X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=src%2Fsyzygy%2Ftbprobe.cpp;h=f2de036df4a540efe6921fce0941bfd75d7ef22c;hb=79c5f3a69247b44ee6362a3d9236cd9bc048c5f5;hp=43af89f0ec9f011b986d3b3f9d4bd7d68ab2edca;hpb=9be2977da7921aedfd3215f1f4b5f522359effa0;p=stockfish

diff --git a/src/syzygy/tbprobe.cpp b/src/syzygy/tbprobe.cpp
index 43af89f0..f2de036d 100644
--- a/src/syzygy/tbprobe.cpp
+++ b/src/syzygy/tbprobe.cpp
@@ -59,6 +59,7 @@ namespace Stockfish {
 namespace {
 
 constexpr int TBPIECES = 7; // Max number of supported pieces
+constexpr int MAX_DTZ = 1 << 18; // Max DTZ supported, large enough to deal with the syzygy TB limit.
 
 enum { BigEndian, LittleEndian };
 enum TBType { WDL, DTZ }; // Used as template parameter
@@ -1522,7 +1523,7 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) {
     // Check whether a position was repeated since the last zeroing move.
     bool rep = pos.has_repeated();
 
-    int dtz, bound = Options["Syzygy50MoveRule"] ? 900 : 1;
+    int dtz, bound = Options["Syzygy50MoveRule"] ? (MAX_DTZ - 100) : 1;
 
     // Probe and rank each move
     for (auto& m : rootMoves)
@@ -1565,8 +1566,8 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) {
 
         // Better moves are ranked higher. Certain wins are ranked equally.
         // Losing moves are ranked equally unless a 50-move draw is in sight.
-        int r =  dtz > 0 ? (dtz + cnt50 <= 99 && !rep ? 1000 : 1000 - (dtz + cnt50))
-               : dtz < 0 ? (-dtz * 2 + cnt50 < 100 ? -1000 : -1000 + (-dtz + cnt50))
+        int r =  dtz > 0 ? (dtz + cnt50 <= 99 && !rep ? MAX_DTZ : MAX_DTZ - (dtz + cnt50))
+               : dtz < 0 ? (-dtz * 2 + cnt50 < 100 ? -MAX_DTZ : -MAX_DTZ + (-dtz + cnt50))
                : 0;
         m.tbRank = r;
 
@@ -1574,9 +1575,9 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) {
         // 1 cp to cursed wins and let it grow to 49 cp as the positions gets
         // closer to a real win.
         m.tbScore =  r >= bound ? VALUE_MATE - MAX_PLY - 1
-                   : r >  0     ? Value((std::max( 3, r - 800) * int(PawnValueEg)) / 200)
+                   : r >  0     ? Value((std::max( 3, r - (MAX_DTZ - 200)) * int(PawnValueEg)) / 200)
                    : r == 0     ? VALUE_DRAW
-                   : r > -bound ? Value((std::min(-3, r + 800) * int(PawnValueEg)) / 200)
+                   : r > -bound ? Value((std::min(-3, r + (MAX_DTZ - 200)) * int(PawnValueEg)) / 200)
                    :             -VALUE_MATE + MAX_PLY + 1;
     }
 
@@ -1590,7 +1591,7 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves) {
 // A return value false indicates that not all probes were successful.
 bool Tablebases::root_probe_wdl(Position& pos, Search::RootMoves& rootMoves) {
 
-    static const int WDL_to_rank[] = { -1000, -899, 0, 899, 1000 };
+    static const int WDL_to_rank[] = { -MAX_DTZ, -MAX_DTZ + 101, 0, MAX_DTZ - 101, MAX_DTZ };
 
     ProbeState result;
     StateInfo st;