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comparison f103c8/Drivers/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_rms_q15.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_rms_q15.c
9 *
10 * Description: Root Mean Square of the elements of a Q15 vector.
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
43 /**
44 * @addtogroup RMS
45 * @{
46 */
47
48 /**
49 * @brief Root Mean Square of the elements of a Q15 vector.
50 * @param[in] *pSrc points to the input vector
51 * @param[in] blockSize length of the input vector
52 * @param[out] *pResult rms value returned here
53 * @return none.
54 *
55 * @details
56 * <b>Scaling and Overflow Behavior:</b>
57 *
58 * \par
59 * The function is implemented using a 64-bit internal accumulator.
60 * The input is represented in 1.15 format.
61 * Intermediate multiplication yields a 2.30 format, and this
62 * result is added without saturation to a 64-bit accumulator in 34.30 format.
63 * With 33 guard bits in the accumulator, there is no risk of overflow, and the
64 * full precision of the intermediate multiplication is preserved.
65 * Finally, the 34.30 result is truncated to 34.15 format by discarding the lower
66 * 15 bits, and then saturated to yield a result in 1.15 format.
67 *
68 */
69
70 void arm_rms_q15(
71 q15_t * pSrc,
72 uint32_t blockSize,
73 q15_t * pResult)
74 {
75 q63_t sum = 0; /* accumulator */
76
77 #ifndef ARM_MATH_CM0_FAMILY
78
79 /* Run the below code for Cortex-M4 and Cortex-M3 */
80
81 q31_t in; /* temporary variable to store the input value */
82 q15_t in1; /* temporary variable to store the input value */
83 uint32_t blkCnt; /* loop counter */
84
85 /* loop Unrolling */
86 blkCnt = blockSize >> 2u;
87
88 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
89 ** a second loop below computes the remaining 1 to 3 samples. */
90 while(blkCnt > 0u)
91 {
92 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
93 /* Compute sum of the squares and then store the results in a temporary variable, sum */
94 in = *__SIMD32(pSrc)++;
95 sum = __SMLALD(in, in, sum);
96 in = *__SIMD32(pSrc)++;
97 sum = __SMLALD(in, in, sum);
98
99 /* Decrement the loop counter */
100 blkCnt--;
101 }
102
103 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
104 ** No loop unrolling is used. */
105 blkCnt = blockSize % 0x4u;
106
107 while(blkCnt > 0u)
108 {
109 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
110 /* Compute sum of the squares and then store the results in a temporary variable, sum */
111 in1 = *pSrc++;
112 sum = __SMLALD(in1, in1, sum);
113
114 /* Decrement the loop counter */
115 blkCnt--;
116 }
117
118 /* Truncating and saturating the accumulator to 1.15 format */
119 /* Store the result in the destination */
120 arm_sqrt_q15(__SSAT((sum / (q63_t)blockSize) >> 15, 16), pResult);
121
122 #else
123
124 /* Run the below code for Cortex-M0 */
125
126 q15_t in; /* temporary variable to store the input value */
127 uint32_t blkCnt; /* loop counter */
128
129 /* Loop over blockSize number of values */
130 blkCnt = blockSize;
131
132 while(blkCnt > 0u)
133 {
134 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
135 /* Compute sum of the squares and then store the results in a temporary variable, sum */
136 in = *pSrc++;
137 sum += ((q31_t) in * in);
138
139 /* Decrement the loop counter */
140 blkCnt--;
141 }
142
143 /* Truncating and saturating the accumulator to 1.15 format */
144 /* Store the result in the destination */
145 arm_sqrt_q15(__SSAT((sum / (q63_t)blockSize) >> 15, 16), pResult);
146
147 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
148
149 }
150
151 /**
152 * @} end of RMS group
153 */