This paper presents a new approach in domain of high level digital circuits simulation and modeling that benefits from high level mathematical environment delivered by MATLAB. It allows to integrate design process and directly verify obtained results with mathematical formulas or complex operations that are not available in standard HDL languages. A part of HDL code can be placed for verification purposes inside the advanced mathematical model or can execute complex calculation. Paper presents problems that are introduced by hybrid simulation and modeling environment concerning data representation, simulation process and optimal performance.