arm_cmplx_mag_f32.c

00001 /* ----------------------------------------------------------------------
00002  * Project:      CMSIS DSP Library
00003  * Title:        arm_cmplx_mag_f32.c
00004  * Description:  Floating-point complex magnitude
00005  *
00006  * $Date:        27. January 2017
00007  * $Revision:    V.1.5.1
00008  *
00009  * Target Processor: Cortex-M cores
00010  * -------------------------------------------------------------------- */
00011 /*
00012  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
00013  *
00014  * SPDX-License-Identifier: Apache-2.0
00015  *
00016  * Licensed under the Apache License, Version 2.0 (the License); you may
00017  * not use this file except in compliance with the License.
00018  * You may obtain a copy of the License at
00019  *
00020  * www.apache.org/licenses/LICENSE-2.0
00021  *
00022  * Unless required by applicable law or agreed to in writing, software
00023  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
00024  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00025  * See the License for the specific language governing permissions and
00026  * limitations under the License.
00027  */
00028 
00029 #include "arm_math.h"
00030 
00031 /**
00032  * @ingroup groupCmplxMath
00033  */
00034 
00035 /**
00036  * @defgroup cmplx_mag Complex Magnitude
00037  *
00038  * Computes the magnitude of the elements of a complex data vector.
00039  *
00040  * The <code>pSrc</code> points to the source data and
00041  * <code>pDst</code> points to the where the result should be written.
00042  * <code>numSamples</code> specifies the number of complex samples
00043  * in the input array and the data is stored in an interleaved fashion
00044  * (real, imag, real, imag, ...).
00045  * The input array has a total of <code>2*numSamples</code> values;
00046  * the output array has a total of <code>numSamples</code> values.
00047  * The underlying algorithm is used:
00048  *
00049  * <pre>
00050  * for(n=0; n<numSamples; n++) {
00051  *     pDst[n] = sqrt(pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2);
00052  * }
00053  * </pre>
00054  *
00055  * There are separate functions for floating-point, Q15, and Q31 data types.
00056  */
00057 
00058 /**
00059  * @addtogroup cmplx_mag
00060  * @{
00061  */
00062 /**
00063  * @brief Floating-point complex magnitude.
00064  * @param[in]       *pSrc points to complex input buffer
00065  * @param[out]      *pDst points to real output buffer
00066  * @param[in]       numSamples number of complex samples in the input vector
00067  * @return none.
00068  *
00069  */
00070 
00071 
00072 void arm_cmplx_mag_f32(
00073   float32_t * pSrc,
00074   float32_t * pDst,
00075   uint32_t numSamples)
00076 {
00077   float32_t realIn, imagIn;                      /* Temporary variables to hold input values */
00078 
00079 #if defined (ARM_MATH_DSP)
00080 
00081   /* Run the below code for Cortex-M4 and Cortex-M3 */
00082   uint32_t blkCnt;                               /* loop counter */
00083 
00084   /*loop Unrolling */
00085   blkCnt = numSamples >> 2U;
00086 
00087   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
00088    ** a second loop below computes the remaining 1 to 3 samples. */
00089   while (blkCnt > 0U)
00090   {
00091 
00092     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
00093     realIn = *pSrc++;
00094     imagIn = *pSrc++;
00095     /* store the result in the destination buffer. */
00096     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00097 
00098     realIn = *pSrc++;
00099     imagIn = *pSrc++;
00100     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00101 
00102     realIn = *pSrc++;
00103     imagIn = *pSrc++;
00104     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00105 
00106     realIn = *pSrc++;
00107     imagIn = *pSrc++;
00108     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00109 
00110 
00111     /* Decrement the loop counter */
00112     blkCnt--;
00113   }
00114 
00115   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
00116    ** No loop unrolling is used. */
00117   blkCnt = numSamples % 0x4U;
00118 
00119   while (blkCnt > 0U)
00120   {
00121     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
00122     realIn = *pSrc++;
00123     imagIn = *pSrc++;
00124     /* store the result in the destination buffer. */
00125     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00126 
00127     /* Decrement the loop counter */
00128     blkCnt--;
00129   }
00130 
00131 #else
00132 
00133   /* Run the below code for Cortex-M0 */
00134 
00135   while (numSamples > 0U)
00136   {
00137     /* out = sqrt((real * real) + (imag * imag)) */
00138     realIn = *pSrc++;
00139     imagIn = *pSrc++;
00140     /* store the result in the destination buffer. */
00141     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
00142 
00143     /* Decrement the loop counter */
00144     numSamples--;
00145   }
00146 
00147 #endif /* #if defined (ARM_MATH_DSP) */
00148 
00149 }
00150 
00151 /**
00152  * @} end of cmplx_mag group
00153  */
00154