Microprocessor point-to-point communication

Abstract

A computer system having at least a first microprocessor for processing information and a first memory coupled to the first microprocessor via a first point-to-point interface. The first point-to-point interface provides communication of signals between the first microprocessor and the first memory irrespective of the phase of the signals received by either the first microprocessor or the first memory. The first point-to-point interface includes a first point-to-point circuit in the microprocessor for receiving the signals from the first memory. The first point-to-point circuit and the microprocessor comprise a single integrated circuit in some implemented embodiments, providing ease of construction and design of systems having a variety of topologies. A second microprocessor may also be coupled to the first memory via a second point-to-point interface, the first microprocessor and the second microprocessor sharing the first memory for storage of information used by the first microprocessor and the second microprocessor. In this configuration, the first memory may include a duplicate cache store for the first microprocessor and the second microprocessor, in order to provide cache consistency for the two processors. The system may also include a first input-output device coupled via a second point-to-point interface to the first memory. A variety of topologies of processors, memories and input/output devices may be designed into 'clusters' wherein each cluster communicated with one another for accesses, remote and local, for accessing input/output devices, and for maintaining cache consistency.