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. 12, 1998
Filed:
Jan. 22, 1996
Ramesh Chandra Agarwal, Yorktown Heights, NY (US);
Bruce Martin Fleischer, Mt. Kisco, NY (US);
Fred Gehrung Gustavson, Briarcliff Manor, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An arithmetic unit keeps a result in carry-save form and uses this form of the result as an input to the next iteration in recurrent computations. The full adder in the recurrent path is eliminated by implementing multiplication by Y(i), where Y(i) is available only in carry-save form. The carry-save arithmetic unit generates a plurality of partial products whose sum is the product AXB, where A is one binary input and B is either a second binary input B' or the sum C'+S' of two binary inputs C' and S'. A selection is made as to whether B is equal to B' or C'+S'. The plurality of partial products and an addition input Z are compressed to two partial products C and S whose sum C+S equals the sum of the plurality of partial products and Z. The partial products C and S are added to produce a binary result X equal to A.times.B+Z. The full adder in the recurrent path is eliminated by a feedback path which returns the partial products C and S to the inputs C' and S' for a next iteration.