Prefetch buffer and information processing system using the same

A data prefetch buffer adapted for use between a cache memory and a main memory in a computer system having a CPU, said data prefetch buffer comprising:

• a data buffer storage unit having at least one entry for storing prefetched data and an address tag, the address tag to be used for searching data stored in said data buffer storage unit;
• means for receiving a request address from the CPU;
• a data searcher for searching, from the data stored in said data buffer storage unit, for data having an address the same as the request address;
• an address estimator for estimating an address of data to be prefetched from the main memory, based on the request address and on the history of addresses of data prefetched in the past from the main memory, said address estimator including means for subtracting the request address and an address immediately previously requested by the CPU, and means for using the result of the subtracting to estimate the address of the data to be prefetched from the main memory;
• and
• an address generator for generating an address of data to be prefetched from the main memory according to the address estimated by said address estimator.