Cache result register for quick cache information lookup

Abstract

Each level of cache within a memory hierarchy of a device is configured with a cache results register (CRR). The caches are coupled to a debugger interface via a peripheral bus. The device is placed in debug mode, and a debugger forwards a transaction address (TA) of a dummy transaction to the device. On receipt of the TA, the device processor forwards the TA via the system bus to the memory hierarchy to initiate an address lookup operation within each level of cache. For each cache in which the TA hits, the cache controller (debug) logic updates the cache's CRR with Hit, Way, and Index values, identifying the physical storage location within the particular cache at which the corresponding instruction/data is stored. The debugger retrieves information about the hit/miss status, the physical storage location and/or a copy of the data via direct requests over the peripheral bus.