Analog Devices / Mbed OS EVAL-CN0540-ARDZ

Dependencies:   platform_drivers LTC26X6 AD77681

CMSIS-DSP_Lib/Source/StatisticsFunctions/arm_rms_q31.c@1:9dd7c64b4a64, 2021-12-06 (annotated)

Committer:
jngarlitos
Date:
Mon Dec 06 05:22:28 2021 +0000
Revision:
1:9dd7c64b4a64
EVAL-CN0540-ARDZ mbed example program Initial Commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jngarlitos 1:9dd7c64b4a64 1 /* ----------------------------------------------------------------------
jngarlitos 1:9dd7c64b4a64 2 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.
jngarlitos 1:9dd7c64b4a64 3 *
jngarlitos 1:9dd7c64b4a64 4 * $Date: 19. March 2015
jngarlitos 1:9dd7c64b4a64 5 * $Revision: V.1.4.5
jngarlitos 1:9dd7c64b4a64 6 *
jngarlitos 1:9dd7c64b4a64 7 * Project: CMSIS DSP Library
jngarlitos 1:9dd7c64b4a64 8 * Title: arm_rms_q31.c
jngarlitos 1:9dd7c64b4a64 9 *
jngarlitos 1:9dd7c64b4a64 10 * Description: Root Mean Square of the elements of a Q31 vector.
jngarlitos 1:9dd7c64b4a64 11 *
jngarlitos 1:9dd7c64b4a64 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
jngarlitos 1:9dd7c64b4a64 13 *
jngarlitos 1:9dd7c64b4a64 14 * Redistribution and use in source and binary forms, with or without
jngarlitos 1:9dd7c64b4a64 15 * modification, are permitted provided that the following conditions
jngarlitos 1:9dd7c64b4a64 16 * are met:
jngarlitos 1:9dd7c64b4a64 17 * - Redistributions of source code must retain the above copyright
jngarlitos 1:9dd7c64b4a64 18 * notice, this list of conditions and the following disclaimer.
jngarlitos 1:9dd7c64b4a64 19 * - Redistributions in binary form must reproduce the above copyright
jngarlitos 1:9dd7c64b4a64 20 * notice, this list of conditions and the following disclaimer in
jngarlitos 1:9dd7c64b4a64 21 * the documentation and/or other materials provided with the
jngarlitos 1:9dd7c64b4a64 22 * distribution.
jngarlitos 1:9dd7c64b4a64 23 * - Neither the name of ARM LIMITED nor the names of its contributors
jngarlitos 1:9dd7c64b4a64 24 * may be used to endorse or promote products derived from this
jngarlitos 1:9dd7c64b4a64 25 * software without specific prior written permission.
jngarlitos 1:9dd7c64b4a64 26 *
jngarlitos 1:9dd7c64b4a64 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
jngarlitos 1:9dd7c64b4a64 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
jngarlitos 1:9dd7c64b4a64 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
jngarlitos 1:9dd7c64b4a64 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
jngarlitos 1:9dd7c64b4a64 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
jngarlitos 1:9dd7c64b4a64 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
jngarlitos 1:9dd7c64b4a64 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
jngarlitos 1:9dd7c64b4a64 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
jngarlitos 1:9dd7c64b4a64 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
jngarlitos 1:9dd7c64b4a64 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
jngarlitos 1:9dd7c64b4a64 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
jngarlitos 1:9dd7c64b4a64 38 * POSSIBILITY OF SUCH DAMAGE.
jngarlitos 1:9dd7c64b4a64 39 * ---------------------------------------------------------------------------- */
jngarlitos 1:9dd7c64b4a64 40
jngarlitos 1:9dd7c64b4a64 41 #include "arm_math.h"
jngarlitos 1:9dd7c64b4a64 42
jngarlitos 1:9dd7c64b4a64 43 /**
jngarlitos 1:9dd7c64b4a64 44 * @addtogroup RMS
jngarlitos 1:9dd7c64b4a64 45 * @{
jngarlitos 1:9dd7c64b4a64 46 */
jngarlitos 1:9dd7c64b4a64 47
jngarlitos 1:9dd7c64b4a64 48
jngarlitos 1:9dd7c64b4a64 49 /**
jngarlitos 1:9dd7c64b4a64 50 * @brief Root Mean Square of the elements of a Q31 vector.
jngarlitos 1:9dd7c64b4a64 51 * @param[in] *pSrc points to the input vector
jngarlitos 1:9dd7c64b4a64 52 * @param[in] blockSize length of the input vector
jngarlitos 1:9dd7c64b4a64 53 * @param[out] *pResult rms value returned here
jngarlitos 1:9dd7c64b4a64 54 * @return none.
jngarlitos 1:9dd7c64b4a64 55 *
jngarlitos 1:9dd7c64b4a64 56 * @details
jngarlitos 1:9dd7c64b4a64 57 * <b>Scaling and Overflow Behavior:</b>
jngarlitos 1:9dd7c64b4a64 58 *
jngarlitos 1:9dd7c64b4a64 59 *\par
jngarlitos 1:9dd7c64b4a64 60 * The function is implemented using an internal 64-bit accumulator.
jngarlitos 1:9dd7c64b4a64 61 * The input is represented in 1.31 format, and intermediate multiplication
jngarlitos 1:9dd7c64b4a64 62 * yields a 2.62 format.
jngarlitos 1:9dd7c64b4a64 63 * The accumulator maintains full precision of the intermediate multiplication results,
jngarlitos 1:9dd7c64b4a64 64 * but provides only a single guard bit.
jngarlitos 1:9dd7c64b4a64 65 * There is no saturation on intermediate additions.
jngarlitos 1:9dd7c64b4a64 66 * If the accumulator overflows, it wraps around and distorts the result.
jngarlitos 1:9dd7c64b4a64 67 * In order to avoid overflows completely, the input signal must be scaled down by
jngarlitos 1:9dd7c64b4a64 68 * log2(blockSize) bits, as a total of blockSize additions are performed internally.
jngarlitos 1:9dd7c64b4a64 69 * Finally, the 2.62 accumulator is right shifted by 31 bits to yield a 1.31 format value.
jngarlitos 1:9dd7c64b4a64 70 *
jngarlitos 1:9dd7c64b4a64 71 */
jngarlitos 1:9dd7c64b4a64 72
jngarlitos 1:9dd7c64b4a64 73 void arm_rms_q31(
jngarlitos 1:9dd7c64b4a64 74 q31_t * pSrc,
jngarlitos 1:9dd7c64b4a64 75 uint32_t blockSize,
jngarlitos 1:9dd7c64b4a64 76 q31_t * pResult)
jngarlitos 1:9dd7c64b4a64 77 {
jngarlitos 1:9dd7c64b4a64 78 q63_t sum = 0; /* accumulator */
jngarlitos 1:9dd7c64b4a64 79 q31_t in; /* Temporary variable to store the input */
jngarlitos 1:9dd7c64b4a64 80 uint32_t blkCnt; /* loop counter */
jngarlitos 1:9dd7c64b4a64 81
jngarlitos 1:9dd7c64b4a64 82 #ifndef ARM_MATH_CM0_FAMILY
jngarlitos 1:9dd7c64b4a64 83
jngarlitos 1:9dd7c64b4a64 84 /* Run the below code for Cortex-M4 and Cortex-M3 */
jngarlitos 1:9dd7c64b4a64 85
jngarlitos 1:9dd7c64b4a64 86 q31_t in1, in2, in3, in4; /* Temporary input variables */
jngarlitos 1:9dd7c64b4a64 87
jngarlitos 1:9dd7c64b4a64 88 /*loop Unrolling */
jngarlitos 1:9dd7c64b4a64 89 blkCnt = blockSize >> 2u;
jngarlitos 1:9dd7c64b4a64 90
jngarlitos 1:9dd7c64b4a64 91 /* First part of the processing with loop unrolling. Compute 8 outputs at a time.
jngarlitos 1:9dd7c64b4a64 92 ** a second loop below computes the remaining 1 to 7 samples. */
jngarlitos 1:9dd7c64b4a64 93 while(blkCnt > 0u)
jngarlitos 1:9dd7c64b4a64 94 {
jngarlitos 1:9dd7c64b4a64 95 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
jngarlitos 1:9dd7c64b4a64 96 /* Compute sum of the squares and then store the result in a temporary variable, sum */
jngarlitos 1:9dd7c64b4a64 97 /* read two samples from source buffer */
jngarlitos 1:9dd7c64b4a64 98 in1 = pSrc[0];
jngarlitos 1:9dd7c64b4a64 99 in2 = pSrc[1];
jngarlitos 1:9dd7c64b4a64 100
jngarlitos 1:9dd7c64b4a64 101 /* calculate power and accumulate to accumulator */
jngarlitos 1:9dd7c64b4a64 102 sum += (q63_t) in1 *in1;
jngarlitos 1:9dd7c64b4a64 103 sum += (q63_t) in2 *in2;
jngarlitos 1:9dd7c64b4a64 104
jngarlitos 1:9dd7c64b4a64 105 /* read two samples from source buffer */
jngarlitos 1:9dd7c64b4a64 106 in3 = pSrc[2];
jngarlitos 1:9dd7c64b4a64 107 in4 = pSrc[3];
jngarlitos 1:9dd7c64b4a64 108
jngarlitos 1:9dd7c64b4a64 109 /* calculate power and accumulate to accumulator */
jngarlitos 1:9dd7c64b4a64 110 sum += (q63_t) in3 *in3;
jngarlitos 1:9dd7c64b4a64 111 sum += (q63_t) in4 *in4;
jngarlitos 1:9dd7c64b4a64 112
jngarlitos 1:9dd7c64b4a64 113
jngarlitos 1:9dd7c64b4a64 114 /* update source buffer to process next samples */
jngarlitos 1:9dd7c64b4a64 115 pSrc += 4u;
jngarlitos 1:9dd7c64b4a64 116
jngarlitos 1:9dd7c64b4a64 117 /* Decrement the loop counter */
jngarlitos 1:9dd7c64b4a64 118 blkCnt--;
jngarlitos 1:9dd7c64b4a64 119 }
jngarlitos 1:9dd7c64b4a64 120
jngarlitos 1:9dd7c64b4a64 121 /* If the blockSize is not a multiple of 8, compute any remaining output samples here.
jngarlitos 1:9dd7c64b4a64 122 ** No loop unrolling is used. */
jngarlitos 1:9dd7c64b4a64 123 blkCnt = blockSize % 0x4u;
jngarlitos 1:9dd7c64b4a64 124
jngarlitos 1:9dd7c64b4a64 125 #else
jngarlitos 1:9dd7c64b4a64 126
jngarlitos 1:9dd7c64b4a64 127 /* Run the below code for Cortex-M0 */
jngarlitos 1:9dd7c64b4a64 128 blkCnt = blockSize;
jngarlitos 1:9dd7c64b4a64 129
jngarlitos 1:9dd7c64b4a64 130 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
jngarlitos 1:9dd7c64b4a64 131
jngarlitos 1:9dd7c64b4a64 132 while(blkCnt > 0u)
jngarlitos 1:9dd7c64b4a64 133 {
jngarlitos 1:9dd7c64b4a64 134 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
jngarlitos 1:9dd7c64b4a64 135 /* Compute sum of the squares and then store the results in a temporary variable, sum */
jngarlitos 1:9dd7c64b4a64 136 in = *pSrc++;
jngarlitos 1:9dd7c64b4a64 137 sum += (q63_t) in *in;
jngarlitos 1:9dd7c64b4a64 138
jngarlitos 1:9dd7c64b4a64 139 /* Decrement the loop counter */
jngarlitos 1:9dd7c64b4a64 140 blkCnt--;
jngarlitos 1:9dd7c64b4a64 141 }
jngarlitos 1:9dd7c64b4a64 142
jngarlitos 1:9dd7c64b4a64 143 /* Convert data in 2.62 to 1.31 by 31 right shifts and saturate */
jngarlitos 1:9dd7c64b4a64 144 /* Compute Rms and store the result in the destination vector */
jngarlitos 1:9dd7c64b4a64 145 arm_sqrt_q31(clip_q63_to_q31((sum / (q63_t) blockSize) >> 31), pResult);
jngarlitos 1:9dd7c64b4a64 146 }
jngarlitos 1:9dd7c64b4a64 147
jngarlitos 1:9dd7c64b4a64 148 /**
jngarlitos 1:9dd7c64b4a64 149 * @} end of RMS group
jngarlitos 1:9dd7c64b4a64 150 */