1  /* ----------------------------------------------------------------------
  2   * Project:      CMSIS DSP Library
  3   * Title:        arm_cfft_radix4_init_q15.c
  4   * Description:  Radix-4 Decimation in Frequency Q15 FFT & IFFT initialization function
  5   *
  6   * $Date:        23 April 2021
  7   * $Revision:    V1.9.0
  8   *
  9   * Target Processor: Cortex-M and Cortex-A cores
 10   * -------------------------------------------------------------------- */
 11  /*
 12   * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
 13   *
 14   * SPDX-License-Identifier: Apache-2.0
 15   *
 16   * Licensed under the Apache License, Version 2.0 (the License); you may
 17   * not use this file except in compliance with the License.
 18   * You may obtain a copy of the License at
 19   *
 20   * www.apache.org/licenses/LICENSE-2.0
 21   *
 22   * Unless required by applicable law or agreed to in writing, software
 23   * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 24   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 25   * See the License for the specific language governing permissions and
 26   * limitations under the License.
 27   */
 28  
 29  #include "dsp/transform_functions.h"
 30  #include "arm_common_tables.h"
 31  
 32  /**
 33    @ingroup groupTransforms
 34   */
 35  
 36  
 37  /**
 38    @addtogroup ComplexFFT
 39    @{
 40   */
 41  
 42  
 43  /**
 44    @brief Initialization function for the Q15 CFFT/CIFFT.
 45    @deprecated    Do not use this function. It has been superseded by \ref arm_cfft_q15 and will be removed in the future.
 46    @param[in,out] S              points to an instance of the Q15 CFFT/CIFFT structure
 47    @param[in]     fftLen         length of the FFT
 48    @param[in]     ifftFlag       flag that selects transform direction
 49                     - value = 0: forward transform
 50                     - value = 1: inverse transform
 51    @param[in]     bitReverseFlag flag that enables / disables bit reversal of output
 52                     - value = 0: disables bit reversal of output
 53                     - value = 1: enables bit reversal of output
 54    @return        execution status
 55                     - \ref ARM_MATH_SUCCESS        : Operation successful
 56                     - \ref ARM_MATH_ARGUMENT_ERROR : <code>fftLen</code> is not a supported length
 57  
 58    @par           Details
 59                     The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.
 60                     Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated
 61    @par
 62                     The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.
 63                     Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.
 64    @par
 65                     The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.
 66    @par
 67                     This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.
 68   */
 69  
 70  arm_status arm_cfft_radix4_init_q15(
 71    arm_cfft_radix4_instance_q15 * S,
 72    uint16_t fftLen,
 73    uint8_t ifftFlag,
 74    uint8_t bitReverseFlag)
 75  {
 76    /*  Initialise the default arm status */
 77    arm_status status = ARM_MATH_ARGUMENT_ERROR;
 78  
 79  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_FFT_ALLOW_TABLES)
 80  
 81  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_TWIDDLECOEF_Q15_4096)
 82  
 83    /*  Initialise the default arm status */
 84    status = ARM_MATH_SUCCESS;
 85    /*  Initialise the FFT length */
 86    S->fftLen = fftLen;
 87    /*  Initialise the Twiddle coefficient pointer */
 88    S->pTwiddle = (q15_t *) twiddleCoef_4096_q15;
 89    /*  Initialise the Flag for selection of CFFT or CIFFT */
 90    S->ifftFlag = ifftFlag;
 91    /*  Initialise the Flag for calculation Bit reversal or not */
 92    S->bitReverseFlag = bitReverseFlag;
 93  
 94  #if !defined(ARM_DSP_CONFIG_TABLES) || defined(ARM_ALL_FFT_TABLES) || defined(ARM_TABLE_BITREV_1024)
 95  
 96    /*  Initializations of structure parameters depending on the FFT length */
 97    switch (S->fftLen)
 98    {
 99    case 4096U:
100      /*  Initializations of structure parameters for 4096 point FFT */
101  
102      /*  Initialise the twiddle coef modifier value */
103      S->twidCoefModifier = 1U;
104      /*  Initialise the bit reversal table modifier */
105      S->bitRevFactor = 1U;
106      /*  Initialise the bit reversal table pointer */
107      S->pBitRevTable = (uint16_t *) armBitRevTable;
108  
109      break;
110  
111    case 1024U:
112      /*  Initializations of structure parameters for 1024 point FFT */
113      S->twidCoefModifier = 4U;
114      S->bitRevFactor = 4U;
115      S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
116  
117      break;
118  
119    case 256U:
120      /*  Initializations of structure parameters for 256 point FFT */
121      S->twidCoefModifier = 16U;
122      S->bitRevFactor = 16U;
123      S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
124  
125      break;
126  
127    case 64U:
128      /*  Initializations of structure parameters for 64 point FFT */
129      S->twidCoefModifier = 64U;
130      S->bitRevFactor = 64U;
131      S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
132  
133      break;
134  
135    case 16U:
136      /*  Initializations of structure parameters for 16 point FFT */
137      S->twidCoefModifier = 256U;
138      S->bitRevFactor = 256U;
139      S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
140  
141      break;
142  
143    default:
144      /*  Reporting argument error if fftSize is not valid value */
145      status = ARM_MATH_ARGUMENT_ERROR;
146      break;
147    }
148  
149  #endif
150  #endif 
151  #endif
152    return (status);
153  }
154  
155  /**
156    @} end of ComplexFFT group
157   */