Diff: TransformFunctions/arm_cfft_radix2_f32.c

Revision:

0:3d9c67d97d6f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TransformFunctions/arm_cfft_radix2_f32.c	Mon Jul 28 15:03:15 2014 +0000
@@ -0,0 +1,485 @@
+/* ----------------------------------------------------------------------   
+* Copyright (C) 2010-2014 ARM Limited. All rights reserved.   
+*   
+* $Date:        12. March 2014  
+* $Revision: 	V1.4.3  
+*   
+* Project: 	    CMSIS DSP Library   
+* Title:	    arm_cfft_radix2_f32.c   
+*   
+* Description:	Radix-2 Decimation in Frequency CFFT & CIFFT Floating point processing 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"
+
+void arm_radix2_butterfly_f32(
+  float32_t * pSrc,
+  uint32_t fftLen,
+  float32_t * pCoef,
+  uint16_t twidCoefModifier);
+
+void arm_radix2_butterfly_inverse_f32(
+  float32_t * pSrc,
+  uint32_t fftLen,
+  float32_t * pCoef,
+  uint16_t twidCoefModifier,
+  float32_t onebyfftLen);
+
+extern void arm_bitreversal_f32(
+    float32_t * pSrc,
+    uint16_t fftSize,
+    uint16_t bitRevFactor,
+    uint16_t * pBitRevTab);
+
+/**   
+* @ingroup groupTransforms   
+*/
+
+/**   
+* @addtogroup ComplexFFT   
+* @{   
+*/
+
+/**   
+* @details
+* @brief Radix-2 CFFT/CIFFT.
+* @deprecated Do not use this function.  It has been superceded by \ref arm_cfft_f32 and will be removed
+* in the future.
+* @param[in]      *S    points to an instance of the floating-point Radix-2 CFFT/CIFFT structure.  
+* @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.  
+* @return none.
+*/
+
+void arm_cfft_radix2_f32(
+const arm_cfft_radix2_instance_f32 * S,
+float32_t * pSrc)
+{
+
+   if(S->ifftFlag == 1u)
+   {
+      /*  Complex IFFT radix-2  */
+      arm_radix2_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle,
+      S->twidCoefModifier, S->onebyfftLen);
+   }
+   else
+   {
+      /*  Complex FFT radix-2  */
+      arm_radix2_butterfly_f32(pSrc, S->fftLen, S->pTwiddle,
+      S->twidCoefModifier);
+   }
+
+   if(S->bitReverseFlag == 1u)
+   {
+      /*  Bit Reversal */
+      arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);
+   }
+
+}
+
+
+/**    
+* @} end of ComplexFFT group    
+*/
+
+
+
+/* ----------------------------------------------------------------------    
+** Internal helper function used by the FFTs    
+** ------------------------------------------------------------------- */
+
+/*    
+* @brief  Core function for the floating-point CFFT butterfly process.   
+* @param[in, out] *pSrc            points to the in-place buffer of floating-point data type.   
+* @param[in]      fftLen           length of the FFT.   
+* @param[in]      *pCoef           points to the twiddle coefficient buffer.   
+* @param[in]      twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.   
+* @return none.   
+*/
+
+void arm_radix2_butterfly_f32(
+float32_t * pSrc,
+uint32_t fftLen,
+float32_t * pCoef,
+uint16_t twidCoefModifier)
+{
+
+   uint32_t i, j, k, l;
+   uint32_t n1, n2, ia;
+   float32_t xt, yt, cosVal, sinVal;
+   float32_t p0, p1, p2, p3;
+   float32_t a0, a1;
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+   /*  Initializations for the first stage */
+   n2 = fftLen >> 1;
+   ia = 0;
+   i = 0;
+
+   // loop for groups 
+   for (k = n2; k > 0; k--)
+   {
+      cosVal = pCoef[ia * 2];
+      sinVal = pCoef[(ia * 2) + 1];
+
+      /*  Twiddle coefficients index modifier */
+      ia += twidCoefModifier;
+
+      /*  index calculation for the input as, */
+      /*  pSrc[i + 0], pSrc[i + fftLen/1] */
+      l = i + n2;
+
+      /*  Butterfly implementation */
+      a0 = pSrc[2 * i] + pSrc[2 * l];
+      xt = pSrc[2 * i] - pSrc[2 * l];
+
+      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+      
+      p0 = xt * cosVal;
+      p1 = yt * sinVal;
+      p2 = yt * cosVal;
+      p3 = xt * sinVal;  
+      
+      pSrc[2 * i]     = a0;   
+      pSrc[2 * i + 1] = a1;       
+      
+      pSrc[2 * l]     = p0 + p1;
+      pSrc[2 * l + 1] = p2 - p3;
+      
+      i++;
+   }                             // groups loop end 
+
+   twidCoefModifier <<= 1u;
+
+   // loop for stage 
+   for (k = n2; k > 2; k = k >> 1)
+   {
+      n1 = n2;
+      n2 = n2 >> 1;
+      ia = 0;
+
+      // loop for groups 
+      j = 0;
+      do
+      {
+         cosVal = pCoef[ia * 2];
+         sinVal = pCoef[(ia * 2) + 1];
+         ia += twidCoefModifier;
+
+         // loop for butterfly 
+         i = j;
+         do
+         {
+            l = i + n2;
+            a0 = pSrc[2 * i] + pSrc[2 * l];
+            xt = pSrc[2 * i] - pSrc[2 * l];
+
+            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+            
+            p0 = xt * cosVal;
+            p1 = yt * sinVal;
+            p2 = yt * cosVal;
+            p3 = xt * sinVal;  
+            
+            pSrc[2 * i] = a0;   
+            pSrc[2 * i + 1] = a1;       
+            
+            pSrc[2 * l]     = p0 + p1;
+            pSrc[2 * l + 1] = p2 - p3;
+            
+            i += n1;
+         } while( i < fftLen );                        // butterfly loop end 
+         j++;
+      } while( j < n2);                          // groups loop end 
+      twidCoefModifier <<= 1u;
+   }                             // stages loop end 
+
+   // loop for butterfly 
+   for (i = 0; i < fftLen; i += 2)
+   {
+      a0 = pSrc[2 * i] + pSrc[2 * i + 2];
+      xt = pSrc[2 * i] - pSrc[2 * i + 2];
+
+      yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];
+      a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];
+      
+      pSrc[2 * i] = a0;   
+      pSrc[2 * i + 1] = a1;
+      pSrc[2 * i + 2] = xt;
+      pSrc[2 * i + 3] = yt;
+   }                             // groups loop end 
+
+#else
+ 
+   n2 = fftLen;
+
+   // loop for stage 
+   for (k = fftLen; k > 1; k = k >> 1)
+   {
+      n1 = n2;
+      n2 = n2 >> 1;
+      ia = 0;
+
+      // loop for groups 
+      j = 0;
+      do
+      {
+         cosVal = pCoef[ia * 2];
+         sinVal = pCoef[(ia * 2) + 1];
+         ia += twidCoefModifier;
+
+         // loop for butterfly 
+         i = j;
+         do
+         {
+            l = i + n2;
+            a0 = pSrc[2 * i] + pSrc[2 * l];
+            xt = pSrc[2 * i] - pSrc[2 * l];
+
+            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+            
+            p0 = xt * cosVal;
+            p1 = yt * sinVal;
+            p2 = yt * cosVal;
+            p3 = xt * sinVal;  
+            
+            pSrc[2 * i] = a0;   
+            pSrc[2 * i + 1] = a1;       
+            
+            pSrc[2 * l]     = p0 + p1;
+            pSrc[2 * l + 1] = p2 - p3;
+            
+            i += n1;
+         } while(i < fftLen);
+         j++;
+      } while(j < n2);
+      twidCoefModifier <<= 1u;
+   }
+
+#endif //    #ifndef ARM_MATH_CM0_FAMILY
+
+}
+
+
+void arm_radix2_butterfly_inverse_f32(
+float32_t * pSrc,
+uint32_t fftLen,
+float32_t * pCoef,
+uint16_t twidCoefModifier,
+float32_t onebyfftLen)
+{
+
+   uint32_t i, j, k, l;
+   uint32_t n1, n2, ia;
+   float32_t xt, yt, cosVal, sinVal;
+   float32_t p0, p1, p2, p3;
+   float32_t a0, a1;
+
+#ifndef ARM_MATH_CM0_FAMILY
+
+   n2 = fftLen >> 1;
+   ia = 0;
+
+   // loop for groups 
+   for (i = 0; i < n2; i++)
+   {
+      cosVal = pCoef[ia * 2];
+      sinVal = pCoef[(ia * 2) + 1];
+      ia += twidCoefModifier;
+
+      l = i + n2;
+      a0 = pSrc[2 * i] + pSrc[2 * l];
+      xt = pSrc[2 * i] - pSrc[2 * l];
+
+      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+      
+      p0 = xt * cosVal;
+      p1 = yt * sinVal;
+      p2 = yt * cosVal;
+      p3 = xt * sinVal;  
+      
+      pSrc[2 * i] = a0;   
+      pSrc[2 * i + 1] = a1;       
+      
+      pSrc[2 * l]     = p0 - p1;
+      pSrc[2 * l + 1] = p2 + p3;  
+   }                             // groups loop end 
+
+   twidCoefModifier <<= 1u;
+
+   // loop for stage 
+   for (k = fftLen / 2; k > 2; k = k >> 1)
+   {
+      n1 = n2;
+      n2 = n2 >> 1;
+      ia = 0;
+
+      // loop for groups 
+      j = 0;
+      do
+      {
+         cosVal = pCoef[ia * 2];
+         sinVal = pCoef[(ia * 2) + 1];
+         ia += twidCoefModifier;
+
+         // loop for butterfly 
+         i = j;
+         do
+         {
+            l = i + n2;
+            a0 = pSrc[2 * i] + pSrc[2 * l];
+            xt = pSrc[2 * i] - pSrc[2 * l];
+
+            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+            
+            p0 = xt * cosVal;
+            p1 = yt * sinVal;
+            p2 = yt * cosVal;
+            p3 = xt * sinVal;  
+            
+            pSrc[2 * i] = a0;   
+            pSrc[2 * i + 1] = a1;       
+            
+            pSrc[2 * l]     = p0 - p1;
+            pSrc[2 * l + 1] = p2 + p3; 
+
+            i += n1;
+         } while( i < fftLen );                 // butterfly loop end 
+         j++;
+      } while(j < n2);                      // groups loop end 
+
+      twidCoefModifier <<= 1u;
+   }                             // stages loop end 
+
+   // loop for butterfly 
+   for (i = 0; i < fftLen; i += 2)
+   {   
+      a0 = pSrc[2 * i] + pSrc[2 * i + 2];
+      xt = pSrc[2 * i] - pSrc[2 * i + 2];
+      
+      a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];
+      yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];
+      
+      p0 = a0 * onebyfftLen;
+      p2 = xt * onebyfftLen;
+      p1 = a1 * onebyfftLen;
+      p3 = yt * onebyfftLen; 
+      
+      pSrc[2 * i] = p0;
+      pSrc[2 * i + 1] = p1;  
+      pSrc[2 * i + 2] = p2;       
+      pSrc[2 * i + 3] = p3;
+   }                             // butterfly loop end 
+
+#else
+
+   n2 = fftLen;
+
+   // loop for stage 
+   for (k = fftLen; k > 2; k = k >> 1)
+   {
+      n1 = n2;
+      n2 = n2 >> 1;
+      ia = 0;
+
+      // loop for groups 
+      j = 0;
+      do
+      {
+         cosVal = pCoef[ia * 2];
+         sinVal = pCoef[(ia * 2) + 1];
+         ia = ia + twidCoefModifier;
+
+         // loop for butterfly 
+         i = j;
+         do
+         {
+            l = i + n2;
+            a0 = pSrc[2 * i] + pSrc[2 * l];
+            xt = pSrc[2 * i] - pSrc[2 * l];
+
+            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+            
+            p0 = xt * cosVal;
+            p1 = yt * sinVal;
+            p2 = yt * cosVal;
+            p3 = xt * sinVal;  
+            
+            pSrc[2 * i] = a0;   
+            pSrc[2 * i + 1] = a1;       
+            
+            pSrc[2 * l]     = p0 - p1;
+            pSrc[2 * l + 1] = p2 + p3;  
+            
+            i += n1;
+         } while( i < fftLen );                    // butterfly loop end 
+         j++;
+      } while( j < n2 );                      // groups loop end 
+
+      twidCoefModifier = twidCoefModifier << 1u;
+   }                             // stages loop end 
+
+   n1 = n2;
+   n2 = n2 >> 1;
+
+   // loop for butterfly 
+   for (i = 0; i < fftLen; i += n1)
+   {
+      l = i + n2;
+      
+      a0 = pSrc[2 * i] + pSrc[2 * l];
+      xt = pSrc[2 * i] - pSrc[2 * l];
+      
+      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];
+      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];
+      
+      p0 = a0 * onebyfftLen;
+      p2 = xt * onebyfftLen;
+      p1 = a1 * onebyfftLen;
+      p3 = yt * onebyfftLen; 
+      
+      pSrc[2 * i] = p0;
+      pSrc[2u * l] = p2;
+     
+      pSrc[2 * i + 1] = p1;    
+      pSrc[2u * l + 1u] = p3;
+   }                             // butterfly loop end 
+
+#endif //      #ifndef ARM_MATH_CM0_FAMILY
+
+}