arm_cfft_radix4_init_q31.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        19. March 2015
00005 * $Revision:    V.1.4.5   
00006 *    
00007 * Project:      CMSIS DSP Library    
00008 * Title:        arm_cfft_radix4_init_q31.c    
00009 *    
00010 * Description:  Radix-4 Decimation in Frequency Q31 FFT & IFFT initialization 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 ComplexFFT    
00050  * @{    
00051  */
00052 
00053 /**    
00054 *    
00055 * @brief  Initialization function for the Q31 CFFT/CIFFT.   
00056 * @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_q31 and will be removed
00057 * @param[in,out] *S             points to an instance of the Q31 CFFT/CIFFT structure.   
00058 * @param[in]     fftLen         length of the FFT.   
00059 * @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.   
00060 * @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.   
00061 * @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.   
00062 *    
00063 * \par Description:   
00064 * \par    
00065 * The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.    
00066 * Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated   
00067 * \par    
00068 * The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.    
00069 * Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.    
00070 * \par    
00071 * The parameter <code>fftLen</code> Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.    
00072 * \par    
00073 * This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.    
00074 */
00075 
00076 arm_status arm_cfft_radix4_init_q31(
00077   arm_cfft_radix4_instance_q31 * S,
00078   uint16_t fftLen,
00079   uint8_t ifftFlag,
00080   uint8_t bitReverseFlag)
00081 {
00082   /*  Initialise the default arm status */
00083   arm_status status = ARM_MATH_SUCCESS;
00084   /*  Initialise the FFT length */
00085   S->fftLen = fftLen;
00086   /*  Initialise the Twiddle coefficient pointer */
00087   S->pTwiddle = (q31_t *) twiddleCoef_4096_q31 ;
00088   /*  Initialise the Flag for selection of CFFT or CIFFT */
00089   S->ifftFlag = ifftFlag;
00090   /*  Initialise the Flag for calculation Bit reversal or not */
00091   S->bitReverseFlag = bitReverseFlag;
00092 
00093   /*  Initializations of Instance structure depending on the FFT length */
00094   switch (S->fftLen)
00095   {
00096     /*  Initializations of structure parameters for 4096 point FFT */
00097   case 4096u:
00098     /*  Initialise the twiddle coef modifier value */
00099     S->twidCoefModifier = 1u;
00100     /*  Initialise the bit reversal table modifier */
00101     S->bitRevFactor = 1u;
00102     /*  Initialise the bit reversal table pointer */
00103     S->pBitRevTable = (uint16_t *) armBitRevTable ;
00104     break;
00105 
00106     /*  Initializations of structure parameters for 1024 point FFT */
00107   case 1024u:
00108     /*  Initialise the twiddle coef modifier value */
00109     S->twidCoefModifier = 4u;
00110     /*  Initialise the bit reversal table modifier */
00111     S->bitRevFactor = 4u;
00112     /*  Initialise the bit reversal table pointer */
00113     S->pBitRevTable = (uint16_t *) & armBitRevTable [3];
00114     break;
00115 
00116   case 256u:
00117     /*  Initializations of structure parameters for 256 point FFT */
00118     S->twidCoefModifier = 16u;
00119     S->bitRevFactor = 16u;
00120     S->pBitRevTable = (uint16_t *) & armBitRevTable [15];
00121     break;
00122 
00123   case 64u:
00124     /*  Initializations of structure parameters for 64 point FFT */
00125     S->twidCoefModifier = 64u;
00126     S->bitRevFactor = 64u;
00127     S->pBitRevTable = (uint16_t *) & armBitRevTable [63];
00128     break;
00129 
00130   case 16u:
00131     /*  Initializations of structure parameters for 16 point FFT */
00132     S->twidCoefModifier = 256u;
00133     S->bitRevFactor = 256u;
00134     S->pBitRevTable = (uint16_t *) & armBitRevTable [255];
00135     break;
00136 
00137   default:
00138     /*  Reporting argument error if fftSize is not valid value */
00139     status = ARM_MATH_ARGUMENT_ERROR;
00140     break;
00141   }
00142 
00143   return (status);
00144 }
00145 
00146 /**    
00147  * @} end of ComplexFFT group    
00148  */