| /* ---------------------------------------------------------------------- |
| * Project: CMSIS DSP Library |
| * Title: arm_cmplx_conj_f32.c |
| * Description: Floating-point complex conjugate |
| * |
| * $Date: 18. March 2019 |
| * $Revision: V1.6.0 |
| * |
| * Target Processor: Cortex-M cores |
| * -------------------------------------------------------------------- */ |
| /* |
| * Copyright (C) 2010-2019 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 |
| */ |
| |
| /** |
| @defgroup cmplx_conj Complex Conjugate |
| |
| Conjugates the elements of a complex data vector. |
| |
| The <code>pSrc</code> points to the source data and |
| <code>pDst</code> points to the destination data where the result should be written. |
| <code>numSamples</code> specifies the number of complex samples |
| and the data in each array is stored in an interleaved fashion |
| (real, imag, real, imag, ...). |
| Each array has a total of <code>2*numSamples</code> values. |
| |
| The underlying algorithm is used: |
| <pre> |
| for (n = 0; n < numSamples; n++) { |
| pDst[(2*n) ] = pSrc[(2*n) ]; // real part |
| pDst[(2*n)+1] = -pSrc[(2*n)+1]; // imag part |
| } |
| </pre> |
| |
| There are separate functions for floating-point, Q15, and Q31 data types. |
| */ |
| |
| /** |
| @addtogroup cmplx_conj |
| @{ |
| */ |
| |
| /** |
| @brief Floating-point complex conjugate. |
| @param[in] pSrc points to the input vector |
| @param[out] pDst points to the output vector |
| @param[in] numSamples number of samples in each vector |
| @return none |
| */ |
| |
| |
| void arm_cmplx_conj_f32( |
| const float32_t * pSrc, |
| float32_t * pDst, |
| uint32_t numSamples) |
| { |
| uint32_t blkCnt; /* Loop counter */ |
| |
| #if defined(ARM_MATH_NEON) |
| float32x4_t zero; |
| float32x4x2_t vec; |
| |
| zero = vdupq_n_f32(0.0); |
| |
| /* Compute 4 outputs at a time */ |
| blkCnt = numSamples >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* C[0]+jC[1] = A[0]+(-1)*jA[1] */ |
| /* Calculate Complex Conjugate and then store the results in the destination buffer. */ |
| vec = vld2q_f32(pSrc); |
| vec.val[1] = vsubq_f32(zero,vec.val[1]); |
| vst2q_f32(pDst,vec); |
| |
| /* Increment pointers */ |
| pSrc += 8; |
| pDst += 8; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* Tail */ |
| blkCnt = numSamples & 0x3; |
| |
| #else |
| #if defined (ARM_MATH_LOOPUNROLL) |
| |
| /* Loop unrolling: Compute 4 outputs at a time */ |
| blkCnt = numSamples >> 2U; |
| |
| while (blkCnt > 0U) |
| { |
| /* C[0] + jC[1] = A[0]+ j(-1)A[1] */ |
| |
| /* Calculate Complex Conjugate and store result in destination buffer. */ |
| *pDst++ = *pSrc++; |
| *pDst++ = -*pSrc++; |
| |
| *pDst++ = *pSrc++; |
| *pDst++ = -*pSrc++; |
| |
| *pDst++ = *pSrc++; |
| *pDst++ = -*pSrc++; |
| |
| *pDst++ = *pSrc++; |
| *pDst++ = -*pSrc++; |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| /* Loop unrolling: Compute remaining outputs */ |
| blkCnt = numSamples % 0x4U; |
| |
| #else |
| |
| /* Initialize blkCnt with number of samples */ |
| blkCnt = numSamples; |
| |
| #endif /* #if defined (ARM_MATH_LOOPUNROLL) */ |
| #endif /* #if defined (ARM_MATH_NEON) */ |
| |
| while (blkCnt > 0U) |
| { |
| /* C[0] + jC[1] = A[0]+ j(-1)A[1] */ |
| |
| /* Calculate Complex Conjugate and store result in destination buffer. */ |
| *pDst++ = *pSrc++; |
| *pDst++ = -*pSrc++; |
| |
| /* Decrement loop counter */ |
| blkCnt--; |
| } |
| |
| } |
| |
| /** |
| @} end of cmplx_conj group |
| */ |