Abstract: The invention sets forth an approach to context switching that utilizes scan chains modified to perform context switching operations. The design requires substantially less additional silicon area and design engineering effort than existing context switch approaches, while operating substantially faster and providing additional debug observability during context switching operations.

Abstract: In a processing pipeline having a plurality of units, an interface unit is provided between a first, upstream pipeline unit that needs to be drained prior to a context switch and a second, downstream pipeline unit that might halt prior to a context switch. The interface unit redirects data that are drained from the first pipeline unit and to be received by the second pipeline unit, to a buffer memory provided in the front end of the processing pipeline. The contents of the buffer memory are subsequently dumped into memory reserved for the context that is being stored. When the processing pipeline is restored with this context, the data that were dumped into memory are retrieved back into the buffer memory and provided to the interface unit. The interface unit receives these commands and directs them to the second pipeline unit.