Integrated hierarchical memory overlay having invariant address space span that inactivates a same address space span in main memory

Abstract

It has been determined that considerable data which is written to stacks is of the type that does not require long term retention (i.e., it is only required to be valid for the duration of a procedure or function which created it). Accordingly, when a stack is employed to handle such data (and other similar data), invalidation and writes to main memory that ordinarily accompany accesses of such data (when the stack is held in a cache memory) can be avoided. The invention therefore improves memory performance by providing an overlay memory, to which is assigned a set of main memory addresses that are utilized for stack operations. When data is either read or written from/to the overlay memory, there is no further communication “downstream” to either a cache memory or main memory. In other words, the overlay memory is used for short term storage and accesses to the overlay memory are invisible to other memory elements of the system. There is thus no need to invalidate any data and nor to write such data to main memory. As a result, substantially improved memory operations result.

Dependencies are inferred from the claim text.