From: Marco Costalba <mcostalba@gmail.com>
Date: Sat, 2 May 2009 12:57:52 +0000 (+0200)
Subject: Change TT interface to ask directly for a position key
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=aabd526f7c9cec1d1f6a8f7da738311487aa42b8

Change TT interface to ask directly for a position key

Instead of a position because the key is all that we
need.

Interface is more clear and also very very little bit faster.

No functional change.

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

diff --git a/src/search.cpp b/src/search.cpp
index 3838375f..22bfe8d6 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -1055,7 +1055,7 @@ namespace {
 
     // Transposition table lookup. At PV nodes, we don't use the TT for
     // pruning, but only for move ordering.
-    const TTEntry* tte = TT.retrieve(pos);
+    const TTEntry* tte = TT.retrieve(pos.get_key());
     Move ttMove = (tte ? tte->move() : MOVE_NONE);
 
     // Go with internal iterative deepening if we don't have a TT move
@@ -1188,7 +1188,7 @@ namespace {
         return bestValue;
 
     if (bestValue <= oldAlpha)
-        TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
 
     else if (bestValue >= beta)
     {
@@ -1199,10 +1199,10 @@ namespace {
             update_history(pos, m, depth, movesSearched, moveCount);
             update_killers(m, ss[ply]);
         }
-        TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
     }
     else
-        TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EXACT, depth, ss[ply].pv[ply]);
 
     return bestValue;
   }
@@ -1244,7 +1244,7 @@ namespace {
         return beta - 1;
 
     // Transposition table lookup
-    const TTEntry* tte = TT.retrieve(pos);
+    const TTEntry* tte = TT.retrieve(pos.get_key());
     Move ttMove = (tte ? tte->move() : MOVE_NONE);
 
     if (tte && ok_to_use_TT(tte, depth, beta, ply))
@@ -1449,7 +1449,7 @@ namespace {
         return bestValue;
 
     if (bestValue < beta)
-        TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, depth, MOVE_NONE);
     else
     {
         BetaCounter.add(pos.side_to_move(), depth, threadID);
@@ -1459,7 +1459,7 @@ namespace {
             update_history(pos, m, depth, movesSearched, moveCount);
             update_killers(m, ss[ply]);
         }
-        TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
+        TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, depth, m);
     }
 
     assert(bestValue > -VALUE_INFINITE && bestValue < VALUE_INFINITE);
@@ -1497,7 +1497,7 @@ namespace {
     bool pvNode = (beta - alpha != 1);
     if (!pvNode)
     {
-        tte = TT.retrieve(pos);
+        tte = TT.retrieve(pos.get_key());
         if (tte && ok_to_use_TT(tte, depth, beta, ply))
         {
             assert(tte->type() != VALUE_TYPE_EVAL);
@@ -1538,7 +1538,7 @@ namespace {
     {
         // Store the score to avoid a future costly evaluation() call
         if (!isCheck && !tte && ei.futilityMargin == 0)
-            TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
+            TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_EVAL, Depth(-127*OnePly), MOVE_NONE);
 
         return bestValue;
     }
@@ -1631,9 +1631,9 @@ namespace {
     {
         Depth d = (depth == Depth(0) ? Depth(0) : Depth(-1));
         if (bestValue < beta)
-            TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE);
+            TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_UPPER, d, MOVE_NONE);
         else
-            TT.store(pos, value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, m);
+            TT.store(pos.get_key(), value_to_tt(bestValue, ply), VALUE_TYPE_LOWER, d, m);
     }
 
     // Update killers only for good check moves
diff --git a/src/tt.cpp b/src/tt.cpp
index fe222106..83eaf800 100644
--- a/src/tt.cpp
+++ b/src/tt.cpp
@@ -97,14 +97,14 @@ void TranspositionTable::clear() {
 /// is bigger than the depth of t2. A TTEntry of type VALUE_TYPE_EVAL
 /// never replaces another entry for the same position.
 
-void TranspositionTable::store(const Position& p, Value v, ValueType t, Depth d, Move m) {
+void TranspositionTable::store(const Key posKey, Value v, ValueType t, Depth d, Move m) {
 
   TTEntry *tte, *replace;
 
-  tte = replace = first_entry(p);
+  tte = replace = first_entry(posKey);
   for (int i = 0; i < 4; i++, tte++)
   {
-      if (!tte->key() || tte->key() == p.get_key()) // empty or overwrite old
+      if (!tte->key() || tte->key() == posKey) // empty or overwrite old
       {
           // Do not overwrite when new type is VALUE_TYPE_EVAL
           if (tte->key() && t == VALUE_TYPE_EVAL)
@@ -113,7 +113,7 @@ void TranspositionTable::store(const Position& p, Value v, ValueType t, Depth d,
           if (m == MOVE_NONE)
               m = tte->move();
 
-          *tte = TTEntry(p.get_key(), v, t, d, m, generation);
+          *tte = TTEntry(posKey, v, t, d, m, generation);
           return;
       }
       else if (i == 0)  // replace would be a no-op in this common case
@@ -126,7 +126,7 @@ void TranspositionTable::store(const Position& p, Value v, ValueType t, Depth d,
       if (c1 + c2 + c3 > 0)
           replace = tte;
   }
-  *replace = TTEntry(p.get_key(), v, t, d, m, generation);
+  *replace = TTEntry(posKey, v, t, d, m, generation);
   writes++;
 }
 
@@ -135,12 +135,12 @@ void TranspositionTable::store(const Position& p, Value v, ValueType t, Depth d,
 /// transposition table. Returns a pointer to the TTEntry or NULL
 /// if position is not found.
 
-TTEntry* TranspositionTable::retrieve(const Position& pos) const {
+TTEntry* TranspositionTable::retrieve(const Key posKey) const {
 
-  TTEntry *tte = first_entry(pos);
+  TTEntry *tte = first_entry(posKey);
 
   for (int i = 0; i < 4; i++, tte++)
-      if (tte->key() == pos.get_key())
+      if (tte->key() == posKey)
           return tte;
 
   return NULL;
@@ -150,9 +150,9 @@ TTEntry* TranspositionTable::retrieve(const Position& pos) const {
 /// TranspositionTable::first_entry returns a pointer to the first
 /// entry of a cluster given a position.
 
-inline TTEntry* TranspositionTable::first_entry(const Position& pos) const {
+inline TTEntry* TranspositionTable::first_entry(const Key posKey) const {
 
-  return entries + (int(pos.get_key() & (size - 1)) << 2);
+  return entries + (int(posKey & (size - 1)) << 2);
 }
 
 /// TranspositionTable::new_search() is called at the beginning of every new
@@ -179,7 +179,7 @@ void TranspositionTable::insert_pv(const Position& pos, Move pv[]) {
 
   for (int i = 0; pv[i] != MOVE_NONE; i++)
   {
-      store(p, VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
+      store(p.get_key(), VALUE_NONE, VALUE_TYPE_NONE, Depth(-127*OnePly), pv[i]);
       p.do_move(pv[i], st);
   }
 }
diff --git a/src/tt.h b/src/tt.h
index 0918e3e8..e8dc021b 100644
--- a/src/tt.h
+++ b/src/tt.h
@@ -83,14 +83,14 @@ public:
   ~TranspositionTable();
   void set_size(unsigned mbSize);
   void clear();
-  void store(const Position& pos, Value v, ValueType type, Depth d, Move m);
-  TTEntry* retrieve(const Position& pos) const;
+  void store(const Key posKey, Value v, ValueType type, Depth d, Move m);
+  TTEntry* retrieve(const Key posKey) const;
   void new_search();
   void insert_pv(const Position& pos, Move pv[]);
   int full() const;
 
 private:
-  inline TTEntry* first_entry(const Position& pos) const;
+  inline TTEntry* first_entry(const Key posKey) const;
 
   unsigned size, writes;
   TTEntry* entries;