X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=src%2Fsearch.cpp;h=0fa78248f8f059e2fea2155e7c48ec81a9a688aa;hp=e6ffcb19f42cf73abcbb082f7a4789442ba36a06;hb=f967f1a25ecddcaaf0317f25fd50f6dc5e983d24;hpb=909e3adede210a124ed9ec4a2f21d73fda61c26d

diff --git a/src/search.cpp b/src/search.cpp
index e6ffcb19..0fa78248 100644
--- a/src/search.cpp
+++ b/src/search.cpp
@@ -257,7 +257,7 @@ namespace {
   int SearchStartTime, MaxNodes, MaxDepth, MaxSearchTime;
   int AbsoluteMaxSearchTime, ExtraSearchTime, ExactMaxTime;
   bool UseTimeManagement, InfiniteSearch, PonderSearch, StopOnPonderhit;
-  bool FirstRootMove, AbortSearch, Quit, AspirationFailLow;
+  bool FirstRootMove, AbortSearch, Quit, AspirationFailLow, ZugDetection;
 
   // Log file
   bool UseLogFile;
@@ -425,6 +425,7 @@ bool think(const Position& pos, bool infinite, bool ponder, int side_to_move,
   MultiPV                 = get_option_value_int("MultiPV");
   Chess960                = get_option_value_bool("UCI_Chess960");
   UseLogFile              = get_option_value_bool("Use Search Log");
+  ZugDetection            = get_option_value_bool("Zugzwang detection"); // To be removed after 1.7.1
 
   if (UseLogFile)
       LogFile.open(get_option_value_string("Search Log Filename").c_str(), std::ios::out | std::ios::app);
@@ -1388,9 +1389,7 @@ namespace {
             {
                 assert(value_to_tt(nullValue, ply) == nullValue);
 
-                // Special flag null values that are not zugzwang checked
-                ValueType vt = (depth < 6 * OnePly ? VALUE_TYPE_NS_LO : VALUE_TYPE_LOWER);
-                TT.store(posKey, nullValue, vt, depth, MOVE_NONE);
+                TT.store(posKey, nullValue, VALUE_TYPE_NS_LO, depth, MOVE_NONE);
                 return nullValue;
             }
         } else {
@@ -2317,7 +2316,7 @@ namespace {
 
     Value v = value_from_tt(tte->value(), ply);
 
-    return   (allowNullmove || !(tte->type() & VALUE_TYPE_NULL))
+    return   (allowNullmove || !(tte->type() & VALUE_TYPE_NULL) || !ZugDetection)
 
           && (   tte->depth() >= depth
               || v >= Max(value_mate_in(PLY_MAX), beta)