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:
Jan. 16, 1996
Filed:
Mar. 03, 1994
Brian N Baker, Kanata, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A method and circuit utilizing first and second tag bits for granting access to a block of memory in a multiprocessor system having a shared memory are provided. When a memory request for exclusive access to a block of memory is granted, the starting address for that block of memory is placed in a register bank, thereby opening a semaphore. The starting address of a memory block of a subsequent memory access request is compared with the starting addresses corresponding to open semaphores within the register bank and access is denied to the requested block of memory if a match is found. The starting address associated with a request which is denied access is placed in a temporary buffer and the request is later granted access after the corresponding open semaphore becomes closed. A request which is granted memory access to a memory block which results in an open semaphore, has exclusive access to that block of memory until the semaphore is closed.