Copy killers in the movepicker

[stockfish] / src / movepick.h

diff --git a/src/movepick.h b/src/movepick.h
index ec8b15541ede4194794f22ee9439ddd601eaad43..ae2ee3814ea838acf096ef3c73d3135892b16607 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -21,7 +21,6 @@
 #ifndef MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 
-#include <algorithm> // For std::max
 #include <cstring>   // For std::memset
 
 #include "movegen.h"
@@ -33,24 +32,25 @@
 /// during the current search, and is used for reduction and move ordering decisions.
 struct HistoryStats {
 
-  static const Value Max = Value(1 << 28);
+  static const int Max = 1 << 28;
 
-  Value get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
+  int get(Color c, Move m) const { return table[c][from_sq(m)][to_sq(m)]; }
   void clear() { std::memset(table, 0, sizeof(table)); }
-  void update(Color c, Move m, Value v) {
-
-    if (abs(int(v)) >= 324)
-        return;
+  void update(Color c, Move m, int v) {
 
     Square from = from_sq(m);
     Square to = to_sq(m);
 
-    table[c][from][to] -= table[c][from][to] * abs(int(v)) / 324;
+    const int D = 324;
+
+    assert(abs(int(v)) <= D); // Consistency check for below formula
+
+    table[c][from][to] -= table[c][from][to] * abs(int(v)) / D;
     table[c][from][to] += int(v) * 32;
   }
 
 private:
-  Value table[COLOR_NB][SQUARE_NB][SQUARE_NB];
+  int table[COLOR_NB][SQUARE_NB][SQUARE_NB];
 };
 
 
@@ -60,18 +60,19 @@ private:
 /// Entries are stored using only the moving piece and destination square, hence
 /// two moves with different origin but same destination and piece will be
 /// considered identical.
-template<typename T, bool CM = false>
+template<typename T>
 struct Stats {
   const T* operator[](Piece pc) const { return table[pc]; }
   T* operator[](Piece pc) { return table[pc]; }
   void clear() { std::memset(table, 0, sizeof(table)); }
   void update(Piece pc, Square to, Move m) { table[pc][to] = m; }
-  void update(Piece pc, Square to, Value v) {
+  void update(Piece pc, Square to, int v) {
+
+    const int D = 936;
 
-    if (abs(int(v)) >= 324)
-        return;
+    assert(abs(int(v)) <= D); // Consistency check for below formula
 
-    table[pc][to] -= table[pc][to] * abs(int(v)) / (CM ? 936 : 324);
+    table[pc][to] -= table[pc][to] * abs(int(v)) / D;
     table[pc][to] += int(v) * 32;
   }
 
@@ -80,7 +81,7 @@ private:
 };
 
 typedef Stats<Move> MoveStats;
-typedef Stats<Value, true> CounterMoveStats;
+typedef Stats<int> CounterMoveStats;
 typedef Stats<CounterMoveStats> CounterMoveHistoryStats;
 
 
@@ -101,7 +102,7 @@ public:
   MovePicker(const Position&, Move, Depth, Square);
   MovePicker(const Position&, Move, Depth, Search::Stack*);
 
-  Move next_move();
+  Move next_move(bool skipQuiets = false);
 
 private:
   template<GenType> void score();
@@ -110,6 +111,7 @@ private:
 
   const Position& pos;
   const Search::Stack* ss;
+  Move killers[2];
   Move countermove;
   Depth depth;
   Move ttMove;