MULTIPROCESSOR SYSTEM INCLUDING SHARED MEMORY UNIT AND PROCESSORS EQUIPPED WITH CACHE MEMORY, AND CACHE-COHERENCY MAINTAINING METHOD THEREOF

摘要

PURPOSE: A multiprocessor system including a shared memory unit and processors equipped with a cache memory, and a cache-coherency maintaining method thereof are provided to maintain the cache-coherency while minimizing design change of the processors not offering a multiprocessor operation environment and reduce power consumption of the system without using a complex logic. CONSTITUTION: The processors(PA-PC) are respectively equipped with at least one cache memory(L1A-L1C,L2A-L2C) and are connected to a bus(110). The memory(140) is shared with at least two processors. A directory memory(130) is arranged to stores sharing information of the cache memories for each data block of the memory. A memory controller(120) is connected between the bus and the directory memory. If a request for accessing the memory is received from one of the processors, the memory controller transfers an interrupt to the sharing processor by referring to the directory memory when the requested data block is shared by other processor.