The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 18, 2002
Filed:
Feb. 01, 1999
Takeo Hosomi, Tokyo, JP;
NEC Corporation, Tokyo, JP;
Abstract
A multiprocessor system has a controller for arbitrating a memory access request and a coherency maintenance control process. A coherency maintenance controller for maintaining coherency of data stored in a main memory and data stored in a cache memory has a local access controller which arbitrates between a memory access from a processor in a local buffer and a message for coherency maintenance control in a request buffer according to reply messages accumulated in a reply buffer. A directory memory stores. the state of data stored in the main memory, which includes a state representing that the coherency maintenance control process is being carried out. When the state stored in the directory memory indicates that the coherency maintenance control process is being carried out on data corresponding to an access request, a home access controller saves the access request in the main memory.