All these tools generate models in C/C++. However SystemC is becoming increasingly popular, and is generated by all the tools as well. However the reference OSCI SystemC simulator carries a serious performance penalty, and in all cases the model is a SystemC wrapper for the top level ports around a plain C/C++ model.

The performance penalty of SystemC wrappers should be a consideration when generating cycle accurate models. Performance can be particularly adversely affected by any ports of wider than 64-bits. The reference SystemC simulator has a very low-performance implementation of such ports.