X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fmovepick.cpp;h=69b7cb3622d4ffdf49b114bc0ed86eb0e9cf9c67;hb=c5ec94d0f1b128fc2c691c7231663a345409d5cc;hp=72601bb3b3f23c4909e9bdf602d21b8a95ba440a;hpb=b8c5ea869ca80338f8b2fa6815fc92349b889750;p=stockfish

diff --git a/src/movepick.cpp b/src/movepick.cpp
index 72601bb3..69b7cb36 100644
--- a/src/movepick.cpp
+++ b/src/movepick.cpp
@@ -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) 2008-2012 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
@@ -35,6 +35,20 @@ namespace {
     STOP
   };
 
+  // Our insertion sort, guaranteed to be stable, as is needed
+  void insertion_sort(MoveStack* begin, MoveStack* end)
+  {
+    MoveStack tmp, *p, *q;
+
+    for (p = begin + 1; p < end; ++p)
+    {
+        tmp = *p;
+        for (q = p; q != begin && *(q-1) < tmp; --q)
+            *q = *(q-1);
+        *q = tmp;
+    }
+  }
+
   // Unary predicate used by std::partition to split positive scores from remaining
   // ones so to sort separately the two sets, and with the second sort delayed.
   inline bool has_positive_score(const MoveStack& ms) { return ms.score > 0; }
@@ -230,14 +244,14 @@ void MovePicker::generate_next() {
       endQuiets = end = generate<QUIETS>(pos, moves);
       score<QUIETS>();
       end = std::partition(cur, end, has_positive_score);
-      sort<MoveStack>(cur, end);
+      insertion_sort(cur, end);
       return;
 
   case QUIETS_2_S1:
       cur = end;
       end = endQuiets;
       if (depth >= 3 * ONE_PLY)
-          sort<MoveStack>(cur, end);
+          insertion_sort(cur, end);
       return;
 
   case BAD_CAPTURES_S1: