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Rev	Author	Line No.	Line
2	mjames	1	/* ----------------------------------------------------------------------
		2	* Project: CMSIS DSP Library
		3	* Title: arm_cmplx_conj_q31.c
		4	* Description: Q31 complex conjugate
		5	*
		6	* $Date: 27. January 2017
		7	* $Revision: V.1.5.1
		8	*
		9	* Target Processor: Cortex-M cores
		10	* -------------------------------------------------------------------- */
		11	/*
		12	* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
		13	*
		14	* SPDX-License-Identifier: Apache-2.0
		15	*
		16	* Licensed under the Apache License, Version 2.0 (the License); you may
		17	* not use this file except in compliance with the License.
		18	* You may obtain a copy of the License at
		19	*
		20	* www.apache.org/licenses/LICENSE-2.0
		21	*
		22	* Unless required by applicable law or agreed to in writing, software
		23	* distributed under the License is distributed on an AS IS BASIS, WITHOUT
		24	* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		25	* See the License for the specific language governing permissions and
		26	* limitations under the License.
		27	*/
		28
		29	#include "arm_math.h"
		30
		31	/**
		32	* @ingroup groupCmplxMath
		33	*/
		34
		35	/**
		36	* @addtogroup cmplx_conj
		37	* @{
		38	*/
		39
		40	/**
		41	* @brief Q31 complex conjugate.
		42	* @param *pSrc points to the input vector
		43	* @param *pDst points to the output vector
		44	* @param numSamples number of complex samples in each vector
		45	* @return none.
		46	*
		47	* <b>Scaling and Overflow Behavior:</b>
		48	* \par
		49	* The function uses saturating arithmetic.
		50	* The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
		51	*/
		52
		53	void arm_cmplx_conj_q31(
		54	q31_t * pSrc,
		55	q31_t * pDst,
		56	uint32_t numSamples)
		57	{
		58	uint32_t blkCnt; /* loop counter */
		59	q31_t in; /* Input value */
		60
		61	#if defined (ARM_MATH_DSP)
		62
		63	/* Run the below code for Cortex-M4 and Cortex-M3 */
		64	q31_t inR1, inR2, inR3, inR4; /* Temporary real variables */
		65	q31_t inI1, inI2, inI3, inI4; /* Temporary imaginary variables */
		66
		67	/loop Unrolling /
		68	blkCnt = numSamples >> 2U;
		69
		70	/* First part of the processing with loop unrolling. Compute 4 outputs at a time.
		71	** a second loop below computes the remaining 1 to 3 samples. */
		72	while (blkCnt > 0U)
		73	{
		74	/* C[0]+jC[1] = A[0]+ j (-1) A[1] */
		75	/* Calculate Complex Conjugate and then store the results in the destination buffer. */
		76	/* Saturated to 0x7fffffff if the input is -1(0x80000000) */
		77	/* read real input sample */
		78	inR1 = pSrc[0];
		79	/* store real input sample */
		80	pDst[0] = inR1;
		81
		82	/* read imaginary input sample */
		83	inI1 = pSrc[1];
		84
		85	/* read real input sample */
		86	inR2 = pSrc[2];
		87	/* store real input sample */
		88	pDst[2] = inR2;
		89
		90	/* read imaginary input sample */
		91	inI2 = pSrc[3];
		92
		93	/* negate imaginary input sample */
		94	inI1 = __QSUB(0, inI1);
		95
		96	/* read real input sample */
		97	inR3 = pSrc[4];
		98	/* store real input sample */
		99	pDst[4] = inR3;
		100
		101	/* read imaginary input sample */
		102	inI3 = pSrc[5];
		103
		104	/* negate imaginary input sample */
		105	inI2 = __QSUB(0, inI2);
		106
		107	/* read real input sample */
		108	inR4 = pSrc[6];
		109	/* store real input sample */
		110	pDst[6] = inR4;
		111
		112	/* negate imaginary input sample */
		113	inI3 = __QSUB(0, inI3);
		114
		115	/* store imaginary input sample */
		116	inI4 = pSrc[7];
		117
		118	/* store imaginary input samples */
		119	pDst[1] = inI1;
		120
		121	/* negate imaginary input sample */
		122	inI4 = __QSUB(0, inI4);
		123
		124	/* store imaginary input samples */
		125	pDst[3] = inI2;
		126
		127	/* increment source pointer by 8 to proecess next samples */
		128	pSrc += 8U;
		129
		130	/* store imaginary input samples */
		131	pDst[5] = inI3;
		132	pDst[7] = inI4;
		133
		134	/* increment destination pointer by 8 to process next samples */
		135	pDst += 8U;
		136
		137	/* Decrement the loop counter */
		138	blkCnt--;
		139	}
		140
		141	/* If the numSamples is not a multiple of 4, compute any remaining output samples here.
		142	** No loop unrolling is used. */
		143	blkCnt = numSamples % 0x4U;
		144
		145	#else
		146
		147	/* Run the below code for Cortex-M0 */
		148	blkCnt = numSamples;
		149
		150
		151	#endif /* #if defined (ARM_MATH_DSP) */
		152
		153	while (blkCnt > 0U)
		154	{
		155	/* C[0]+jC[1] = A[0]+ j (-1) A[1] */
		156	/* Calculate Complex Conjugate and then store the results in the destination buffer. */
		157	/* Saturated to 0x7fffffff if the input is -1(0x80000000) */
		158	pDst++ = pSrc++;
		159	in = *pSrc++;
		160	*pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;
		161
		162	/* Decrement the loop counter */
		163	blkCnt--;
		164	}
		165	}
		166
		167	/**
		168	* @} end of cmplx_conj group
		169	*/

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(root)/branches/dashGPS-bmp/Drivers/CMSIS/DSP/Source/ComplexMathFunctions/arm_cmplx_conj_q31.c – Rev 18