Patent ID: 7472225

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