tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/TransformFunctions/arm_cfft_radix4_init_f32.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:            arm_cfft_radix4_init_f32.c
   9 *
  10 * Description:  Radix-4 Decimation in Frequency Floating-point CFFT & CIFFT Initialization function
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * -------------------------------------------------------------------- */
  40
  41
  42 #include "arm_math.h"
  43 #include "arm_common_tables.h"
  44
  45 /**
  46  * @ingroup groupTransforms
  47  */
  48
  49 /**
  50  * @addtogroup ComplexFFT
  51  * @{
  52  */
  53
  54 /**
  55 * @brief  Initialization function for the floating-point CFFT/CIFFT.
  56 * @deprecated Do not use this function.  It has been superceded by \ref arm_cfft_f32 and will be removed
  57 * in the future.
  58 * @param[in,out] *S             points to an instance of the floating-point CFFT/CIFFT structure.
  59 * @param[in]     fftLen         length of the FFT.
  60 * @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.
  61 * @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.
  62 * @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.
  63 *
  64 * \par Description:
  65 * \par
  66 * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
  67 * Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
  68 * \par
  69 * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
  70 * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
  71 * \par
  72 * The parameter <code>fftLen</code>     Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
  73 * \par
  74 * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
  75 */
  76
  77 arm_status arm_cfft_radix4_init_f32(
  78   arm_cfft_radix4_instance_f32 * S,
  79   uint16_t fftLen,
  80   uint8_t ifftFlag,
  81   uint8_t bitReverseFlag)
  82 {
  83   /*  Initialise the default arm status */
  84   arm_status status = ARM_MATH_SUCCESS;
  85
  86   /*  Initialise the FFT length */
  87   S->fftLen = fftLen;
  88
  89   /*  Initialise the Twiddle coefficient pointer */
  90   S->pTwiddle = (float32_t *) twiddleCoef;
  91
  92   /*  Initialise the Flag for selection of CFFT or CIFFT */
  93   S->ifftFlag = ifftFlag;
  94
  95   /*  Initialise the Flag for calculation Bit reversal or not */
  96   S->bitReverseFlag = bitReverseFlag;
  97
  98   /*  Initializations of structure parameters depending on the FFT length */
  99   switch (S->fftLen)
 100   {
 101
 102   case 4096u:
 103     /*  Initializations of structure parameters for 4096 point FFT */
 104
 105     /*  Initialise the twiddle coef modifier value */
 106     S->twidCoefModifier = 1u;
 107     /*  Initialise the bit reversal table modifier */
 108     S->bitRevFactor = 1u;
 109     /*  Initialise the bit reversal table pointer */
 110     S->pBitRevTable = (uint16_t *) armBitRevTable;
 111     /*  Initialise the 1/fftLen Value */
 112     S->onebyfftLen = 0.000244140625;
 113     break;
 114
 115   case 1024u:
 116     /*  Initializations of structure parameters for 1024 point FFT */
 117
 118     /*  Initialise the twiddle coef modifier value */
 119     S->twidCoefModifier = 4u;
 120     /*  Initialise the bit reversal table modifier */
 121     S->bitRevFactor = 4u;
 122     /*  Initialise the bit reversal table pointer */
 123     S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
 124     /*  Initialise the 1/fftLen Value */
 125     S->onebyfftLen = 0.0009765625f;
 126     break;
 127
 128
 129   case 256u:
 130     /*  Initializations of structure parameters for 256 point FFT */
 131     S->twidCoefModifier = 16u;
 132     S->bitRevFactor = 16u;
 133     S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
 134     S->onebyfftLen = 0.00390625f;
 135     break;
 136
 137   case 64u:
 138     /*  Initializations of structure parameters for 64 point FFT */
 139     S->twidCoefModifier = 64u;
 140     S->bitRevFactor = 64u;
 141     S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
 142     S->onebyfftLen = 0.015625f;
 143     break;
 144
 145   case 16u:
 146     /*  Initializations of structure parameters for 16 point FFT */
 147     S->twidCoefModifier = 256u;
 148     S->bitRevFactor = 256u;
 149     S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
 150     S->onebyfftLen = 0.0625f;
 151     break;
 152
 153
 154   default:
 155     /*  Reporting argument error if fftSize is not valid value */
 156     status = ARM_MATH_ARGUMENT_ERROR;
 157     break;
 158   }
 159
 160   return (status);
 161 }
 162
 163 /**
 164  * @} end of ComplexFFT group
 165  */