Patent ID: 6374334
Filing Date: 2002-04-16
Classification: G06F

Abstract:
A data processing apparatus including a cache storing device, comprising:a cache storage data storing unit temporarily storing data to be stored in said cache storing device; and a cache controlling unit executing one of a first control operation causing a data read request to have precedence over a data storage request and a second control operation causing the data storage request to have precedence with priority over the data read request in contention with the data storage request and a state transition request occurs, wherein the state transition request is presented separately from the contention, and the state transition request results from at least canceling of the data read request, wherein the cache storage data storing unit outputs a control signal to the cache controlling unit, said control signal controlling whether the cache controlling unit executes the first control operation or the second control operation and based upon whether valid data is stored in the cache storage data storing unit.