1. A method of simulating performed on a host system comprising: executing a functional component and a behavior prediction component in a simulator partitioned into the functional component, which models a target digital system's functionality, and the behavior prediction component, which predicts behavior of the target digital system; passing an output of the functional component to the behavior prediction component that uses that output to predict behavior; comparing information from the functional component output with behavior predicted by the behavior prediction component; and when the output of the functional component is inconsistent with the predicted behavior, providing information from the behavior prediction component to the functional component to correct the functional component output.