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. 19, 1994
Filed:
Sep. 24, 1991
Kazuhiko Iijima, Ebina, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An automatic logic synthesis method wherein lower-rank descriptions defining a logic device in terms of expressions of lower abstraction are synthesized from higher-rank descriptions defining the logic device in terms of expressions of higher abstraction, comprising: providing first identifiers each of which indicates the presence of a description change of the corresponding description unit data of the higher-rank description, and providing second identifiers each of which indicates the presence of a description change of the corresponding description unit data of the lower-rank description; setting the first identifier of changed description unit data at the change of the higher-rank description, and setting the second identifier of changed description unit at the change of the lower-rank description directly made without any synthesis process from the higher-rank description; originating new lower-rank description unit data from the higher-rank description unit whose first identifier is set; and registering the new lower-rank description unit data as lower-rank description unit data on condition that the second identifier of the current lower-rank description unit data corresponding to the new lower-rank description unit data is not set, and merging the new lower-rank description unit data and the current lower-rank description unit data and then registering a merged result as lower-rank description unit data on condition that the second identifier of the current lower-rank description unit data is set.