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CMSIS-DSP/Source/ControllerFunctions/arm_sin_cos_f32.c

115 lines
3.3 KiB
C

/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_sin_cos_f32.c
* Description: Sine and Cosine calculation for floating-point values
*
* $Date: 23 April 2021
* $Revision: V1.9.0
*
* Target Processor: Cortex-M and Cortex-A cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "dsp/controller_functions.h"
#include "arm_common_tables.h"
/**
@addtogroup SinCos
@{
*/
/**
@brief Floating-point sin_cos function.
@param[in] theta input value in degrees
@param[out] pSinVal points to processed sine output
@param[out] pCosVal points to processed cosine output
@return none
*/
void arm_sin_cos_f32(
float32_t theta,
float32_t * pSinVal,
float32_t * pCosVal)
{
float32_t fract, in; /* Temporary input, output variables */
uint16_t indexS, indexC; /* Index variable */
float32_t f1, f2, d1, d2; /* Two nearest output values */
float32_t Dn, Df;
float32_t temp, findex;
/* input x is in degrees */
/* Scale input, divide input by 360, for cosine add 0.25 (pi/2) to read sine table */
in = theta * 0.00277777777778f;
if (in < 0.0f)
{
in = -in;
}
in = in - (int32_t)in;
/* Calculate the nearest index */
findex = (float32_t)FAST_MATH_TABLE_SIZE * in;
indexS = ((uint16_t)findex) & 0x1ff;
indexC = (indexS + (FAST_MATH_TABLE_SIZE / 4)) & 0x1ff;
/* Calculation of fractional value */
fract = findex - (float32_t) indexS;
/* Read two nearest values of input value from the cos & sin tables */
f1 = sinTable_f32[indexC ];
f2 = sinTable_f32[indexC+1];
d1 = -sinTable_f32[indexS ];
d2 = -sinTable_f32[indexS+1];
Dn = 0.0122718463030f; /* delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE */
Df = f2 - f1; /* delta between the values of the functions */
temp = Dn * (d1 + d2) - 2 * Df;
temp = fract * temp + (3 * Df - (d2 + 2 * d1) * Dn);
temp = fract * temp + d1 * Dn;
/* Calculation of cosine value */
*pCosVal = fract * temp + f1;
/* Read two nearest values of input value from the cos & sin tables */
f1 = sinTable_f32[indexS ];
f2 = sinTable_f32[indexS+1];
d1 = sinTable_f32[indexC ];
d2 = sinTable_f32[indexC+1];
Df = f2 - f1; // delta between the values of the functions
temp = Dn * (d1 + d2) - 2 * Df;
temp = fract * temp + (3 * Df - (d2 + 2 * d1) * Dn);
temp = fract * temp + d1 * Dn;
/* Calculation of sine value */
*pSinVal = fract * temp + f1;
if (theta < 0.0f)
{
*pSinVal = -*pSinVal;
}
}
/**
@} end of SinCos group
*/