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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_q15.c    
  9. *    
  10. * Description:  Radix-4 Decimation in Frequency Q15 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. /**    
  50.  * @addtogroup ComplexFFT    
  51.  * @{    
  52.  */
  53.  
  54.  
  55. /**    
  56. * @brief Initialization function for the Q15 CFFT/CIFFT.  
  57. * @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_q15 and will be removed
  58. * @param[in,out] *S             points to an instance of the Q15 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_q15(
  78.   arm_cfft_radix4_instance_q15 * 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.   /*  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.   /*  Initializations of structure parameters depending on the FFT length */
  95.   switch (S->fftLen)
  96.   {
  97.   case 4096u:
  98.     /*  Initializations of structure parameters for 4096 point FFT */
  99.  
  100.     /*  Initialise the twiddle coef modifier value */
  101.     S->twidCoefModifier = 1u;
  102.     /*  Initialise the bit reversal table modifier */
  103.     S->bitRevFactor = 1u;
  104.     /*  Initialise the bit reversal table pointer */
  105.     S->pBitRevTable = (uint16_t *) armBitRevTable;
  106.  
  107.     break;
  108.  
  109.   case 1024u:
  110.     /*  Initializations of structure parameters for 1024 point FFT */
  111.     S->twidCoefModifier = 4u;
  112.     S->bitRevFactor = 4u;
  113.     S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
  114.  
  115.     break;
  116.  
  117.   case 256u:
  118.     /*  Initializations of structure parameters for 256 point FFT */
  119.     S->twidCoefModifier = 16u;
  120.     S->bitRevFactor = 16u;
  121.     S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
  122.  
  123.     break;
  124.  
  125.   case 64u:
  126.     /*  Initializations of structure parameters for 64 point FFT */
  127.     S->twidCoefModifier = 64u;
  128.     S->bitRevFactor = 64u;
  129.     S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
  130.  
  131.     break;
  132.  
  133.   case 16u:
  134.     /*  Initializations of structure parameters for 16 point FFT */
  135.     S->twidCoefModifier = 256u;
  136.     S->bitRevFactor = 256u;
  137.     S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
  138.  
  139.     break;
  140.  
  141.   default:
  142.     /*  Reporting argument error if fftSize is not valid value */
  143.     status = ARM_MATH_ARGUMENT_ERROR;
  144.     break;
  145.   }
  146.  
  147.   return (status);
  148. }
  149.  
  150. /**    
  151.  * @} end of ComplexFFT group    
  152.  */
  153.