Streamlline reduction based on movecount

[stockfish] / src / movepick.h

diff --git a/src/movepick.h b/src/movepick.h
index 41a83604e09e99b768360ebb66b382d7510918a8..66fc1bdba4a929bd1680eeb5715a9786581881f2 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -35,6 +35,16 @@ struct StatBoards : public std::array<std::array<T, Size2>, Size1> {
     T* p = &(*this)[0][0];
     std::fill(p, p + sizeof(*this) / sizeof(*p), v);
   }
+
+  void update(T& entry, int bonus, const int D) {
+
+    assert(abs(bonus) <= D); // Ensure range is [-32 * D, 32 * D]
+    assert(abs(32 * D) < INT16_MAX); // Ensure we don't overflow
+
+    entry += bonus * 32 - entry * abs(bonus) / D;
+
+    assert(abs(entry) <= 32 * D);
+  }
 };
 
 /// ButterflyBoards are 2 tables (one for each color) indexed by the move's from
@@ -50,19 +60,7 @@ typedef StatBoards<PIECE_NB, SQUARE_NB> PieceToBoards;
 struct ButterflyHistory : public ButterflyBoards {
 
   void update(Color c, Move m, int bonus) {
-
-    const int D = 324;
-    auto& entry = (*this)[c][from_to(m)];
-
-    assert(abs(bonus) <= D); // Consistency check for below formula
-    assert([&]{
-      int v = entry + bonus * 32 - entry * abs(bonus) / D;
-      return INT16_MIN < v && v < INT16_MAX;
-    }());
-
-    entry += bonus * 32 - entry * abs(bonus) / D;
-
-    assert(abs(entry) <= 32 * D);
+    StatBoards::update((*this)[c][from_to(m)], bonus, 324);
   }
 };
 
@@ -70,19 +68,7 @@ struct ButterflyHistory : public ButterflyBoards {
 struct PieceToHistory : public PieceToBoards {
 
   void update(Piece pc, Square to, int bonus) {
-
-    const int D = 936;
-    auto& entry = (*this)[pc][to];
-
-    assert(abs(bonus) <= D); // Consistency check for below formula
-    assert([&]{
-      int v = entry + bonus * 32 - entry * abs(bonus) / D;
-      return INT16_MIN < v && v < INT16_MAX;
-    }());
-
-    entry += bonus * 32 - entry * abs(bonus) / D;
-
-    assert(abs(entry) <= 32 * D);
+    StatBoards::update((*this)[pc][to], bonus, 936);
   }
 };
 
@@ -108,7 +94,7 @@ public:
   MovePicker(const MovePicker&) = delete;
   MovePicker& operator=(const MovePicker&) = delete;
   MovePicker(const Position&, Move, Value);
-  MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Square);
+  MovePicker(const Position&, Move, Depth, const ButterflyHistory*, Square);
   MovePicker(const Position&, Move, Depth, const ButterflyHistory*, const PieceToHistory**, Move, Move*);
   Move next_move(bool skipQuiets = false);