Approximation of non-linear functions in fixed point using look-up tables

US10037306B2 · kind B2 · utility

Assignee

• QUALCOMM Incorporated · US

Inventors

• Dexu Lin · San Diego, US
• Edward Hanyu LIAO · San Diego, US
• Somdeb Majumdar · San Diego, US
• Aaron Douglass LAMB · San Diego, US
• Karamvir CHATHA · San Diego, US

Key dates

• Filing date: Sep 1, 2016
• Grant date: Jul 31, 2018
• Expiry date: Oct 27, 2036

Classification

• Technology area (CPC G): Physics
• CPC primary: G06F2207/5354
• WIPO field: Computer technology
• WIPO sector: Electrical engineering

Abstract

Computing a non-linear function ƒ(x) in hardware or embedded systems can be complex and resource intensive. In one or more aspects of the disclosure, a method, a computer-readable medium, and an apparatus are provided for computing a non-linear function ƒ(x) accurately and efficiently in hardware using look-up tables (LUTs) and interpolation or extrapolation. The apparatus may be a processor. The processor computes a non-linear function ƒ(x) for an input variable x, where ƒ(x)=g(y(x),z(x)). The processor determines an integer n by determining a position of a most significant bit (MSB) of an input variable x. In addition, the processor determines a value for y(x) based on a first look-up table and the determined integer n. Also, the processor determines a value for z(x) based on n and the input variable x, and based on a second look-up table. Further, the processor computes ƒ(x) based on the determined values for y(x) and z(x).