Abstract: A data processing apparatus and a method for caching data values in data processing apparatus comprising a level one cache and a level two cache is disclosed. Both the level one cache and the level two cache are operable to store the data values. The method comprises the steps of: a) receiving a transaction request in which a data transaction relating to a data value is requested to occur, the transaction request including cache policy attributes associated with an address of the data value; and b) determining from the cache policy attributes whether or not the data value can be stored by the level one cache and the level two cache and, if so, in which one of the level one cache and the level two cache the data value is to be stored in order to ensure that the data value is prevented from being stored in both the level one cache and the level two cache.

Abstract: A data processing apparatus operable to access data values, each data value being associated with a respective address value is disclosed.

Abstract: The present invention provides a data processing apparatus and method for storing trace data. The data processing apparatus comprises a bus operable to interconnect a number of master devices and slave devices to enable transactions to be routed between the master and slave devices. Each master device is able to initiate a transaction, with the transaction specifying a transaction address. A cache is interposed between at least one of the master devices and the bus and is operable to receive the transaction issued by that master device. The cache has a cache memory and a cache controller operable to control access to the cache memory. The cache controller comprises caching logic operable to selectively cache a data value of the transaction at a location in the cache memory chosen dependent on the transaction address. Control storage is provided identifying a trace address range specifying a trace region.

Abstract: A data processing apparatus controls cross-triggering of diagnostic processes on a plurality of processing devices. The data processing apparatus comprises a routing module having a plurality of broadcast channels, one or more of the broadcast channels being operable to indicate the occurrence of a diagnostic event on one or more of the plurality of processing devices. The data processing apparatus also comprises an mapping module associated with a corresponding processing device. The interface module programmably asserts diagnostic event signals from the associated processing device to one or more of the plurality of broadcast channels and programmably retrieves diagnostic events signals from processing devices other than the associated processing device from one or more of the plurality of broadcast channels. The retrieved diagnostic event data is used to facilitate triggering of a diagnostic process on the associated processing device in dependence upon said retrieved diagnostic event data.