1 files changed, 34 insertions, 0 deletions
diff --git a/src/root.c b/src/root.c
index 9ead880..aa678b1 100755
--- a/src/root.c
+++ b/src/root.c
@@ -456,6 +456,13 @@ Return value:
     ASSERT(d);
     Trace("Null move cutoff rate: %5.3f percent.\n",
           ((n / d) * 100.0));
+    if (ctx->sCounters.egtb.uProbes > 0)
+    {
+        n = (double)(ctx->sCounters.egtb.uHits);
+        d = (double)(ctx->sCounters.egtb.uProbes);
+        Trace("EGTB probes: %u (%5.3f percent hit rate).\n",
+              ctx->sCounters.egtb.uProbes, ((n / d) * 100.0));
+    }
 #ifdef TEST_ENDGAME
     n = (double)(ctx->sCounters.tree.u64EndgamePruningSuccess);
     d = n + (double)(ctx->sCounters.tree.u64EndgamePruningFailures);
@@ -1092,6 +1099,33 @@ Return value:
         goto end;
     }
 
+    //
+    // If we're within Syzygy tablebase range at the root, let DTZ pick
+    // our move directly instead of relying on ordinary search.  WDL
+    // alone (used at interior nodes via RecognLookup/ProbeEGTB) has no
+    // notion of "closer to mate", so relying on it exclusively could
+    // shuffle forever inside a won position; DTZ is what actually
+    // drives progress towards mate / the fifty-move-rule reset.
+    //
+    if (TRUE == ProbeEGTBRoot(ctx, &mv, &iScore))
+    {
+        ctx->mvRootMove = mv;
+        ctx->iRootScore = iScore;
+        ctx->uRootDepth = 0;
+        ctx->sPlyInfo[0].PV[0] = mv;
+        ctx->sPlyInfo[0].PV[1] = NULLMOVE;
+        strcpy(ctx->szLastPV, "tb");
+        if (!g_Options.fPondering) {
+            Trace("TABLEBASE MOVE --> stop searching now\n");
+            g_MoveTimer.bvFlags |= TIMER_STOPPING;
+            g_MoveTimer.bvFlags |= TIMER_CURRENT_OBVIOUS;
+        } else {
+            g_MoveTimer.bvFlags |= TIMER_MOVE_IMMEDIATELY;
+            g_MoveTimer.bvFlags |= TIMER_CURRENT_OBVIOUS;
+        }
+        goto end;
+    }
+
     for (uDepth = 1;
          uDepth <= g_Options.uMaxDepth;
          uDepth++)