System and method for checking data accumulators for consistency

Abstract

A system and method checks whether messages exchanged between first and second modules are being lost or gained. The first module has a request counter and a capture register. The second module has a request accumulator and a capture register. As the first module issues and receives messages, it increments and decrements its request counter. As the second module receives and issues messages, it increments and decrements its request accumulator. To check for lost or gained messages, the first module copies the current value of its request counter into its capture register, and issues a marker to the second module. The first module decrements its capture register in response to receiving post-marker messages, but does not increment its capture register. Upon receipt of the marker, the second module copies the current value of its request accumulator into its capture register, and returns the marker to the first module. When the first module receives the marker, it stops decrementing its capture register. The two capture registers should then contain the same values provided that no messages have been lost or gained.