Merge remote-tracking branch 'upstream/master' into HEAD

[stockfish] / src / syzygy / tbprobe.cpp

diff --git a/src/syzygy/tbprobe.cpp b/src/syzygy/tbprobe.cpp
index 831c8259c538c103b6d4eb4a15fe1577ca8fbd79..887160c7cfa3081b5ff8f521dcf755e2fac31363 100644 (file)
--- a/src/syzygy/tbprobe.cpp
+++ b/src/syzygy/tbprobe.cpp
@@ -76,7 +76,7 @@ int MapB1H1H7[SQUARE_NB];
 int MapA1D1D4[SQUARE_NB];
 int MapKK[10][SQUARE_NB]; // [MapA1D1D4][SQUARE_NB]
 
-int Binomial[6][SQUARE_NB];    // [k][n] k elements from a set of n elements
+int Binomial[7][SQUARE_NB];    // [k][n] k elements from a set of n elements
 int LeadPawnIdx[6][SQUARE_NB]; // [leadPawnsCnt][SQUARE_NB]
 int LeadPawnsSize[6][4];       // [leadPawnsCnt][FILE_A..FILE_D]
 
@@ -105,9 +105,6 @@ template<> inline void swap_endian<uint8_t>(uint8_t&) {}
 
 template<typename T, int LE> T number(void* addr)
 {
-    static const union { uint32_t i; char c[4]; } Le = { 0x01020304 };
-    static const bool IsLittleEndian = (Le.c[0] == 4);
-
     T v;
 
     if ((uintptr_t)addr & (alignof(T) - 1)) // Unaligned pointer (very rare)
@@ -1325,7 +1322,7 @@ void Tablebases::init(const std::string& paths) {
     Binomial[0][0] = 1;
 
     for (int n = 1; n < 64; n++) // Squares
-        for (int k = 0; k < 6 && k <= n; ++k) // Pieces
+        for (int k = 0; k < 7 && k <= n; ++k) // Pieces
             Binomial[k][n] =  (k > 0 ? Binomial[k - 1][n - 1] : 0)
                             + (k < n ? Binomial[k    ][n - 1] : 0);
 
@@ -1539,6 +1536,14 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) {
             WDLScore wdl = -probe_wdl(pos, &result);
             dtz = dtz_before_zeroing(wdl);
         }
+        else if (pos.is_draw(1))
+        {
+            // In case a root move leads to a draw by repetition or
+            // 50-move rule, we set dtz to zero. Note: since we are
+            // only 1 ply from the root, this must be a true 3-fold
+            // repetition inside the game history.
+            dtz = 0;
+        }
         else
         {
             // Otherwise, take dtz for the new position and correct by 1 ply
@@ -1589,6 +1594,7 @@ bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves) {
 
     ProbeState result;
     StateInfo st;
+    WDLScore wdl;
 
     bool rule50 = Options["Syzygy50MoveRule"];
 
@@ -1597,7 +1603,10 @@ bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves) {
     {
         pos.do_move(m.pv[0], st);
 
-        WDLScore wdl = -probe_wdl(pos, &result);
+        if (pos.is_draw(1))
+            wdl = WDLDraw;
+        else
+            wdl = -probe_wdl(pos, &result);
 
         pos.undo_move(m.pv[0]);