Interlock for controlling processor ownership of pipelined data for a

Abstract

Insures data integrity in process ownership indications by providing an ownership interlock on the data units in a pipeline to a store-in type of cache. An ownership interlock prevents any processor ownership change to occur (i.e. exclusive or readonly ownership) for a cache data unit until all outstanding stores have been made in the cache data unit, after which the ownership may be changed. An ownership change may be signalled by a cross-invalidate (XI) signal to a processor. Outstanding stores are received by the pipeline after the stores are completed by a processor, and the outstanding stores output from the pipeline into a store-in cache. A continuous flow of stores is enabled into and out of the pipeline to expedite a change of ownership requested of a data unit in the cache. The continuous flow avoids having to stop a processor from putting stores into the pipeline and avoids forcing all outstanding stores out of the pipeline into the cache before indicating a change of processor ownership.