Patent ID: 7739436

Claim:
An apparatus, comprising: an arbitration unit for a shared bi-directional communication bus that implements a round robin policy where each requesting device, of a plurality of requesting devices, has an equal chance of accessing the shared bi-directional communication bus based upon a current request priority assigned to that requesting device, wherein the arbitration unit includes at least a state block that includes a plurality of state registers, each of the state registers is to store information that indicates which requesting device of a respective pair of the plurality of requesting devices will win if both devices of the respective pair are requesting access to the shared resource; an update logic block configured to track a current request priority of each of the respective pairs of requesting devices relative to the other pairs that could request access to the shared bi-directional communication bus, and wherein the update logic block and the state block act to pre-compute an ordered list in which the requesting devices from the plurality of requesting devices are prioritized to win the arbitration process if a given requesting device was to present a request to the arbitration unit on an initial arbitration cycle; and an arbiter output logic of the arbitration unit, wherein the arbiter output logic is composed of logic gates that are two levels or less deep to determine a request to grant time and the two levels of logic are increased by logic to buffer the request inputs to reduce request fanout, or by splitting the final output gate to reduce fanin, and a time period from the initial arbitration cycle to the grant time is less than or equal to two clock cycles in the apparatus.