In order to combine the power of simulation-based and formal techniques, semi-formal methods have been widely explored. Among these methods, abstraction-guided simulation is a quite promising one. In this paper, the authors propose an abstraction-guided simulation approach aiming to cover hard-to-reach states in functional verification of microprocessors. A Markov model is constructed utilizing the high level functional specification, i.e. ISA. Such model integrates vector correlations. Furthermore, several strategies utilizing abstraction information are proposed as an effective guidance to the test generation.