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| 2 | mjames | 1 | /* ---------------------------------------------------------------------- |
| 2 | * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
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| 3 | * |
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| 4 | * $Date: 19. March 2015 |
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| 5 | * $Revision: V.1.4.5 |
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| 6 | * |
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| 7 | * Project: CMSIS DSP Library |
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| 8 | * Title: arm_abs_q15.c |
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| 9 | * |
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| 10 | * Description: Q15 vector absolute value. |
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| 11 | * |
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| 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
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| 13 | * |
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| 14 | * Redistribution and use in source and binary forms, with or without |
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| 15 | * modification, are permitted provided that the following conditions |
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| 16 | * are met: |
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| 17 | * - Redistributions of source code must retain the above copyright |
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| 18 | * notice, this list of conditions and the following disclaimer. |
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| 19 | * - Redistributions in binary form must reproduce the above copyright |
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| 20 | * notice, this list of conditions and the following disclaimer in |
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| 21 | * the documentation and/or other materials provided with the |
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| 22 | * distribution. |
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| 23 | * - Neither the name of ARM LIMITED nor the names of its contributors |
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| 24 | * may be used to endorse or promote products derived from this |
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| 25 | * software without specific prior written permission. |
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| 26 | * |
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| 27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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| 28 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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| 29 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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| 30 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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| 31 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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| 33 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
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| 34 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
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| 35 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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| 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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| 37 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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| 38 | * POSSIBILITY OF SUCH DAMAGE. |
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| 39 | * -------------------------------------------------------------------- */ |
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| 40 | |||
| 41 | #include "arm_math.h" |
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| 42 | |||
| 43 | /** |
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| 44 | * @ingroup groupMath |
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| 45 | */ |
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| 46 | |||
| 47 | /** |
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| 48 | * @addtogroup BasicAbs |
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| 49 | * @{ |
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| 50 | */ |
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| 51 | |||
| 52 | /** |
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| 53 | * @brief Q15 vector absolute value. |
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| 54 | * @param[in] *pSrc points to the input buffer |
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| 55 | * @param[out] *pDst points to the output buffer |
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| 56 | * @param[in] blockSize number of samples in each vector |
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| 57 | * @return none. |
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| 58 | * |
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| 59 | * <b>Scaling and Overflow Behavior:</b> |
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| 60 | * \par |
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| 61 | * The function uses saturating arithmetic. |
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| 62 | * The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF. |
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| 63 | */ |
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| 64 | |||
| 65 | void arm_abs_q15( |
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| 66 | q15_t * pSrc, |
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| 67 | q15_t * pDst, |
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| 68 | uint32_t blockSize) |
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| 69 | { |
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| 70 | uint32_t blkCnt; /* loop counter */ |
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| 71 | |||
| 72 | #ifndef ARM_MATH_CM0_FAMILY |
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| 73 | __SIMD32_TYPE *simd; |
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| 74 | |||
| 75 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
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| 76 | |||
| 77 | q15_t in1; /* Input value1 */ |
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| 78 | q15_t in2; /* Input value2 */ |
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| 79 | |||
| 80 | |||
| 81 | /*loop Unrolling */ |
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| 82 | blkCnt = blockSize >> 2u; |
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| 83 | |||
| 84 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
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| 85 | ** a second loop below computes the remaining 1 to 3 samples. */ |
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| 86 | simd = __SIMD32_CONST(pDst); |
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| 87 | while(blkCnt > 0u) |
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| 88 | { |
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| 89 | /* C = |A| */ |
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| 90 | /* Read two inputs */ |
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| 91 | in1 = *pSrc++; |
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| 92 | in2 = *pSrc++; |
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| 93 | |||
| 94 | |||
| 95 | /* Store the Absolute result in the destination buffer by packing the two values, in a single cycle */ |
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| 96 | #ifndef ARM_MATH_BIG_ENDIAN |
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| 97 | *simd++ = |
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| 98 | __PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), |
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| 99 | ((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16); |
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| 100 | |||
| 101 | #else |
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| 102 | |||
| 103 | |||
| 104 | *simd++ = |
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| 105 | __PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), |
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| 106 | ((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16); |
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| 107 | |||
| 108 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
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| 109 | |||
| 110 | in1 = *pSrc++; |
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| 111 | in2 = *pSrc++; |
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| 112 | |||
| 113 | |||
| 114 | #ifndef ARM_MATH_BIG_ENDIAN |
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| 115 | |||
| 116 | *simd++ = |
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| 117 | __PKHBT(((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), |
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| 118 | ((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), 16); |
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| 119 | |||
| 120 | #else |
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| 121 | |||
| 122 | |||
| 123 | *simd++ = |
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| 124 | __PKHBT(((in2 > 0) ? in2 : (q15_t)__QSUB16(0, in2)), |
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| 125 | ((in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1)), 16); |
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| 126 | |||
| 127 | #endif /* #ifndef ARM_MATH_BIG_ENDIAN */ |
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| 128 | |||
| 129 | /* Decrement the loop counter */ |
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| 130 | blkCnt--; |
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| 131 | } |
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| 132 | pDst = (q15_t *)simd; |
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| 133 | |||
| 134 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
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| 135 | ** No loop unrolling is used. */ |
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| 136 | blkCnt = blockSize % 0x4u; |
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| 137 | |||
| 138 | while(blkCnt > 0u) |
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| 139 | { |
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| 140 | /* C = |A| */ |
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| 141 | /* Read the input */ |
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| 142 | in1 = *pSrc++; |
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| 143 | |||
| 144 | /* Calculate absolute value of input and then store the result in the destination buffer. */ |
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| 145 | *pDst++ = (in1 > 0) ? in1 : (q15_t)__QSUB16(0, in1); |
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| 146 | |||
| 147 | /* Decrement the loop counter */ |
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| 148 | blkCnt--; |
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| 149 | } |
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| 150 | |||
| 151 | #else |
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| 152 | |||
| 153 | /* Run the below code for Cortex-M0 */ |
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| 154 | |||
| 155 | q15_t in; /* Temporary input variable */ |
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| 156 | |||
| 157 | /* Initialize blkCnt with number of samples */ |
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| 158 | blkCnt = blockSize; |
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| 159 | |||
| 160 | while(blkCnt > 0u) |
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| 161 | { |
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| 162 | /* C = |A| */ |
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| 163 | /* Read the input */ |
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| 164 | in = *pSrc++; |
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| 165 | |||
| 166 | /* Calculate absolute value of input and then store the result in the destination buffer. */ |
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| 167 | *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in); |
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| 168 | |||
| 169 | /* Decrement the loop counter */ |
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| 170 | blkCnt--; |
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| 171 | } |
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| 172 | |||
| 173 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
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| 174 | |||
| 175 | } |
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| 176 | |||
| 177 | /** |
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| 178 | * @} end of BasicAbs group |
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| 179 | */ |