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Browse Prior Art Database

Floating Point Sine and Cosine Generator

IP.com Disclosure Number: IPCOM000046869D
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07

Publishing Venue

IBM

Related People

Authors:
Moran, JT Sproul, WW [+details]

Abstract

The problem solved is to generate both the sine and the cosine in floating point representation of a given angle in fixed point at a very high speed with minimal hardware. The basic approach is a table lookup which takes advantage of the sin/cos symmetry and aspects of floating point numeric representation to reduce the table to the smallest possible size. A block diagram overview of this invention is shown in the figure. The angle or argument for the sin and cos generation is contained in the r register 7. This 16-bit register represents any angle from 0 to 2f in increments of f/215 . The most significant bit of the angle has a value of f. Thirteen of the r register bits are used to address the 8K table lookup (TLU) memory (1, 2, 3, 4, 5, 6).