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. 18, 1993
Filed:
Aug. 02, 1990
Hu H Chao, Pleasantville, NY (US);
Jung H Chang, Saratoga, CA (US);
IBM Corporation, Armonk, NY (US);
Abstract
An apparatus for correcting a faulty microcode contained in a control store of a microprogrammed processor. The apparatus comprises two functional parts; namely, the detection circuit for detecting operational codes that correspond to faulty microinstructions in the main control store ROM of the system and a programmable array which is used as the storage area for substitute microinstructions. The detection circuit is a circuit which operates as a logic NOR circuit and is utilized to detect valid operational codes of macroinstructions that correspond to microcode sequences that contain errors or faults. The programmable array consists of two loadable RAM's which contain error free microcode to replace the faulty microcode. The detection and correction occurs in parallel with the instruction decoding so that it does not have any impact on system cycle time.