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| 2 | mjames | 1 | /* ---------------------------------------------------------------------- |
| 2 | * Project: CMSIS DSP Library |
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| 3 | * Title: arm_mult_q31.c |
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| 4 | * Description: Q31 vector multiplication |
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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 | |||
| 29 | #include "arm_math.h" |
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| 30 | |||
| 31 | /** |
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| 32 | * @ingroup groupMath |
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| 33 | */ |
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| 34 | |||
| 35 | /** |
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| 36 | * @addtogroup BasicMult |
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| 37 | * @{ |
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| 38 | */ |
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| 39 | |||
| 40 | /** |
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| 41 | * @brief Q31 vector multiplication. |
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| 42 | * @param[in] *pSrcA points to the first input vector |
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| 43 | * @param[in] *pSrcB points to the second input vector |
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| 44 | * @param[out] *pDst points to the output vector |
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| 45 | * @param[in] blockSize number of samples in each vector |
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| 46 | * @return none. |
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| 47 | * |
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| 48 | * <b>Scaling and Overflow Behavior:</b> |
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| 49 | * \par |
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| 50 | * The function uses saturating arithmetic. |
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| 51 | * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated. |
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| 52 | */ |
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| 53 | |||
| 54 | void arm_mult_q31( |
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| 55 | q31_t * pSrcA, |
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| 56 | q31_t * pSrcB, |
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| 57 | q31_t * pDst, |
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| 58 | uint32_t blockSize) |
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| 59 | { |
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| 60 | uint32_t blkCnt; /* loop counters */ |
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| 61 | |||
| 62 | #if defined (ARM_MATH_DSP) |
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| 63 | |||
| 64 | /* Run the below code for Cortex-M4 and Cortex-M3 */ |
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| 65 | q31_t inA1, inA2, inA3, inA4; /* temporary input variables */ |
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| 66 | q31_t inB1, inB2, inB3, inB4; /* temporary input variables */ |
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| 67 | q31_t out1, out2, out3, out4; /* temporary output variables */ |
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| 68 | |||
| 69 | /* loop Unrolling */ |
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| 70 | blkCnt = blockSize >> 2U; |
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| 71 | |||
| 72 | /* First part of the processing with loop unrolling. Compute 4 outputs at a time. |
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| 73 | ** a second loop below computes the remaining 1 to 3 samples. */ |
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| 74 | while (blkCnt > 0U) |
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| 75 | { |
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| 76 | /* C = A * B */ |
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| 77 | /* Multiply the inputs and then store the results in the destination buffer. */ |
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| 78 | inA1 = *pSrcA++; |
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| 79 | inA2 = *pSrcA++; |
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| 80 | inA3 = *pSrcA++; |
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| 81 | inA4 = *pSrcA++; |
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| 82 | inB1 = *pSrcB++; |
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| 83 | inB2 = *pSrcB++; |
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| 84 | inB3 = *pSrcB++; |
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| 85 | inB4 = *pSrcB++; |
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| 86 | |||
| 87 | out1 = ((q63_t) inA1 * inB1) >> 32; |
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| 88 | out2 = ((q63_t) inA2 * inB2) >> 32; |
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| 89 | out3 = ((q63_t) inA3 * inB3) >> 32; |
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| 90 | out4 = ((q63_t) inA4 * inB4) >> 32; |
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| 91 | |||
| 92 | out1 = __SSAT(out1, 31); |
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| 93 | out2 = __SSAT(out2, 31); |
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| 94 | out3 = __SSAT(out3, 31); |
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| 95 | out4 = __SSAT(out4, 31); |
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| 96 | |||
| 97 | *pDst++ = out1 << 1U; |
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| 98 | *pDst++ = out2 << 1U; |
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| 99 | *pDst++ = out3 << 1U; |
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| 100 | *pDst++ = out4 << 1U; |
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| 101 | |||
| 102 | /* Decrement the blockSize loop counter */ |
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| 103 | blkCnt--; |
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| 104 | } |
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| 105 | |||
| 106 | /* If the blockSize is not a multiple of 4, compute any remaining output samples here. |
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| 107 | ** No loop unrolling is used. */ |
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| 108 | blkCnt = blockSize % 0x4U; |
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| 109 | |||
| 110 | while (blkCnt > 0U) |
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| 111 | { |
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| 112 | /* C = A * B */ |
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| 113 | /* Multiply the inputs and then store the results in the destination buffer. */ |
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| 114 | inA1 = *pSrcA++; |
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| 115 | inB1 = *pSrcB++; |
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| 116 | out1 = ((q63_t) inA1 * inB1) >> 32; |
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| 117 | out1 = __SSAT(out1, 31); |
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| 118 | *pDst++ = out1 << 1U; |
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| 119 | |||
| 120 | /* Decrement the blockSize loop counter */ |
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| 121 | blkCnt--; |
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| 122 | } |
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| 123 | |||
| 124 | #else |
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| 125 | |||
| 126 | /* Run the below code for Cortex-M0 */ |
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| 127 | |||
| 128 | /* Initialize blkCnt with number of samples */ |
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| 129 | blkCnt = blockSize; |
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| 130 | |||
| 131 | |||
| 132 | while (blkCnt > 0U) |
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| 133 | { |
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| 134 | /* C = A * B */ |
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| 135 | /* Multiply the inputs and then store the results in the destination buffer. */ |
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| 136 | *pDst++ = |
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| 137 | (q31_t) clip_q63_to_q31(((q63_t) (*pSrcA++) * (*pSrcB++)) >> 31); |
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| 138 | |||
| 139 | /* Decrement the blockSize loop counter */ |
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| 140 | blkCnt--; |
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| 141 | } |
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| 142 | |||
| 143 | #endif /* #if defined (ARM_MATH_DSP) */ |
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| 144 | } |
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| 145 | |||
| 146 | /** |
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| 147 | * @} end of BasicMult group |
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| 148 | */ |