Suspending procedures in simulation of a circuit design

When a wait statement is encountered in an HDL simulation, the simulation kernel executes functions corresponding to other processes while waiting for the wait to mature. However, the preservation of variables and states of each process and procedure in the call chain can be complex and inefficient. An embodiment of the present invention provides a method to suspend procedures in simulation of an HDL circuit design such that processes that call procedures containing wait statements are executed on a secondary runtime stack and can be suspended by saving the state of simulation and switching simulation execution to the primary runtime stack.