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