Hi, I was previously involved with the Synthesis working group and supported efforts to facilitate a version of the SystemC data types that could be used for both simulation and synthesis. I found the AC datatypes to be very useful for both and in my last project where I worked on HLS synthesis, we decided to continue to use the AC datatypes for simulation even though we decided to drop synthesis efforts. The current SystemC types are difficult to use for simulation because of the lack of compile time sizing information and the very slow simulation times. The templated types allowed higher level templated functions to be written with predetermined and known sizes which were very important for system simulations. When complex arithmetic is needed these types become even more useful and also allow a framework where higher level simulation code can easily switch between floating point types and fixed point that is not possible with the current SystemC types.