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. 05, 1988
Filed:
Apr. 29, 1987
Yeshayahu Mor, Cupertino, CA (US);
Fairchild Camera and Instrument, Mountain View, CA (US);
Abstract
A modified Booth algorithm is implemented in the arithmetic logic of the ALU data path to cut the number of cycles to do a multiply in half thereby improving execution time of the multiplication operation. A Booth Encoder examines the two least significant bits of the multiplier stored in the Q2 register and the bit which was previously shifted out on the last partial product shift cycle. Based upon the status of these three bits, the Booth Encoder causes the ALU to add or substract one times the multiplicand to the contents of the partial product register and shift twice, add or substract two times the multiplicand to the contents of the partial product register and shift twice, or do nothing but shift twice. A pre ALU B shifter provides a single left shift of the multiplicand to provide the multiplication by two when same is necessary.