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:
Aug. 03, 2004
Filed:
Jul. 18, 2000
Motonobu Tonomura, Kodaira, JP;
Fumio Arakawa, Kodaira, JP;
Renesas Technology Corp., Tokyo, JP;
Abstract
A multimedia processor is capable of concurrently carrying out processing tasks at different degrees of precision suitable for a variety of purposes and displays high performance of consecutively outputting a new cumulative result by adding or subtracting a result of multiplication to or from an existing cumulative result. To prevent the processing precision from deteriorating in applications where the processing precision is critical, critical processing precision is assured by multiplication of a signed number by an unsigned number. A partial product output by a multiplication and an existing cumulative result are supplied. The number of inputs is counted by a carry-save counter based on a 7-3 counter. A ripple adder is employed on the low-order-digit side where propagation of carry is completed early. On the other hand, a carry select/look-ahead adder is employed on the high-order-digit side to speed up the propagation of a carry. In this way, a multimedia multiply adder/subtractor can be assembled with a small number of gate stages. As a result, there is exhibited an effect that, when it is desired to store a series of multiplication results obtained consecutively, a carry-save result produced in a middle of one machine cycle can be input and stored for further use when an eventual result of propagation of a carry can not be output during the one machine cycle.