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Official ARM version: v5.6.0

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rihab kouki 2020-07-28 11:24:49 +01:00
parent 9f95ff5b6b
commit 96d6da4e25
2939 changed files with 339304 additions and 113320 deletions
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48
DSP/Source/FastMathFunctions/arm_cos_q31.c
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@ -3,13 +3,13 @@
* Title: arm_cos_q31.c
* Description: Fast cosine calculation for Q31 values
*
* $Date: 27. January 2017
* $Revision: V.1.5.1
* $Date: 18. March 2019
* $Revision: V1.6.0
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
@ -30,36 +30,35 @@
#include "arm_common_tables.h"
/**
* @ingroup groupFastMath
*/
/**
* @addtogroup cos
* @{
@ingroup groupFastMath
*/
/**
* @brief Fast approximation to the trigonometric cosine function for Q31 data.
* @param[in] x Scaled input value in radians.
* @return cos(x).
*
* The Q31 input value is in the range [0 +0.9999] and is mapped to a radian
* value in the range [0 2*pi).
@addtogroup cos
@{
*/
/**
@brief Fast approximation to the trigonometric cosine function for Q31 data.
@param[in] x Scaled input value in radians
@return cos(x)
The Q31 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*PI).
*/
q31_t arm_cos_q31(
q31_t x)
{
q31_t cosVal; /* Temporary variables for input, output */
int32_t index; /* Index variables */
q31_t a, b; /* Four nearest output values */
q31_t cosVal; /* Temporary input, output variables */
int32_t index; /* Index variable */
q31_t a, b; /* Two nearest output values */
q31_t fract; /* Temporary values for fractional values */
/* add 0.25 (pi/2) to read sine table */
x = (uint32_t)x + 0x20000000;
if (x < 0)
{ /* convert negative numbers to corresponding positive ones */
x = (uint32_t)x + 0x80000000;
{ /* convert negative numbers to corresponding positive ones */
x = (uint32_t)x + 0x80000000;
}
/* Calculate the nearest index */
@ -73,12 +72,13 @@ q31_t arm_cos_q31(
b = sinTable_q31[index+1];
/* Linear interpolation process */
cosVal = (q63_t)(0x80000000-fract)*a >> 32;
cosVal = (q31_t)((((q63_t)cosVal << 32) + ((q63_t)fract*b)) >> 32);
cosVal = (q63_t) (0x80000000 - fract) * a >> 32;
cosVal = (q31_t) ((((q63_t) cosVal << 32) + ((q63_t) fract * b)) >> 32);
return cosVal << 1;
/* Return output value */
return (cosVal << 1);
}
/**
* @} end of cos group
@} end of cos group
*/