The CMSIS DSP 5 library
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functions/ControllerFunctions/arm_sin_cos_q31.c
- Committer:
- xorjoep
- Date:
- 2018-06-21
- Revision:
- 3:4098b9d3d571
- Parent:
- 1:24714b45cd1b
File content as of revision 3:4098b9d3d571:
/* ---------------------------------------------------------------------- * Project: CMSIS DSP Library * Title: arm_sin_cos_q31.c * Description: Cosine & Sine calculation for Q31 values * * $Date: 27. January 2017 * $Revision: V.1.5.1 * * Target Processor: Cortex-M cores * -------------------------------------------------------------------- */ /* * Copyright (C) 2010-2017 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 "arm_math.h" #include "arm_common_tables.h" /** * @ingroup groupController */ /** * @addtogroup SinCos * @{ */ /** * @brief Q31 sin_cos function. * @param[in] theta scaled input value in degrees * @param[out] *pSinVal points to the processed sine output. * @param[out] *pCosVal points to the 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 variables for input, output */ 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+0]; f2 = sinTable_q31[indexC+1]; d1 = -sinTable_q31[indexS+0]; 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+0]; f2 = sinTable_q31[indexS+1]; d1 = sinTable_q31[indexC+0]; 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 */