arm_cmplx_mag_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_f32.c  
00009 *  
00010 * Description:  Floating-point complex magnitude.  
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 Complex Magnitude  
00035  *  
00036  * Computes the magnitude 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  * The underlying algorithm is used:  
00046  *  
00047  * <pre>  
00048  * for(n=0; n<numSamples; n++) {  
00049  *     pDst[n] = sqrt(pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2);  
00050  * }  
00051  * </pre>  
00052  *  
00053  * There are separate functions for floating-point, Q15, and Q31 data types.  
00054  */ 
00055  
00056 /**  
00057  * @addtogroup cmplx_mag  
00058  * @{  
00059  */ 
00060 /**  
00061  * @brief Floating-point complex magnitude.  
00062  * @param[in]       *pSrc points to complex input buffer  
00063  * @param[out]      *pDst points to real output buffer  
00064  * @param[in]       numSamples number of complex samples in the input vector  
00065  * @return none.  
00066  *  
00067  */ 
00068  
00069  
00070 void arm_cmplx_mag_f32( 
00071   float32_t * pSrc, 
00072   float32_t * pDst, 
00073   uint32_t numSamples) 
00074 { 
00075   uint32_t blkCnt;                               /* loop counter */ 
00076   float32_t realIn, imagIn;                      /* Temporary variables to hold input values */ 
00077  
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  
00087     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */ 
00088     realIn = *pSrc++; 
00089     imagIn = *pSrc++; 
00090     /* store the result in the destination buffer. */ 
00091     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++); 
00092  
00093     realIn = *pSrc++; 
00094     imagIn = *pSrc++; 
00095     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++); 
00096  
00097     realIn = *pSrc++; 
00098     imagIn = *pSrc++; 
00099     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++); 
00100  
00101     realIn = *pSrc++; 
00102     imagIn = *pSrc++; 
00103     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++); 
00104  
00105  
00106     /* Decrement the loop counter */ 
00107     blkCnt--; 
00108   } 
00109  
00110   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.  
00111    ** No loop unrolling is used. */ 
00112   blkCnt = numSamples % 0x4u; 
00113  
00114   while(blkCnt > 0u) 
00115   { 
00116     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */ 
00117     realIn = *pSrc++; 
00118     imagIn = *pSrc++; 
00119     /* store the result in the destination buffer. */ 
00120     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++); 
00121  
00122     /* Decrement the loop counter */ 
00123     blkCnt--; 
00124   } 
00125 } 
00126  
00127 /**  
00128  * @} end of cmplx_mag group  
00129  */