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CMSIS DSP library

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cmsis_dsp/ControllerFunctions/arm_sin_cos_f32.c@5:3762170b6d4d, 2015-11-20 (annotated)

Committer:
mbed_official
Date:
Fri Nov 20 08:45:18 2015 +0000
Revision:
5:3762170b6d4d
Parent:
3:7a284390b0ce 
Synchronized with git revision 2eb940b9a73af188d3004a2575fdfbb05febe62b



Full URL: https://github.com/mbedmicro/mbed/commit/2eb940b9a73af188d3004a2575fdfbb05febe62b/



Added option to build rpc library. closes #1426

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------
mbed_official 5:3762170b6d4d 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
mbed_official 5:3762170b6d4d 4 * $Date: 19. March 2015
mbed_official 5:3762170b6d4d 5 * $Revision: V.1.4.5
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_sin_cos_f32.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Sine and Cosine calculation for floating-point values.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
mbed_official 3:7a284390b0ce 14 * Redistribution and use in source and binary forms, with or without
mbed_official 3:7a284390b0ce 15 * modification, are permitted provided that the following conditions
mbed_official 3:7a284390b0ce 16 * are met:
mbed_official 3:7a284390b0ce 17 * - Redistributions of source code must retain the above copyright
mbed_official 3:7a284390b0ce 18 * notice, this list of conditions and the following disclaimer.
mbed_official 3:7a284390b0ce 19 * - Redistributions in binary form must reproduce the above copyright
mbed_official 3:7a284390b0ce 20 * notice, this list of conditions and the following disclaimer in
mbed_official 3:7a284390b0ce 21 * the documentation and/or other materials provided with the
mbed_official 3:7a284390b0ce 22 * distribution.
mbed_official 3:7a284390b0ce 23 * - Neither the name of ARM LIMITED nor the names of its contributors
mbed_official 3:7a284390b0ce 24 * may be used to endorse or promote products derived from this
mbed_official 3:7a284390b0ce 25 * software without specific prior written permission.
mbed_official 3:7a284390b0ce 26 *
mbed_official 3:7a284390b0ce 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
mbed_official 3:7a284390b0ce 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
mbed_official 3:7a284390b0ce 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
mbed_official 3:7a284390b0ce 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
mbed_official 3:7a284390b0ce 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
mbed_official 3:7a284390b0ce 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
mbed_official 3:7a284390b0ce 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
mbed_official 3:7a284390b0ce 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 3:7a284390b0ce 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
mbed_official 3:7a284390b0ce 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
mbed_official 3:7a284390b0ce 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
mbed_official 3:7a284390b0ce 38 * POSSIBILITY OF SUCH DAMAGE.
emilmont 1:fdd22bb7aa52 39 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 40
emilmont 1:fdd22bb7aa52 41 #include "arm_math.h"
mbed_official 5:3762170b6d4d 42 #include "arm_common_tables.h"
emilmont 1:fdd22bb7aa52 43
emilmont 1:fdd22bb7aa52 44 /**
emilmont 1:fdd22bb7aa52 45 * @ingroup groupController
emilmont 1:fdd22bb7aa52 46 */
emilmont 1:fdd22bb7aa52 47
emilmont 1:fdd22bb7aa52 48 /**
emilmont 1:fdd22bb7aa52 49 * @defgroup SinCos Sine Cosine
emilmont 1:fdd22bb7aa52 50 *
emilmont 1:fdd22bb7aa52 51 * Computes the trigonometric sine and cosine values using a combination of table lookup
emilmont 1:fdd22bb7aa52 52 * and linear interpolation.
emilmont 1:fdd22bb7aa52 53 * There are separate functions for Q31 and floating-point data types.
emilmont 1:fdd22bb7aa52 54 * The input to the floating-point version is in degrees while the
emilmont 1:fdd22bb7aa52 55 * fixed-point Q31 have a scaled input with the range
mbed_official 5:3762170b6d4d 56 * [-1 0.9999] mapping to [-180 +180] degrees.
mbed_official 5:3762170b6d4d 57 *
mbed_official 5:3762170b6d4d 58 * The floating point function also allows values that are out of the usual range. When this happens, the function will
mbed_official 5:3762170b6d4d 59 * take extra time to adjust the input value to the range of [-180 180].
emilmont 1:fdd22bb7aa52 60 *
emilmont 1:fdd22bb7aa52 61 * The implementation is based on table lookup using 360 values together with linear interpolation.
emilmont 1:fdd22bb7aa52 62 * The steps used are:
emilmont 1:fdd22bb7aa52 63 * -# Calculation of the nearest integer table index.
emilmont 1:fdd22bb7aa52 64 * -# Compute the fractional portion (fract) of the input.
emilmont 1:fdd22bb7aa52 65 * -# Fetch the value corresponding to \c index from sine table to \c y0 and also value from \c index+1 to \c y1.
emilmont 1:fdd22bb7aa52 66 * -# Sine value is computed as <code> *psinVal = y0 + (fract * (y1 - y0))</code>.
emilmont 1:fdd22bb7aa52 67 * -# Fetch the value corresponding to \c index from cosine table to \c y0 and also value from \c index+1 to \c y1.
emilmont 1:fdd22bb7aa52 68 * -# Cosine value is computed as <code> *pcosVal = y0 + (fract * (y1 - y0))</code>.
emilmont 1:fdd22bb7aa52 69 */
emilmont 1:fdd22bb7aa52 70
emilmont 1:fdd22bb7aa52 71 /**
emilmont 1:fdd22bb7aa52 72 * @addtogroup SinCos
emilmont 1:fdd22bb7aa52 73 * @{
emilmont 1:fdd22bb7aa52 74 */
emilmont 1:fdd22bb7aa52 75
emilmont 1:fdd22bb7aa52 76 /**
emilmont 1:fdd22bb7aa52 77 * @brief Floating-point sin_cos function.
emilmont 1:fdd22bb7aa52 78 * @param[in] theta input value in degrees
emilmont 1:fdd22bb7aa52 79 * @param[out] *pSinVal points to the processed sine output.
emilmont 1:fdd22bb7aa52 80 * @param[out] *pCosVal points to the processed cos output.
emilmont 1:fdd22bb7aa52 81 * @return none.
emilmont 1:fdd22bb7aa52 82 */
emilmont 1:fdd22bb7aa52 83
emilmont 1:fdd22bb7aa52 84 void arm_sin_cos_f32(
emilmont 1:fdd22bb7aa52 85 float32_t theta,
emilmont 1:fdd22bb7aa52 86 float32_t * pSinVal,
emilmont 1:fdd22bb7aa52 87 float32_t * pCosVal)
emilmont 1:fdd22bb7aa52 88 {
mbed_official 5:3762170b6d4d 89 float32_t fract, in; /* Temporary variables for input, output */
mbed_official 5:3762170b6d4d 90 uint16_t indexS, indexC; /* Index variable */
mbed_official 5:3762170b6d4d 91 float32_t f1, f2, d1, d2; /* Two nearest output values */
mbed_official 5:3762170b6d4d 92 int32_t n;
mbed_official 5:3762170b6d4d 93 float32_t findex, Dn, Df, temp;
emilmont 1:fdd22bb7aa52 94
mbed_official 5:3762170b6d4d 95 /* input x is in degrees */
mbed_official 5:3762170b6d4d 96 /* Scale the input, divide input by 360, for cosine add 0.25 (pi/2) to read sine table */
mbed_official 5:3762170b6d4d 97 in = theta * 0.00277777777778f;
emilmont 1:fdd22bb7aa52 98
mbed_official 5:3762170b6d4d 99 /* Calculation of floor value of input */
mbed_official 5:3762170b6d4d 100 n = (int32_t) in;
emilmont 1:fdd22bb7aa52 101
mbed_official 5:3762170b6d4d 102 /* Make negative values towards -infinity */
mbed_official 5:3762170b6d4d 103 if(in < 0.0f)
emilmont 1:fdd22bb7aa52 104 {
mbed_official 5:3762170b6d4d 105 n--;
emilmont 1:fdd22bb7aa52 106 }
mbed_official 5:3762170b6d4d 107 /* Map input value to [0 1] */
mbed_official 5:3762170b6d4d 108 in = in - (float32_t) n;
emilmont 1:fdd22bb7aa52 109
mbed_official 5:3762170b6d4d 110 /* Calculation of index of the table */
mbed_official 5:3762170b6d4d 111 findex = (float32_t) FAST_MATH_TABLE_SIZE * in;
mbed_official 5:3762170b6d4d 112 indexS = ((uint16_t)findex) & 0x1ff;
mbed_official 5:3762170b6d4d 113 indexC = (indexS + (FAST_MATH_TABLE_SIZE / 4)) & 0x1ff;
emilmont 1:fdd22bb7aa52 114
mbed_official 5:3762170b6d4d 115 /* fractional value calculation */
mbed_official 5:3762170b6d4d 116 fract = findex - (float32_t) indexS;
emilmont 1:fdd22bb7aa52 117
mbed_official 5:3762170b6d4d 118 /* Read two nearest values of input value from the cos & sin tables */
mbed_official 5:3762170b6d4d 119 f1 = sinTable_f32[indexC+0];
mbed_official 5:3762170b6d4d 120 f2 = sinTable_f32[indexC+1];
mbed_official 5:3762170b6d4d 121 d1 = -sinTable_f32[indexS+0];
mbed_official 5:3762170b6d4d 122 d2 = -sinTable_f32[indexS+1];
emilmont 1:fdd22bb7aa52 123
mbed_official 5:3762170b6d4d 124 Dn = 0.0122718463030f; // delta between the two points (fixed), in this case 2*pi/FAST_MATH_TABLE_SIZE
mbed_official 5:3762170b6d4d 125 Df = f2 - f1; // delta between the values of the functions
mbed_official 5:3762170b6d4d 126 temp = Dn*(d1 + d2) - 2*Df;
mbed_official 5:3762170b6d4d 127 temp = fract*temp + (3*Df - (d2 + 2*d1)*Dn);
mbed_official 5:3762170b6d4d 128 temp = fract*temp + d1*Dn;
emilmont 1:fdd22bb7aa52 129
emilmont 1:fdd22bb7aa52 130 /* Calculation of cosine value */
mbed_official 5:3762170b6d4d 131 *pCosVal = fract*temp + f1;
mbed_official 5:3762170b6d4d 132
mbed_official 5:3762170b6d4d 133 /* Read two nearest values of input value from the cos & sin tables */
mbed_official 5:3762170b6d4d 134 f1 = sinTable_f32[indexS+0];
mbed_official 5:3762170b6d4d 135 f2 = sinTable_f32[indexS+1];
mbed_official 5:3762170b6d4d 136 d1 = sinTable_f32[indexC+0];
mbed_official 5:3762170b6d4d 137 d2 = sinTable_f32[indexC+1];
emilmont 1:fdd22bb7aa52 138
mbed_official 5:3762170b6d4d 139 Df = f2 - f1; // delta between the values of the functions
mbed_official 5:3762170b6d4d 140 temp = Dn*(d1 + d2) - 2*Df;
mbed_official 5:3762170b6d4d 141 temp = fract*temp + (3*Df - (d2 + 2*d1)*Dn);
mbed_official 5:3762170b6d4d 142 temp = fract*temp + d1*Dn;
mbed_official 5:3762170b6d4d 143
mbed_official 5:3762170b6d4d 144 /* Calculation of sine value */
mbed_official 5:3762170b6d4d 145 *pSinVal = fract*temp + f1;
emilmont 1:fdd22bb7aa52 146 }
emilmont 1:fdd22bb7aa52 147 /**
emilmont 1:fdd22bb7aa52 148 * @} end of SinCos group
emilmont 1:fdd22bb7aa52 149 */