| /* ---------------------------------------------------------------------- |
| * 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 |
| */ |