/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_mult_cmplx_f32.c
* Description: Floating-point complex-by-complex multiplication
*
* $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
*/
/**
* @defgroup CmplxByCmplxMult Complex-by-Complex Multiplication
*
* Multiplies a complex vector by another complex vector and generates a complex result.
* The data in the complex arrays is stored in an interleaved fashion
* (real, imag, real, imag, ...).
* The parameter <code>numSamples</code> represents the number of complex
* samples processed. The complex arrays have a total of <code>2*numSamples</code>
* real values.
*
* The underlying algorithm is used:
*
* <pre>
* for(n=0; n<numSamples; n++) {
* pDst[(2*n)+0] = pSrcA[(2*n)+0] * pSrcB[(2*n)+0] - pSrcA[(2*n)+1] * pSrcB[(2*n)+1];
* pDst[(2*n)+1] = pSrcA[(2*n)+0] * pSrcB[(2*n)+1] + pSrcA[(2*n)+1] * pSrcB[(2*n)+0];
* }
* </pre>
*
* There are separate functions for floating-point, Q15, and Q31 data types.
*/
/**
* @addtogroup CmplxByCmplxMult
* @{
*/
/**
* @brief Floating-point complex-by-complex multiplication
* @param[in] *pSrcA points to the first input vector
* @param[in] *pSrcB points to the second input vector
* @param[out] *pDst points to the output vector
* @param[in] numSamples number of complex samples in each vector
* @return none.
*/
void arm_cmplx_mult_cmplx_f32(
float32_t * pSrcA,
float32_t * pSrcB,
float32_t * pDst,
uint32_t numSamples)
{
float32_t a1, b1, c1, d1; /* Temporary variables to store real and imaginary values */
uint32_t blkCnt; /* loop counters */
#if defined (ARM_MATH_DSP)
/* Run the below code for Cortex-M4 and Cortex-M3 */
float32_t a2, b2, c2, d2; /* Temporary variables to store real and imaginary values */
float32_t acc1, acc2, acc3, acc4;
/* 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[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
a1 = *pSrcA; /* A[2 * i] */
c1 = *pSrcB; /* B[2 * i] */
b1 = *(pSrcA + 1); /* A[2 * i + 1] */
acc1 = a1 * c1; /* acc1 = A[2 * i] * B[2 * i] */
a2 = *(pSrcA + 2); /* A[2 * i + 2] */
acc2 = (b1 * c1); /* acc2 = A[2 * i + 1] * B[2 * i] */
d1 = *(pSrcB + 1); /* B[2 * i + 1] */
c2 = *(pSrcB + 2); /* B[2 * i + 2] */
acc1 -= b1 * d1; /* acc1 = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
d2 = *(pSrcB + 3); /* B[2 * i + 3] */
acc3 = a2 * c2; /* acc3 = A[2 * i + 2] * B[2 * i + 2] */
b2 = *(pSrcA + 3); /* A[2 * i + 3] */
acc2 += (a1 * d1); /* acc2 = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
a1 = *(pSrcA + 4); /* A[2 * i + 4] */
acc4 = (a2 * d2); /* acc4 = A[2 * i + 2] * B[2 * i + 3] */
c1 = *(pSrcB + 4); /* B[2 * i + 4] */
acc3 -= (b2 * d2); /* acc3 = A[2 * i + 2] * B[2 * i + 2] - A[2 * i + 3] * B[2 * i + 3] */
*pDst = acc1; /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1] */
b1 = *(pSrcA + 5); /* A[2 * i + 5] */
acc4 += b2 * c2; /* acc4 = A[2 * i + 2] * B[2 * i + 3] + A[2 * i + 3] * B[2 * i + 2] */
*(pDst + 1) = acc2; /* C[2 * i + 1] = A[2 * i + 1] * B[2 * i] + A[2 * i] * B[2 * i + 1] */
acc1 = (a1 * c1);
d1 = *(pSrcB + 5);
acc2 = (b1 * c1);
*(pDst + 2) = acc3;
*(pDst + 3) = acc4;
a2 = *(pSrcA + 6);
acc1 -= (b1 * d1);
c2 = *(pSrcB + 6);
acc2 += (a1 * d1);
b2 = *(pSrcA + 7);
acc3 = (a2 * c2);
d2 = *(pSrcB + 7);
acc4 = (b2 * c2);
*(pDst + 4) = acc1;
pSrcA += 8U;
acc3 -= (b2 * d2);
acc4 += (a2 * d2);
*(pDst + 5) = acc2;
pSrcB += 8U;
*(pDst + 6) = acc3;
*(pDst + 7) = acc4;
pDst += 8U;
/* Decrement the numSamples 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[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1]. */
/* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i]. */
a1 = *pSrcA++;
b1 = *pSrcA++;
c1 = *pSrcB++;
d1 = *pSrcB++;
/* store the result in the destination buffer. */
*pDst++ = (a1 * c1) - (b1 * d1);
*pDst++ = (a1 * d1) + (b1 * c1);
/* Decrement the numSamples loop counter */
blkCnt--;
}
}
/**
* @} end of CmplxByCmplxMult group
*/