Patent ID: 8499125

Claim:
A control device of a snoop tag, the control device comprising: a snoop tag retaining unit to retain the snoop tag corresponding to a content of a cache memory of a processor; a pipeline to receive requests including a replace request and a read request for access to the snoop tag; a queue stored with an entry including a replace target way number and an index associated with the replace request received from the processor, the replace target way number indicating a way that is a replace target; a comparator to compare the index included in the entry stored in the queue with an index in the read request when the read request is received; and a replacing unit to replace a way number based on the read request with the replace target way number included in the entry stored in the queue, the entry including the index which has matched the index in the read request, wherein when there is no free space in the queue upon receiving the replace request, none of the entry is stored in the queue, and the replace request is invalidated, wherein when the queue is stored with an entry including the same index upon receiving the replace request, none of the entry is stored in the queue, and the replace request is invalidated, wherein the entry stored in the queue is deleted after an elapse of a predetermined period, and wherein when an index in a request is matched with an index in another request already existing on the pipeline, the request is canceled and retried, and, when the request is the read request containing the index which has matched the index included in the entry stored in the queue, the request is not canceled.