1  /* ----------------------------------------------------------------------
 2   * Project:      CMSIS DSP Library
 3   * Title:        arm_cmplx_mult_cmplx_f64.c
 4   * Description:  Floating-point complex-by-complex multiplication
 5   *
 6   * $Date:        13 September 2021
 7   * $Revision:    V1.10.0
 8   *
 9   * Target Processor: Cortex-M and Cortex-A cores
10   * -------------------------------------------------------------------- */
11  /*
12   * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13   *
14   * SPDX-License-Identifier: Apache-2.0
15   *
16   * Licensed under the Apache License, Version 2.0 (the License); you may
17   * not use this file except in compliance with the License.
18   * You may obtain a copy of the License at
19   *
20   * www.apache.org/licenses/LICENSE-2.0
21   *
22   * Unless required by applicable law or agreed to in writing, software
23   * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25   * See the License for the specific language governing permissions and
26   * limitations under the License.
27   */
28  
29  #include "dsp/complex_math_functions.h"
30  
31  /**
32    @ingroup groupCmplxMath
33   */
34  
35  /**
36    @addtogroup CmplxByCmplxMult
37    @{
38   */
39  
40  /**
41    @brief         Floating-point complex-by-complex multiplication.
42    @param[in]     pSrcA       points to first input vector
43    @param[in]     pSrcB       points to second input vector
44    @param[out]    pDst        points to output vector
45    @param[in]     numSamples  number of samples in each vector
46    @return        none
47   */
48  
49  void arm_cmplx_mult_cmplx_f64(
50    const float64_t * pSrcA,
51    const float64_t * pSrcB,
52          float64_t * pDst,
53          uint32_t numSamples)
54  {
55    uint32_t blkCnt;                               /* Loop counter */
56    float64_t a, b, c, d;  /* Temporary variables to store real and imaginary values */
57  
58    /* Initialize blkCnt with number of samples */
59    blkCnt = numSamples;
60  
61    while (blkCnt > 0U)
62    {
63      /* C[2 * i    ] = A[2 * i] * B[2 * i    ] - A[2 * i + 1] * B[2 * i + 1]. */
64      /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i    ]. */
65  
66      a = *pSrcA++;
67      b = *pSrcA++;
68      c = *pSrcB++;
69      d = *pSrcB++;
70  
71      /* store result in destination buffer. */
72      *pDst++ = (a * c) - (b * d);
73      *pDst++ = (a * d) + (b * c);
74  
75      /* Decrement loop counter */
76      blkCnt--;
77    }
78  
79  }
80  
81  /**
82    @} end of CmplxByCmplxMult group
83   */