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.

Date of Patent:
Oct. 05, 1999

Filed:

Feb. 26, 1996
Applicant:
Inventors:

Mark W Hervin, Dallas, TX (US);

David B Erickson, Plano, TX (US);

Assignee:

National Semiconductor Corporation, Santa Clara, CA (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
708209 ; 712223 ; 712-1 ;
Abstract

Circuit for performing arithmetic operations in a 32-bit architecture. The circuit includes a five stage shift and rotate circuit coupled between first and second 32-bit busses in the following sequence: an 8-bit shift and rotate circuit, a 16-bit shift and rotate circuit, a 1-bit shift and rotate circuit, a 2-bit shift and rotate circuit and a 4-bit shift and rotate circuit. For double word sized (32-bit) operands, the variously sized shift and rotate circuits may be selectively enabled to perform between 1-bit and 31-bit shift/rotate/pass operations. For byte sized operands, the 8-bit and 16-bit shift and rotate circuits are used to pre-process the operands while the 1-bit, 2-bit and 4-bit shift and rotate circuits are selectively enabled to perform the full range, i.e., 1-bit to 7-bit, of possible shift/rotate operations. For word sized (16-bit) operands, the 16-bit or 8-bit and 16-bit shift and rotate circuits are used to pre-process the operands while the 1-bit, 2-bit and 4-bit shift and rotate circuits are selectively enabled to perform the full range of shift/rotate operations.


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