/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_cmplx_mult_cmplx_f32.c
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* Description: Floating-point complex-by-complex multiplication
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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 CmplxByCmplxMult Complex-by-Complex Multiplication
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*
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* Multiplies a complex vector by another complex vector and generates a complex result.
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* The data in the complex arrays is stored in an interleaved fashion
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* (real, imag, real, imag, ...).
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* The parameter <code>numSamples</code> represents the number of complex
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* samples processed. The complex arrays have a total of <code>2*numSamples</code>
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* real values.
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*
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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] = pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
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* pDst[(2*n)+1] = pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
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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 CmplxByCmplxMult
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* @{
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*/
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/**
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* @brief Floating-point complex-by-complex multiplication
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* @param[in] *pSrcA points to the first input vector
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* @param[in] *pSrcB points to the second input vector
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* @param[out] *pDst points to the output vector
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* @param[in] 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_mult_cmplx_f32(
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float32_t * pSrcA,
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float32_t * pSrcB,
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float32_t * pDst,
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uint32_t numSamples)
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{
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float32_t a1, b1, c1, d1; /* Temporary variables to store real and imaginary values */
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uint32_t blkCnt; /* loop counters */
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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 a2, b2, c2, d2; /* Temporary variables to store real and imaginary values */
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float32_t acc1, acc2, acc3, acc4;
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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[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
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/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
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a1 = *pSrcA; /* A[2 * i] */
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c1 = *pSrcB; /* B[2 * i] */
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b1 = *(pSrcA + 1); /* A[2 * i + 1] */
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acc1 = a1 * c1; /* acc1 = A[2 * i] * B[2 * i] */
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a2 = *(pSrcA + 2); /* A[2 * i + 2] */
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acc2 = (b1 * c1); /* acc2 = A[2 * i + 1] * B[2 * i] */
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d1 = *(pSrcB + 1); /* B[2 * i + 1] */
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c2 = *(pSrcB + 2); /* B[2 * i + 2] */
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acc1 -= b1 * d1; /* acc1 = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
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d2 = *(pSrcB + 3); /* B[2 * i + 3] */
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acc3 = a2 * c2; /* acc3 = A[2 * i + 2] * B[2 * i + 2] */
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b2 = *(pSrcA + 3); /* A[2 * i + 3] */
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acc2 += (a1 * d1); /* acc2 = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
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a1 = *(pSrcA + 4); /* A[2 * i + 4] */
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acc4 = (a2 * d2); /* acc4 = A[2 * i + 2] * B[2 * i + 3] */
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c1 = *(pSrcB + 4); /* B[2 * i + 4] */
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acc3 -= (b2 * d2); /* acc3 = A[2 * i + 2] * B[2 * i + 2] - A[2 * i + 3] * B[2 * i + 3] */
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*pDst = acc1; /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
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b1 = *(pSrcA + 5); /* A[2 * i + 5] */
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acc4 += b2 * c2; /* acc4 = A[2 * i + 2] * B[2 * i + 3] + A[2 * i + 3] * B[2 * i + 2] */
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*(pDst + 1) = acc2; /* C[2 * i + 1] = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
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acc1 = (a1 * c1);
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d1 = *(pSrcB + 5);
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acc2 = (b1 * c1);
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*(pDst + 2) = acc3;
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*(pDst + 3) = acc4;
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a2 = *(pSrcA + 6);
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acc1 -= (b1 * d1);
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c2 = *(pSrcB + 6);
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acc2 += (a1 * d1);
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b2 = *(pSrcA + 7);
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acc3 = (a2 * c2);
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d2 = *(pSrcB + 7);
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acc4 = (b2 * c2);
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*(pDst + 4) = acc1;
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pSrcA += 8U;
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acc3 -= (b2 * d2);
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acc4 += (a2 * d2);
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*(pDst + 5) = acc2;
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pSrcB += 8U;
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*(pDst + 6) = acc3;
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*(pDst + 7) = acc4;
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pDst += 8U;
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/* Decrement the numSamples 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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/* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
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/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
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a1 = *pSrcA++;
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b1 = *pSrcA++;
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c1 = *pSrcB++;
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d1 = *pSrcB++;
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/* store the result in the destination buffer. */
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*pDst++ = (a1 * c1) - (b1 * d1);
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*pDst++ = (a1 * d1) + (b1 * c1);
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/* Decrement the numSamples 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 CmplxByCmplxMult group
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*/
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