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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_mag_squared_f32.c
* Description: Floating-point complex magnitude squared
*
* $Date: 27. January 2017
* $Revision: V.1.5.1
*
* Target Processor: Cortex-M cores
* -------------------------------------------------------------------- */
/*
* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the License); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an AS IS BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "arm_math.h"
/**
* @ingroup groupCmplxMath
*/
/**
* @defgroup cmplx_mag_squared Complex Magnitude Squared
*
* Computes the magnitude squared of the elements of a complex data vector.
*
* The <code>pSrc</code> points to the source data and
* <code>pDst</code> points to the where the result should be written.
* <code>numSamples</code> specifies the number of complex samples
* in the input array and the data is stored in an interleaved fashion
* (real, imag, real, imag, ...).
* The input array has a total of <code>2*numSamples</code> values;
* the output array has a total of <code>numSamples</code> values.
*
* The underlying algorithm is used:
*
* <pre>
* for(n=0; n<numSamples; n++) {
* pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;
* }
* </pre>
*
* There are separate functions for floating-point, Q15, and Q31 data types.
*/
/**
* @addtogroup cmplx_mag_squared
* @{
*/
/**
* @brief Floating-point complex magnitude squared
* @param[in] *pSrc points to the complex input vector
* @param[out] *pDst points to the real output vector
* @param[in] numSamples number of complex samples in the input vector
* @return none.
*/
void arm_cmplx_mag_squared_f32(
float32_t * pSrc,
float32_t * pDst,
uint32_t numSamples)
{
float32_t real, imag; /* Temporary variables to store real and imaginary values */
uint32_t blkCnt; /* loop counter */
#if defined (ARM_MATH_DSP)
float32_t real1, real2, real3, real4; /* Temporary variables to hold real values */
float32_t imag1, imag2, imag3, imag4; /* Temporary variables to hold imaginary values */
float32_t mul1, mul2, mul3, mul4; /* Temporary variables */
float32_t mul5, mul6, mul7, mul8; /* Temporary variables */
float32_t out1, out2, out3, out4; /* Temporary variables to hold output values */
/*loop Unrolling */
blkCnt = numSamples >> 2U;
/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
** a second loop below computes the remaining 1 to 3 samples. */
while (blkCnt > 0U)
{
/* C[0] = (A[0] * A[0] + A[1] * A[1]) */
/* read real input sample from source buffer */
real1 = pSrc[0];
/* read imaginary input sample from source buffer */
imag1 = pSrc[1];
/* calculate power of real value */
mul1 = real1 * real1;
/* read real input sample from source buffer */
real2 = pSrc[2];
/* calculate power of imaginary value */
mul2 = imag1 * imag1;
/* read imaginary input sample from source buffer */
imag2 = pSrc[3];
/* calculate power of real value */
mul3 = real2 * real2;
/* read real input sample from source buffer */
real3 = pSrc[4];
/* calculate power of imaginary value */
mul4 = imag2 * imag2;
/* read imaginary input sample from source buffer */
imag3 = pSrc[5];
/* calculate power of real value */
mul5 = real3 * real3;
/* calculate power of imaginary value */
mul6 = imag3 * imag3;
/* read real input sample from source buffer */
real4 = pSrc[6];
/* accumulate real and imaginary powers */
out1 = mul1 + mul2;
/* read imaginary input sample from source buffer */
imag4 = pSrc[7];
/* accumulate real and imaginary powers */
out2 = mul3 + mul4;
/* calculate power of real value */
mul7 = real4 * real4;
/* calculate power of imaginary value */
mul8 = imag4 * imag4;
/* store output to destination */
pDst[0] = out1;
/* accumulate real and imaginary powers */
out3 = mul5 + mul6;
/* store output to destination */
pDst[1] = out2;
/* accumulate real and imaginary powers */
out4 = mul7 + mul8;
/* store output to destination */
pDst[2] = out3;
/* increment destination pointer by 8 to process next samples */
pSrc += 8U;
/* store output to destination */
pDst[3] = out4;
/* increment destination pointer by 4 to process next samples */
pDst += 4U;
/* Decrement the loop counter */
blkCnt--;
}
/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
** No loop unrolling is used. */
blkCnt = numSamples % 0x4U;
#else
/* Run the below code for Cortex-M0 */
blkCnt = numSamples;
#endif /* #if defined (ARM_MATH_DSP) */
while (blkCnt > 0U)
{
/* C[0] = (A[0] * A[0] + A[1] * A[1]) */
real = *pSrc++;
imag = *pSrc++;
/* out = (real * real) + (imag * imag) */
/* store the result in the destination buffer. */
*pDst++ = (real * real) + (imag * imag);
/* Decrement the loop counter */
blkCnt--;
}
}
/**
* @} end of cmplx_mag_squared group
*/
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