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:
Apr. 19, 1994
Filed:
Apr. 23, 1993
Lawrence M Ammann, Winchester, VA (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus implement reciprocal and square root calculations using Chebyshev polynomial approximation by scaling the mantissas of IEEE floating point numbers based on splitting them into intervals, thereby allowing Chebyshev polynomials of few terms to approximate each interval and resulting in high performance. A reciprocal or square root operation is implemented in a floating point unit (FPU) of a computer having a pipelined multiply accumulate function using a Chebyshev polynomial approximation. A plurality of Chebyshev coefficients are stored in read only storage. Mantissas m of floating point numbers are scaled based on splitting the mantissas into 2.sup.n intervals i as: