| 1 | /* ----------------------------------------------------------------------
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| 2 | * Project: CMSIS DSP Library
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| 3 | * Title: arm_abs_q7.c
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| 4 | * Description: Q7 vector absolute value
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| 5 | *
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| 6 | * $Date: 27. January 2017
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| 7 | * $Revision: V.1.5.1
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| 8 | *
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| 9 | * Target Processor: Cortex-M cores
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| 10 | * -------------------------------------------------------------------- */
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| 11 | /*
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| 12 | * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
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| 13 | *
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| 14 | * SPDX-License-Identifier: Apache-2.0
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| 15 | *
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| 16 | * Licensed under the Apache License, Version 2.0 (the License); you may
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| 17 | * not use this file except in compliance with the License.
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| 18 | * You may obtain a copy of the License at
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| 19 | *
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| 20 | * www.apache.org/licenses/LICENSE-2.0
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| 21 | *
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| 22 | * Unless required by applicable law or agreed to in writing, software
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| 23 | * distributed under the License is distributed on an AS IS BASIS, WITHOUT
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| 24 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| 25 | * See the License for the specific language governing permissions and
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| 26 | * limitations under the License.
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| 27 | */
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| 28 |
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| 29 | #include "arm_math.h"
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| 30 |
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| 31 | /**
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| 32 | * @ingroup groupMath
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| 33 | */
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| 34 |
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| 35 | /**
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| 36 | * @addtogroup BasicAbs
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| 37 | * @{
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| 38 | */
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| 39 |
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| 40 | /**
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| 41 | * @brief Q7 vector absolute value.
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| 42 | * @param[in] *pSrc points to the input buffer
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| 43 | * @param[out] *pDst points to the output buffer
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| 44 | * @param[in] blockSize number of samples in each vector
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| 45 | * @return none.
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| 46 | *
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| 47 | * \par Conditions for optimum performance
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| 48 | * Input and output buffers should be aligned by 32-bit
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| 49 | *
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| 50 | *
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| 51 | * <b>Scaling and Overflow Behavior:</b>
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| 52 | * \par
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| 53 | * The function uses saturating arithmetic.
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| 54 | * The Q7 value -1 (0x80) will be saturated to the maximum allowable positive value 0x7F.
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| 55 | */
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| 56 |
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| 57 | void arm_abs_q7(
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| 58 | q7_t * pSrc,
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| 59 | q7_t * pDst,
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| 60 | uint32_t blockSize)
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| 61 | {
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| 62 | uint32_t blkCnt; /* loop counter */
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| 63 | q7_t in; /* Input value1 */
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| 64 |
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| 65 | #if defined (ARM_MATH_DSP)
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| 66 |
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| 67 | /* Run the below code for Cortex-M4 and Cortex-M3 */
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| 68 | q31_t in1, in2, in3, in4; /* temporary input variables */
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| 69 | q31_t out1, out2, out3, out4; /* temporary output variables */
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| 70 |
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| 71 | /*loop Unrolling */
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| 72 | blkCnt = blockSize >> 2U;
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| 73 |
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| 74 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
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| 75 | ** a second loop below computes the remaining 1 to 3 samples. */
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| 76 | while (blkCnt > 0U)
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| 77 | {
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| 78 | /* C = |A| */
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| 79 | /* Read inputs */
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| 80 | in1 = (q31_t) * pSrc;
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| 81 | in2 = (q31_t) * (pSrc + 1);
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| 82 | in3 = (q31_t) * (pSrc + 2);
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| 83 |
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| 84 | /* find absolute value */
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| 85 | out1 = (in1 > 0) ? in1 : (q31_t)__QSUB8(0, in1);
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| 86 |
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| 87 | /* read input */
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| 88 | in4 = (q31_t) * (pSrc + 3);
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| 89 |
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| 90 | /* find absolute value */
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| 91 | out2 = (in2 > 0) ? in2 : (q31_t)__QSUB8(0, in2);
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| 92 |
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| 93 | /* store result to destination */
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| 94 | *pDst = (q7_t) out1;
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| 95 |
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| 96 | /* find absolute value */
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| 97 | out3 = (in3 > 0) ? in3 : (q31_t)__QSUB8(0, in3);
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| 98 |
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| 99 | /* find absolute value */
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| 100 | out4 = (in4 > 0) ? in4 : (q31_t)__QSUB8(0, in4);
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| 101 |
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| 102 | /* store result to destination */
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| 103 | *(pDst + 1) = (q7_t) out2;
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| 104 |
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| 105 | /* store result to destination */
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| 106 | *(pDst + 2) = (q7_t) out3;
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| 107 |
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| 108 | /* store result to destination */
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| 109 | *(pDst + 3) = (q7_t) out4;
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| 110 |
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| 111 | /* update pointers to process next samples */
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| 112 | pSrc += 4U;
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| 113 | pDst += 4U;
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| 114 |
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| 115 | /* Decrement the loop counter */
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| 116 | blkCnt--;
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| 117 | }
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| 118 |
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| 119 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
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| 120 | ** No loop unrolling is used. */
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| 121 | blkCnt = blockSize % 0x4U;
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| 122 | #else
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| 123 |
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| 124 | /* Run the below code for Cortex-M0 */
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| 125 | blkCnt = blockSize;
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| 126 |
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| 127 | #endif /* #define ARM_MATH_CM0_FAMILY */
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| 128 |
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| 129 | while (blkCnt > 0U)
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| 130 | {
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| 131 | /* C = |A| */
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| 132 | /* Read the input */
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| 133 | in = *pSrc++;
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| 134 |
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| 135 | /* Store the Absolute result in the destination buffer */
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| 136 | *pDst++ = (in > 0) ? in : ((in == (q7_t) 0x80) ? 0x7f : -in);
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| 137 |
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| 138 | /* Decrement the loop counter */
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| 139 | blkCnt--;
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| 140 | }
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| 141 | }
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| 142 |
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| 143 | /**
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| 144 | * @} end of BasicAbs group
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| 145 | */
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