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:
Sep. 28, 1999
Filed:
Aug. 31, 1995
Timothy Don Davis, Arlington, TX (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A multiplier which uses Booth recoding to multiply large word length operands. A first operand is fully loaded into a shift register. The loading of the second operand is then begun, with the recoding operation beginning after the loading of the minimum number of bits of the second operand required for the first stage of the recoding. The recoded portions of the second operand are used to select what factor of the first operand to use in forming the partial product terms. The partial product terms are added using carry save addition, with the least significant bits being used to form the least significant bits of the final product. The most significant bits of the final product are then formed by adding the carry save data from the partial product summations. The present invention performs squaring operations used in exponentiation functions by shifting the first operand value (A) by one bit to form twice that value (2*A) prior to multiplying by the second operand (B) to form the 2*(A*B) term needed in such calculations. This shifting is performed in the multiplexer used to select the appropriate factor of the first operand for each partial product term, rather than after the accumulation of the final product term.