Speed up sorting of non-captures

[stockfish] / src / move.h

diff --git a/src/move.h b/src/move.h
index 6a5678f02c6f48a34a71a377ab94ef73b5886fbd..9702d9fbebcfbd0ab6a9088b3889f4807eb754c2 100644 (file)
--- a/src/move.h
+++ b/src/move.h
@@ -62,9 +62,103 @@ struct MoveStack {
   int score;
 };
 
   int score;
 };
 

-// Note that operator< is set up such that std::sort() will sort in descending order
+// Note that operator< is set up such that sorting will be in descending order

 inline bool operator<(const MoveStack& f, const MoveStack& s) { return s.score < f.score; }
 
 inline bool operator<(const MoveStack& f, const MoveStack& s) { return s.score < f.score; }
 

+// An helper insertion sort implementation
+template<typename T>
+inline void insertion_sort(T* firstMove, T* lastMove)
+{
+    T value;
+    T *cur, *p, *d;
+
+    if (firstMove != lastMove)
+        for (cur = firstMove + 1; cur != lastMove; cur++)
+        {
+            p = d = cur;
+            value = *p--;
+            if (value < *p)
+            {
+                do *d = *p;
+                while (--d != firstMove && value < *--p);
+                *d = value;
+            }
+        }
+}
+
+// Our dedicated sort in range [firstMove, lastMove), it is well
+// tuned for non-captures where we have a lot of zero scored moves.
+template<typename T>
+inline void sort_moves(T* firstMove, T* lastMove)
+{
+    T tmp;
+    T *p, *d;
+
+    d = lastMove;
+    p = firstMove - 1;
+
+    d->score = -1; // right guard
+
+    // Split positives vs non-positives
+    do {
+        while ((++p)->score > 0);
+
+        if (p != d)
+        {
+            while (--d != p && d->score <= 0);
+
+            tmp = *p;
+            *p = *d;
+            *d = tmp;
+        }
+
+    } while (p != d);
+
+    // Sort positives
+    insertion_sort<T>(firstMove, p);
+
+    d = lastMove;
+    p--;
+
+    // Split zero vs negatives
+    do {
+        while ((++p)->score == 0);
+
+        if (p != d)
+        {
+            while (--d != p && d->score < 0);
+
+            tmp = *p;
+            *p = *d;
+            *d = tmp;
+        }
+
+    } while (p != d);
+
+    // Sort negatives
+    insertion_sort<T>(p, lastMove);
+}
+
+// Picks up the best move in range [curMove, lastMove), one per cycle.
+// It is faster then sorting all the moves in advance when moves are few,
+// as normally are the possible captures. Note that is not a stable alghoritm.
+template<typename T>
+inline T pick_best(T* curMove, T* lastMove)
+{
+    T bestMove, tmp;
+
+    bestMove = *curMove;
+    while (++curMove != lastMove)
+    {
+        if (*curMove < bestMove)
+        {
+            tmp = *curMove;
+            *curMove = bestMove;
+            bestMove = tmp;
+        }
+    }
+    return bestMove;
+}

 
 ////
 //// Inline functions
 
 ////
 //// Inline functions


@@ -78,10 +172,18 @@ inline Square move_to(Move m) {
   return Square(m & 0x3F);
 }
 
   return Square(m & 0x3F);
 }
 

-inline PieceType move_promotion(Move m) {
+inline PieceType move_promotion_piece(Move m) {

   return PieceType((int(m) >> 12) & 7);
 }
 
   return PieceType((int(m) >> 12) & 7);
 }
 

+inline int move_is_special(Move m) {
+  return m & (0x1F << 12);
+}
+
+inline int move_is_promotion(Move m) {
+  return m & (7 << 12);
+}
+

 inline int move_is_ep(Move m) {
   return m & (1 << 15);
 }
 inline int move_is_ep(Move m) {
   return m & (1 << 15);
 }


@@ -119,7 +221,7 @@ inline Move make_ep_move(Square from, Square to) {
 //// Prototypes
 ////
 
 //// Prototypes
 ////
 

-extern std::ostream &operator << (std::ostream &os, Move m);
+extern std::ostream& operator<<(std::ostream &os, Move m);

 extern Move move_from_string(const Position &pos, const std::string &str);
 extern const std::string move_to_string(Move m);
 extern bool move_is_ok(Move m);
 extern Move move_from_string(const Position &pos, const std::string &str);
 extern const std::string move_to_string(Move m);
 extern bool move_is_ok(Move m);