Move prefetch() out of TT

[stockfish] / src / tt.h

diff --git a/src/tt.h b/src/tt.h
index c1dd8508c2fadde864d8eb3a4932ca1b0812d3b1..bcc761acf325da0999838b2f209cb4faab92bb33 100644 (file)
--- a/src/tt.h
+++ b/src/tt.h
@@ -1,13 +1,14 @@
 /*
-  Glaurung, a UCI chess playing engine.
-  Copyright (C) 2004-2008 Tord Romstad
+  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
 
-  Glaurung is free software: you can redistribute it and/or modify
+  Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
-  Glaurung is distributed in the hope that it will be useful,
+  Stockfish is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
@@ -33,60 +34,108 @@
 //// Types
 ////
 
-/// The TTEntry class is the class of transposition table entries.
+/// The TTEntry class is the class of transposition table entries
+///
+/// A TTEntry needs 96 bits to be stored
+///
+/// bit  0-31: key
+/// bit 32-63: data
+/// bit 64-79: value
+/// bit 80-95: depth
+///
+/// the 32 bits of the data field are so defined
+///
+/// bit  0-16: move
+/// bit 17-19: not used
+/// bit 20-22: value type
+/// bit 23-31: generation
 
 class TTEntry {
 
 public:
-  TTEntry();
-  TTEntry(Key k, Value v, ValueType t, Depth d, Move m, int generation);
-  Key key() const { return key_; }
-  Depth depth() const { return Depth(depth_); }
-  Move move() const { return Move(data & 0x7FFFF); }
-  Value value() const { return Value(value_); }
-  ValueType type() const { return ValueType((data >> 20) & 3); }
-  int generation() const { return (data >> 23); }
+  void save(uint32_t k, Value v, ValueType t, Depth d, Move m, int g, Value statV, Value kd) {
+
+      key32 = k;
+      data = (m & 0x1FFFF) | (t << 20) | (g << 23);
+      value16     = int16_t(v);
+      depth16     = int16_t(d);
+      staticValue = int16_t(statV);
+      kingDanger  = int16_t(kd);
+  }
+
+  uint32_t key() const { return key32; }
+  Depth depth() const { return Depth(depth16); }
+  Move move() const { return Move(data & 0x1FFFF); }
+  Value value() const { return Value(value16); }
+  ValueType type() const { return ValueType((data >> 20) & 7); }
+  int generation() const { return data >> 23; }
+  Value static_value() const { return Value(staticValue); }
+  Value king_danger() const { return Value(kingDanger); }
 
 private:
-  Key key_;
+  uint32_t key32;
   uint32_t data;
-  int16_t value_;
-  int16_t depth_;
+  int16_t value16;
+  int16_t depth16;
+  int16_t staticValue;
+  int16_t kingDanger;
 };
 
-/// The transposition table class.  This is basically just a huge array
+
+/// This is the number of TTEntry slots for each position
+const int ClusterSize = 4;
+
+/// Each group of ClusterSize number of TTEntry form a TTCluster
+/// that is indexed by a single position key. TTCluster size must
+///  be not bigger then a cache line size, in case it is less then
+/// it should be padded to guarantee always aligned accesses.
+
+struct TTCluster {
+  TTEntry data[ClusterSize];
+};
+
+
+/// The transposition table class. This is basically just a huge array
 /// containing TTEntry objects, and a few methods for writing new entries
 /// and reading new ones.
 
 class TranspositionTable {
 
 public:
-  TranspositionTable(unsigned mbSize);
+  TranspositionTable();
   ~TranspositionTable();
-  void set_size(unsigned mbSize);
+  void set_size(size_t mbSize);
   void clear();
-  void store(const Position &pos, Value v, Depth d, Move m, ValueType type);
-  const TTEntry* retrieve(const Position &pos) const;
+  void store(const Key posKey, Value v, ValueType type, Depth d, Move m, Value statV, Value kingD);
+  TTEntry* retrieve(const Key posKey) const;
   void new_search();
-  void insert_pv(const Position &pos, Move pv[]);
-  int full();
+  void insert_pv(const Position& pos, Move pv[]);
+  void extract_pv(const Position& pos, Move pv[], const int PLY_MAX);
+  int full() const;
+  TTEntry* first_entry(const Key posKey) const;
 
 private:
-  inline TTEntry* first_entry(const Position &pos) const;
-
-  unsigned size;
-  int writes;
-  TTEntry* entries;
+  // Be sure 'writes' is at least one cache line away
+  // from read only variables.
+  unsigned char pad_before[64 - sizeof(unsigned)];
+  unsigned writes; // heavy SMP read/write access here
+  unsigned char pad_after[64];
+
+  size_t size;
+  TTCluster* entries;
   uint8_t generation;
 };
 
+extern TranspositionTable TT;
 
-////
-//// Constants and variables
-////
 
-// Default transposition table size, in megabytes:
-const int TTDefaultSize = 32;
+/// 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;
+}
 
 #endif // !defined(TT_H_INCLUDED)