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| 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_abs_q15.c |
| 9 | +* |
| 10 | +* Description: Q15 vector absolute value. |
| 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 groupMath |
| 45 | + */ |
| 46 | + |
| 47 | +/** |
| 48 | + * @addtogroup BasicAbs |
| 49 | + * @{ |
| 50 | + */ |
| 51 | + |
| 52 | +/** |
| 53 | + * @brief Q15 vector absolute value. |
| 54 | + * @param[in] *pSrc points to the input buffer |
| 55 | + * @param[out] *pDst points to the output buffer |
| 56 | + * @param[in] blockSize number of samples in each vector |
| 57 | + * @return none. |
| 58 | + * |
| 59 | + * <b>Scaling and Overflow Behavior:</b> |
| 60 | + * \par |
| 61 | + * The function uses saturating arithmetic. |
| 62 | + * The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF. |
| 63 | + */ |
| 64 | + |
| 65 | +void arm_abs_q15( |
| 66 | + q15_t * pSrc, |
| 67 | + q15_t * pDst, |
| 68 | + uint32_t blockSize) |
| 69 | +{ |
| 70 | + uint32_t blkCnt; /* loop counter */ |
| 71 | + |
| 72 | +#ifndef ARM_MATH_CM0_FAMILY |
| 73 | + __SIMD32_TYPE *simd; |
| 74 | + |
| 75 | +/* Run the below code for Cortex-M4 and Cortex-M3 */ |
| 76 | + |
| 77 | + q15_t in1; /* Input value1 */ |
| 78 | + q15_t in2; /* Input value2 */ |
| 79 | + |
| 80 | + |
| 81 | + /*loop Unrolling */ |
| 82 | + blkCnt = blockSize >> 2u; |
| 83 | + |
| 84 | + /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
| 85 | + ** a second loop below computes the remaining 1 to 3 samples. */ |
| 86 | + simd = __SIMD32_CONST(pDst); |
| 87 | + while(blkCnt > 0u) |
| 88 | + { |
| 89 | + /* C = |A| */ |
| 90 | + /* Read two inputs */ |
| 91 | + in1 = *pSrc++; |
| 92 | + in2 = *pSrc++; |
| 93 | + |
| 94 | + |
| 95 | + /* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */ |
| 96 | +#ifndef ARM_MATH_BIG_ENDIAN |
| 97 | + *simd++ = |
| 98 | + __PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), |
| 99 | + ((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16); |
| 100 | + |
| 101 | +#else |
| 102 | + |
| 103 | + |
| 104 | + *simd++ = |
| 105 | + __PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), |
| 106 | + ((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16); |
| 107 | + |
| 108 | +#endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| 109 | + |
| 110 | + in1 = *pSrc++; |
| 111 | + in2 = *pSrc++; |
| 112 | + |
| 113 | + |
| 114 | +#ifndef ARM_MATH_BIG_ENDIAN |
| 115 | + |
| 116 | + *simd++ = |
| 117 | + __PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), |
| 118 | + ((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16); |
| 119 | + |
| 120 | +#else |
| 121 | + |
| 122 | + |
| 123 | + *simd++ = |
| 124 | + __PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), |
| 125 | + ((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16); |
| 126 | + |
| 127 | +#endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
| 128 | + |
| 129 | + /* Decrement the loop counter */ |
| 130 | + blkCnt--; |
| 131 | + } |
| 132 | + pDst = (q15_t *)simd; |
| 133 | + |
| 134 | + /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
| 135 | + ** No loop unrolling is used. */ |
| 136 | + blkCnt = blockSize % 0x4u; |
| 137 | + |
| 138 | + while(blkCnt > 0u) |
| 139 | + { |
| 140 | + /* C = |A| */ |
| 141 | + /* Read the input */ |
| 142 | + in1 = *pSrc++; |
| 143 | + |
| 144 | + /* Calculate absolute value of input and then store the result in the destination buffer. */ |
| 145 | + *pDst++ = (in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1); |
| 146 | + |
| 147 | + /* Decrement the loop counter */ |
| 148 | + blkCnt--; |
| 149 | + } |
| 150 | + |
| 151 | +#else |
| 152 | + |
| 153 | + /* Run the below code for Cortex-M0 */ |
| 154 | + |
| 155 | + q15_t in; /* Temporary input variable */ |
| 156 | + |
| 157 | + /* Initialize blkCnt with number of samples */ |
| 158 | + blkCnt = blockSize; |
| 159 | + |
| 160 | + while(blkCnt > 0u) |
| 161 | + { |
| 162 | + /* C = |A| */ |
| 163 | + /* Read the input */ |
| 164 | + in = *pSrc++; |
| 165 | + |
| 166 | + /* Calculate absolute value of input and then store the result in the destination buffer. */ |
| 167 | + *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in); |
| 168 | + |
| 169 | + /* Decrement the loop counter */ |
| 170 | + blkCnt--; |
| 171 | + } |
| 172 | + |
| 173 | +#endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
| 174 | + |
| 175 | +} |
| 176 | + |
| 177 | +/** |
| 178 | + * @} end of BasicAbs group |
| 179 | + */ |
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