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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5  
  6. *    
  7. * Project:          CMSIS DSP Library    
  8. * Title:            arm_cfft_radix4_init_q31.c    
  9. *    
  10. * Description:  Radix-4 Decimation in Frequency Q31 FFT & IFFT 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. #include "arm_math.h"
  42. #include "arm_common_tables.h"
  43.  
  44. /**    
  45.  * @ingroup groupTransforms    
  46.  */
  47.  
  48. /**    
  49.  * @addtogroup ComplexFFT    
  50.  * @{    
  51.  */
  52.  
  53. /**    
  54. *    
  55. * @brief  Initialization function for the Q31 CFFT/CIFFT.  
  56. * @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_q31 and will be removed
  57. * @param[in,out] *S             points to an instance of the Q31 CFFT/CIFFT structure.  
  58. * @param[in]     fftLen         length of the FFT.  
  59. * @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.  
  60. * @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.  
  61. * @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.  
  62. *    
  63. * \par Description:  
  64. * \par    
  65. * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.    
  66. * Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated  
  67. * \par    
  68. * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.    
  69. * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.    
  70. * \par    
  71. * The parameter <code>fftLen</code>     Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.    
  72. * \par    
  73. * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.    
  74. */
  75.  
  76. arm_status arm_cfft_radix4_init_q31(
  77.   arm_cfft_radix4_instance_q31 * S,
  78.   uint16_t fftLen,
  79.   uint8_t ifftFlag,
  80.   uint8_t bitReverseFlag)
  81. {
  82.   /*  Initialise the default arm status */
  83.   arm_status status = ARM_MATH_SUCCESS;
  84.   /*  Initialise the FFT length */
  85.   S->fftLen = fftLen;
  86.   /*  Initialise the Twiddle coefficient pointer */
  87.   S->pTwiddle = (q31_t *) twiddleCoef_4096_q31;
  88.   /*  Initialise the Flag for selection of CFFT or CIFFT */
  89.   S->ifftFlag = ifftFlag;
  90.   /*  Initialise the Flag for calculation Bit reversal or not */
  91.   S->bitReverseFlag = bitReverseFlag;
  92.  
  93.   /*  Initializations of Instance structure depending on the FFT length */
  94.   switch (S->fftLen)
  95.   {
  96.     /*  Initializations of structure parameters for 4096 point FFT */
  97.   case 4096u:
  98.     /*  Initialise the twiddle coef modifier value */
  99.     S->twidCoefModifier = 1u;
  100.     /*  Initialise the bit reversal table modifier */
  101.     S->bitRevFactor = 1u;
  102.     /*  Initialise the bit reversal table pointer */
  103.     S->pBitRevTable = (uint16_t *) armBitRevTable;
  104.     break;
  105.  
  106.     /*  Initializations of structure parameters for 1024 point FFT */
  107.   case 1024u:
  108.     /*  Initialise the twiddle coef modifier value */
  109.     S->twidCoefModifier = 4u;
  110.     /*  Initialise the bit reversal table modifier */
  111.     S->bitRevFactor = 4u;
  112.     /*  Initialise the bit reversal table pointer */
  113.     S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
  114.     break;
  115.  
  116.   case 256u:
  117.     /*  Initializations of structure parameters for 256 point FFT */
  118.     S->twidCoefModifier = 16u;
  119.     S->bitRevFactor = 16u;
  120.     S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
  121.     break;
  122.  
  123.   case 64u:
  124.     /*  Initializations of structure parameters for 64 point FFT */
  125.     S->twidCoefModifier = 64u;
  126.     S->bitRevFactor = 64u;
  127.     S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
  128.     break;
  129.  
  130.   case 16u:
  131.     /*  Initializations of structure parameters for 16 point FFT */
  132.     S->twidCoefModifier = 256u;
  133.     S->bitRevFactor = 256u;
  134.     S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
  135.     break;
  136.  
  137.   default:
  138.     /*  Reporting argument error if fftSize is not valid value */
  139.     status = ARM_MATH_ARGUMENT_ERROR;
  140.     break;
  141.   }
  142.  
  143.   return (status);
  144. }
  145.  
  146. /**    
  147.  * @} end of ComplexFFT group    
  148.  */
  149.