X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Ftt.h;h=f2928fb9e84b4b754ae9c1ecfb9a1c01b7778a56;hp=6833c67db0b36a2395a859a5033f79b64943e30c;hb=0ddf84870ad9f7fb4309e992e1e5eae968577958;hpb=e0056c3851c3caa1fed7114d551017e502c0f4be

diff --git a/src/tt.h b/src/tt.h
index 6833c67d..f2928fb9 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -26,7 +26,7 @@
 ////
 
 #include "depth.h"
-#include "position.h"
+#include "move.h"
 #include "value.h"
 
 
@@ -34,6 +34,39 @@
 //// Types
 ////
 
+
+/// A simple fixed size hash table used to store pawns and material
+/// configurations. It is basically just an array of Entry objects.
+/// Without cluster concept or overwrite policy.
+
+template<class Entry, int HashSize>
+class SimpleHash {
+
+  SimpleHash(const SimpleHash&);
+  SimpleHash& operator=(const SimpleHash&);
+
+public:
+  SimpleHash() {
+
+    entries = new Entry[HashSize];
+    if (!entries)
+    {
+        std::cerr << "Failed to allocate " << HashSize * sizeof(Entry)
+                  << " bytes for material hash table." << std::endl;
+        exit(EXIT_FAILURE);
+    }
+    memset(entries, 0, HashSize * sizeof(Entry));
+  }
+
+  ~SimpleHash() { delete [] entries; }
+
+  Entry* find(Key key) const { return entries + unsigned(key & (HashSize - 1)); }
+
+protected:
+  Entry* entries;
+};
+
+
 /// The TTEntry class is the class of transposition table entries
 ///
 /// A TTEntry needs 128 bits to be stored
@@ -43,13 +76,13 @@
 /// bit 64-79: value
 /// bit 80-95: depth
 /// bit 96-111: static value
-/// bit 112-127: king danger value
+/// bit 112-127: margin of static value
 ///
 /// 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 17-20: not used
+/// bit 21-22: value type
 /// bit 23-31: generation
 
 class TTEntry {
@@ -58,21 +91,22 @@ public:
   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);
+      data = (m & 0x1FFFF) | (t << 21) | (g << 23);
+      value16     = (int16_t)v;
+      depth16     = (int16_t)d;
+      staticValue = (int16_t)statV;
+      staticValueMargin  = (int16_t)kd;
   }
+  void set_generation(int g) { data = move() | (type() << 21) | (g << 23); }
 
   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); }
+  ValueType type() const { return ValueType((data >> 21) & 3); }
   int generation() const { return data >> 23; }
   Value static_value() const { return Value(staticValue); }
-  Value king_danger() const { return Value(kingDanger); }
+  Value static_value_margin() const { return Value(staticValueMargin); }
 
 private:
   uint32_t key32;
@@ -80,17 +114,16 @@ private:
   int16_t value16;
   int16_t depth16;
   int16_t staticValue;
-  int16_t kingDanger;
+  int16_t staticValueMargin;
 };
 
 
-/// This is the number of TTEntry slots for each position
+/// This is the number of TTEntry slots for each cluster
 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.
+/// TTCluster consists of ClusterSize number of TTEntries.
+/// Size of TTCluster must not be bigger than a cache line size.
+/// In case it is less, it should be padded to guarantee always aligned accesses.
 
 struct TTCluster {
   TTEntry data[ClusterSize];
@@ -98,11 +131,14 @@ struct TTCluster {
 
 
 /// The transposition table class. This is basically just a huge array
-/// containing TTEntry objects, and a few methods for writing new entries
+/// containing TTCluster objects, and a few methods for writing new entries
 /// and reading new ones.
 
 class TranspositionTable {
 
+  TranspositionTable(const TranspositionTable&);
+  TranspositionTable& operator=(const TranspositionTable&);
+
 public:
   TranspositionTable();
   ~TranspositionTable();
@@ -111,33 +147,34 @@ public:
   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[]);
-  void extract_pv(const Position& pos, Move bestMove, Move pv[], const int PLY_MAX);
-  int full() const;
   TTEntry* first_entry(const Key posKey) const;
+  void refresh(const TTEntry* tte) const;
 
 private:
-  // Be sure 'overwrites' is at least one cache line away
-  // from read only variables.
-  unsigned char pad_before[64 - sizeof(unsigned)];
-  unsigned overwrites; // heavy SMP read/write access here
-  unsigned char pad_after[64];
-
   size_t size;
   TTCluster* entries;
-  uint8_t generation;
+  uint8_t generation; // To properly compare, size must be smaller then TT stored value
 };
 
 extern TranspositionTable TT;
 
 
 /// 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.
+/// entry of a cluster given a position. The lowest order bits of the key
+/// are used to get the index of the cluster.
 
 inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
 
-  return entries[uint32_t(posKey) & (size - 1)].data;
+  return entries[((uint32_t)posKey) & (size - 1)].data;
+}
+
+
+/// TranspositionTable::refresh updates the 'generation' value of the TTEntry
+/// to avoid aging. Normally called after a TT hit, before to return.
+
+inline void TranspositionTable::refresh(const TTEntry* tte) const {
+
+  const_cast<TTEntry*>(tte)->set_generation(generation);
 }
 
 #endif // !defined(TT_H_INCLUDED)