摘要 |
A multiprocessor computer system which maintains cache coherency includes first and second microprocessors each having an associated cache memory storing lines of data. Each line of data has associated protocol bits that indicate a protocol state consistent with write-through, write-back, or write-once cache coherency policies that are selected via a protocol selection terminal for different system configurations. In one configuration, the output and external address terminals of the first microprocessor are coupled to the external and output address terminals, respectively, of the second microprocessor. This configuration enables each microprocessor to snoop memory cycles to main memory initiated by the other microprocessor so that it can be readily determined if a particular cache has the latest version of data.
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