Patent ID: 8166250

Claim:
An information processing unit, comprising: an instruction execution section executing a memory access instruction; a storage section holding data related to the memory access instruction executed by the instruction execution section; at least one cache memory provided between the instruction execution section and the storage section; an address information holding section holding first address information based on an address of the memory access instruction executed by the instruction execution section; a hardware prefetch request issuing section issuing a hardware prefetch request to the cache memory based on a result of comparison processing between an address requested by the instruction execution section for memory access and the first address information held in the address information holding section; a hardware prefetch target indication section that attaches indication information, which indicates whether or not the memory access instruction is a hardware prefetch request issuance target by the hardware prefetch request issuing section, to the memory access instruction; and a control section controlling content of the first address information held by the address information holding section based on the result of the comparison processing, wherein the hardware prefetch request issuing section performs the comparison processing and issuance processing of a hardware prefetch request based on the indication information; and when the address information holding section is caused to hold the first address information or when the first address information in the address information holding section is updated, until a predetermined period elapses after the first address information is held or updated, the control section inhibits overwrite processing on the first address information with second address information which belongs to second sequence different from first sequence to which the first address information belongs, while permits updating processing on the first address information held in the address information holding section.