Joep D / CMSIS_DSP_5

The CMSIS DSP 5 library

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functions/ControllerFunctions/arm_sin_cos_q31.c@3:4098b9d3d571, 2018-06-21 (annotated)

Committer:
xorjoep
Date:
Thu Jun 21 11:56:27 2018 +0000
Revision:
3:4098b9d3d571
Parent:
1:24714b45cd1b 
headers is a folder not a library

Who changed what in which revision?

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xorjoep 1:24714b45cd1b 1 /* ----------------------------------------------------------------------
xorjoep 1:24714b45cd1b 2 * Project: CMSIS DSP Library
xorjoep 1:24714b45cd1b 3 * Title: arm_sin_cos_q31.c
xorjoep 1:24714b45cd1b 4 * Description: Cosine & Sine calculation for Q31 values
xorjoep 1:24714b45cd1b 5 *
xorjoep 1:24714b45cd1b 6 * $Date: 27. January 2017
xorjoep 1:24714b45cd1b 7 * $Revision: V.1.5.1
xorjoep 1:24714b45cd1b 8 *
xorjoep 1:24714b45cd1b 9 * Target Processor: Cortex-M cores
xorjoep 1:24714b45cd1b 10 * -------------------------------------------------------------------- */
xorjoep 1:24714b45cd1b 11 /*
xorjoep 1:24714b45cd1b 12 * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
xorjoep 1:24714b45cd1b 13 *
xorjoep 1:24714b45cd1b 14 * SPDX-License-Identifier: Apache-2.0
xorjoep 1:24714b45cd1b 15 *
xorjoep 1:24714b45cd1b 16 * Licensed under the Apache License, Version 2.0 (the License); you may
xorjoep 1:24714b45cd1b 17 * not use this file except in compliance with the License.
xorjoep 1:24714b45cd1b 18 * You may obtain a copy of the License at
xorjoep 1:24714b45cd1b 19 *
xorjoep 1:24714b45cd1b 20 * www.apache.org/licenses/LICENSE-2.0
xorjoep 1:24714b45cd1b 21 *
xorjoep 1:24714b45cd1b 22 * Unless required by applicable law or agreed to in writing, software
xorjoep 1:24714b45cd1b 23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
xorjoep 1:24714b45cd1b 24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
xorjoep 1:24714b45cd1b 25 * See the License for the specific language governing permissions and
xorjoep 1:24714b45cd1b 26 * limitations under the License.
xorjoep 1:24714b45cd1b 27 */
xorjoep 1:24714b45cd1b 28
xorjoep 1:24714b45cd1b 29 #include "arm_math.h"
xorjoep 1:24714b45cd1b 30 #include "arm_common_tables.h"
xorjoep 1:24714b45cd1b 31
xorjoep 1:24714b45cd1b 32 /**
xorjoep 1:24714b45cd1b 33 * @ingroup groupController
xorjoep 1:24714b45cd1b 34 */
xorjoep 1:24714b45cd1b 35
xorjoep 1:24714b45cd1b 36 /**
xorjoep 1:24714b45cd1b 37 * @addtogroup SinCos
xorjoep 1:24714b45cd1b 38 * @{
xorjoep 1:24714b45cd1b 39 */
xorjoep 1:24714b45cd1b 40
xorjoep 1:24714b45cd1b 41 /**
xorjoep 1:24714b45cd1b 42 * @brief Q31 sin_cos function.
xorjoep 1:24714b45cd1b 43 * @param[in] theta scaled input value in degrees
xorjoep 1:24714b45cd1b 44 * @param[out] *pSinVal points to the processed sine output.
xorjoep 1:24714b45cd1b 45 * @param[out] *pCosVal points to the processed cosine output.
xorjoep 1:24714b45cd1b 46 * @return none.
xorjoep 1:24714b45cd1b 47 *
xorjoep 1:24714b45cd1b 48 * The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179].
xorjoep 1:24714b45cd1b 49 *
xorjoep 1:24714b45cd1b 50 */
xorjoep 1:24714b45cd1b 51
xorjoep 1:24714b45cd1b 52 void arm_sin_cos_q31(
xorjoep 1:24714b45cd1b 53 q31_t theta,
xorjoep 1:24714b45cd1b 54 q31_t * pSinVal,
xorjoep 1:24714b45cd1b 55 q31_t * pCosVal)
xorjoep 1:24714b45cd1b 56 {
xorjoep 1:24714b45cd1b 57 q31_t fract; /* Temporary variables for input, output */
xorjoep 1:24714b45cd1b 58 uint16_t indexS, indexC; /* Index variable */
xorjoep 1:24714b45cd1b 59 q31_t f1, f2, d1, d2; /* Two nearest output values */
xorjoep 1:24714b45cd1b 60 q31_t Dn, Df;
xorjoep 1:24714b45cd1b 61 q63_t temp;
xorjoep 1:24714b45cd1b 62
xorjoep 1:24714b45cd1b 63 /* Calculate the nearest index */
xorjoep 1:24714b45cd1b 64 indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT;
xorjoep 1:24714b45cd1b 65 indexC = (indexS + 128) & 0x1ff;
xorjoep 1:24714b45cd1b 66
xorjoep 1:24714b45cd1b 67 /* Calculation of fractional value */
xorjoep 1:24714b45cd1b 68 fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8;
xorjoep 1:24714b45cd1b 69
xorjoep 1:24714b45cd1b 70 /* Read two nearest values of input value from the cos & sin tables */
xorjoep 1:24714b45cd1b 71 f1 = sinTable_q31[indexC+0];
xorjoep 1:24714b45cd1b 72 f2 = sinTable_q31[indexC+1];
xorjoep 1:24714b45cd1b 73 d1 = -sinTable_q31[indexS+0];
xorjoep 1:24714b45cd1b 74 d2 = -sinTable_q31[indexS+1];
xorjoep 1:24714b45cd1b 75
xorjoep 1:24714b45cd1b 76 Dn = 0x1921FB5; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
xorjoep 1:24714b45cd1b 77 Df = f2 - f1; // delta between the values of the functions
xorjoep 1:24714b45cd1b 78 temp = Dn*((q63_t)d1 + d2);
xorjoep 1:24714b45cd1b 79 temp = temp - ((q63_t)Df << 32);
xorjoep 1:24714b45cd1b 80 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 81 temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
xorjoep 1:24714b45cd1b 82 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 83 temp = temp + (q63_t)d1*Dn;
xorjoep 1:24714b45cd1b 84 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 85
xorjoep 1:24714b45cd1b 86 /* Calculation of cosine value */
xorjoep 1:24714b45cd1b 87 *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
xorjoep 1:24714b45cd1b 88
xorjoep 1:24714b45cd1b 89 /* Read two nearest values of input value from the cos & sin tables */
xorjoep 1:24714b45cd1b 90 f1 = sinTable_q31[indexS+0];
xorjoep 1:24714b45cd1b 91 f2 = sinTable_q31[indexS+1];
xorjoep 1:24714b45cd1b 92 d1 = sinTable_q31[indexC+0];
xorjoep 1:24714b45cd1b 93 d2 = sinTable_q31[indexC+1];
xorjoep 1:24714b45cd1b 94
xorjoep 1:24714b45cd1b 95 Df = f2 - f1; // delta between the values of the functions
xorjoep 1:24714b45cd1b 96 temp = Dn*((q63_t)d1 + d2);
xorjoep 1:24714b45cd1b 97 temp = temp - ((q63_t)Df << 32);
xorjoep 1:24714b45cd1b 98 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 99 temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn);
xorjoep 1:24714b45cd1b 100 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 101 temp = temp + (q63_t)d1*Dn;
xorjoep 1:24714b45cd1b 102 temp = (q63_t)fract*(temp >> 31);
xorjoep 1:24714b45cd1b 103
xorjoep 1:24714b45cd1b 104 /* Calculation of sine value */
xorjoep 1:24714b45cd1b 105 *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1);
xorjoep 1:24714b45cd1b 106 }
xorjoep 1:24714b45cd1b 107
xorjoep 1:24714b45cd1b 108 /**
xorjoep 1:24714b45cd1b 109 * @} end of SinCos group
xorjoep 1:24714b45cd1b 110 */