-/// to be replaced later. A TTEntry t1 is considered to be more valuable than a
-/// TTEntry t2 if t1 is from the current search and t2 is from a previous search,
-/// or if the depth of t1 is bigger than the depth of t2.
+/// to be replaced later. TTEntry t1 is considered more valuable than TTEntry t2 if
+/// both are from the current search and the depth of t1 is greater than the depth of t2,
+/// or if t1 is from a previous search but its depth is at least 8 ply deeper than t2.