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comparison f103c8/Drivers/CMSIS/DSP_Lib/Source/FastMathFunctions/arm_sin_q31.c @ 2:0c59e7a7782a

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Working on GPIO and RCC
author cin
date Mon, 16 Jan 2017 11:04:47 +0300
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1:a0b14b11ad9f 2:0c59e7a7782a
1 /* ----------------------------------------------------------------------
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_q31.c
9 *
10 * Description: Fast 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 groupFastMath
46 */
47
48 /**
49 * @addtogroup sin
50 * @{
51 */
52
53 /**
54 * @brief Fast approximation to the trigonometric sine function for Q31 data.
55 * @param[in] x Scaled input value in radians.
56 * @return sin(x).
57 *
58 * The Q31 input value is in the range [0 +0.9999] and is mapped to a radian value in the range [0 2*pi). */
59
60 q31_t arm_sin_q31(
61 q31_t x)
62 {
63 q31_t sinVal; /* Temporary variables for input, output */
64 int32_t index; /* Index variables */
65 q31_t a, b; /* Four nearest output values */
66 q31_t fract; /* Temporary values for fractional values */
67
68 /* Calculate the nearest index */
69 index = (uint32_t)x >> FAST_MATH_Q31_SHIFT;
70
71 /* Calculation of fractional value */
72 fract = (x - (index << FAST_MATH_Q31_SHIFT)) << 9;
73
74 /* Read two nearest values of input value from the sin table */
75 a = sinTable_q31[index];
76 b = sinTable_q31[index+1];
77
78 /* Linear interpolation process */
79 sinVal = (q63_t)(0x80000000-fract)*a >> 32;
80 sinVal = (q31_t)((((q63_t)sinVal << 32) + ((q63_t)fract*b)) >> 32);
81
82 return sinVal << 1;
83 }
84
85 /**
86 * @} end of sin group
87 */