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| bfc108 | 1 | /* ---------------------------------------------------------------------- |
| Q | 2 | * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| 3 | * | |
| 4 | * $Date: 19. March 2015 | |
| 5 | * $Revision: V.1.4.5 | |
| 6 | * | |
| 7 | * Project: CMSIS DSP Library | |
| 8 | * Title: arm_sin_cos_q31.c | |
| 9 | * | |
| 10 | * Description: Cosine & Sine calculation for Q31 values. | |
| 11 | * | |
| 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | |
| 13 | * | |
| 14 | * Redistribution and use in source and binary forms, with or without | |
| 15 | * modification, are permitted provided that the following conditions | |
| 16 | * are met: | |
| 17 | * - Redistributions of source code must retain the above copyright | |
| 18 | * notice, this list of conditions and the following disclaimer. | |
| 19 | * - Redistributions in binary form must reproduce the above copyright | |
| 20 | * notice, this list of conditions and the following disclaimer in | |
| 21 | * the documentation and/or other materials provided with the | |
| 22 | * distribution. | |
| 23 | * - Neither the name of ARM LIMITED nor the names of its contributors | |
| 24 | * may be used to endorse or promote products derived from this | |
| 25 | * software without specific prior written permission. | |
| 26 | * | |
| 27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 28 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 29 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 30 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 31 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
| 33 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 34 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| 35 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
| 37 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 38 | * POSSIBILITY OF SUCH DAMAGE. | |
| 39 | * -------------------------------------------------------------------- */ | |
| 40 | ||
| 41 | #include "arm_math.h" | |
| 42 | #include "arm_common_tables.h" | |
| 43 | ||
| 44 | /** | |
| 45 | * @ingroup groupController | |
| 46 | */ | |
| 47 | ||
| 48 | /** | |
| 49 | * @addtogroup SinCos | |
| 50 | * @{ | |
| 51 | */ | |
| 52 | ||
| 53 | /** | |
| 54 | * @brief Q31 sin_cos function. | |
| 55 | * @param[in] theta scaled input value in degrees | |
| 56 | * @param[out] *pSinVal points to the processed sine output. | |
| 57 | * @param[out] *pCosVal points to the processed cosine output. | |
| 58 | * @return none. | |
| 59 | * | |
| 60 | * The Q31 input value is in the range [-1 0.999999] and is mapped to a degree value in the range [-180 179]. | |
| 61 | * | |
| 62 | */ | |
| 63 | ||
| 64 | void arm_sin_cos_q31( | |
| 65 | q31_t theta, | |
| 66 | q31_t * pSinVal, | |
| 67 | q31_t * pCosVal) | |
| 68 | { | |
| 69 | q31_t fract; /* Temporary variables for input, output */ | |
| 70 | uint16_t indexS, indexC; /* Index variable */ | |
| 71 | q31_t f1, f2, d1, d2; /* Two nearest output values */ | |
| 72 | q31_t Dn, Df; | |
| 73 | q63_t temp; | |
| 74 | ||
| 75 | /* Calculate the nearest index */ | |
| 76 | indexS = (uint32_t)theta >> CONTROLLER_Q31_SHIFT; | |
| 77 | indexC = (indexS + 128) & 0x1ff; | |
| 78 | ||
| 79 | /* Calculation of fractional value */ | |
| 80 | fract = (theta - (indexS << CONTROLLER_Q31_SHIFT)) << 8; | |
| 81 | ||
| 82 | /* Read two nearest values of input value from the cos & sin tables */ | |
| 83 | f1 = sinTable_q31[indexC+0]; | |
| 84 | f2 = sinTable_q31[indexC+1]; | |
| 85 | d1 = -sinTable_q31[indexS+0]; | |
| 86 | d2 = -sinTable_q31[indexS+1]; | |
| 87 | ||
| 88 | Dn = 0x1921FB5; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE | |
| 89 | Df = f2 - f1; // delta between the values of the functions | |
| 90 | temp = Dn*((q63_t)d1 + d2); | |
| 91 | temp = temp - ((q63_t)Df << 32); | |
| 92 | temp = (q63_t)fract*(temp >> 31); | |
| 93 | temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn); | |
| 94 | temp = (q63_t)fract*(temp >> 31); | |
| 95 | temp = temp + (q63_t)d1*Dn; | |
| 96 | temp = (q63_t)fract*(temp >> 31); | |
| 97 | ||
| 98 | /* Calculation of cosine value */ | |
| 99 | *pCosVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1); | |
| 100 | ||
| 101 | /* Read two nearest values of input value from the cos & sin tables */ | |
| 102 | f1 = sinTable_q31[indexS+0]; | |
| 103 | f2 = sinTable_q31[indexS+1]; | |
| 104 | d1 = sinTable_q31[indexC+0]; | |
| 105 | d2 = sinTable_q31[indexC+1]; | |
| 106 | ||
| 107 | Df = f2 - f1; // delta between the values of the functions | |
| 108 | temp = Dn*((q63_t)d1 + d2); | |
| 109 | temp = temp - ((q63_t)Df << 32); | |
| 110 | temp = (q63_t)fract*(temp >> 31); | |
| 111 | temp = temp + ((3*(q63_t)Df << 31) - (d2 + ((q63_t)d1 << 1))*Dn); | |
| 112 | temp = (q63_t)fract*(temp >> 31); | |
| 113 | temp = temp + (q63_t)d1*Dn; | |
| 114 | temp = (q63_t)fract*(temp >> 31); | |
| 115 | ||
| 116 | /* Calculation of sine value */ | |
| 117 | *pSinVal = clip_q63_to_q31((temp >> 31) + (q63_t)f1); | |
| 118 | } | |
| 119 | ||
| 120 | /** | |
| 121 | * @} end of SinCos group | |
| 122 | */ | |
