Abstract: Each processor in a distributed shared memory system has an associated memory and a coherence directory. The processor that controls a memory is the Home processor. Under certain conditions, another processor may obtain exclusive control of a data block by issuing a Load Lock instruction, and obtaining a writeable copy of the data block that is stored in the cache of the Owner processor. If the Owner processor does not complete operations on the writeable copy of the data prior to the time that the data block is displaced from the cache, it issues a Victim To Shared message, thereby indicating to the Home processor that it should remain a sharer of the data block. In the event that another processor seeks exclusive rights to the same data block, the Home processor issues an Invalidate message to the Owner processor.

Abstract: Systems and methods for cache coherency in multi-processor systems. A cache coherency system is used in a multi-processor computer system having a physical memory system in communication with the processors via a communication medium. A processor-side cache memory subsystem is associated with each processor of the multi-processor computer system. The cache coherency system includes a cache tag memory structure having a number of entries substantially equal to the defined number of entries for each processor-side cache memory. Each entry of the cache tag memory structure has at least one field corresponding to each processor-side cache memory subsystem.

Abstract: Each processor in a distributed shared memory system has an associated memory and a coherence directory. The processor that controls a memory is the Home processor. Under certain conditions, another processor may obtain exclusive control of a data block by issuing a Load Lock instruction, and obtaining a writeable copy of the data block that is stored in the cache of the Owner processor. If the Owner processor does not complete operations on the writeable copy of the data prior to the time that the data block is displaced from the cache, it issues a Victim To Shared message, thereby indicating to the Home processor that it should remain a sharer of the data block. In the event that another processor seeks exclusive rights to the same data block, the Home processor issues an Invalidate message to the Owner processor.

Abstract: A programmable digital signal processor usable in a variety of configurations and controlled by stored coefficients and control words which are addressable to be provided to a plurality of processing sections as often as once per clock cycle. The processor arrangement is suitable for use as a decoder of multiple analog component (MAC) television signals.