111 lines
3.4 KiB
C
111 lines
3.4 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_sin_cos_q31.c
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* Description: Cosine & Sine calculation for Q31 values
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*
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* $Date: 18. March 2019
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* $Revision: V1.6.0
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*
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* Target Processor: Cortex-M cores
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* -------------------------------------------------------------------- */
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/*
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* Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed under the Apache License, Version 2.0 (the License); you may
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* not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an AS IS BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "arm_math.h"
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#include "arm_common_tables.h"
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/**
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@ingroup groupController
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*/
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/**
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@addtogroup SinCos
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@{
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*/
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/**
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@brief Q31 sin_cos function.
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@param[in] theta scaled input value in degrees
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@param[out] pSinVal points to processed sine output
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@param[out] pCosVal points to processed cosine output
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@return none
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The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
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*/
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void arm_sin_cos_q31(
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q31_t theta,
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q31_t * pSinVal,
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q31_t * pCosVal)
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{
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q31_t fract; /* Temporary input, output variables */
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uint16_t indexS, indexC; /* Index variable */
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q31_t f1, f2, d1, d2; /* Two nearest output values */
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q31_t Dn, Df;
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q63_t temp;
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/* Calculate the nearest index */
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indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
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indexC = (indexS + 128) & 0x1ff;
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/* Calculation of fractional value */
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fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;
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/* Read two nearest values of input value from the cos & sin tables */
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f1 = sinTable_q31[indexC ];
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f2 = sinTable_q31[indexC+1];
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d1 = -sinTable_q31[indexS ];
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d2 = -sinTable_q31[indexS+1];
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Dn = 0x1921FB5; /* delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE */
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Df = f2 - f1; /* delta between the values of the functions */
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temp = Dn * ((q63_t)d1 + d2);
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temp = temp - ((q63_t)Df << 32);
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temp = (q63_t)fract * (temp >> 31);
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temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn);
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temp = (q63_t)fract * (temp >> 31);
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temp = temp + (q63_t)d1 * Dn;
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temp = (q63_t)fract * (temp >> 31);
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/* Calculation of cosine value */
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*pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
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/* Read two nearest values of input value from the cos & sin tables */
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f1 = sinTable_q31[indexS ];
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f2 = sinTable_q31[indexS+1];
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d1 = sinTable_q31[indexC ];
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d2 = sinTable_q31[indexC+1];
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Df = f2 - f1; // delta between the values of the functions
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temp = Dn * ((q63_t)d1 + d2);
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temp = temp - ((q63_t)Df << 32);
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temp = (q63_t)fract * (temp >> 31);
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temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn);
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temp = (q63_t)fract * (temp >> 31);
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temp = temp + (q63_t)d1 * Dn;
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temp = (q63_t)fract * (temp >> 31);
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/* Calculation of sine value */
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*pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
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}
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/**
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@} end of SinCos group
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*/
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