Hi,
Can someone tell me what is the exact difference between cycle based simulators and event based simulators with some example?
You might want to read these two rather old articles
http://www.edn.com/design/systems-design/4351824/EDN-Access--07-04-96-Digital-logic-simulation-event-driven-cycle-based-and-home-brewe
http://www.ohio.edu/people/starzykj/webcad/class/ee616/slides/Berkeley/lec13.ppt
You don’t see cycle-based simulators much anymore because it’s rare to have a system with a single synchronous clock. As soon as you introduce a few different clocks, and/or asynchronous signals, the performance advantage of a cycle-based simulator goes down rapidly.
However, many techniques for optimizing cycle based simulation have work their way into event-based simulators. For example, all of the combinational logic between a set of synchronous registers will get optimized to evaluate as a single evaluation event, instead of propagating events between each piece of the combinational logic in a ripple fashion.