arm_cmplx_conj_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_conj_f32.c  
00009 *  
00010 * Description:  Floating-point complex conjugate.  
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_conj Complex Conjugate  
00035  *  
00036  * Conjugates 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  * and the data in each array is stored in an interleaved fashion  
00042  * (real, imag, real, imag, ...).  
00043  * Each array has a total of <code>2*numSamples</code> values.  
00044  * The underlying algorithm is used:  
00045  *  
00046  * <pre>  
00047  * for(n=0; n<numSamples; n++) {  
00048  *     pDst[(2*n)+0)] = pSrc[(2*n)+0];     // real part  
00049  *     pDst[(2*n)+1)] = -pSrc[(2*n)+1];    // imag part  
00050  * }  
00051  * </pre>  
00052  *  
00053  * There are separate functions for floating-point, Q15, and Q31 data types.  
00054  */ 
00055  
00056 /**  
00057  * @addtogroup cmplx_conj  
00058  * @{  
00059  */ 
00060  
00061 /**  
00062  * @brief  Floating-point complex conjugate.  
00063  * @param  *pSrc points to the input vector  
00064  * @param  *pDst points to the output vector  
00065  * @param  numSamples number of complex samples in each vector  
00066  * @return none.  
00067  */ 
00068  
00069 void arm_cmplx_conj_f32( 
00070   float32_t * pSrc, 
00071   float32_t * pDst, 
00072   uint32_t numSamples) 
00073 { 
00074   uint32_t blkCnt;                               /* loop counter */ 
00075  
00076   /*loop Unrolling */ 
00077   blkCnt = numSamples >> 2u; 
00078  
00079   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.  
00080    ** a second loop below computes the remaining 1 to 3 samples. */ 
00081   while(blkCnt > 0u) 
00082   { 
00083     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */ 
00084     /* Calculate Complex Conjugate and then store the results in the destination buffer. */ 
00085     *pDst++ = *pSrc++; 
00086     *pDst++ = -*pSrc++; 
00087     *pDst++ = *pSrc++; 
00088     *pDst++ = -*pSrc++; 
00089     *pDst++ = *pSrc++; 
00090     *pDst++ = -*pSrc++; 
00091     *pDst++ = *pSrc++; 
00092     *pDst++ = -*pSrc++; 
00093  
00094     /* Decrement the loop counter */ 
00095     blkCnt--; 
00096   } 
00097  
00098   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.  
00099    ** No loop unrolling is used. */ 
00100   blkCnt = numSamples % 0x4u; 
00101  
00102   while(blkCnt > 0u) 
00103   { 
00104     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */ 
00105     /* Calculate Complex Conjugate and then store the results in the destination buffer. */ 
00106     *pDst++ = *pSrc++; 
00107     *pDst++ = -*pSrc++; 
00108  
00109     /* Decrement the loop counter */ 
00110     blkCnt--; 
00111   } 
00112 } 
00113  
00114 /**  
00115  * @} end of cmplx_conj group  
00116  */