172 lines
4.4 KiB
C
172 lines
4.4 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cmplx_conj_f32.c
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* Description: Floating-point complex conjugate
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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_conj Complex Conjugate
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*
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* Conjugates 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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* and the data in each array is stored in an interleaved fashion
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* (real, imag, real, imag, ...).
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* Each array has a total of <code>2*numSamples</code> values.
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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[(2*n)+0)] = pSrc[(2*n)+0]; // real part
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* pDst[(2*n)+1)] = -pSrc[(2*n)+1]; // imag part
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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_conj
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* @{
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*/
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/**
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* @brief Floating-point complex conjugate.
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* @param *pSrc points to the input vector
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* @param *pDst points to the output vector
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* @param numSamples number of complex samples in each vector
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* @return none.
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*/
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void arm_cmplx_conj_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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uint32_t blkCnt; /* loop counter */
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#if defined (ARM_MATH_DSP)
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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float32_t inR1, inR2, inR3, inR4;
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float32_t inI1, inI2, inI3, inI4;
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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]+jC[1] = A[0]+ j (-1) A[1] */
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/* Calculate Complex Conjugate and then store the results in the destination buffer. */
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/* read real input samples */
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inR1 = pSrc[0];
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/* store real samples to destination */
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pDst[0] = inR1;
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inR2 = pSrc[2];
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pDst[2] = inR2;
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inR3 = pSrc[4];
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pDst[4] = inR3;
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inR4 = pSrc[6];
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pDst[6] = inR4;
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/* read imaginary input samples */
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inI1 = pSrc[1];
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inI2 = pSrc[3];
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/* conjugate input */
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inI1 = -inI1;
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/* read imaginary input samples */
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inI3 = pSrc[5];
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/* conjugate input */
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inI2 = -inI2;
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/* read imaginary input samples */
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inI4 = pSrc[7];
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/* conjugate input */
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inI3 = -inI3;
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/* store imaginary samples to destination */
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pDst[1] = inI1;
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pDst[3] = inI2;
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/* conjugate input */
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inI4 = -inI4;
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/* store imaginary samples to destination */
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pDst[5] = inI3;
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/* increment source pointer by 8 to process next sampels */
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pSrc += 8U;
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/* store imaginary sample to destination */
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pDst[7] = inI4;
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/* increment destination pointer by 8 to store next samples */
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pDst += 8U;
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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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/* realOut + j (imagOut) = realIn + j (-1) imagIn */
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/* Calculate Complex Conjugate and then store the results in the destination buffer. */
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*pDst++ = *pSrc++;
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*pDst++ = -*pSrc++;
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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_conj group
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*/
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