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| Rev | Author | Line No. | Line |
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| 2 | mjames | 1 | /* ---------------------------------------------------------------------- |
| 2 | * Project: CMSIS DSP Library |
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| 3 | * Title: arm_cfft_init_f32.c |
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| 4 | * Description: Split Radix Decimation in Frequency CFFT Floating point processing function |
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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 | #include "arm_common_tables.h" |
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| 31 | |||
| 32 | /** |
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| 33 | * @ingroup groupTransforms |
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| 34 | */ |
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| 35 | |||
| 36 | /** |
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| 37 | * @addtogroup RealFFT |
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| 38 | * @{ |
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| 39 | */ |
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| 40 | |||
| 41 | /** |
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| 42 | * @brief Initialization function for the floating-point real FFT. |
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| 43 | * @param[in,out] *S points to an arm_rfft_fast_instance_f32 structure. |
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| 44 | * @param[in] fftLen length of the Real Sequence. |
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| 45 | * @return The function returns ARM_MATH_SUCCESS if initialization is successful or ARM_MATH_ARGUMENT_ERROR if <code>fftLen</code> is not a supported value. |
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| 46 | * |
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| 47 | * \par Description: |
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| 48 | * \par |
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| 49 | * The parameter <code>fftLen</code> Specifies length of RFFT/CIFFT process. Supported FFT Lengths are 32, 64, 128, 256, 512, 1024, 2048, 4096. |
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| 50 | * \par |
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| 51 | * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer. |
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| 52 | */ |
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| 53 | arm_status arm_rfft_fast_init_f32( |
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| 54 | arm_rfft_fast_instance_f32 * S, |
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| 55 | uint16_t fftLen) |
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| 56 | { |
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| 57 | arm_cfft_instance_f32 * Sint; |
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| 58 | /* Initialise the default arm status */ |
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| 59 | arm_status status = ARM_MATH_SUCCESS; |
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| 60 | /* Initialise the FFT length */ |
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| 61 | Sint = &(S->Sint); |
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| 62 | Sint->fftLen = fftLen/2; |
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| 63 | S->fftLenRFFT = fftLen; |
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| 64 | |||
| 65 | /* Initializations of structure parameters depending on the FFT length */ |
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| 66 | switch (Sint->fftLen) |
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| 67 | { |
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| 68 | case 2048U: |
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| 69 | /* Initializations of structure parameters for 2048 point FFT */ |
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| 70 | /* Initialise the bit reversal table length */ |
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| 71 | Sint->bitRevLength = ARMBITREVINDEXTABLE_2048_TABLE_LENGTH; |
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| 72 | /* Initialise the bit reversal table pointer */ |
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| 73 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048; |
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| 74 | /* Initialise the Twiddle coefficient pointers */ |
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| 75 | Sint->pTwiddle = (float32_t *) twiddleCoef_2048; |
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| 76 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_4096; |
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| 77 | break; |
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| 78 | case 1024U: |
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| 79 | Sint->bitRevLength = ARMBITREVINDEXTABLE_1024_TABLE_LENGTH; |
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| 80 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024; |
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| 81 | Sint->pTwiddle = (float32_t *) twiddleCoef_1024; |
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| 82 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_2048; |
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| 83 | break; |
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| 84 | case 512U: |
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| 85 | Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH; |
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| 86 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512; |
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| 87 | Sint->pTwiddle = (float32_t *) twiddleCoef_512; |
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| 88 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_1024; |
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| 89 | break; |
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| 90 | case 256U: |
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| 91 | Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH; |
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| 92 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256; |
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| 93 | Sint->pTwiddle = (float32_t *) twiddleCoef_256; |
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| 94 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_512; |
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| 95 | break; |
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| 96 | case 128U: |
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| 97 | Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH; |
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| 98 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128; |
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| 99 | Sint->pTwiddle = (float32_t *) twiddleCoef_128; |
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| 100 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_256; |
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| 101 | break; |
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| 102 | case 64U: |
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| 103 | Sint->bitRevLength = ARMBITREVINDEXTABLE_64_TABLE_LENGTH; |
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| 104 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64; |
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| 105 | Sint->pTwiddle = (float32_t *) twiddleCoef_64; |
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| 106 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_128; |
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| 107 | break; |
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| 108 | case 32U: |
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| 109 | Sint->bitRevLength = ARMBITREVINDEXTABLE_32_TABLE_LENGTH; |
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| 110 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32; |
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| 111 | Sint->pTwiddle = (float32_t *) twiddleCoef_32; |
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| 112 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_64; |
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| 113 | break; |
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| 114 | case 16U: |
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| 115 | Sint->bitRevLength = ARMBITREVINDEXTABLE_16_TABLE_LENGTH; |
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| 116 | Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16; |
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| 117 | Sint->pTwiddle = (float32_t *) twiddleCoef_16; |
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| 118 | S->pTwiddleRFFT = (float32_t *) twiddleCoef_rfft_32; |
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| 119 | break; |
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| 120 | default: |
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| 121 | /* Reporting argument error if fftSize is not valid value */ |
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| 122 | status = ARM_MATH_ARGUMENT_ERROR; |
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| 123 | break; |
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| 124 | } |
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| 125 | |||
| 126 | return (status); |
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| 127 | } |
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| 128 | |||
| 129 | /** |
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| 130 | * @} end of RealFFT group |
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| 131 | */ |