Abstract: A network processor useful in network switch apparatus and methods of operating such a processor in which data flow handling and flexibility is enhanced by the cooperation of an embedded processor complex with a suite of peripherals, all formed on a common semiconductor substrate. The interface processors provide data paths for inbound and outbound data flow and operate under the control of instructions stored in an instruction store formed on the semiconductor substrate, while storage of transiting data flow portions is provided by memory peripherals and interfaces to external memory elements.

Abstract: A central processor-coprocessor assembly comprising an assembler software tool for extending the base central processor tasks into at least one coprocessor. What is important is that the assembler software tool does not need to be rebuilt when changes are made to the coprocessor elements. The invention allows assembly time extension of a base core language processing (CLP) programming model, without the need to rebuild the assembler tool itself. The assembler tool comprises a set of commands which enable the central processor to manipulate the coprocessor registers, and a coprocessor execute instruction, which initiates command processing on the coprocessor. The present invention simplifies the maintenance of the assembler tool through multiple hardware revisions by enabling hardware designers to update their coprocessor definition files to reflect new or modified coprocessors.

Abstract: In an ordered semaphore management system a pending state allows threads not competing for a locked semaphore to bypass one or more threads waiting for the same locked semaphore. The number of pending levels determines the number of consecutive threads vying for the same locked semaphore which can be bypassed. When more than one level is provided the pending levels are prioritized in the queued order.

Abstract: Processor threads in a multi-processor system can concurrently lock multiple semaphores by providing a lock command which includes the semaphore value and a semaphore number. Each processor is allocated two or more addressable semaphore stores, each of which include a multi-bit field identifying the requested semaphore and a one bit field identifying the locked status of the requested semaphore. The semaphore number determines which of the allocated semaphore stores are to be used for processing the lock command.

Abstract: A generic method and apparatus for managing semaphores in a multi-threaded processing system has a storage area for each of the threads in the processing system. Each storage area includes a first part for storing at least one indicia for identifying at least one unique semaphore from a plurality of semaphores utilized by the multi-threaded processing system and a second part for storing an indicia for indicating a locked status for the stored semaphore. A thread requiring a semaphore sends a semaphore lock request to the semaphore manager which examines the contents of all of the storage areas to determine the status of the requested semaphore. If the requested semaphore is not locked, it is locked for the requesting thread by inserting the requested semaphore and locked status in the memory location assigned to the requesting thread.

Abstract: An ordered semaphore management subsystem and method for use in an application system which includes a plurality of processors competing for shared resources each of which is controlled by a unique semaphore. The subsystem generates an ordered semaphore field (OSF) corresponding to each processor in a linked list of processors and assigns one of four statuses to the OSF depending on the position the processor occupies in the linked list of processors competing for the shared resources. The four states are (1) semaphore head (SH); (2) behind semaphore head (BSH); (3) semaphore head behind (SHB); and (4) skip (Skip). Only the SH processor is allocated the semaphore when requested. A processor not in the SH state will be denied the semaphore even if is available to assure sequential access.