| /* ---------------------------------------------------------------------- | |
| * Project: CMSIS DSP Library | |
| * Title: arm_sin_cos_q31.c | |
| * Description: Cosine & Sine calculation for Q31 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. | |
| */ | |
| /** | |
| @ingroup groupController | |
| */ | |
| /** | |
| @addtogroup SinCos | |
| @{ | |
| */ | |
| /** | |
| @brief Q31 sin_cos function. | |
| @param[in] theta scaled input value in degrees | |
| @param[out] pSinVal points to processed sine output | |
| @param[out] pCosVal points to processed cosine output | |
| @return none | |
| The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179]. | |
| */ | |
| void arm_sin_cos_q31( | |
| q31_t theta, | |
| q31_t * pSinVal, | |
| q31_t * pCosVal) | |
| { | |
| q31_t fract; /* Temporary input, output variables */ | |
| uint16_t indexS, indexC; /* Index variable */ | |
| q31_t f1, f2, d1, d2; /* Two nearest output values */ | |
| q31_t Dn, Df; | |
| q63_t temp; | |
| /* Calculate the nearest index */ | |
| indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT; | |
| indexC = (indexS + 128) & 0x1ff; | |
| /* Calculation of fractional value */ | |
| fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8; | |
| /* Read two nearest values of input value from the cos & sin tables */ | |
| f1 = sinTable_q31[indexC ]; | |
| f2 = sinTable_q31[indexC+1]; | |
| d1 = -sinTable_q31[indexS ]; | |
| d2 = -sinTable_q31[indexS+1]; | |
| Dn = 0x1921FB5; /* 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 * ((q63_t)d1 + d2); | |
| temp = temp - ((q63_t)Df << 32); | |
| temp = (q63_t)fract * (temp >> 31); | |
| temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn); | |
| temp = (q63_t)fract * (temp >> 31); | |
| temp = temp + (q63_t)d1 * Dn; | |
| temp = (q63_t)fract * (temp >> 31); | |
| /* Calculation of cosine value */ | |
| *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1); | |
| /* Read two nearest values of input value from the cos & sin tables */ | |
| f1 = sinTable_q31[indexS ]; | |
| f2 = sinTable_q31[indexS+1]; | |
| d1 = sinTable_q31[indexC ]; | |
| d2 = sinTable_q31[indexC+1]; | |
| Df = f2 - f1; // delta between the values of the functions | |
| temp = Dn * ((q63_t)d1 + d2); | |
| temp = temp - ((q63_t)Df << 32); | |
| temp = (q63_t)fract * (temp >> 31); | |
| temp = temp + ((3 * (q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1)) * Dn); | |
| temp = (q63_t)fract * (temp >> 31); | |
| temp = temp + (q63_t)d1 * Dn; | |
| temp = (q63_t)fract * (temp >> 31); | |
| /* Calculation of sine value */ | |
| *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1); | |
| } | |
| /** | |
| @} end of SinCos group | |
| */ | |