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comparison f103c8/Drivers/CMSIS/DSP_Lib/Source/StatisticsFunctions/arm_mean_q7.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_mean_q7.c
9 *
10 * Description: Mean value of a Q7 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 * @ingroup groupStats
45 */
46
47 /**
48 * @addtogroup mean
49 * @{
50 */
51
52 /**
53 * @brief Mean value of a Q7 vector.
54 * @param[in] *pSrc points to the input vector
55 * @param[in] blockSize length of the input vector
56 * @param[out] *pResult mean value returned here
57 * @return none.
58 *
59 * @details
60 * <b>Scaling and Overflow Behavior:</b>
61 * \par
62 * The function is implemented using a 32-bit internal accumulator.
63 * The input is represented in 1.7 format and is accumulated in a 32-bit
64 * accumulator in 25.7 format.
65 * There is no risk of internal overflow with this approach, and the
66 * full precision of intermediate result is preserved.
67 * Finally, the accumulator is truncated to yield a result of 1.7 format.
68 *
69 */
70
71
72 void arm_mean_q7(
73 q7_t * pSrc,
74 uint32_t blockSize,
75 q7_t * pResult)
76 {
77 q31_t sum = 0; /* Temporary result storage */
78 uint32_t blkCnt; /* loop counter */
79
80 #ifndef ARM_MATH_CM0_FAMILY
81
82 /* Run the below code for Cortex-M4 and Cortex-M3 */
83 q31_t in;
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[1] + A[2] + ... + A[blockSize-1]) */
93 in = *__SIMD32(pSrc)++;
94
95 sum += ((in << 24) >> 24);
96 sum += ((in << 16) >> 24);
97 sum += ((in << 8) >> 24);
98 sum += (in >> 24);
99
100 /* Decrement the loop counter */
101 blkCnt--;
102 }
103
104 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
105 ** No loop unrolling is used. */
106 blkCnt = blockSize % 0x4u;
107
108 #else
109
110 /* Run the below code for Cortex-M0 */
111
112 /* Loop over blockSize number of values */
113 blkCnt = blockSize;
114
115 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
116
117 while(blkCnt > 0u)
118 {
119 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */
120 sum += *pSrc++;
121
122 /* Decrement the loop counter */
123 blkCnt--;
124 }
125
126 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) / blockSize */
127 /* Store the result to the destination */
128 *pResult = (q7_t) (sum / (int32_t) blockSize);
129 }
130
131 /**
132 * @} end of mean group
133 */