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:
Jan. 01, 2008
Filed:
Feb. 16, 2006
Daisuke Takeuchi, Osaka, JP;
Daisuke Takeuchi, Osaka, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
In order to correct an overflow of a multiplication result while improving the operation speed, an overflow detection unit detects an overflow based on whether a multiplicand A and a multiplier B are both a negative value with the largest absolute value. A carry-save adder adds together in carry-save addition partial products and −1 (where all bits are 1) as a first correction value to output an intermediate sum and an intermediate carry corresponding to A×B−1. A carry-propagate adder adds together in carry-propagate addition the intermediate sum, the intermediate carry and a second correction value to output the multiplication result. Where there is no overflow, the second correction value becomes 1 to cancel out the first correction value, whereby the operation result is A×B. Where there is an overflow, the second correction value becomes 0, whereby the operation result is A×B−1 in which the overflow is corrected by the first correction value.