msts/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_mult_f32.c

/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_mult_f32.c
 * Description:  Floating-point vector 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 groupMath
 */

/**
 * @defgroup BasicMult Vector Multiplication
 *
 * Element-by-element multiplication of two vectors.
 *
 * <pre>
 *     pDst[n] = pSrcA[n] * pSrcB[n],   0 <= n < blockSize.
 * </pre>
 *
 * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
 */

/**
 * @addtogroup BasicMult
 * @{
 */

/**
 * @brief Floating-point vector 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]       blockSize number of samples in each vector
 * @return none.
 */

void arm_mult_f32(
  float32_t * pSrcA,
  float32_t * pSrcB,
  float32_t * pDst,
  uint32_t blockSize)
{
  uint32_t blkCnt;                               /* loop counters */
#if defined (ARM_MATH_DSP)

  /* Run the below code for Cortex-M4 and Cortex-M3 */
  float32_t inA1, inA2, inA3, inA4;              /* temporary input variables */
  float32_t inB1, inB2, inB3, inB4;              /* temporary input variables */
  float32_t out1, out2, out3, out4;              /* temporary output variables */

  /* loop Unrolling */
  blkCnt = blockSize >> 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 = A * B */
    /* Multiply the inputs and store the results in output buffer */
    /* read sample from sourceA */
    inA1 = *pSrcA;
    /* read sample from sourceB */
    inB1 = *pSrcB;
    /* read sample from sourceA */
    inA2 = *(pSrcA + 1);
    /* read sample from sourceB */
    inB2 = *(pSrcB + 1);

    /* out = sourceA * sourceB */
    out1 = inA1 * inB1;

    /* read sample from sourceA */
    inA3 = *(pSrcA + 2);
    /* read sample from sourceB */
    inB3 = *(pSrcB + 2);

    /* out = sourceA * sourceB */
    out2 = inA2 * inB2;

    /* read sample from sourceA */
    inA4 = *(pSrcA + 3);

    /* store result to destination buffer */
    *pDst = out1;

    /* read sample from sourceB */
    inB4 = *(pSrcB + 3);

    /* out = sourceA * sourceB */
    out3 = inA3 * inB3;

    /* store result to destination buffer */
    *(pDst + 1) = out2;

    /* out = sourceA * sourceB */
    out4 = inA4 * inB4;
    /* store result to destination buffer */
    *(pDst + 2) = out3;
    /* store result to destination buffer */
    *(pDst + 3) = out4;


    /* update pointers to process next samples */
    pSrcA += 4U;
    pSrcB += 4U;
    pDst += 4U;

    /* Decrement the blockSize loop counter */
    blkCnt--;
  }

  /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
   ** No loop unrolling is used. */
  blkCnt = blockSize % 0x4U;

#else

  /* Run the below code for Cortex-M0 */

  /* Initialize blkCnt with number of samples */
  blkCnt = blockSize;

#endif /* #if defined (ARM_MATH_DSP) */

  while (blkCnt > 0U)
  {
    /* C = A * B */
    /* Multiply the inputs and store the results in output buffer */
    *pDst++ = (*pSrcA++) * (*pSrcB++);

    /* Decrement the blockSize loop counter */
    blkCnt--;
  }
}

/**
 * @} end of BasicMult group
 */