State machine based bus cycle completion checking in a bus bridge

Abstract

In a computer system having a bus bridge connecting a plurality of system buses, a methodology for checking completion of a bus cycle in a bus bridge verification system is disclosed. The methodology verifies that the bus bridge is asserting proper signals for each bus protocol. As each bus cycle begins, a state machine object corresponding to that bus cycle is instantiated and each byte of said bus cycle state machine object is checked for resolution. A stimulator object may provide a bus stimulus to said bus cycle state machine object which may update its states in response thereto. Upon transitioning into its holding state, the bus cycle state machine object may verify that each byte of its transaction is accounted for and has been routed to the proper destination. The state machine object for a particular bus cycle may contain storage for that bus cycle's properties such as clock cycle number, cycle address, cycle type, cycle data and the status of byte enables. This methodology maintains a static bus cycle object that can determine if its transaction has been resolved. The cycle-based approach avoids instances of false failures arising from address remapping, byte merging or byte collapsing.