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:
Nov. 20, 1984
Filed:
Dec. 24, 1980
Virendra S Negi, Pepperell, MA (US);
Steven A Tague, Billerica, MA (US);
Honeywell Information Systems Inc., Waltham, MA (US);
Abstract
A data processing system executes a decimal multiply instruction by storing the product of a multiplier decimal digit and a multiplicand decimal digit in a read only memory and storing partial product decimal digits in a register. The units product decimal digit is read from the read only memory during one cycle and added to a partial product decimal digit. A resulting units carry is stored in a units carry flip-flop. The tens product decimal digit is read from the read only memory during another cycle and added to a higher order partial product decimal digit. A resulting tens carry is stored in a tens carry flip-flop. A multiplexer selects the output of the units carry flip-flop for adding the units carry during the next units cycle in which the next units product decimal digit is added to the higher order partial product decimal digit. The multiplexer selects the output of the tens carry flip-flop for adding the tens carry during the next tens cycle in which the next tens product decimal digit is added to a next higher order partial product decimal digit.