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/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_conj_q31.c
* Description: Q31 complex conjugate
*
* $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
*/
/**
* @addtogroup cmplx_conj
* @{
*/
/**
* @brief Q31 complex conjugate.
* @param *pSrc points to the input vector
* @param *pDst points to the output vector
* @param numSamples number of complex samples in each vector
* @return none.
*
* <b>Scaling and Overflow Behavior:</b>
* \par
* The function uses saturating arithmetic.
* The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
*/
void arm_cmplx_conj_q31(
q31_t * pSrc,
q31_t * pDst,
uint32_t numSamples)
{
uint32_t blkCnt; /* loop counter */
q31_t in; /* Input value */
#if defined (ARM_MATH_DSP)
/* Run the below code for Cortex-M4 and Cortex-M3 */
q31_t inR1, inR2, inR3, inR4; /* Temporary real variables */
q31_t inI1, inI2, inI3, inI4; /* Temporary imaginary variables */
/*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]+jC[1] = A[0]+ j (-1) A[1] */
/* Calculate Complex Conjugate and then store the results in the destination buffer. */
/* Saturated to 0x7fffffff if the input is -1(0x80000000) */
/* read real input sample */
inR1 = pSrc[0];
/* store real input sample */
pDst[0] = inR1;
/* read imaginary input sample */
inI1 = pSrc[1];
/* read real input sample */
inR2 = pSrc[2];
/* store real input sample */
pDst[2] = inR2;
/* read imaginary input sample */
inI2 = pSrc[3];
/* negate imaginary input sample */
inI1 = __QSUB(0, inI1);
/* read real input sample */
inR3 = pSrc[4];
/* store real input sample */
pDst[4] = inR3;
/* read imaginary input sample */
inI3 = pSrc[5];
/* negate imaginary input sample */
inI2 = __QSUB(0, inI2);
/* read real input sample */
inR4 = pSrc[6];
/* store real input sample */
pDst[6] = inR4;
/* negate imaginary input sample */
inI3 = __QSUB(0, inI3);
/* store imaginary input sample */
inI4 = pSrc[7];
/* store imaginary input samples */
pDst[1] = inI1;
/* negate imaginary input sample */
inI4 = __QSUB(0, inI4);
/* store imaginary input samples */
pDst[3] = inI2;
/* increment source pointer by 8 to proecess next samples */
pSrc += 8U;
/* store imaginary input samples */
pDst[5] = inI3;
pDst[7] = inI4;
/* increment destination pointer by 8 to process next samples */
pDst += 8U;
/* 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]+jC[1] = A[0]+ j (-1) A[1] */
/* Calculate Complex Conjugate and then store the results in the destination buffer. */
/* Saturated to 0x7fffffff if the input is -1(0x80000000) */
*pDst++ = *pSrc++;
in = *pSrc++;
*pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;
/* Decrement the loop counter */
blkCnt--;
}
}
/**
* @} end of cmplx_conj group
*/
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