1 | /* ----------------------------------------------------------------------
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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 |
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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 BasicMult
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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 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 |
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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 |
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62 | #if defined (ARM_MATH_DSP)
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63 |
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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 |
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69 | /* loop Unrolling */
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70 | blkCnt = blockSize >> 2U;
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71 |
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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 |
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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 |
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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 |
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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 |
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102 | /* Decrement the blockSize loop counter */
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103 | blkCnt--;
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104 | }
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105 |
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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 |
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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 |
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120 | /* Decrement the blockSize loop counter */
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121 | blkCnt--;
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122 | }
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123 |
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124 | #else
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125 |
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126 | /* Run the below code for Cortex-M0 */
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127 |
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128 | /* Initialize blkCnt with number of samples */
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129 | blkCnt = blockSize;
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130 |
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131 |
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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 |
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139 | /* Decrement the blockSize loop counter */
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140 | blkCnt--;
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141 | }
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142 |
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143 | #endif /* #if defined (ARM_MATH_DSP) */
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144 | }
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145 |
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146 | /**
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147 | * @} end of BasicMult group
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148 | */
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