Rename MoveStack to ExtMove

[stockfish] / src / movepick.h

diff --git a/src/movepick.h b/src/movepick.h
index 34329582d18854ed989a87f8119a824baec0db85..60a44a6fac71ee3e24b5aab6bb782be7a4ecd287 100644 (file)
--- a/src/movepick.h
+++ b/src/movepick.h
@@ -1,7 +1,7 @@
 /*
   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
+  Copyright (C) 2008-2013 Marco Costalba, Joona Kiiski, Tord Romstad
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
@@ -20,46 +20,91 @@
 #if !defined MOVEPICK_H_INCLUDED
 #define MOVEPICK_H_INCLUDED
 
-#include "history.h"
+#include <algorithm> // For std::max
+#include <cstring>   // For std::memset
+
+#include "movegen.h"
 #include "position.h"
+#include "search.h"
 #include "types.h"
 
-struct SearchStack;
 
-/// MovePicker is a class which is used to pick one pseudo legal move at a time
-/// from the current position. It is initialized with a Position object and a few
-/// moves we have reason to believe are good. The most important method is
-/// MovePicker::get_next_move(), which returns a new pseudo legal move each time
-/// it is called, until there are no moves left, when MOVE_NONE is returned.
-/// In order to improve the efficiency of the alpha beta algorithm, MovePicker
-/// attempts to return the moves which are most likely to get a cut-off first.
+/// The Stats struct stores moves statistics. According to the template parameter
+/// the class can store History, Gains and Countermoves. History records how often
+/// different moves have been successful or unsuccessful during the current search
+/// and is used for reduction and move ordering decisions. Gains records the move's
+/// best evaluation gain from one ply to the next and is used for pruning decisions.
+/// Countermoves store the move that refute a previous one. Entries are stored
+/// according only to moving piece and destination square, hence two moves with
+/// different origin but same destination and piece will be considered identical.
+template<bool Gain, typename T>
+struct Stats {
+
+  static const Value Max = Value(2000);
+
+  const T* operator[](Piece p) const { return table[p]; }
+  void clear() { std::memset(table, 0, sizeof(table)); }
+
+  void update(Piece p, Square to, Move m) {
+
+    if (m == table[p][to].first)
+        return;
+
+    table[p][to].second = table[p][to].first;
+    table[p][to].first = m;
+  }
+
+  void update(Piece p, Square to, Value v) {
+
+    if (Gain)
+        table[p][to] = std::max(v, table[p][to] - 1);
+
+    else if (abs(table[p][to] + v) < Max)
+        table[p][to] +=  v;
+  }
+
+private:
+  T table[PIECE_NB][SQUARE_NB];
+};
+
+typedef Stats< true, Value> GainsStats;
+typedef Stats<false, Value> HistoryStats;
+typedef Stats<false, std::pair<Move, Move> > CountermovesStats;
+
+
+/// MovePicker class is used to pick one pseudo legal move at a time from the
+/// current position. The most important method is next_move(), which returns a
+/// new pseudo legal move each time it is called, until there are no moves left,
+/// when MOVE_NONE is returned. In order to improve the efficiency of the alpha
+/// beta algorithm, MovePicker attempts to return the moves which are most likely
+/// to get a cut-off first.
 
 class MovePicker {
 
   MovePicker& operator=(const MovePicker&); // Silence a warning under MSVC
 
 public:
-  MovePicker(const Position&, Move, Depth, const History&, SearchStack*, Value);
-  MovePicker(const Position&, Move, Depth, const History&, Square recaptureSq);
-  MovePicker(const Position&, Move, const History&, PieceType parentCapture);
-  Move get_next_move();
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, Square);
+  MovePicker(const Position&, Move, const HistoryStats&, PieceType);
+  MovePicker(const Position&, Move, Depth, const HistoryStats&, Move*, Search::Stack*, Value);
+
+  template<bool SpNode> Move next_move();
 
 private:
-  void score_captures();
-  void score_noncaptures();
-  void score_evasions();
-  void go_next_phase();
+  template<GenType> void score();
+  void generate_next();
 
   const Position& pos;
-  const History& H;
+  const HistoryStats& history;
+  Search::Stack* ss;
+  Move* countermoves;
   Depth depth;
   Move ttMove;
-  MoveStack killers[2];
+  ExtMove killers[4];
   Square recaptureSquare;
   int captureThreshold, phase;
-  const uint8_t* phasePtr;
-  MoveStack *curMove, *lastMove, *lastNonCapture, *badCaptures;
-  MoveStack moves[MAX_MOVES];
+  ExtMove *cur, *end, *endQuiets, *endBadCaptures;
+  ExtMove moves[MAX_MOVES];
 };
 
 #endif // !defined(MOVEPICK_H_INCLUDED)