diff --git a/CPP/register_modeling/example_project/utils/BitField.hpp b/CPP/register_modeling/example_project/utils/BitField.hpp
index e89d2a8..9dc87d8 100644
--- a/CPP/register_modeling/example_project/utils/BitField.hpp
+++ b/CPP/register_modeling/example_project/utils/BitField.hpp
@@ -47,8 +47,9 @@ struct BitField
      */
     BitField& operator =(T v)
     {
+        //TODO: test = problem with |= instead of =
         // mask creation for v : https://stackoverflow.com/questions/1392059/algorithm-to-generate-bit-mask
-        _raw = ((v & ((1ULL << SIZE)-1)) << START) ;
+        _raw |= ((v & ((1ULL << SIZE)-1)) << START) ;
         return *this;
     }