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