Patent ID: 8205064

Claim:
Apparatus for use in a system coupled to a bus, the system issuing local requests, a local request requiring corresponding associated information in order to be serviced, the apparatus comprising: a local memory for storing some of said associated information, said associated information necessary to complete a given local request, such that for each given local request, said associated information is either present in the local memory or must be retrieved via a bus request; an output request queue coupled between the local memory and the bus for storing bus requests; a bypass path element coupled between the local memory and the bus, in parallel with the output request queue, for forwarding bus requests between the local memory and the bus, a first end of the output request queue and a first end of the bypass path element each connected to the local memory, a second end of the output request queue opposite the first end of the output request queue and a second end of the bypass path element opposite the first end of the bypass path element each in communication with the bus; logic for servicing local requests, the logic operable for each local request by controlling the output request queue and bypass path element operations as follows: if the associated information is present in the local memory, place in the output request queue by outputting to the first end of the output request queue a bus request to service the local request; if the associated information is not present in the local memory, place on the bypass path element by outputting to the first end of the bypass path element instead of the output request queue a first stage request of a multi-stage bus request to retrieve the associated information, and place a second stage request of the multi-stage bus request in the output request queue in response to the first stage request; the logic further operable to issue bus requests on the bypass path element with priority over bus requests in the output request queue so that bus requests placed in the output request queue prior to the servicing of the local request can continue to issue from the second end of the output request queue opposite the first end of the output request queue to the bus while the associated information is retrieved.