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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_init_f32.c  
  9. *    
  10. * Description:  Split Radix Decimation in Frequency CFFT Floating point processing 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 RealFFT  
  50.  * @{  
  51.  */
  52.  
  53. /**  
  54. * @brief  Initialization function for the floating-point real FFT.  
  55. * @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
  56. * @param[in]     fftLen         length of the Real Sequence.  
  57. * @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.  
  58. *  
  59. * \par Description:  
  60. * \par  
  61. * The parameter <code>fftLen</code>     Specifies length of RFFT/CIFFT process. Supported FFT Lengths are 32, 64, 128, 256, 512, 1024, 2048, 4096.  
  62. * \par  
  63. * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.  
  64. */
  65. arm_status arm_rfft_fast_init_f32(
  66.   arm_rfft_fast_instance_f32 * S,
  67.   uint16_t fftLen)
  68. {
  69.   arm_cfft_instance_f32 * Sint;
  70.   /*  Initialise the default arm status */
  71.   arm_status status = ARM_MATH_SUCCESS;
  72.   /*  Initialise the FFT length */
  73.   Sint = &(S->Sint);
  74.   Sint->fftLen = fftLen/2;
  75.   S->fftLenRFFT = fftLen;
  76.  
  77.   /*  Initializations of structure parameters depending on the FFT length */
  78.   switch (Sint->fftLen)
  79.   {
  80.   case 2048u:
  81.     /*  Initializations of structure parameters for 2048 point FFT */
  82.     /*  Initialise the bit reversal table length */
  83.     Sint->bitRevLength = ARMBITREVINDEXTABLE2048_TABLE_LENGTH;
  84.     /*  Initialise the bit reversal table pointer */
  85.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048;
  86.     /*  Initialise the Twiddle coefficient pointers */
  87.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_2048;
  88.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_4096;
  89.     break;
  90.   case 1024u:
  91.     Sint->bitRevLength = ARMBITREVINDEXTABLE1024_TABLE_LENGTH;
  92.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024;
  93.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_1024;
  94.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_2048;
  95.     break;
  96.   case 512u:
  97.     Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH;
  98.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512;
  99.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_512;
  100.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_1024;
  101.     break;
  102.   case 256u:
  103.     Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH;
  104.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256;
  105.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_256;
  106.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_512;
  107.     break;
  108.   case 128u:
  109.     Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH;
  110.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128;
  111.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_128;
  112.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_256;
  113.     break;
  114.   case 64u:
  115.     Sint->bitRevLength = ARMBITREVINDEXTABLE__64_TABLE_LENGTH;
  116.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64;
  117.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_64;
  118.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_128;
  119.     break;
  120.   case 32u:
  121.     Sint->bitRevLength = ARMBITREVINDEXTABLE__32_TABLE_LENGTH;
  122.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32;
  123.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_32;
  124.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_64;
  125.     break;
  126.   case 16u:
  127.     Sint->bitRevLength = ARMBITREVINDEXTABLE__16_TABLE_LENGTH;
  128.     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16;
  129.                 Sint->pTwiddle     = (float32_t *) twiddleCoef_16;
  130.                 S->pTwiddleRFFT    = (float32_t *) twiddleCoef_rfft_32;
  131.     break;
  132.   default:
  133.     /*  Reporting argument error if fftSize is not valid value */
  134.     status = ARM_MATH_ARGUMENT_ERROR;
  135.     break;
  136.   }
  137.  
  138.   return (status);
  139. }
  140.  
  141. /**  
  142.  * @} end of RealFFT group  
  143.  */
  144.