diff --git a/src/cpp/flann/algorithms/dist.h b/src/cpp/flann/algorithms/dist.h
index 4e6eb73..bbcdda1 100644
--- a/src/cpp/flann/algorithms/dist.h
+++ b/src/cpp/flann/algorithms/dist.h
@@ -519,7 +519,7 @@ struct HammingPopcnt
 #else
         HammingLUT lut;
         result = lut(reinterpret_cast<const unsigned char*> (a),
-                     reinterpret_cast<const unsigned char*> (b), size * sizeof(pop_t));
+                     reinterpret_cast<const unsigned char*> (b), size);
 #endif
         return result;
     }