arm_cmplx_mag_f32.c

00001 /* ----------------------------------------------------------------------    
00002 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.    
00003 *    
00004 * $Date:        17. January 2013
00005 * $Revision:    V1.4.1
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/Cortex-M0
00013 *  
00014 * Redistribution and use in source and binary forms, with or without 
00015 * modification, are permitted provided that the following conditions
00016 * are met:
00017 *   - Redistributions of source code must retain the above copyright
00018 *     notice, this list of conditions and the following disclaimer.
00019 *   - Redistributions in binary form must reproduce the above copyright
00020 *     notice, this list of conditions and the following disclaimer in
00021 *     the documentation and/or other materials provided with the 
00022 *     distribution.
00023 *   - Neither the name of ARM LIMITED nor the names of its contributors
00024 *     may be used to endorse or promote products derived from this
00025 *     software without specific prior written permission.
00026 *
00027 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00028 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00029 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00030 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
00031 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
00032 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
00033 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
00034 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
00035 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00036 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
00037 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00038 * POSSIBILITY OF SUCH DAMAGE.  
00039 * ---------------------------------------------------------------------------- */
00040 
00041 #include "arm_math.h"
00042 
00043 /**    
00044  * @ingroup groupCmplxMath    
00045  */
00046 
00047 /**    
00048  * @defgroup cmplx_mag Complex Magnitude    
00049  *    
00050  * Computes the magnitude of the elements of a complex data vector.    
00051  *   
00052  * The <code>pSrc</code> points to the source data and    
00053  * <code>pDst</code> points to the where the result should be written.    
00054  * <code>numSamples</code> specifies the number of complex samples    
00055  * in the input array and the data is stored in an interleaved fashion    
00056  * (real, imag, real, imag, ...).    
00057  * The input array has a total of <code>2*numSamples</code> values;    
00058  * the output array has a total of <code>numSamples</code> values.    
00059  * The underlying algorithm is used:    
00060  *    
00061  * <pre>    
00062  * for(n=0; n<numSamples; n++) {    
00063  *     pDst[n] = sqrt(pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2);    
00064  * }    
00065  * </pre>    
00066  *    
00067  * There are separate functions for floating-point, Q15, and Q31 data types.    
00068  */
00069 
00070 /**    
00071  * @addtogroup cmplx_mag    
00072  * @{    
00073  */
00074 /**    
00075  * @brief Floating-point complex magnitude.    
00076  * @param[in]       *pSrc points to complex input buffer    
00077  * @param[out]      *pDst points to real output buffer    
00078  * @param[in]       numSamples number of complex samples in the input vector    
00079  * @return none.    
00080  *    
00081  */
00082 
00083 
00084 void arm_cmplx_mag_f32(
00085   float32_t * pSrc,
00086   float32_t * pDst,
00087   uint32_t numSamples)
00088 {
00089   float32_t realIn, imagIn;                      /* Temporary variables to hold input values */
00090 
00091 #ifndef ARM_MATH_CM0_FAMILY
00092 
00093   /* Run the below code for Cortex-M4 and Cortex-M3 */
00094   uint32_t blkCnt;                               /* loop counter */
00095 
00096   /*loop Unrolling */
00097   blkCnt = numSamples >> 2u;
00098 
00099   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
00100    ** a second loop below computes the remaining 1 to 3 samples. */
00101   while(blkCnt > 0u)
00102   {
00103 
00104     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
00105     realIn = *pSrc++;
00106     imagIn = *pSrc++;
00107     /* store the result in the destination buffer. */
00108     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00109 
00110     realIn = *pSrc++;
00111     imagIn = *pSrc++;
00112     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00113 
00114     realIn = *pSrc++;
00115     imagIn = *pSrc++;
00116     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00117 
00118     realIn = *pSrc++;
00119     imagIn = *pSrc++;
00120     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00121 
00122 
00123     /* Decrement the loop counter */
00124     blkCnt--;
00125   }
00126 
00127   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.    
00128    ** No loop unrolling is used. */
00129   blkCnt = numSamples % 0x4u;
00130 
00131   while(blkCnt > 0u)
00132   {
00133     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
00134     realIn = *pSrc++;
00135     imagIn = *pSrc++;
00136     /* store the result in the destination buffer. */
00137     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00138 
00139     /* Decrement the loop counter */
00140     blkCnt--;
00141   }
00142 
00143 #else
00144 
00145   /* Run the below code for Cortex-M0 */
00146 
00147   while(numSamples > 0u)
00148   {
00149     /* out = sqrt((real * real) + (imag * imag)) */
00150     realIn = *pSrc++;
00151     imagIn = *pSrc++;
00152     /* store the result in the destination buffer. */
00153     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00154 
00155     /* Decrement the loop counter */
00156     numSamples--;
00157   }
00158 
00159 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
00160 
00161 }
00162 
00163 /**    
00164  * @} end of cmplx_mag group    
00165  */