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. 02, 1994
Filed:
Jul. 12, 1991
Yutaka Murao, Tokyo, JP;
Tetsuro Wada, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
To increase the kinds of executable instructions of a microcomputer without increasing the number of bits (e.g. 8 bits) constituting one word or instruction, that is, without decreasing the execution speed or increasing the ROM usage, two or more instruction groups including instructions of different kinds, respectively, are provided operation modes are determined for the respective instruction groups; and the respective instruction groups to be executed are switched according to the respective operation modes. The microcomputer includes an instruction register, an execution control unit, a mode memory flip-flop, gates, two predecoders, a programmable logic array, an arithmetic logic unit, etc. The ordinary and special instruction groups can be selected in response to an interrupt entry signal and an interrupt return signal and a specific bit of an instruction, for instance.