Speed up sorting of non-captures

[stockfish] / src / move.h

diff --git a/src/move.h b/src/move.h
index ad7c8378c3a8da003a034d77cb3c4e9529b68a9e..9702d9fbebcfbd0ab6a9088b3889f4807eb754c2 100644 (file)
--- a/src/move.h
+++ b/src/move.h
@@ -1,18 +1,18 @@
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)
 /*
   Stockfish, a UCI chess playing engine derived from Glaurung 2.1
   Copyright (C) 2004-2008 Tord Romstad (Glaurung author)

-  Copyright (C) 2008 Marco Costalba
+  Copyright (C) 2008-2009 Marco Costalba

 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
 
   Stockfish is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

-  
+

   Stockfish is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   Stockfish is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

-  
+

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


@@ -38,10 +38,22 @@
 
 class Position;
 
 
 class Position;
 

+/// A move needs 17 bits to be stored
+///
+/// bit  0- 5: destination square (from 0 to 63)
+/// bit  6-11: origin square (from 0 to 63)
+/// bit 12-14: promotion piece type
+/// bit    15: en passant flag
+/// bit    16: castle flag
+///
+/// Special cases are MOVE_NONE and MOVE_NULL. We can sneak these in
+/// because in any normal move destination square is always different
+/// from origin square while MOVE_NONE and MOVE_NULL have the same
+/// origin and destination square, 0 and 1 respectively.
+

 enum Move {
   MOVE_NONE = 0,
 enum Move {
   MOVE_NONE = 0,

-  MOVE_NULL = 65, 
-  MOVE_MAX = 0xFFFFFF
+  MOVE_NULL = 65

 };
 
 
 };
 
 


@@ -50,29 +62,134 @@ struct MoveStack {
   int score;
 };
 
   int score;
 };
 

+// 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; }
+
+// 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 Square move_from(Move m) {
 
 ////
 //// Inline functions
 ////
 
 inline Square move_from(Move m) {

-  return Square((int(m) >> 6) & 077);
+  return Square((int(m) >> 6) & 0x3F);

 }
 
 inline Square move_to(Move m) {
 }
 
 inline Square move_to(Move m) {

-  return Square(m & 077);
+  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 bool move_is_ep(Move m) {
-  return bool((int(m) >> 15) & 1);
+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 bool move_is_castle(Move m) {
-  return bool((int(m) >> 16) & 1);
+inline int move_is_castle(Move m) {
+  return m & (1 << 16);

 }
 
 inline bool move_is_short_castle(Move m) {
 }
 
 inline bool move_is_short_castle(Move m) {


@@ -104,7 +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);