Eli Hughes / CMSIS_DSP_401

V4.0.1 of the ARM CMSIS DSP libraries. Note that arm_bitreversal2.s, arm_cfft_f32.c and arm_rfft_fast_f32.c had to be removed. arm_bitreversal2.s will not assemble with the online tools. So, the fast f32 FFT functions are not yet available. All the other FFT functions are available.

Dependents:   MPU9150_Example fir_f32 fir_f32 MPU9150_nucleo_noni2cdev ... more

StatisticsFunctions/arm_var_q15.c@0:3d9c67d97d6f, 2014-07-28 (annotated)

Committer:
emh203
Date:
Mon Jul 28 15:03:15 2014 +0000
Revision:
0:3d9c67d97d6f
1st working commit.   Had to remove arm_bitreversal2.s     arm_cfft_f32.c and arm_rfft_fast_f32.c.    The .s will not assemble.      For now I removed these functions so we could at least have a library for the other functions.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emh203 0:3d9c67d97d6f 1 /* ----------------------------------------------------------------------
emh203 0:3d9c67d97d6f 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
emh203 0:3d9c67d97d6f 3 *
emh203 0:3d9c67d97d6f 4 * $Date: 12. March 2014
emh203 0:3d9c67d97d6f 5 * $Revision: V1.4.3
emh203 0:3d9c67d97d6f 6 *
emh203 0:3d9c67d97d6f 7 * Project: CMSIS DSP Library
emh203 0:3d9c67d97d6f 8 * Title: arm_var_q15.c
emh203 0:3d9c67d97d6f 9 *
emh203 0:3d9c67d97d6f 10 * Description: Variance of an array of Q15 type.
emh203 0:3d9c67d97d6f 11 *
emh203 0:3d9c67d97d6f 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emh203 0:3d9c67d97d6f 13 *
emh203 0:3d9c67d97d6f 14 * Redistribution and use in source and binary forms, with or without
emh203 0:3d9c67d97d6f 15 * modification, are permitted provided that the following conditions
emh203 0:3d9c67d97d6f 16 * are met:
emh203 0:3d9c67d97d6f 17 * - Redistributions of source code must retain the above copyright
emh203 0:3d9c67d97d6f 18 * notice, this list of conditions and the following disclaimer.
emh203 0:3d9c67d97d6f 19 * - Redistributions in binary form must reproduce the above copyright
emh203 0:3d9c67d97d6f 20 * notice, this list of conditions and the following disclaimer in
emh203 0:3d9c67d97d6f 21 * the documentation and/or other materials provided with the
emh203 0:3d9c67d97d6f 22 * distribution.
emh203 0:3d9c67d97d6f 23 * - Neither the name of ARM LIMITED nor the names of its contributors
emh203 0:3d9c67d97d6f 24 * may be used to endorse or promote products derived from this
emh203 0:3d9c67d97d6f 25 * software without specific prior written permission.
emh203 0:3d9c67d97d6f 26 *
emh203 0:3d9c67d97d6f 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
emh203 0:3d9c67d97d6f 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
emh203 0:3d9c67d97d6f 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
emh203 0:3d9c67d97d6f 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
emh203 0:3d9c67d97d6f 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
emh203 0:3d9c67d97d6f 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
emh203 0:3d9c67d97d6f 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
emh203 0:3d9c67d97d6f 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
emh203 0:3d9c67d97d6f 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
emh203 0:3d9c67d97d6f 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
emh203 0:3d9c67d97d6f 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
emh203 0:3d9c67d97d6f 38 * POSSIBILITY OF SUCH DAMAGE.
emh203 0:3d9c67d97d6f 39 * -------------------------------------------------------------------- */
emh203 0:3d9c67d97d6f 40
emh203 0:3d9c67d97d6f 41 #include "arm_math.h"
emh203 0:3d9c67d97d6f 42
emh203 0:3d9c67d97d6f 43 /**
emh203 0:3d9c67d97d6f 44 * @ingroup groupStats
emh203 0:3d9c67d97d6f 45 */
emh203 0:3d9c67d97d6f 46
emh203 0:3d9c67d97d6f 47 /**
emh203 0:3d9c67d97d6f 48 * @addtogroup variance
emh203 0:3d9c67d97d6f 49 * @{
emh203 0:3d9c67d97d6f 50 */
emh203 0:3d9c67d97d6f 51
emh203 0:3d9c67d97d6f 52 /**
emh203 0:3d9c67d97d6f 53 * @brief Variance of the elements of a Q15 vector.
emh203 0:3d9c67d97d6f 54 * @param[in] *pSrc points to the input vector
emh203 0:3d9c67d97d6f 55 * @param[in] blockSize length of the input vector
emh203 0:3d9c67d97d6f 56 * @param[out] *pResult variance value returned here
emh203 0:3d9c67d97d6f 57 * @return none.
emh203 0:3d9c67d97d6f 58 *
emh203 0:3d9c67d97d6f 59 * @details
emh203 0:3d9c67d97d6f 60 * <b>Scaling and Overflow Behavior:</b>
emh203 0:3d9c67d97d6f 61 *
emh203 0:3d9c67d97d6f 62 * \par
emh203 0:3d9c67d97d6f 63 * The function is implemented using a 64-bit internal accumulator.
emh203 0:3d9c67d97d6f 64 * The input is represented in 1.15 format.
emh203 0:3d9c67d97d6f 65 * Intermediate multiplication yields a 2.30 format, and this
emh203 0:3d9c67d97d6f 66 * result is added without saturation to a 64-bit accumulator in 34.30 format.
emh203 0:3d9c67d97d6f 67 * With 33 guard bits in the accumulator, there is no risk of overflow, and the
emh203 0:3d9c67d97d6f 68 * full precision of the intermediate multiplication is preserved.
emh203 0:3d9c67d97d6f 69 * Finally, the 34.30 result is truncated to 34.15 format by discarding the lower
emh203 0:3d9c67d97d6f 70 * 15 bits, and then saturated to yield a result in 1.15 format.
emh203 0:3d9c67d97d6f 71 *
emh203 0:3d9c67d97d6f 72 */
emh203 0:3d9c67d97d6f 73
emh203 0:3d9c67d97d6f 74
emh203 0:3d9c67d97d6f 75 void arm_var_q15(
emh203 0:3d9c67d97d6f 76 q15_t * pSrc,
emh203 0:3d9c67d97d6f 77 uint32_t blockSize,
emh203 0:3d9c67d97d6f 78 q15_t * pResult)
emh203 0:3d9c67d97d6f 79 {
emh203 0:3d9c67d97d6f 80
emh203 0:3d9c67d97d6f 81 q31_t sum = 0; /* Accumulator */
emh203 0:3d9c67d97d6f 82 q31_t meanOfSquares, squareOfMean; /* square of mean and mean of square */
emh203 0:3d9c67d97d6f 83 uint32_t blkCnt; /* loop counter */
emh203 0:3d9c67d97d6f 84 q63_t sumOfSquares = 0; /* Accumulator */
emh203 0:3d9c67d97d6f 85
emh203 0:3d9c67d97d6f 86 #ifndef ARM_MATH_CM0_FAMILY
emh203 0:3d9c67d97d6f 87
emh203 0:3d9c67d97d6f 88 /* Run the below code for Cortex-M4 and Cortex-M3 */
emh203 0:3d9c67d97d6f 89
emh203 0:3d9c67d97d6f 90 q31_t in; /* input value */
emh203 0:3d9c67d97d6f 91 q15_t in1; /* input value */
emh203 0:3d9c67d97d6f 92
emh203 0:3d9c67d97d6f 93 if(blockSize == 1)
emh203 0:3d9c67d97d6f 94 {
emh203 0:3d9c67d97d6f 95 *pResult = 0;
emh203 0:3d9c67d97d6f 96 return;
emh203 0:3d9c67d97d6f 97 }
emh203 0:3d9c67d97d6f 98
emh203 0:3d9c67d97d6f 99 /*loop Unrolling */
emh203 0:3d9c67d97d6f 100 blkCnt = blockSize >> 2u;
emh203 0:3d9c67d97d6f 101
emh203 0:3d9c67d97d6f 102 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emh203 0:3d9c67d97d6f 103 ** a second loop below computes the remaining 1 to 3 samples. */
emh203 0:3d9c67d97d6f 104 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 105 {
emh203 0:3d9c67d97d6f 106 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 107 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 108 * and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 109 in = *__SIMD32(pSrc)++;
emh203 0:3d9c67d97d6f 110 sum += ((in << 16) >> 16);
emh203 0:3d9c67d97d6f 111 sum += (in >> 16);
emh203 0:3d9c67d97d6f 112 sumOfSquares = __SMLALD(in, in, sumOfSquares);
emh203 0:3d9c67d97d6f 113 in = *__SIMD32(pSrc)++;
emh203 0:3d9c67d97d6f 114 sum += ((in << 16) >> 16);
emh203 0:3d9c67d97d6f 115 sum += (in >> 16);
emh203 0:3d9c67d97d6f 116 sumOfSquares = __SMLALD(in, in, sumOfSquares);
emh203 0:3d9c67d97d6f 117
emh203 0:3d9c67d97d6f 118 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 119 blkCnt--;
emh203 0:3d9c67d97d6f 120 }
emh203 0:3d9c67d97d6f 121
emh203 0:3d9c67d97d6f 122 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emh203 0:3d9c67d97d6f 123 ** No loop unrolling is used. */
emh203 0:3d9c67d97d6f 124 blkCnt = blockSize % 0x4u;
emh203 0:3d9c67d97d6f 125
emh203 0:3d9c67d97d6f 126 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 127 {
emh203 0:3d9c67d97d6f 128 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 129 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 130 * and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 131 in1 = *pSrc++;
emh203 0:3d9c67d97d6f 132 sumOfSquares = __SMLALD(in1, in1, sumOfSquares);
emh203 0:3d9c67d97d6f 133 sum += in1;
emh203 0:3d9c67d97d6f 134
emh203 0:3d9c67d97d6f 135 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 136 blkCnt--;
emh203 0:3d9c67d97d6f 137 }
emh203 0:3d9c67d97d6f 138
emh203 0:3d9c67d97d6f 139 /* Compute Mean of squares of the input samples
emh203 0:3d9c67d97d6f 140 * and then store the result in a temporary variable, meanOfSquares. */
emh203 0:3d9c67d97d6f 141 meanOfSquares = (q31_t) (sumOfSquares / (q63_t)(blockSize - 1));
emh203 0:3d9c67d97d6f 142
emh203 0:3d9c67d97d6f 143 /* Compute square of mean */
emh203 0:3d9c67d97d6f 144 squareOfMean = (q31_t)((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1)));
emh203 0:3d9c67d97d6f 145
emh203 0:3d9c67d97d6f 146 /* mean of the squares minus the square of the mean. */
emh203 0:3d9c67d97d6f 147 *pResult = (meanOfSquares - squareOfMean) >> 15;
emh203 0:3d9c67d97d6f 148
emh203 0:3d9c67d97d6f 149 #else
emh203 0:3d9c67d97d6f 150
emh203 0:3d9c67d97d6f 151 /* Run the below code for Cortex-M0 */
emh203 0:3d9c67d97d6f 152 q15_t in; /* input value */
emh203 0:3d9c67d97d6f 153
emh203 0:3d9c67d97d6f 154 if(blockSize == 1)
emh203 0:3d9c67d97d6f 155 {
emh203 0:3d9c67d97d6f 156 *pResult = 0;
emh203 0:3d9c67d97d6f 157 return;
emh203 0:3d9c67d97d6f 158 }
emh203 0:3d9c67d97d6f 159
emh203 0:3d9c67d97d6f 160 /* Loop over blockSize number of values */
emh203 0:3d9c67d97d6f 161 blkCnt = blockSize;
emh203 0:3d9c67d97d6f 162
emh203 0:3d9c67d97d6f 163 while(blkCnt > 0u)
emh203 0:3d9c67d97d6f 164 {
emh203 0:3d9c67d97d6f 165 /* C = (A[0] * A[0] + A[1] * A[1] + ... + A[blockSize-1] * A[blockSize-1]) */
emh203 0:3d9c67d97d6f 166 /* Compute Sum of squares of the input samples
emh203 0:3d9c67d97d6f 167 * and then store the result in a temporary variable, sumOfSquares. */
emh203 0:3d9c67d97d6f 168 in = *pSrc++;
emh203 0:3d9c67d97d6f 169 sumOfSquares += (in * in);
emh203 0:3d9c67d97d6f 170
emh203 0:3d9c67d97d6f 171 /* C = (A[0] + A[1] + A[2] + ... + A[blockSize-1]) */
emh203 0:3d9c67d97d6f 172 /* Compute sum of all input values and then store the result in a temporary variable, sum. */
emh203 0:3d9c67d97d6f 173 sum += in;
emh203 0:3d9c67d97d6f 174
emh203 0:3d9c67d97d6f 175 /* Decrement the loop counter */
emh203 0:3d9c67d97d6f 176 blkCnt--;
emh203 0:3d9c67d97d6f 177 }
emh203 0:3d9c67d97d6f 178
emh203 0:3d9c67d97d6f 179 /* Compute Mean of squares of the input samples
emh203 0:3d9c67d97d6f 180 * and then store the result in a temporary variable, meanOfSquares. */
emh203 0:3d9c67d97d6f 181 meanOfSquares = (q31_t) (sumOfSquares / (q63_t)(blockSize - 1));
emh203 0:3d9c67d97d6f 182
emh203 0:3d9c67d97d6f 183 /* Compute square of mean */
emh203 0:3d9c67d97d6f 184 squareOfMean = (q31_t)((q63_t)sum * sum / (q63_t)(blockSize * (blockSize - 1)));
emh203 0:3d9c67d97d6f 185
emh203 0:3d9c67d97d6f 186 /* mean of the squares minus the square of the mean. */
emh203 0:3d9c67d97d6f 187 *pResult = (meanOfSquares - squareOfMean) >> 15;
emh203 0:3d9c67d97d6f 188
emh203 0:3d9c67d97d6f 189 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emh203 0:3d9c67d97d6f 190
emh203 0:3d9c67d97d6f 191 }
emh203 0:3d9c67d97d6f 192
emh203 0:3d9c67d97d6f 193 /**
emh203 0:3d9c67d97d6f 194 * @} end of variance group
emh203 0:3d9c67d97d6f 195 */