| /* ---------------------------------------------------------------------- |
| * 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 |
| */ |