Simplify 50 move rule condition

We never reach a position where rule50 > 100.
When rule50 == 100, it's either draw or mate and
there is no way search could go deeper.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

diff --git a/src/position.cpp b/src/position.cpp
index ae28805..aac03eb 100644 (file)
--- a/src/position.cpp
+++ b/src/position.cpp
@@ -1691,7 +1691,7 @@ bool Position::is_draw() const {
       return true;
 
   // Draw by the 50 moves rule?
-  if (st->rule50 > 99 && (st->rule50 > 100 || !is_mate()))
+  if (st->rule50 > 99 && !is_mate())
       return true;
 
   // Draw by repetition?