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CMSIS DSP library

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cmsis_dsp/TransformFunctions/arm_cfft_radix2_init_q15.c@3:7a284390b0ce, 2013-11-08 (annotated)

Committer:
mbed_official
Date:
Fri Nov 08 13:45:10 2013 +0000
Revision:
3:7a284390b0ce
Parent:
2:da51fb522205 
Synchronized with git revision e69956aba2f68a2a26ac26b051f8d349deaa1ce8

Who changed what in which revision?

UserRevisionLine numberNew contents of line
emilmont 1:fdd22bb7aa52 1 /* ----------------------------------------------------------------------
mbed_official 3:7a284390b0ce 2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
emilmont 1:fdd22bb7aa52 3 *
mbed_official 3:7a284390b0ce 4 * $Date: 17. January 2013
mbed_official 3:7a284390b0ce 5 * $Revision: V1.4.1
emilmont 1:fdd22bb7aa52 6 *
emilmont 2:da51fb522205 7 * Project: CMSIS DSP Library
emilmont 2:da51fb522205 8 * Title: arm_cfft_radix2_init_q15.c
emilmont 1:fdd22bb7aa52 9 *
emilmont 2:da51fb522205 10 * Description: Radix-2 Decimation in Frequency Q15 FFT & IFFT initialization function
emilmont 1:fdd22bb7aa52 11 *
emilmont 1:fdd22bb7aa52 12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
emilmont 1:fdd22bb7aa52 13 *
mbed_official 3:7a284390b0ce 14 * Redistribution and use in source and binary forms, with or without
mbed_official 3:7a284390b0ce 15 * modification, are permitted provided that the following conditions
mbed_official 3:7a284390b0ce 16 * are met:
mbed_official 3:7a284390b0ce 17 * - Redistributions of source code must retain the above copyright
mbed_official 3:7a284390b0ce 18 * notice, this list of conditions and the following disclaimer.
mbed_official 3:7a284390b0ce 19 * - Redistributions in binary form must reproduce the above copyright
mbed_official 3:7a284390b0ce 20 * notice, this list of conditions and the following disclaimer in
mbed_official 3:7a284390b0ce 21 * the documentation and/or other materials provided with the
mbed_official 3:7a284390b0ce 22 * distribution.
mbed_official 3:7a284390b0ce 23 * - Neither the name of ARM LIMITED nor the names of its contributors
mbed_official 3:7a284390b0ce 24 * may be used to endorse or promote products derived from this
mbed_official 3:7a284390b0ce 25 * software without specific prior written permission.
mbed_official 3:7a284390b0ce 26 *
mbed_official 3:7a284390b0ce 27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
mbed_official 3:7a284390b0ce 28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
mbed_official 3:7a284390b0ce 29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
mbed_official 3:7a284390b0ce 30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
mbed_official 3:7a284390b0ce 31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
mbed_official 3:7a284390b0ce 32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
mbed_official 3:7a284390b0ce 33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
mbed_official 3:7a284390b0ce 34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
mbed_official 3:7a284390b0ce 35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
mbed_official 3:7a284390b0ce 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
mbed_official 3:7a284390b0ce 37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
mbed_official 3:7a284390b0ce 38 * POSSIBILITY OF SUCH DAMAGE.
emilmont 1:fdd22bb7aa52 39 * -------------------------------------------------------------------- */
emilmont 1:fdd22bb7aa52 40
emilmont 1:fdd22bb7aa52 41 #include "arm_math.h"
emilmont 1:fdd22bb7aa52 42 #include "arm_common_tables.h"
emilmont 1:fdd22bb7aa52 43
emilmont 1:fdd22bb7aa52 44 /**
emilmont 1:fdd22bb7aa52 45 * @ingroup groupTransforms
emilmont 1:fdd22bb7aa52 46 */
emilmont 1:fdd22bb7aa52 47
emilmont 1:fdd22bb7aa52 48
emilmont 1:fdd22bb7aa52 49 /**
mbed_official 3:7a284390b0ce 50 * @addtogroup ComplexFFT
emilmont 1:fdd22bb7aa52 51 * @{
emilmont 1:fdd22bb7aa52 52 */
emilmont 1:fdd22bb7aa52 53
emilmont 1:fdd22bb7aa52 54 /**
emilmont 1:fdd22bb7aa52 55 * @brief Initialization function for the Q15 CFFT/CIFFT.
emilmont 1:fdd22bb7aa52 56 * @param[in,out] *S points to an instance of the Q15 CFFT/CIFFT structure.
emilmont 1:fdd22bb7aa52 57 * @param[in] fftLen length of the FFT.
emilmont 1:fdd22bb7aa52 58 * @param[in] ifftFlag flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
emilmont 1:fdd22bb7aa52 59 * @param[in] bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
emilmont 1:fdd22bb7aa52 60 * @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 61 *
emilmont 1:fdd22bb7aa52 62 * \par Description:
emilmont 1:fdd22bb7aa52 63 * \par
emilmont 1:fdd22bb7aa52 64 * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
emilmont 1:fdd22bb7aa52 65 * Set(=1) ifftFlag for calculation of CIFFT otherwise CFFT is calculated
emilmont 1:fdd22bb7aa52 66 * \par
emilmont 1:fdd22bb7aa52 67 * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
emilmont 1:fdd22bb7aa52 68 * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
emilmont 1:fdd22bb7aa52 69 * \par
emilmont 2:da51fb522205 70 * The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
emilmont 1:fdd22bb7aa52 71 * \par
emilmont 1:fdd22bb7aa52 72 * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
emilmont 1:fdd22bb7aa52 73 */
emilmont 1:fdd22bb7aa52 74
emilmont 1:fdd22bb7aa52 75 arm_status arm_cfft_radix2_init_q15(
emilmont 1:fdd22bb7aa52 76 arm_cfft_radix2_instance_q15 * S,
emilmont 1:fdd22bb7aa52 77 uint16_t fftLen,
emilmont 1:fdd22bb7aa52 78 uint8_t ifftFlag,
emilmont 1:fdd22bb7aa52 79 uint8_t bitReverseFlag)
emilmont 1:fdd22bb7aa52 80 {
emilmont 1:fdd22bb7aa52 81 /* Initialise the default arm status */
emilmont 1:fdd22bb7aa52 82 arm_status status = ARM_MATH_SUCCESS;
emilmont 1:fdd22bb7aa52 83
emilmont 1:fdd22bb7aa52 84 /* Initialise the FFT length */
emilmont 1:fdd22bb7aa52 85 S->fftLen = fftLen;
emilmont 1:fdd22bb7aa52 86
emilmont 1:fdd22bb7aa52 87 /* Initialise the Twiddle coefficient pointer */
emilmont 1:fdd22bb7aa52 88 S->pTwiddle = (q15_t *) twiddleCoefQ15;
emilmont 1:fdd22bb7aa52 89 /* Initialise the Flag for selection of CFFT or CIFFT */
emilmont 1:fdd22bb7aa52 90 S->ifftFlag = ifftFlag;
emilmont 1:fdd22bb7aa52 91 /* Initialise the Flag for calculation Bit reversal or not */
emilmont 1:fdd22bb7aa52 92 S->bitReverseFlag = bitReverseFlag;
emilmont 1:fdd22bb7aa52 93
emilmont 1:fdd22bb7aa52 94 /* Initializations of structure parameters depending on the FFT length */
emilmont 1:fdd22bb7aa52 95 switch (S->fftLen)
emilmont 1:fdd22bb7aa52 96 {
emilmont 1:fdd22bb7aa52 97 case 4096u:
emilmont 1:fdd22bb7aa52 98 /* Initializations of structure parameters for 4096 point FFT */
emilmont 1:fdd22bb7aa52 99
emilmont 1:fdd22bb7aa52 100 /* Initialise the twiddle coef modifier value */
emilmont 1:fdd22bb7aa52 101 S->twidCoefModifier = 1u;
emilmont 1:fdd22bb7aa52 102 /* Initialise the bit reversal table modifier */
emilmont 1:fdd22bb7aa52 103 S->bitRevFactor = 1u;
emilmont 1:fdd22bb7aa52 104 /* Initialise the bit reversal table pointer */
emilmont 1:fdd22bb7aa52 105 S->pBitRevTable = (uint16_t *) armBitRevTable;
emilmont 1:fdd22bb7aa52 106
emilmont 1:fdd22bb7aa52 107 break;
emilmont 1:fdd22bb7aa52 108
emilmont 1:fdd22bb7aa52 109 case 2048u:
emilmont 1:fdd22bb7aa52 110 /* Initializations of structure parameters for 2048 point FFT */
emilmont 1:fdd22bb7aa52 111
emilmont 1:fdd22bb7aa52 112 /* Initialise the twiddle coef modifier value */
emilmont 1:fdd22bb7aa52 113 S->twidCoefModifier = 2u;
emilmont 1:fdd22bb7aa52 114 /* Initialise the bit reversal table modifier */
emilmont 1:fdd22bb7aa52 115 S->bitRevFactor = 2u;
emilmont 1:fdd22bb7aa52 116 /* Initialise the bit reversal table pointer */
emilmont 1:fdd22bb7aa52 117 S->pBitRevTable = (uint16_t *) & armBitRevTable[1];
emilmont 1:fdd22bb7aa52 118
emilmont 1:fdd22bb7aa52 119 break;
emilmont 1:fdd22bb7aa52 120
emilmont 1:fdd22bb7aa52 121 case 1024u:
emilmont 1:fdd22bb7aa52 122 /* Initializations of structure parameters for 1024 point FFT */
emilmont 1:fdd22bb7aa52 123 S->twidCoefModifier = 4u;
emilmont 1:fdd22bb7aa52 124 S->bitRevFactor = 4u;
emilmont 1:fdd22bb7aa52 125 S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
emilmont 1:fdd22bb7aa52 126
emilmont 1:fdd22bb7aa52 127 break;
emilmont 1:fdd22bb7aa52 128
emilmont 1:fdd22bb7aa52 129 case 512u:
emilmont 1:fdd22bb7aa52 130 /* Initializations of structure parameters for 512 point FFT */
emilmont 1:fdd22bb7aa52 131 S->twidCoefModifier = 8u;
emilmont 1:fdd22bb7aa52 132 S->bitRevFactor = 8u;
emilmont 1:fdd22bb7aa52 133 S->pBitRevTable = (uint16_t *) & armBitRevTable[7];
emilmont 1:fdd22bb7aa52 134
emilmont 1:fdd22bb7aa52 135 break;
emilmont 1:fdd22bb7aa52 136
emilmont 1:fdd22bb7aa52 137 case 256u:
emilmont 1:fdd22bb7aa52 138 /* Initializations of structure parameters for 256 point FFT */
emilmont 1:fdd22bb7aa52 139 S->twidCoefModifier = 16u;
emilmont 1:fdd22bb7aa52 140 S->bitRevFactor = 16u;
emilmont 1:fdd22bb7aa52 141 S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
emilmont 1:fdd22bb7aa52 142
emilmont 1:fdd22bb7aa52 143 break;
emilmont 1:fdd22bb7aa52 144
emilmont 1:fdd22bb7aa52 145 case 128u:
emilmont 1:fdd22bb7aa52 146 /* Initializations of structure parameters for 128 point FFT */
emilmont 1:fdd22bb7aa52 147 S->twidCoefModifier = 32u;
emilmont 1:fdd22bb7aa52 148 S->bitRevFactor = 32u;
emilmont 1:fdd22bb7aa52 149 S->pBitRevTable = (uint16_t *) & armBitRevTable[31];
emilmont 1:fdd22bb7aa52 150
emilmont 1:fdd22bb7aa52 151 break;
emilmont 1:fdd22bb7aa52 152
emilmont 1:fdd22bb7aa52 153 case 64u:
emilmont 1:fdd22bb7aa52 154 /* Initializations of structure parameters for 64 point FFT */
emilmont 1:fdd22bb7aa52 155 S->twidCoefModifier = 64u;
emilmont 1:fdd22bb7aa52 156 S->bitRevFactor = 64u;
emilmont 1:fdd22bb7aa52 157 S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
emilmont 1:fdd22bb7aa52 158
emilmont 1:fdd22bb7aa52 159 break;
emilmont 1:fdd22bb7aa52 160
emilmont 1:fdd22bb7aa52 161 case 32u:
emilmont 1:fdd22bb7aa52 162 /* Initializations of structure parameters for 32 point FFT */
emilmont 1:fdd22bb7aa52 163 S->twidCoefModifier = 128u;
emilmont 1:fdd22bb7aa52 164 S->bitRevFactor = 128u;
emilmont 1:fdd22bb7aa52 165 S->pBitRevTable = (uint16_t *) & armBitRevTable[127];
emilmont 1:fdd22bb7aa52 166
emilmont 1:fdd22bb7aa52 167 break;
emilmont 1:fdd22bb7aa52 168
emilmont 1:fdd22bb7aa52 169 case 16u:
emilmont 1:fdd22bb7aa52 170 /* Initializations of structure parameters for 16 point FFT */
emilmont 1:fdd22bb7aa52 171 S->twidCoefModifier = 256u;
emilmont 1:fdd22bb7aa52 172 S->bitRevFactor = 256u;
emilmont 1:fdd22bb7aa52 173 S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
emilmont 1:fdd22bb7aa52 174
emilmont 1:fdd22bb7aa52 175 break;
emilmont 1:fdd22bb7aa52 176
emilmont 1:fdd22bb7aa52 177 default:
emilmont 1:fdd22bb7aa52 178 /* Reporting argument error if fftSize is not valid value */
emilmont 1:fdd22bb7aa52 179 status = ARM_MATH_ARGUMENT_ERROR;
emilmont 1:fdd22bb7aa52 180 break;
emilmont 1:fdd22bb7aa52 181 }
emilmont 1:fdd22bb7aa52 182
emilmont 1:fdd22bb7aa52 183 return (status);
emilmont 1:fdd22bb7aa52 184 }
emilmont 1:fdd22bb7aa52 185
emilmont 1:fdd22bb7aa52 186 /**
mbed_official 3:7a284390b0ce 187 * @} end of ComplexFFT group
emilmont 1:fdd22bb7aa52 188 */