mbed-os 6.10 versione
cmsis_dsp/TransformFunctions/arm_cfft_radix2_init_q31.c@1:fdd22bb7aa52, 2012-11-28 (annotated)
- Committer:
- emilmont
- Date:
- Wed Nov 28 12:30:09 2012 +0000
- Revision:
- 1:fdd22bb7aa52
- Child:
- 2:da51fb522205
DSP library code
Who changed what in which revision?
User | Revision | Line number | New contents of line |
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emilmont | 1:fdd22bb7aa52 | 1 | /* ---------------------------------------------------------------------- |
emilmont | 1:fdd22bb7aa52 | 2 | * Copyright (C) 2010 ARM Limited. All rights reserved. |
emilmont | 1:fdd22bb7aa52 | 3 | * |
emilmont | 1:fdd22bb7aa52 | 4 | * $Date: 15. February 2012 |
emilmont | 1:fdd22bb7aa52 | 5 | * $Revision: V1.1.0 |
emilmont | 1:fdd22bb7aa52 | 6 | * |
emilmont | 1:fdd22bb7aa52 | 7 | * Project: CMSIS DSP Library |
emilmont | 1:fdd22bb7aa52 | 8 | * Title: arm_cfft_radix2_init_q31.c |
emilmont | 1:fdd22bb7aa52 | 9 | * |
emilmont | 1:fdd22bb7aa52 | 10 | * Description: Radix-2 Decimation in Frequency Fixed-point CFFT & CIFFT Initialization function |
emilmont | 1:fdd22bb7aa52 | 11 | * |
emilmont | 1:fdd22bb7aa52 | 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
emilmont | 1:fdd22bb7aa52 | 13 | * |
emilmont | 1:fdd22bb7aa52 | 14 | * Version 1.1.0 2012/02/15 |
emilmont | 1:fdd22bb7aa52 | 15 | * Updated with more optimizations, bug fixes and minor API changes. |
emilmont | 1:fdd22bb7aa52 | 16 | * |
emilmont | 1:fdd22bb7aa52 | 17 | * -------------------------------------------------------------------- */ |
emilmont | 1:fdd22bb7aa52 | 18 | |
emilmont | 1:fdd22bb7aa52 | 19 | |
emilmont | 1:fdd22bb7aa52 | 20 | #include "arm_math.h" |
emilmont | 1:fdd22bb7aa52 | 21 | #include "arm_common_tables.h" |
emilmont | 1:fdd22bb7aa52 | 22 | |
emilmont | 1:fdd22bb7aa52 | 23 | /** |
emilmont | 1:fdd22bb7aa52 | 24 | * @ingroup groupTransforms |
emilmont | 1:fdd22bb7aa52 | 25 | */ |
emilmont | 1:fdd22bb7aa52 | 26 | |
emilmont | 1:fdd22bb7aa52 | 27 | /** |
emilmont | 1:fdd22bb7aa52 | 28 | * @addtogroup Radix2_CFFT_CIFFT |
emilmont | 1:fdd22bb7aa52 | 29 | * @{ |
emilmont | 1:fdd22bb7aa52 | 30 | */ |
emilmont | 1:fdd22bb7aa52 | 31 | |
emilmont | 1:fdd22bb7aa52 | 32 | |
emilmont | 1:fdd22bb7aa52 | 33 | /** |
emilmont | 1:fdd22bb7aa52 | 34 | * |
emilmont | 1:fdd22bb7aa52 | 35 | * @brief Initialization function for the Q31 CFFT/CIFFT. |
emilmont | 1:fdd22bb7aa52 | 36 | * @param[in,out] *S points to an instance of the Q31 CFFT/CIFFT structure. |
emilmont | 1:fdd22bb7aa52 | 37 | * @param[in] fftLen length of the FFT. |
emilmont | 1:fdd22bb7aa52 | 38 | * @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform. |
emilmont | 1:fdd22bb7aa52 | 39 | * @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output. |
emilmont | 1:fdd22bb7aa52 | 40 | * @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. |
emilmont | 1:fdd22bb7aa52 | 41 | * |
emilmont | 1:fdd22bb7aa52 | 42 | * \par Description: |
emilmont | 1:fdd22bb7aa52 | 43 | * \par |
emilmont | 1:fdd22bb7aa52 | 44 | * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed. |
emilmont | 1:fdd22bb7aa52 | 45 | * Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated |
emilmont | 1:fdd22bb7aa52 | 46 | * \par |
emilmont | 1:fdd22bb7aa52 | 47 | * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order. |
emilmont | 1:fdd22bb7aa52 | 48 | * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order. |
emilmont | 1:fdd22bb7aa52 | 49 | * \par |
emilmont | 1:fdd22bb7aa52 | 50 | * The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024. |
emilmont | 1:fdd22bb7aa52 | 51 | * \par |
emilmont | 1:fdd22bb7aa52 | 52 | * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer. |
emilmont | 1:fdd22bb7aa52 | 53 | */ |
emilmont | 1:fdd22bb7aa52 | 54 | |
emilmont | 1:fdd22bb7aa52 | 55 | arm_status arm_cfft_radix2_init_q31( |
emilmont | 1:fdd22bb7aa52 | 56 | arm_cfft_radix2_instance_q31 * S, |
emilmont | 1:fdd22bb7aa52 | 57 | uint16_t fftLen, |
emilmont | 1:fdd22bb7aa52 | 58 | uint8_t ifftFlag, |
emilmont | 1:fdd22bb7aa52 | 59 | uint8_t bitReverseFlag) |
emilmont | 1:fdd22bb7aa52 | 60 | { |
emilmont | 1:fdd22bb7aa52 | 61 | /* Initialise the default arm status */ |
emilmont | 1:fdd22bb7aa52 | 62 | arm_status status = ARM_MATH_SUCCESS; |
emilmont | 1:fdd22bb7aa52 | 63 | |
emilmont | 1:fdd22bb7aa52 | 64 | /* Initialise the FFT length */ |
emilmont | 1:fdd22bb7aa52 | 65 | S->fftLen = fftLen; |
emilmont | 1:fdd22bb7aa52 | 66 | |
emilmont | 1:fdd22bb7aa52 | 67 | /* Initialise the Twiddle coefficient pointer */ |
emilmont | 1:fdd22bb7aa52 | 68 | S->pTwiddle = (q31_t *) twiddleCoefQ31; |
emilmont | 1:fdd22bb7aa52 | 69 | /* Initialise the Flag for selection of CFFT or CIFFT */ |
emilmont | 1:fdd22bb7aa52 | 70 | S->ifftFlag = ifftFlag; |
emilmont | 1:fdd22bb7aa52 | 71 | /* Initialise the Flag for calculation Bit reversal or not */ |
emilmont | 1:fdd22bb7aa52 | 72 | S->bitReverseFlag = bitReverseFlag; |
emilmont | 1:fdd22bb7aa52 | 73 | |
emilmont | 1:fdd22bb7aa52 | 74 | /* Initializations of Instance structure depending on the FFT length */ |
emilmont | 1:fdd22bb7aa52 | 75 | switch (S->fftLen) |
emilmont | 1:fdd22bb7aa52 | 76 | { |
emilmont | 1:fdd22bb7aa52 | 77 | /* Initializations of structure parameters for 4096 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 78 | case 4096u: |
emilmont | 1:fdd22bb7aa52 | 79 | /* Initialise the twiddle coef modifier value */ |
emilmont | 1:fdd22bb7aa52 | 80 | S->twidCoefModifier = 1u; |
emilmont | 1:fdd22bb7aa52 | 81 | /* Initialise the bit reversal table modifier */ |
emilmont | 1:fdd22bb7aa52 | 82 | S->bitRevFactor = 1u; |
emilmont | 1:fdd22bb7aa52 | 83 | /* Initialise the bit reversal table pointer */ |
emilmont | 1:fdd22bb7aa52 | 84 | S->pBitRevTable = (uint16_t *) armBitRevTable; |
emilmont | 1:fdd22bb7aa52 | 85 | break; |
emilmont | 1:fdd22bb7aa52 | 86 | |
emilmont | 1:fdd22bb7aa52 | 87 | /* Initializations of structure parameters for 2048 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 88 | case 2048u: |
emilmont | 1:fdd22bb7aa52 | 89 | /* Initialise the twiddle coef modifier value */ |
emilmont | 1:fdd22bb7aa52 | 90 | S->twidCoefModifier = 2u; |
emilmont | 1:fdd22bb7aa52 | 91 | /* Initialise the bit reversal table modifier */ |
emilmont | 1:fdd22bb7aa52 | 92 | S->bitRevFactor = 2u; |
emilmont | 1:fdd22bb7aa52 | 93 | /* Initialise the bit reversal table pointer */ |
emilmont | 1:fdd22bb7aa52 | 94 | S->pBitRevTable = (uint16_t *) & armBitRevTable[1]; |
emilmont | 1:fdd22bb7aa52 | 95 | break; |
emilmont | 1:fdd22bb7aa52 | 96 | |
emilmont | 1:fdd22bb7aa52 | 97 | /* Initializations of structure parameters for 1024 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 98 | case 1024u: |
emilmont | 1:fdd22bb7aa52 | 99 | /* Initialise the twiddle coef modifier value */ |
emilmont | 1:fdd22bb7aa52 | 100 | S->twidCoefModifier = 4u; |
emilmont | 1:fdd22bb7aa52 | 101 | /* Initialise the bit reversal table modifier */ |
emilmont | 1:fdd22bb7aa52 | 102 | S->bitRevFactor = 4u; |
emilmont | 1:fdd22bb7aa52 | 103 | /* Initialise the bit reversal table pointer */ |
emilmont | 1:fdd22bb7aa52 | 104 | S->pBitRevTable = (uint16_t *) & armBitRevTable[3]; |
emilmont | 1:fdd22bb7aa52 | 105 | break; |
emilmont | 1:fdd22bb7aa52 | 106 | |
emilmont | 1:fdd22bb7aa52 | 107 | /* Initializations of structure parameters for 512 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 108 | case 512u: |
emilmont | 1:fdd22bb7aa52 | 109 | /* Initialise the twiddle coef modifier value */ |
emilmont | 1:fdd22bb7aa52 | 110 | S->twidCoefModifier = 8u; |
emilmont | 1:fdd22bb7aa52 | 111 | /* Initialise the bit reversal table modifier */ |
emilmont | 1:fdd22bb7aa52 | 112 | S->bitRevFactor = 8u; |
emilmont | 1:fdd22bb7aa52 | 113 | /* Initialise the bit reversal table pointer */ |
emilmont | 1:fdd22bb7aa52 | 114 | S->pBitRevTable = (uint16_t *) & armBitRevTable[7]; |
emilmont | 1:fdd22bb7aa52 | 115 | break; |
emilmont | 1:fdd22bb7aa52 | 116 | |
emilmont | 1:fdd22bb7aa52 | 117 | case 256u: |
emilmont | 1:fdd22bb7aa52 | 118 | /* Initializations of structure parameters for 256 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 119 | S->twidCoefModifier = 16u; |
emilmont | 1:fdd22bb7aa52 | 120 | S->bitRevFactor = 16u; |
emilmont | 1:fdd22bb7aa52 | 121 | S->pBitRevTable = (uint16_t *) & armBitRevTable[15]; |
emilmont | 1:fdd22bb7aa52 | 122 | break; |
emilmont | 1:fdd22bb7aa52 | 123 | |
emilmont | 1:fdd22bb7aa52 | 124 | case 128u: |
emilmont | 1:fdd22bb7aa52 | 125 | /* Initializations of structure parameters for 128 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 126 | S->twidCoefModifier = 32u; |
emilmont | 1:fdd22bb7aa52 | 127 | S->bitRevFactor = 32u; |
emilmont | 1:fdd22bb7aa52 | 128 | S->pBitRevTable = (uint16_t *) & armBitRevTable[31]; |
emilmont | 1:fdd22bb7aa52 | 129 | break; |
emilmont | 1:fdd22bb7aa52 | 130 | |
emilmont | 1:fdd22bb7aa52 | 131 | case 64u: |
emilmont | 1:fdd22bb7aa52 | 132 | /* Initializations of structure parameters for 64 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 133 | S->twidCoefModifier = 64u; |
emilmont | 1:fdd22bb7aa52 | 134 | S->bitRevFactor = 64u; |
emilmont | 1:fdd22bb7aa52 | 135 | S->pBitRevTable = (uint16_t *) & armBitRevTable[63]; |
emilmont | 1:fdd22bb7aa52 | 136 | break; |
emilmont | 1:fdd22bb7aa52 | 137 | |
emilmont | 1:fdd22bb7aa52 | 138 | case 32u: |
emilmont | 1:fdd22bb7aa52 | 139 | /* Initializations of structure parameters for 32 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 140 | S->twidCoefModifier = 128u; |
emilmont | 1:fdd22bb7aa52 | 141 | S->bitRevFactor = 128u; |
emilmont | 1:fdd22bb7aa52 | 142 | S->pBitRevTable = (uint16_t *) & armBitRevTable[127]; |
emilmont | 1:fdd22bb7aa52 | 143 | break; |
emilmont | 1:fdd22bb7aa52 | 144 | |
emilmont | 1:fdd22bb7aa52 | 145 | case 16u: |
emilmont | 1:fdd22bb7aa52 | 146 | /* Initializations of structure parameters for 16 point FFT */ |
emilmont | 1:fdd22bb7aa52 | 147 | S->twidCoefModifier = 256u; |
emilmont | 1:fdd22bb7aa52 | 148 | S->bitRevFactor = 256u; |
emilmont | 1:fdd22bb7aa52 | 149 | S->pBitRevTable = (uint16_t *) & armBitRevTable[255]; |
emilmont | 1:fdd22bb7aa52 | 150 | break; |
emilmont | 1:fdd22bb7aa52 | 151 | |
emilmont | 1:fdd22bb7aa52 | 152 | |
emilmont | 1:fdd22bb7aa52 | 153 | default: |
emilmont | 1:fdd22bb7aa52 | 154 | /* Reporting argument error if fftSize is not valid value */ |
emilmont | 1:fdd22bb7aa52 | 155 | status = ARM_MATH_ARGUMENT_ERROR; |
emilmont | 1:fdd22bb7aa52 | 156 | break; |
emilmont | 1:fdd22bb7aa52 | 157 | } |
emilmont | 1:fdd22bb7aa52 | 158 | |
emilmont | 1:fdd22bb7aa52 | 159 | return (status); |
emilmont | 1:fdd22bb7aa52 | 160 | } |
emilmont | 1:fdd22bb7aa52 | 161 | |
emilmont | 1:fdd22bb7aa52 | 162 | /** |
emilmont | 1:fdd22bb7aa52 | 163 | * @} end of Radix2_CFFT_CIFFT group |
emilmont | 1:fdd22bb7aa52 | 164 | */ |