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:
Jul. 13, 1993
Filed:
Mar. 06, 1991
Tatsuya Ueda, Itami, JP;
Toyohiko Yoshida, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The data processor related to the invention enables to designate whether the branch prediction mechanism itself should be activated or not for a conditional branch instruction, and the data processor enables to initialize branch history as required and also designates activation or inactivation of the branch prediction mechanism by setting a specific value to a specific bit of an exclusive usable register by software means. Also when a specific instruction is executed, the data processor automatically clears the branch history. As a result, in the event when the data processing efficiency is adversely declined by application of branch prediction mechanism or when monitoring external address bus, the branching prediction mechanism can be inactivated by setting the predetermined value to the exclusive usable register. Likewise, when the reliability of the branch history lowers due to such as variation in the program running condition, the data processor is capable of clearing the branch history by writing a specific value into the exclusive usable register, and when executing a specific instruction which varies the program executing condition, branch history is automatically cleared.