Appeal No. 96-3359
Application 08/204,592
1. In a computer system including a memory coupled to a
first processor having an internal cache, said first processor
coupled to at least one remote agent on a bus, said bus
supporting snooping by said first processor and said at least
one remote agent, a method of operation comprising the steps
of:
(a) acquiring by said first processor an exclusive copy
of a cache line;
(b) setting a lock bit by said first processor to lock
said internal cache;
(c) processing said exclusive copy of said cache line by
said first processor;
(d) receiving by said first processor a request from said
remote agent for said cache line;
(e) transferring ownership, but not the data associated
with, said cache line from said first processor to said remote
agent;
(f) clearing said lock bit by said first processor;
(g) transferring the data associated with said cache line
from said first processor to said remote agent.
The examiner’s Answer cites the following prior art:
Chan et al. (Chan) 4,513,367 Apr. 23, 1985
Arnold et al. (Arnold) 5,175,837 Dec. 29, 1992
Tetzlaff et al. (Telzlaff) 5,301,290 Apr. 5, 1994
Santeler et al. (Santeler) 5,325,535 Jun. 28, 1994
Tipley 5,369,753 Nov. 29, 1994
OPINION
The claimed invention relates to a distributed computer
system that includes multiple processors (or agents). A
processor sets a lock bit to lock its internal cache.
Ownership of a locked cache line is transferred before the
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