The present invention realizes pre-fetch based on a high-accuracy
prediction. A plurality of address values are registered in advance in a
pre-fetch address queue, based on previous memory accesses. If a request
address from the processor unit of a request address register matches
this address value, a pre-fetch address obtained by adding a block size
to the request address is output to a secondary cache as a pre-fetch
request. This pre-fetch address is written back into the pre-fetch
address queue.