Do not modify alpha in split()

[stockfish] / src / thread.h

diff --git a/src/thread.h b/src/thread.h
index 558a6752da9c679cfa59f6c4b614356703df2680..6ee07d34668d6bcada9cfdd34473a96135c1d6e2 100644 (file)
--- a/src/thread.h
+++ b/src/thread.h
@@ -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
@@ -17,66 +17,116 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
-
 #if !defined(THREAD_H_INCLUDED)
 #define THREAD_H_INCLUDED
 
+#include <cstring>
 
-////
-//// Includes
-////
-
-#include "history.h"
 #include "lock.h"
+#include "material.h"
 #include "movepick.h"
+#include "pawns.h"
 #include "position.h"
-#include "search.h"
 
+const int MAX_THREADS = 32;
+const int MAX_ACTIVE_SPLIT_POINTS = 8;
 
-////
-//// Constants and variables
-////
-
-const int THREAD_MAX = 8;
+struct SplitPoint {
 
+  // Const data after splitPoint has been setup
+  SplitPoint* parent;
+  const Position* pos;
+  Depth depth;
+  Value beta;
+  int nodeType;
+  int ply;
+  int master;
+  Move threatMove;
 
-////
-//// Types
-////
+  // Const pointers to shared data
+  MovePicker* mp;
+  SearchStack* ss;
 
-struct SplitPoint {
-  SplitPoint *parent;
-  Position pos;
-  SearchStack sstack[THREAD_MAX][PLY_MAX];
-  SearchStack *parentSstack;
-  int ply;
-  Depth depth;
-  volatile Value alpha, beta, bestValue;
-  bool pvNode;
-  Bitboard dcCandidates;
-  int master, slaves[THREAD_MAX];
+  // Shared data
   Lock lock;
-  MovePicker *mp;
-  volatile int moves;
-  volatile int cpus;
-  bool finished;
+  volatile int64_t nodes;
+  volatile Value alpha;
+  volatile Value bestValue;
+  volatile int moveCount;
+  volatile bool is_betaCutoff;
+  volatile bool is_slave[MAX_THREADS];
 };
 
 
+/// Thread struct is used to keep together all the thread related stuff like locks,
+/// state and especially split points. We also use per-thread pawn and material hash
+/// tables so that once we get a pointer to an entry its life time is unlimited and
+/// we don't have to care about someone changing the entry under our feet.
+
 struct Thread {
-  SplitPoint *splitPoint;
-  int activeSplitPoints;
-  uint64_t nodes;
-  uint64_t betaCutOffs[2];
-  bool failHighPly1;
-  volatile bool stop;
-  volatile bool running;
-  volatile bool idle;
-  volatile bool workIsWaiting;
-  volatile bool printCurrentLine;
-  History H;
-  unsigned char pad[64]; // set some distance among local data for each thread
+
+  enum ThreadState
+  {
+    INITIALIZING,  // Thread is initializing itself
+    SEARCHING,     // Thread is performing work
+    AVAILABLE,     // Thread is waiting for work
+    BOOKED,        // Other thread (master) has booked us as a slave
+    WORKISWAITING, // Master has ordered us to start
+    TERMINATED     // We are quitting and thread is terminated
+  };
+
+  void wake_up();
+  bool cutoff_occurred() const;
+  bool is_available_to(int master) const;
+
+  SplitPoint splitPoints[MAX_ACTIVE_SPLIT_POINTS];
+  MaterialInfoTable materialTable;
+  PawnInfoTable pawnTable;
+  int maxPly;
+  Lock sleepLock;
+  WaitCondition sleepCond;
+  volatile ThreadState state;
+  SplitPoint* volatile splitPoint;
+  volatile int activeSplitPoints;
+};
+
+
+/// ThreadsManager class is used to handle all the threads related stuff like init,
+/// starting, parking and, the most important, launching a slave thread at a split
+/// point. All the access to shared thread data is done through this class.
+
+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:
+  Thread& operator[](int threadID) { return threads[threadID]; }
+  void init();
+  void exit();
+  void init_hash_tables();
+
+  int min_split_depth() const { return minimumSplitDepth; }
+  int size() const { return activeThreads; }
+  void set_size(int cnt) { activeThreads = cnt; }
+
+  void read_uci_options();
+  bool available_slave_exists(int master) const;
+  void idle_loop(int threadID, SplitPoint* sp);
+
+  template <bool Fake>
+  Value split(Position& pos, SearchStack* ss, Value alpha, Value beta, Value bestValue,
+              Depth depth, Move threatMove, int moveCount, MovePicker* mp, int nodeType);
+private:
+  Thread threads[MAX_THREADS];
+  Lock threadsLock;
+  Depth minimumSplitDepth;
+  int maxThreadsPerSplitPoint;
+  int activeThreads;
+  bool useSleepingThreads;
+  volatile bool allThreadsShouldExit;
 };
 
+extern ThreadsManager Threads;
 
 #endif // !defined(THREAD_H_INCLUDED)