/* ----------------------------------------------------------------------
* Project: CMSIS DSP Library
* Title: arm_cmplx_mult_cmplx_f32.c
* Description: Floating-point complex-by-complex multiplication
*
* $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 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 first input vector
@param[in] pSrcB points to second input vector
@param[out] pDst points to output vector
@param[in] numSamples number of samples in each vector
@return none
*/
void arm_cmplx_mult_cmplx_f32(
const float32_t * pSrcA,
const float32_t * pSrcB,
float32_t * pDst,
uint32_t numSamples)
{
uint32_t blkCnt; /* Loop counter */
float32_t a, b, c, d; /* Temporary variables to store real and imaginary values */
#if defined(ARM_MATH_NEON)
float32x4x2_t va, vb;
float32x4_t real, imag;
float32x4x2_t outCplx;
/* Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
while (blkCnt > 0U)
{
va = vld2q_f32(pSrcA); // load & separate real/imag pSrcA (de-interleave 2)
vb = vld2q_f32(pSrcB); // load & separate real/imag pSrcB
/* Increment pointers */
pSrcA += 8;
pSrcB += 8;
/* Re{C} = Re{A}*Re{B} - Im{A}*Im{B} */
outCplx.val[0] = vmulq_f32(va.val[0], vb.val[0]);
outCplx.val[0] = vmlsq_f32(outCplx.val[0], va.val[1], vb.val[1]);
/* Im{C} = Re{A}*Im{B} + Im{A}*Re{B} */
outCplx.val[1] = vmulq_f32(va.val[0], vb.val[1]);
outCplx.val[1] = vmlaq_f32(outCplx.val[1], va.val[1], vb.val[0]);
vst2q_f32(pDst, outCplx);
/* Increment pointer */
pDst += 8;
/* Decrement the loop counter */
blkCnt--;
}
/* Tail */
blkCnt = numSamples & 3;
#else
#if defined (ARM_MATH_LOOPUNROLL)
/* Loop unrolling: Compute 4 outputs at a time */
blkCnt = numSamples >> 2U;
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 ]. */
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
/* store result in destination buffer. */
*pDst++ = (a * c) - (b * d);
*pDst++ = (a * d) + (b * c);
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (a * c) - (b * d);
*pDst++ = (a * d) + (b * c);
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (a * c) - (b * d);
*pDst++ = (a * d) + (b * c);
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
*pDst++ = (a * c) - (b * d);
*pDst++ = (a * d) + (b * c);
/* 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[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 ]. */
a = *pSrcA++;
b = *pSrcA++;
c = *pSrcB++;
d = *pSrcB++;
/* store result in destination buffer. */
*pDst++ = (a * c) - (b * d);
*pDst++ = (a * d) + (b * c);
/* Decrement loop counter */
blkCnt--;
}
}
/**
@} end of CmplxByCmplxMult group
*/
