);
+            else
+                sp_search(threads[threadID].splitPoint, threadID);

 
 

-          Threads[threadID].idle = true;
-      }
+            threads[threadID].idle = true;
+        }

 
 

-      // If this thread is the master of a split point and all threads have
-      // finished their work at this split point, return from the idle loop.
-      if (waitSp != NULL && waitSp->cpus == 0)
-          return;
+        // If this thread is the master of a split point and all threads have
+        // finished their work at this split point, return from the idle loop.
+        if (waitSp != NULL && waitSp->cpus == 0)
+            return;

     }
 
     }
 

-    Threads[threadID].running = false;
+    threads[threadID].running = false;

   }
 
 
   }
 
 

-  // init_split_point_stack() is called during program initialization, and
-  // initializes all split point objects.
+  // init_threads() is called during startup. It launches all helper threads,
+  // and initializes the split point stack and the global locks and condition
+  // objects.

 
 

-  void init_split_point_stack() {
+  void ThreadsManager::init_threads() {

 
 

+    volatile int i;
+    bool ok;
+
+#if !defined(_MSC_VER)
+    pthread_t pthread[1];
+#endif
+
+    // Initialize global locks
+    lock_init(&MPLock, NULL);
+    lock_init(&IOLock, NULL);
+
+    // Initialize SplitPointStack locks

     for (int i = 0; i < THREAD_MAX; i++)
         for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
         {
             SplitPointStack[i][j].parent = NULL;
             lock_init(&(SplitPointStack[i][j].lock), NULL);
         }
     for (int i = 0; i < THREAD_MAX; i++)
         for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
         {
             SplitPointStack[i][j].parent = NULL;
             lock_init(&(SplitPointStack[i][j].lock), NULL);
         }

+
+#if !defined(_MSC_VER)
+    pthread_mutex_init(&WaitLock, NULL);
+    pthread_cond_init(&WaitCond, NULL);
+#else
+    for (i = 0; i < THREAD_MAX; i++)
+        SitIdleEvent[i] = CreateEvent(0, FALSE, FALSE, 0);
+#endif
+
+    // Will be set just before program exits to properly end the threads
+    AllThreadsShouldExit = false;
+
+    // Threads will be put to sleep as soon as created
+    AllThreadsShouldSleep = true;
+
+    // All threads except the main thread should be initialized to idle state
+    ActiveThreads = 1;
+    for (i = 1; i < THREAD_MAX; i++)
+        threads[i].idle = true;
+
+    // Launch the helper threads
+    for (i = 1; i < THREAD_MAX; i++)
+    {
+
+#if !defined(_MSC_VER)
+        ok = (pthread_create(pthread, NULL, init_thread, (void*)(&i)) == 0);
+#else
+        DWORD iID[1];
+        ok = (CreateThread(NULL, 0, init_thread, (LPVOID)(&i), 0, iID) != NULL);
+#endif
+
+        if (!ok)
+        {
+            cout << "Failed to create thread number " << i << endl;
+            Application::exit_with_failure();
+        }
+
+        // Wait until the thread has finished launching and is gone to sleep
+        while (!threads[i].running || !threads[i].sleeping);
+    }

   }
 
 
   }
 
 

-  // destroy_split_point_stack() is called when the program exits, and
-  // destroys all locks in the precomputed split point objects.
+  // exit_threads() is called when the program exits. It makes all the
+  // helper threads exit cleanly.
+
+  void ThreadsManager::exit_threads() {

 
 

-  void destroy_split_point_stack() {
+    ActiveThreads = THREAD_MAX;  // HACK
+    AllThreadsShouldSleep = true;  // HACK
+    wake_sleeping_threads();
+    AllThreadsShouldExit = true;
+    for (int i = 1; i < THREAD_MAX; i++)
+    {
+        threads[i].stop = true;
+        while (threads[i].running);
+    }

 
 

+    // Now we can safely destroy the locks

     for (int i = 0; i < THREAD_MAX; i++)
         for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
             lock_destroy(&(SplitPointStack[i][j].lock));
     for (int i = 0; i < THREAD_MAX; i++)
         for (int j = 0; j < ACTIVE_SPLIT_POINTS_MAX; j++)
             lock_destroy(&(SplitPointStack[i][j].lock));


@@ -2855,22 +2764,25 @@ namespace {
   // cutoff has occurred in the thread's currently active split point, or in
   // some ancestor of the current split point.
 
   // cutoff has occurred in the thread's currently active split point, or in
   // some ancestor of the current split point.
 

-  bool thread_should_stop(int threadID) {
+  bool ThreadsManager::thread_should_stop(int threadID) {

 
     assert(threadID >= 0 && threadID < ActiveThreads);
 
     SplitPoint* sp;
 
 
     assert(threadID >= 0 && threadID < ActiveThreads);
 
     SplitPoint* sp;
 

-    if (Threads[threadID].stop)
+    if (threads[threadID].stop)

         return true;
         return true;

+

     if (ActiveThreads <= 2)
         return false;
     if (ActiveThreads <= 2)
         return false;

-    for (sp = Threads[threadID].splitPoint; sp != NULL; sp = sp->parent)
+
+    for (sp = threads[threadID].splitPoint; sp != NULL; sp = sp->parent)

         if (sp->finished)
         {
         if (sp->finished)
         {

-            Threads[threadID].stop = true;
+            threads[threadID].stop = true;

             return true;
         }
             return true;
         }

+

     return false;
   }
 
     return false;
   }
 


@@ -2883,17 +2795,17 @@ namespace {
   // threads which are busy searching the split point at the top of "slave"'s
   // split point stack (the "helpful master concept" in YBWC terminology).
 
   // threads which are busy searching the split point at the top of "slave"'s
   // split point stack (the "helpful master concept" in YBWC terminology).
 

-  bool thread_is_available(int slave, int master) {
+  bool ThreadsManager::thread_is_available(int slave, int master) const {

 
     assert(slave >= 0 && slave < ActiveThreads);
     assert(master >= 0 && master < ActiveThreads);
     assert(ActiveThreads > 1);
 
 
     assert(slave >= 0 && slave < ActiveThreads);
     assert(master >= 0 && master < ActiveThreads);
     assert(ActiveThreads > 1);
 

-    if (!Threads[slave].idle || slave == master)
+    if (!threads[slave].idle || slave == master)

         return false;
 
     // Make a local copy to be sure doesn't change under our feet
         return false;
 
     // Make a local copy to be sure doesn't change under our feet

-    int localActiveSplitPoints = Threads[slave].activeSplitPoints;
+    int localActiveSplitPoints = threads[slave].activeSplitPoints;

 
     if (localActiveSplitPoints == 0)
         // No active split points means that the thread is available as
 
     if (localActiveSplitPoints == 0)
         // No active split points means that the thread is available as


@@ -2904,7 +2816,7 @@ namespace {
         return true;
 
     // Apply the "helpful master" concept if possible. Use localActiveSplitPoints
         return true;
 
     // Apply the "helpful master" concept if possible. Use localActiveSplitPoints

-    // that is known to be > 0, instead of Threads[slave].activeSplitPoints that
+    // that is known to be > 0, instead of threads[slave].activeSplitPoints that

     // could have been set to 0 by another thread leading to an out of bound access.
     if (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master])
         return true;
     // could have been set to 0 by another thread leading to an out of bound access.
     if (SplitPointStack[slave][localActiveSplitPoints - 1].slaves[master])
         return true;


@@ -2916,7 +2828,7 @@ namespace {
   // idle_thread_exists() tries to find an idle thread which is available as
   // a slave for the thread with threadID "master".
 
   // idle_thread_exists() tries to find an idle thread which is available as
   // a slave for the thread with threadID "master".
 

-  bool idle_thread_exists(int master) {
+  bool ThreadsManager::idle_thread_exists(int master) const {

 
     assert(master >= 0 && master < ActiveThreads);
     assert(ActiveThreads > 1);
 
     assert(master >= 0 && master < ActiveThreads);
     assert(ActiveThreads > 1);


@@ -2941,7 +2853,7 @@ namespace {
   // threads have returned from sp_search_pv (or, equivalently, when
   // splitPoint->cpus becomes 0), split() returns true.
 
   // threads have returned from sp_search_pv (or, equivalently, when
   // splitPoint->cpus becomes 0), split() returns true.
 

-  bool split(const Position& p, SearchStack* sstck, int ply,
+  bool ThreadsManager::split(const Position& p, SearchStack* sstck, int ply,

              Value* alpha, Value* beta, Value* bestValue, const Value futilityValue,
              Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) {
 
              Value* alpha, Value* beta, Value* bestValue, const Value futilityValue,
              Depth depth, int* moves, MovePicker* mp, int master, bool pvNode) {
 


@@ -2962,18 +2874,18 @@ namespace {
     // If no other thread is available to help us, or if we have too many
     // active split points, don't split.
     if (   !idle_thread_exists(master)
     // If no other thread is available to help us, or if we have too many
     // active split points, don't split.
     if (   !idle_thread_exists(master)

-        || Threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX)
+        || threads[master].activeSplitPoints >= ACTIVE_SPLIT_POINTS_MAX)

     {
         lock_release(&MPLock);
         return false;
     }
 
     // Pick the next available split point object from the split point stack
     {
         lock_release(&MPLock);
         return false;
     }
 
     // Pick the next available split point object from the split point stack

-    splitPoint = SplitPointStack[master] + Threads[master].activeSplitPoints;
-    Threads[master].activeSplitPoints++;
+    splitPoint = SplitPointStack[master] + threads[master].activeSplitPoints;
+    threads[master].activeSplitPoints++;

 
     // Initialize the split point object
 
     // Initialize the split point object

-    splitPoint->parent = Threads[master].splitPoint;
+    splitPoint->parent = threads[master].splitPoint;

     splitPoint->finished = false;
     splitPoint->ply = ply;
     splitPoint->depth = depth;
     splitPoint->finished = false;
     splitPoint->ply = ply;
     splitPoint->depth = depth;


@@ -2991,17 +2903,17 @@ namespace {
     for (int i = 0; i < ActiveThreads; i++)
         splitPoint->slaves[i] = 0;
 
     for (int i = 0; i < ActiveThreads; i++)
         splitPoint->slaves[i] = 0;
 

-    Threads[master].idle = false;
-    Threads[master].stop = false;
-    Threads[master].splitPoint = splitPoint;
+    threads[master].idle = false;
+    threads[master].stop = false;
+    threads[master].splitPoint = splitPoint;

 
     // Allocate available threads setting idle flag to false
     for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
         if (thread_is_available(i, master))
         {
 
     // Allocate available threads setting idle flag to false
     for (int i = 0; i < ActiveThreads && splitPoint->cpus < MaxThreadsPerSplitPoint; i++)
         if (thread_is_available(i, master))
         {

-            Threads[i].idle = false;
-            Threads[i].stop = false;
-            Threads[i].splitPoint = splitPoint;
+            threads[i].idle = false;
+            threads[i].stop = false;
+            threads[i].splitPoint = splitPoint;

             splitPoint->slaves[i] = 1;
             splitPoint->cpus++;
         }
             splitPoint->slaves[i] = 1;
             splitPoint->cpus++;
         }


@@ -3017,7 +2929,7 @@ namespace {
         if (i == master || splitPoint->slaves[i])
         {
             memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 4 * sizeof(SearchStack));
         if (i == master || splitPoint->slaves[i])
         {
             memcpy(splitPoint->sstack[i] + ply - 1, sstck + ply - 1, 4 * sizeof(SearchStack));

-            Threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop()
+            threads[i].workIsWaiting = true; // This makes the slave to exit from idle_loop()

         }
 
     // Everything is set up. The master thread enters the idle loop, from
         }
 
     // Everything is set up. The master thread enters the idle loop, from


@@ -3037,10 +2949,10 @@ namespace {
 
     *beta = splitPoint->beta;
     *bestValue = splitPoint->bestValue;
 
     *beta = splitPoint->beta;
     *bestValue = splitPoint->bestValue;

-    Threads[master].stop = false;
-    Threads[master].idle = false;
-    Threads[master].activeSplitPoints--;
-    Threads[master].splitPoint = splitPoint->parent;
+    threads[master].stop = false;
+    threads[master].idle = false;
+    threads[master].activeSplitPoints--;
+    threads[master].splitPoint = splitPoint->parent;

 
     lock_release(&MPLock);
     return true;
 
     lock_release(&MPLock);
     return true;


@@ -3050,43 +2962,44 @@ namespace {
   // wake_sleeping_threads() wakes up all sleeping threads when it is time
   // to start a new search from the root.
 
   // wake_sleeping_threads() wakes up all sleeping threads when it is time
   // to start a new search from the root.
 

-  void wake_sleeping_threads() {
+  void ThreadsManager::wake_sleeping_threads() {

 
     assert(AllThreadsShouldSleep);
 
     assert(AllThreadsShouldSleep);

+    assert(ActiveThreads > 0);

 
     AllThreadsShouldSleep = false;
 
 
     AllThreadsShouldSleep = false;
 

-    if (ActiveThreads > 1)
+    if (ActiveThreads == 1)
+        return;
+
+    for (int i = 1; i < ActiveThreads; i++)

     {
     {

-        for (int i = 1; i < ActiveThreads; i++)
-        {
-            assert(Threads[i].sleeping == true);
+        assert(threads[i].sleeping == true);

 
 

-            Threads[i].idle = true;
-            Threads[i].workIsWaiting = false;
-        }
+        threads[i].idle = true;
+        threads[i].workIsWaiting = false;
+    }

 
 #if !defined(_MSC_VER)
 
 #if !defined(_MSC_VER)

-      pthread_mutex_lock(&WaitLock);
-      pthread_cond_broadcast(&WaitCond);
-      pthread_mutex_unlock(&WaitLock);
+    pthread_mutex_lock(&WaitLock);
+    pthread_cond_broadcast(&WaitCond);
+    pthread_mutex_unlock(&WaitLock);

 #else
 #else

-      for (int i = 1; i < THREAD_MAX; i++)
-          SetEvent(SitIdleEvent[i]);
+    for (int i = 1; i < THREAD_MAX; i++)
+        SetEvent(SitIdleEvent[i]);

 #endif
 
 #endif
 

-      // Wait for the threads to be all woken up
-      for (int i = 1; i < ActiveThreads; i++)
-           while (Threads[i].sleeping);
-    }
+    // Wait for the threads to be all woken up
+    for (int i = 1; i < ActiveThreads; i++)
+        while (threads[i].sleeping);

   }
 
 
   // put_threads_to_sleep() makes all the threads go to sleep just before
   }
 
 
   // put_threads_to_sleep() makes all the threads go to sleep just before

-  // to leave think(), at the end of the search. Threads should have already
+  // to leave think(), at the end of the search. threads should have already

   // finished the job and should be idle.
 
   // finished the job and should be idle.
 

-  void put_threads_to_sleep() {
+  void ThreadsManager::put_threads_to_sleep() {

 
     assert(!AllThreadsShouldSleep);
 
 
     assert(!AllThreadsShouldSleep);
 


@@ -3094,31 +3007,131 @@ namespace {
 
     // Wait for the threads to be all sleeping
     for (int i = 1; i < ActiveThreads; i++)
 
     // Wait for the threads to be all sleeping
     for (int i = 1; i < ActiveThreads; i++)

-        while (!Threads[i].sleeping);
+        while (!threads[i].sleeping);

   }
 
 
   }
 
 

-  // init_thread() is the function which is called when a new thread is
-  // launched. It simply calls the idle_loop() function with the supplied
-  // threadID. There are two versions of this function; one for POSIX
-  // threads and one for Windows threads.
+  // print_current_line() prints _once_ the current line of search for a
+  // given thread and then setup the print request for the next thread.
+  // Called when the UCI option UCI_ShowCurrLine is 'true'.

 
 

-#if !defined(_MSC_VER)
+  void ThreadsManager::print_current_line(SearchStack ss[], int ply, int threadID) {

 
 

-  void* init_thread(void *threadID) {
+    assert(ply >= 0 && ply < PLY_MAX);
+    assert(threadID >= 0 && threadID < ActiveThreads);

 
 

-    idle_loop(*(int*)threadID, NULL);
-    return NULL;
+    if (!threads[threadID].printCurrentLineRequest)
+        return;
+
+    // One shot only
+    threads[threadID].printCurrentLineRequest = false;
+
+    if (!threads[threadID].idle)
+    {
+        lock_grab(&IOLock);
+        cout << "info currline " << (threadID + 1);
+        for (int p = 0; p < ply; p++)
+            cout << " " << ss[p].currentMove;
+
+        cout << endl;
+        lock_release(&IOLock);
+    }
+
+    // Setup print request for the next thread ID
+    if (threadID + 1 < ActiveThreads)
+        threads[threadID + 1].printCurrentLineRequest = true;

   }
 
   }
 

-#else

 
 

-  DWORD WINAPI init_thread(LPVOID threadID) {
+  /// The RootMoveList class

 
 

-    idle_loop(*(int*)threadID, NULL);
-    return NULL;
+  // RootMoveList c'tor
+
+  RootMoveList::RootMoveList(Position& pos, Move searchMoves[]) : count(0) {
+
+    SearchStack ss[PLY_MAX_PLUS_2];
+    MoveStack mlist[MaxRootMoves];
+    StateInfo st;
+    bool includeAllMoves = (searchMoves[0] == MOVE_NONE);
+
+    // Generate all legal moves
+    MoveStack* last = generate_moves(pos, mlist);
+
+    // Add each move to the moves[] array
+    for (MoveStack* cur = mlist; cur != last; cur++)
+    {
+        bool includeMove = includeAllMoves;
+
+        for (int k = 0; !includeMove && searchMoves[k] != MOVE_NONE; k++)
+            includeMove = (searchMoves[k] == cur->move);
+
+        if (!includeMove)
+            continue;
+
+        // Find a quick score for the move
+        init_ss_array(ss);
+        pos.do_move(cur->move, st);
+        moves[count].move = cur->move;
+        moves[count].score = -qsearch(pos, ss, -VALUE_INFINITE, VALUE_INFINITE, Depth(0), 1, 0);
+        moves[count].pv[0] = cur->move;
+        moves[count].pv[1] = MOVE_NONE;
+        pos.undo_move(cur->move);
+        count++;
+    }
+    sort();

   }
 
   }
 

-#endif

 
 

-}
+  // RootMoveList simple methods definitions
+
+  void RootMoveList::set_move_nodes(int moveNum, int64_t nodes) {
+
+    moves[moveNum].nodes = nodes;
+    moves[moveNum].cumulativeNodes += nodes;
+  }
+
+  void RootMoveList::set_beta_counters(int moveNum, int64_t our, int64_t their) {
+
+    moves[moveNum].ourBeta = our;
+    moves[moveNum].theirBeta = their;
+  }
+
+  void RootMoveList::set_move_pv(int moveNum, const Move pv[]) {
+
+    int j;
+
+    for (j = 0; pv[j] != MOVE_NONE; j++)
+        moves[moveNum].pv[j] = pv[j];
+
+    moves[moveNum].pv[j] = MOVE_NONE;
+  }
+
+
+  // RootMoveList::sort() sorts the root move list at the beginning of a new
+  // iteration.
+
+  void RootMoveList::sort() {
+
+    sort_multipv(count - 1); // Sort all items
+  }
+
+
+  // RootMoveList::sort_multipv() sorts the first few moves in the root move
+  // list by their scores and depths. It is used to order the different PVs
+  // correctly in MultiPV mode.
+
+  void RootMoveList::sort_multipv(int n) {
+
+    int i,j;
+
+    for (i = 1; i <= n; i++)
+    {
+        RootMove rm = moves[i];
+        for (j = i; j > 0 && moves[j - 1] < rm; j--)
+            moves[j] = moves[j - 1];
+
+        moves[j] = rm;
+    }
+  }
+
+} // namspace

diff --git a/src/thread.h b/src/thread.h
index 14924bf2280662be82523e81e94d09a7136d1c16..3dc0f274ba7d21a853bcfc11ad2948b3dbb537c1 100644 (file)
--- a/src/thread.h
+++ b/src/thread.h
@@ -66,9 +66,6 @@ struct SplitPoint {
 
 
 struct Thread {
 
 
 struct Thread {

-
-  Thread() { memset(this, 0, sizeof(Thread)); }
-

   SplitPoint *splitPoint;
   volatile int activeSplitPoints;
   uint64_t nodes;
   SplitPoint *splitPoint;
   volatile int activeSplitPoints;
   uint64_t nodes;


@@ -78,7 +75,7 @@ struct Thread {
   volatile bool idle;
   volatile bool sleeping;
   volatile bool workIsWaiting;
   volatile bool idle;
   volatile bool sleeping;
   volatile bool workIsWaiting;

-  volatile bool printCurrentLine;
+  volatile bool printCurrentLineRequest;

   unsigned char pad[64]; // set some distance among local data for each thread
 };
 
   unsigned char pad[64]; // set some distance among local data for each thread
 };