Method and device for realizing calculation of sine and cosine functions

Abstract

The invention discloses a method and device for realizing calculation of sine and cosine functions. The method comprises the following steps of: 1) judging whether an input angle is in an appointed range or not, if the judging result is positive, outputting the input angle as a target calculation angle, and otherwise, compressing the input angle and outputting the compressed angle as the target calculation angle; and 2) carrying out sine or cosine function calculation on the target calculation angle by adoption of a TCORDIC algorithm, when the difference between the target calculation angle and a degree of 0 or Pi / 2 is smaller than an appointed threshold value, completing the sine or cosine function calculation through a Taylor expanded form, and otherwise, completing the sine or cosine function calculation by using a CORDIC algorithm. The device comprises an angle compression unit and a TCORDIC calculation unit. According to the method and device, the calculation of sine and cosine functions of any angle can be realized; and the method and device have the advantages of being simple in realization method, low in calculation complexity and high in calculation efficiency and precision.

Description

technical field [0001] The invention relates to the technical field of function calculations, in particular to a method and device for realizing sine and cosine function calculations. Background technique [0002] Calculation of sine and cosine functions is an important part of scientific computing and engineering applications. This type of calculation usually requires that the error of the calculation result can be small, and it needs to be applicable to any input angle range. CORDIC (COordinate Rotation DIgital Computer, Coordinate Rotation Digital Computer) is a digital iterative algorithm for calculating a variety of transcendental functions. The CORDIC algorithm can complete the calculation of trigonometric functions through simple addition and shift operations, and the algorithm is regular , the structure is simple, and can be easily implemented on hardware, the expression is as follows: [0003] [0004] where X 0 = K n ,Y 0 =0, Z 0 ∈[0,π / 2], the iteration res...

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Problems solved by technology

[0008] However, when using the CORDIC algorithm to calculate the sine and cosine functions, errors will occur due to the limited operand bit width and the number of iterations, and the input angle belongs to Z R ε[0,π / 2], when the input angle Z R Approaching to 0 or π / 2, the relative floating point error of the calculation result using the CORDIC algorithm is relatively large, resulting in a large error in the final calculation result

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