arm_cmplx_mag_squared_f32.c

00001 /* ----------------------------------------------------------------------  
00002 * Copyright (C) 2010 ARM Limited. All rights reserved.  
00003 *  
00004 * $Date:        29. November 2010  
00005 * $Revision:    V1.0.3  
00006 *  
00007 * Project:      CMSIS DSP Library  
00008 * Title:        arm_cmplx_mag_squared_f32.c  
00009 *  
00010 * Description:  Floating-point complex magnitude squared.  
00011 *  
00012 * Target Processor: Cortex-M4/Cortex-M3
00013 *  
00014 * Version 1.0.3 2010/11/29 
00015 *    Re-organized the CMSIS folders and updated documentation.  
00016 *   
00017 * Version 1.0.2 2010/11/11  
00018 *    Documentation updated.   
00019 *  
00020 * Version 1.0.1 2010/10/05   
00021 *    Production release and review comments incorporated.  
00022 *  
00023 * Version 1.0.0 2010/09/20   
00024 *    Production release and review comments incorporated.  
00025 * ---------------------------------------------------------------------------- */ 
00026  
00027 #include "arm_math.h" 
00028  
00029 /**  
00030  * @ingroup groupCmplxMath  
00031  */ 
00032  
00033 /**  
00034  * @defgroup cmplx_mag_squared Complex Magnitude Squared  
00035  *  
00036  * Computes the magnitude squared of the elements of a complex data vector.  
00037  * 
00038  * The <code>pSrc</code> points to the source data and  
00039  * <code>pDst</code> points to the where the result should be written.  
00040  * <code>numSamples</code> specifies the number of complex samples  
00041  * in the input array and the data is stored in an interleaved fashion  
00042  * (real, imag, real, imag, ...).  
00043  * The input array has a total of <code>2*numSamples</code> values;  
00044  * the output array has a total of <code>numSamples</code> values.  
00045  *  
00046  * The underlying algorithm is used:  
00047  *  
00048  * <pre>  
00049  * for(n=0; n<numSamples; n++) {  
00050  *     pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;  
00051  * }  
00052  * </pre>  
00053  *  
00054  * There are separate functions for floating-point, Q15, and Q31 data types.  
00055  */ 
00056  
00057 /**  
00058  * @addtogroup cmplx_mag_squared  
00059  * @{  
00060  */ 
00061  
00062  
00063 /**  
00064  * @brief  Floating-point complex magnitude squared  
00065  * @param[in]  *pSrc points to the complex input vector  
00066  * @param[out]  *pDst points to the real output vector  
00067  * @param[in]  numSamples number of complex samples in the input vector  
00068  * @return none.  
00069  */ 
00070  
00071 void arm_cmplx_mag_squared_f32( 
00072   float32_t * pSrc, 
00073   float32_t * pDst, 
00074   uint32_t numSamples) 
00075 { 
00076   float32_t real, imag;                          /* Temporary variables to store real and imaginary values */ 
00077   uint32_t blkCnt;                               /* loop counter */ 
00078  
00079   /*loop Unrolling */ 
00080   blkCnt = numSamples >> 2u; 
00081  
00082   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00083    ** a second loop below computes the remaining 1 to 3 samples. */ 
00084   while(blkCnt > 0u) 
00085   { 
00086     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */ 
00087     real = *pSrc++; 
00088     imag = *pSrc++; 
00089     /* store the result in the destination buffer. */ 
00090     *pDst++ = (real * real) + (imag * imag); 
00091  
00092     real = *pSrc++; 
00093     imag = *pSrc++; 
00094     *pDst++ = (real * real) + (imag * imag); 
00095  
00096     real = *pSrc++; 
00097     imag = *pSrc++; 
00098     *pDst++ = (real * real) + (imag * imag); 
00099  
00100     real = *pSrc++; 
00101     imag = *pSrc++; 
00102     *pDst++ = (real * real) + (imag * imag); 
00103  
00104     /* Decrement the loop counter */ 
00105     blkCnt--; 
00106   } 
00107  
00108   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.  
00109    ** No loop unrolling is used. */ 
00110   blkCnt = numSamples % 0x4u; 
00111  
00112   while(blkCnt > 0u) 
00113   { 
00114     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */ 
00115     real = *pSrc++; 
00116     imag = *pSrc++; 
00117     /* store the result in the destination buffer. */ 
00118     *pDst++ = (real * real) + (imag * imag); 
00119  
00120     /* Decrement the loop counter */ 
00121     blkCnt--; 
00122   } 
00123 } 
00124  
00125 /**  
00126  * @} end of cmplx_mag_squared group  
00127  */