#if !defined MOVEPICK_H_INCLUDED
#define MOVEPICK_H_INCLUDED
-#include "history.h"
+#include <algorithm> // For std::max
+#include <cstring> // For memset
+
#include "position.h"
#include "search.h"
#include "types.h"
+/// The Stats struct stores moves statistics. According to the template parameter
+/// the class can store both History and Gains type statistics. 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. Entries are stored according only to moving piece and
+/// destination square, in particular two moves with different origin but same
+/// destination and same piece will be considered identical.
+template<bool Gain>
+struct Stats {
+
+ static const Value Max = Value(2000);
+
+ const Value* operator[](Piece p) const { return &table[p][0]; }
+ void clear() { memset(table, 0, sizeof(table)); }
+
+ 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:
+ Value table[PIECE_NB][SQUARE_NB];
+};
+
+typedef Stats<false> History;
+typedef Stats<true> Gains;
+
+
/// 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,
MovePicker(const Position&, Move, Depth, const History&, Search::Stack*, Value);
MovePicker(const Position&, Move, Depth, const History&, Square);
MovePicker(const Position&, Move, const History&, PieceType);
- Move next_move();
+ template<bool SpNode> Move next_move();
private:
void score_captures();
void score_noncaptures();
void score_evasions();
- void next_phase();
+ void generate_next();
const Position& pos;
- const History& H;
+ const History& Hist;
+ Search::Stack* ss;
Depth depth;
Move ttMove;
MoveStack killers[2];
Square recaptureSquare;
int captureThreshold, phase;
- MoveStack *curMove, *lastMove, *lastQuiet, *badCaptures;
+ MoveStack *cur, *end, *endQuiets, *endBadCaptures;
MoveStack moves[MAX_MOVES];
};