US Patent 8352709 Direct memory access techniques that include caching segmentation data

A memory access technique, in accordance with one embodiment of the present invention, includes caching segmentation data. The technique utilizes a separate memory for storing a plurality of context specifiers and an MMU. The MMU includes an on-chip cache and a segmentation unit. The MMU receives a location of a particular context specifier and a corresponding context index for each of one or more of the plurality of context specifiers stored in the separate memory. The segmentation unit retrieves the particular context specifier and caches it locally. The segmentation unit also binds the cache location of the particular context specifier to the corresponding context index. After caching one or more context specifiers and generating a corresponding binding, the segmentation unit may receive a memory access request that includes a given context index. A given context specifier that is cached locally is accessed by the segmentation unit using the context index to get a base address. The base address from the given context specifier is utilized by the segmentation unit to generate a virtual address for the memory access request.