Importance

Loading Importance Indicators...

Abstract

Method and apparatus for a filtered stream buffer coupled to a memory and a processor, and operating to prefetch data from the memory. The filtered stream buffer includes a cache block storage area and a filter controller. The filter controller determines whether a pattern of references has a predetermined relationship, and if so, prefetches stream data into the cache block storage area. Such stream data prefetches are particularly useful in vector processing computers, where once the processor starts to fetch a vector, the addresses of future fetches can be predicted based in the pattern of past fetches. According to various aspects of the present invention, the filtered stream buffer further includes a history table, a validity indicator which is associated with the cache block storage area and indicates which cache blocks, if any, are valid. According to yet another aspect of the present invention, the filtered stream buffer controls random access memory (RAM) chips to stream the plurality of consecutive cache blocks from the RAM into the cache block storage area. According to yet another aspect of the present invention, the stream data includes data for a plurality of strided cache blocks, wherein each of which these strided cache blocks corresponds to an address determined by adding to the first address an integer multiple of the difference between the second address and the first address. According to yet another aspect of the present invention, the processor generates three addresses of data words in the memory, and the filter controller determines whether a predetermined relationship exists among three addresses, and if so, prefetches strided stream data into said cache block storage area.

Loading the Abstract Image...

First Claim