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:
May. 09, 1995
Filed:
Jul. 19, 1990
Shinobu Koizumi, Sagamihara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a data processing system having a central processing unit including a register file for storage of often-used data, a method and system is provided for saving and restoring the contents of the register file from the main memory only when necessary. Each register unit in the register file includes a register protection flag, a save area pointer and a plurality of general purpose registers. The register protection flag is coded to identify if the register unit is in actual use by having contents stored in any of the general purpose registers. Before saving or restoring the register unit, its register protection flag is checked, and only if the flag indicates actual use is the saving or restoring performed.