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:
Nov. 23, 1993
Filed:
Apr. 12, 1993
Peter A Mehring, Wilmington, MA (US);
Robert Becker, Shirley, MA (US);
Varoujan Garapetian, Cambridge, MA (US);
Sun Microsystems, Inc., Mountain View, CA (US);
Abstract
In the memory access unit of the present invention, the memory request logic is centralized in the memory management unit (MMU). The MMU instructs the MCU, which interfaces directly with the DRAMs, on the type of memory access to perform. By centralizing the memory requests, the MMU is able to maintain an account of each memory access, thereby providing the MMU the means to determine if a memory access fulfills the requirements of a fast page mode access before a request is made to the MCU. The MMU comprises the row address comparator which can execute the row address comparison in parallel with the cache lookup. Therefore, if the cache lookup determines a memory access is required, a specific fast page mode memory access request can be made, without the memory controller incurring the additional delay of checking the row address. Thus, by using the memory access unit of the present invention, the system can default to fast page mode access without the additional penalty normally incurred by comparing the row address in a serial manner.