Laxmi Kant Tiwari / mbed-dsp

CMSIS DSP Lib

Fork of mbed-dsp by mbed official

cmsis_dsp/BasicMathFunctions/arm_abs_q31.c@4:9cee975aadce, 2014-06-23 (annotated)

Committer:
mbed_official
Date:
Mon Jun 23 09:30:09 2014 +0100
Revision:
4:9cee975aadce
Parent:
3:7a284390b0ce 
Synchronized with git revision 6e7c7bcec41226f536474daae3c13d49e4c0e865



Full URL: https://github.com/mbedmicro/mbed/commit/6e7c7bcec41226f536474daae3c13d49e4c0e865/



Fix signed unsigned compare in dsp library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------
mbed_official 3:7a284390b0ce 2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
mbed_official 3:7a284390b0ce 4 * $Date: 17. January 2013
mbed_official 3:7a284390b0ce 5 * $Revision: V1.4.1
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_abs_q31.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Q31 vector absolute value.
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
mbed_official 3:7a284390b0ce 14 * Redistribution and use in source and binary forms, with or without
mbed_official 3:7a284390b0ce 15 * modification, are permitted provided that the following conditions
mbed_official 3:7a284390b0ce 16 * are met:
mbed_official 3:7a284390b0ce 17 * - Redistributions of source code must retain the above copyright
mbed_official 3:7a284390b0ce 18 * notice, this list of conditions and the following disclaimer.
mbed_official 3:7a284390b0ce 19 * - Redistributions in binary form must reproduce the above copyright
mbed_official 3:7a284390b0ce 20 * notice, this list of conditions and the following disclaimer in
mbed_official 3:7a284390b0ce 21 * the documentation and/or other materials provided with the
mbed_official 3:7a284390b0ce 22 * distribution.
mbed_official 3:7a284390b0ce 23 * - Neither the name of ARM LIMITED nor the names of its contributors
mbed_official 3:7a284390b0ce 24 * may be used to endorse or promote products derived from this
mbed_official 3:7a284390b0ce 25 * software without specific prior written permission.
mbed_official 3:7a284390b0ce 26 *
mbed_official 3:7a284390b0ce 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
mbed_official 3:7a284390b0ce 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
mbed_official 3:7a284390b0ce 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
mbed_official 3:7a284390b0ce 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
mbed_official 3:7a284390b0ce 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
mbed_official 3:7a284390b0ce 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
mbed_official 3:7a284390b0ce 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
mbed_official 3:7a284390b0ce 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 3:7a284390b0ce 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
mbed_official 3:7a284390b0ce 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
mbed_official 3:7a284390b0ce 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
mbed_official 3:7a284390b0ce 38 * POSSIBILITY OF SUCH DAMAGE.
emilmont 1:fdd22bb7aa52 39 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 40
emilmont 1:fdd22bb7aa52 41 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 42
emilmont 1:fdd22bb7aa52 43 /**
emilmont 1:fdd22bb7aa52 44 * @ingroup groupMath
emilmont 1:fdd22bb7aa52 45 */
emilmont 1:fdd22bb7aa52 46
emilmont 1:fdd22bb7aa52 47 /**
emilmont 1:fdd22bb7aa52 48 * @addtogroup BasicAbs
emilmont 1:fdd22bb7aa52 49 * @{
emilmont 1:fdd22bb7aa52 50 */
emilmont 1:fdd22bb7aa52 51
emilmont 1:fdd22bb7aa52 52
emilmont 1:fdd22bb7aa52 53 /**
emilmont 1:fdd22bb7aa52 54 * @brief Q31 vector absolute value.
emilmont 1:fdd22bb7aa52 55 * @param[in] *pSrc points to the input buffer
emilmont 1:fdd22bb7aa52 56 * @param[out] *pDst points to the output buffer
emilmont 1:fdd22bb7aa52 57 * @param[in] blockSize number of samples in each vector
emilmont 1:fdd22bb7aa52 58 * @return none.
emilmont 1:fdd22bb7aa52 59 *
emilmont 1:fdd22bb7aa52 60 * <b>Scaling and Overflow Behavior:</b>
emilmont 1:fdd22bb7aa52 61 * \par
emilmont 1:fdd22bb7aa52 62 * The function uses saturating arithmetic.
emilmont 1:fdd22bb7aa52 63 * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
emilmont 1:fdd22bb7aa52 64 */
emilmont 1:fdd22bb7aa52 65
emilmont 1:fdd22bb7aa52 66 void arm_abs_q31(
emilmont 1:fdd22bb7aa52 67 q31_t * pSrc,
emilmont 1:fdd22bb7aa52 68 q31_t * pDst,
emilmont 1:fdd22bb7aa52 69 uint32_t blockSize)
emilmont 1:fdd22bb7aa52 70 {
emilmont 1:fdd22bb7aa52 71 uint32_t blkCnt; /* loop counter */
emilmont 1:fdd22bb7aa52 72 q31_t in; /* Input value */
emilmont 1:fdd22bb7aa52 73
mbed_official 3:7a284390b0ce 74 #ifndef ARM_MATH_CM0_FAMILY
emilmont 1:fdd22bb7aa52 75
emilmont 1:fdd22bb7aa52 76 /* Run the below code for Cortex-M4 and Cortex-M3 */
emilmont 1:fdd22bb7aa52 77 q31_t in1, in2, in3, in4;
emilmont 1:fdd22bb7aa52 78
emilmont 1:fdd22bb7aa52 79 /*loop Unrolling */
emilmont 1:fdd22bb7aa52 80 blkCnt = blockSize >> 2u;
emilmont 1:fdd22bb7aa52 81
emilmont 1:fdd22bb7aa52 82 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
emilmont 1:fdd22bb7aa52 83 ** a second loop below computes the remaining 1 to 3 samples. */
emilmont 1:fdd22bb7aa52 84 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 85 {
emilmont 1:fdd22bb7aa52 86 /* C = |A| */
emilmont 1:fdd22bb7aa52 87 /* Calculate absolute of input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
emilmont 1:fdd22bb7aa52 88 in1 = *pSrc++;
emilmont 1:fdd22bb7aa52 89 in2 = *pSrc++;
emilmont 1:fdd22bb7aa52 90 in3 = *pSrc++;
emilmont 1:fdd22bb7aa52 91 in4 = *pSrc++;
emilmont 1:fdd22bb7aa52 92
mbed_official 3:7a284390b0ce 93 *pDst++ = (in1 > 0) ? in1 : (q31_t)__QSUB(0, in1);
mbed_official 3:7a284390b0ce 94 *pDst++ = (in2 > 0) ? in2 : (q31_t)__QSUB(0, in2);
mbed_official 3:7a284390b0ce 95 *pDst++ = (in3 > 0) ? in3 : (q31_t)__QSUB(0, in3);
mbed_official 3:7a284390b0ce 96 *pDst++ = (in4 > 0) ? in4 : (q31_t)__QSUB(0, in4);
emilmont 1:fdd22bb7aa52 97
emilmont 1:fdd22bb7aa52 98 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 99 blkCnt--;
emilmont 1:fdd22bb7aa52 100 }
emilmont 1:fdd22bb7aa52 101
emilmont 1:fdd22bb7aa52 102 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
emilmont 1:fdd22bb7aa52 103 ** No loop unrolling is used. */
emilmont 1:fdd22bb7aa52 104 blkCnt = blockSize % 0x4u;
emilmont 1:fdd22bb7aa52 105
emilmont 1:fdd22bb7aa52 106 #else
emilmont 1:fdd22bb7aa52 107
emilmont 1:fdd22bb7aa52 108 /* Run the below code for Cortex-M0 */
emilmont 1:fdd22bb7aa52 109
emilmont 1:fdd22bb7aa52 110 /* Initialize blkCnt with number of samples */
emilmont 1:fdd22bb7aa52 111 blkCnt = blockSize;
emilmont 1:fdd22bb7aa52 112
mbed_official 3:7a284390b0ce 113 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
emilmont 1:fdd22bb7aa52 114
emilmont 1:fdd22bb7aa52 115 while(blkCnt > 0u)
emilmont 1:fdd22bb7aa52 116 {
emilmont 1:fdd22bb7aa52 117 /* C = |A| */
emilmont 1:fdd22bb7aa52 118 /* Calculate absolute value of the input (if -1 then saturated to 0x7fffffff) and then store the results in the destination buffer. */
emilmont 1:fdd22bb7aa52 119 in = *pSrc++;
mbed_official 3:7a284390b0ce 120 *pDst++ = (in > 0) ? in : ((in == INT32_MIN) ? INT32_MAX : -in);
emilmont 1:fdd22bb7aa52 121
emilmont 1:fdd22bb7aa52 122 /* Decrement the loop counter */
emilmont 1:fdd22bb7aa52 123 blkCnt--;
emilmont 1:fdd22bb7aa52 124 }
emilmont 1:fdd22bb7aa52 125
emilmont 1:fdd22bb7aa52 126 }
emilmont 1:fdd22bb7aa52 127
emilmont 1:fdd22bb7aa52 128 /**
emilmont 1:fdd22bb7aa52 129 * @} end of BasicAbs group
emilmont 1:fdd22bb7aa52 130 */