arm_rfft_fast_init_f32.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013  
00005 * $Revision:    V1.4.1  
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_cfft_init_f32.c   
00009 *    
00010 * Description:  Split Radix Decimation in Frequency CFFT Floating point processing function   
00011 *    
00012 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.   
00039 * -------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 #include "arm_common_tables.h"
00043 
00044 /**   
00045  * @ingroup groupTransforms   
00046  */
00047 
00048 /**   
00049  * @addtogroup RealFFT   
00050  * @{   
00051  */
00052 
00053 /**   
00054 * @brief  Initialization function for the floating-point real FFT.  
00055 * @param[in,out] *S             points to an arm_rfft_fast_instance_f32 structure.
00056 * @param[in]     fftLen         length of the Real Sequence.  
00057 * @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.  
00058 *   
00059 * \par Description:  
00060 * \par   
00061 * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.   
00062 * Set(=1) ifftFlag for calculation of CIFFT otherwise  RFFT is calculated  
00063 * \par   
00064 * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.   
00065 * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.   
00066 * \par   
00067 * The parameter <code>fftLen</code> Specifies length of RFFT/CIFFT process. Supported FFT Lengths are 16, 32, 64, 128, 256, 512, 1024, 2048, 4096.   
00068 * \par   
00069 * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.   
00070 */
00071 arm_status arm_rfft_fast_init_f32(
00072   arm_rfft_fast_instance_f32 * S,
00073   uint16_t fftLen)
00074 {
00075   arm_cfft_instance_f32 * Sint;
00076   /*  Initialise the default arm status */
00077   arm_status status = ARM_MATH_SUCCESS;
00078   /*  Initialise the FFT length */
00079   Sint = &(S->Sint);
00080   Sint->fftLen = fftLen/2;
00081   S->fftLenRFFT = fftLen;
00082   /*  Initialise the Twiddle coefficient pointer */
00083   //  S->pTwiddle = (float32_t *) twiddleCoef;
00084 
00085   /*  Initializations of structure parameters depending on the FFT length */
00086   switch (Sint->fftLen)
00087   {
00088   case 4096u:
00089     /*  Initializations of structure parameters for 4096 point FFT */
00090     /*  Initialise the bit reversal table length */
00091     Sint->bitRevLength = ARMBITREVINDEXTABLE4096_TABLE_LENGTH;
00092     /*  Initialise the bit reversal table pointer */
00093     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable4096;
00094     /*  Initialise the 1/fftLen Value */
00095     break;
00096   case 2048u:
00097     Sint->bitRevLength = ARMBITREVINDEXTABLE2048_TABLE_LENGTH;
00098     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable2048;
00099     break;
00100   case 1024u:
00101     Sint->bitRevLength = ARMBITREVINDEXTABLE1024_TABLE_LENGTH;
00102     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable1024;
00103     break;
00104   case 512u:
00105     Sint->bitRevLength = ARMBITREVINDEXTABLE_512_TABLE_LENGTH;
00106     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable512;
00107     break;
00108   case 256u:
00109     Sint->bitRevLength = ARMBITREVINDEXTABLE_256_TABLE_LENGTH;
00110     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable256;
00111     break;
00112   case 128u:
00113     Sint->bitRevLength = ARMBITREVINDEXTABLE_128_TABLE_LENGTH;
00114     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable128;
00115     break;
00116   case 64u:
00117     Sint->bitRevLength = ARMBITREVINDEXTABLE__64_TABLE_LENGTH;
00118     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable64;
00119     break;
00120   case 32u:
00121     Sint->bitRevLength = ARMBITREVINDEXTABLE__32_TABLE_LENGTH;
00122     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable32;
00123     break;
00124   case 16u:
00125     Sint->bitRevLength = ARMBITREVINDEXTABLE__16_TABLE_LENGTH;
00126     Sint->pBitRevTable = (uint16_t *)armBitRevIndexTable16;
00127     break;
00128   default:
00129     /*  Reporting argument error if fftSize is not valid value */
00130     status = ARM_MATH_ARGUMENT_ERROR;
00131     break;
00132   }
00133 
00134   return (status);
00135 }
00136 
00137 /**   
00138  * @} end of RealFFT group   
00139  */