Patent ID: 9471493
Filing Date: 2016-10-18
CPC Classification: G06F

Claim Text:
1. A data processing apparatus comprising: a temporary data store configured to store data items retrieved from a memory, wherein the temporary data store has plural data storage locations configured to store the data items and the temporary data store is configured to select a storage location of the plural data storage locations in which to store a newly retrieved data item according to a predetermined circular sequence of the plural data storage locations; an index data store configured to store index items corresponding to the data items stored in the temporary data store, wherein presence of a valid index item in the index data store is indicative of a corresponding data item in the temporary data store; and invalidation control circuitry configured to perform a rolling invalidation process with respect to the index items stored in the index data store, wherein the rolling invalidation process comprises sequentially processing the index items stored in the index data store and selectively marking the index items as invalid according to a predetermined criterion, wherein the invalidation control circuitry is configured, when performing the rolling invalidation process, such that the predetermined criterion is fulfilled if a duration for which a selected index item has been stored in the index data store exceeds a predetermined period, and wherein the invalidation control circuitry is configured to determine the duration for which the selected index item has been stored in the index data store with reference to a count of a number of index items which have been stored in the index data store since the selected index item was stored in the index data store.