Diff: TransformFunctions/arm_cfft_radix4_init_q31.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TransformFunctions/arm_cfft_radix4_init_q31.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,147 @@
+/* ----------------------------------------------------------------------    
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
+*    
+* $Date:        12. March 2014 
+* $Revision: 	V1.4.3   
+*    
+* Project: 	    CMSIS DSP Library    
+* Title:	    arm_cfft_radix4_init_q31.c    
+*    
+* Description:	Radix-4 Decimation in Frequency Q31 FFT & IFFT initialization function    
+*    
+* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
+*  
+* Redistribution and use in source and binary forms, with or without 
+* modification, are permitted provided that the following conditions
+* are met:
+*   - Redistributions of source code must retain the above copyright
+*     notice, this list of conditions and the following disclaimer.
+*   - Redistributions in binary form must reproduce the above copyright
+*     notice, this list of conditions and the following disclaimer in
+*     the documentation and/or other materials provided with the 
+*     distribution.
+*   - Neither the name of ARM LIMITED nor the names of its contributors
+*     may be used to endorse or promote products derived from this
+*     software without specific prior written permission.
+*
+* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
+* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+* POSSIBILITY OF SUCH DAMAGE.     
+* -------------------------------------------------------------------- */
+
+#include "arm_math.h"
+#include "arm_common_tables.h"
+
+/**    
+ * @ingroup groupTransforms    
+ */
+
+/**    
+ * @addtogroup ComplexFFT    
+ * @{    
+ */
+
+/**    
+*    
+* @brief  Initialization function for the Q31 CFFT/CIFFT.   
+* @param[in,out] *S             points to an instance of the Q31 CFFT/CIFFT structure.   
+* @param[in]     fftLen         length of the FFT.   
+* @param[in]     ifftFlag       flag that selects forward (ifftFlag=0) or inverse (ifftFlag=1) transform.   
+* @param[in]     bitReverseFlag flag that enables (bitReverseFlag=1) or disables (bitReverseFlag=0) bit reversal of output.   
+* @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.   
+*    
+* \par Description:   
+* \par    
+* The parameter <code>ifftFlag</code> controls whether a forward or inverse transform is computed.    
+* Set(=1) ifftFlag for calculation of CIFFT otherwise  CFFT is calculated   
+* \par    
+* The parameter <code>bitReverseFlag</code> controls whether output is in normal order or bit reversed order.    
+* Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.    
+* \par    
+* The parameter <code>fftLen</code>	Specifies length of CFFT/CIFFT process. Supported FFT Lengths are 16, 64, 256, 1024.    
+* \par    
+* This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.    
+*/
+
+arm_status arm_cfft_radix4_init_q31(
+  arm_cfft_radix4_instance_q31 * S,
+  uint16_t fftLen,
+  uint8_t ifftFlag,
+  uint8_t bitReverseFlag)
+{
+  /*  Initialise the default arm status */
+  arm_status status = ARM_MATH_SUCCESS;
+  /*  Initialise the FFT length */
+  S->fftLen = fftLen;
+  /*  Initialise the Twiddle coefficient pointer */
+  S->pTwiddle = (q31_t *) twiddleCoefQ31;
+  /*  Initialise the Flag for selection of CFFT or CIFFT */
+  S->ifftFlag = ifftFlag;
+  /*  Initialise the Flag for calculation Bit reversal or not */
+  S->bitReverseFlag = bitReverseFlag;
+
+  /*  Initializations of Instance structure depending on the FFT length */
+  switch (S->fftLen)
+  {
+    /*  Initializations of structure parameters for 4096 point FFT */
+  case 4096u:
+    /*  Initialise the twiddle coef modifier value */
+    S->twidCoefModifier = 1u;
+    /*  Initialise the bit reversal table modifier */
+    S->bitRevFactor = 1u;
+    /*  Initialise the bit reversal table pointer */
+    S->pBitRevTable = (uint16_t *) armBitRevTable;
+    break;
+
+    /*  Initializations of structure parameters for 1024 point FFT */
+  case 1024u:
+    /*  Initialise the twiddle coef modifier value */
+    S->twidCoefModifier = 4u;
+    /*  Initialise the bit reversal table modifier */
+    S->bitRevFactor = 4u;
+    /*  Initialise the bit reversal table pointer */
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[3];
+    break;
+
+  case 256u:
+    /*  Initializations of structure parameters for 256 point FFT */
+    S->twidCoefModifier = 16u;
+    S->bitRevFactor = 16u;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[15];
+    break;
+
+  case 64u:
+    /*  Initializations of structure parameters for 64 point FFT */
+    S->twidCoefModifier = 64u;
+    S->bitRevFactor = 64u;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[63];
+    break;
+
+  case 16u:
+    /*  Initializations of structure parameters for 16 point FFT */
+    S->twidCoefModifier = 256u;
+    S->bitRevFactor = 256u;
+    S->pBitRevTable = (uint16_t *) & armBitRevTable[255];
+    break;
+
+  default:
+    /*  Reporting argument error if fftSize is not valid value */
+    status = ARM_MATH_ARGUMENT_ERROR;
+    break;
+  }
+
+  return (status);
+}
+
+/**    
+ * @} end of ComplexFFT group    
+ */