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:
Aug. 13, 1996
Filed:
Jun. 01, 1994
Ichiro Kyushima, Yokohama, JP;
Masahiro Kainaga, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A control system for a cache provided between a central processing unit and a main memory. The control system includes a plurality of entries each having a data area and a control information area. A reuse information field in the control information area is set at the same time as a load/store instruction from the central processing unit. When the central processing unit issues an access instruction to desired data in the main memory, an entry storing the desired data to be accessed is searched from a plurality of entries of the cache. If the desired data is not present in any of the plurality of entries, the desired data is read from the main memory. Then, an empty entry is searched from the plurality of entries. If there is no empty entry, an entry is selected which is not set with the reuse information in the control information area of the entry, the reuse information instructing to preferentially maintaining the data in the data field of the entry. The data of the selected entry is replaced by the data read from the main memory. Reuse information in an access command from the central processing unit for maintaining data in a particular entry is set to the reuse information field.