text: /* ----------------------------------------------------------------------
   * Project:      CMSIS DSP Library
   * Title:        arm_scale_f32.c
   * Description:  Multiplies a floating-point vector by a scalar
   *
   * $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 "edge-impulse-sdk/CMSIS/DSP/Include/dsp/basic_math_functions.h"
  
  /**
    @ingroup groupMath
   */
  
  /**
    @defgroup BasicScale Vector Scale
  
    Multiply a vector by a scalar value.  For floating-point data, the algorithm used is:
  
    <pre>
        pDst[n] = pSrc[n] * scale,   0 <= n < blockSize.
    </pre>
  
    In the fixed-point Q7, Q15, and Q31 functions, <code>scale</code> is represented by
    a fractional multiplication <code>scaleFract</code> and an arithmetic shift <code>shift</code>.
    The shift allows the gain of the scaling operation to exceed 1.0.
    The algorithm used with fixed-point data is:
  
    <pre>
        pDst[n] = (pSrc[n] * scaleFract) << shift,   0 <= n < blockSize.
    </pre>
  
    The overall scale factor applied to the fixed-point data is
    <pre>
        scale = scaleFract * 2^shift.
    </pre>
  
    The functions support in-place computation allowing the source and destination
    pointers to reference the same memory buffer.
   */
  
  /**
    @addtogroup BasicScale
    @{
   */
  
  /**
    @brief         Multiplies a floating-point vector by a scalar.
    @param[in]     pSrc       points to the input vector
    @param[in]     scale      scale factor to be applied
    @param[out]    pDst       points to the output vector
    @param[in]     blockSize  number of samples in each vector
    @return        none
   */
  
  #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
  
  #include "edge-impulse-sdk/CMSIS/DSP/Include/arm_helium_utils.h"
  
  void arm_scale_f32(
    const float32_t * pSrc,
          float32_t scale,
          float32_t * pDst,
          uint32_t blockSize)
  {
          uint32_t blkCnt;                               /* Loop counter */
  
      f32x4_t vec1;
      f32x4_t res;
  
      /* Compute 4 outputs at a time */
      blkCnt = blockSize >> 2U;
  
      while (blkCnt > 0U)
      {
          /* C = A + offset */
   
          /* Add offset and then store the results in the destination buffer. */
          vec1 = vld1q(pSrc);
          res = vmulq(vec1,scale);
          vst1q(pDst, res);
  
          /* Increment pointers */
          pSrc += 4;
          pDst += 4;
          
          /* Decrement the loop counter */
          blkCnt--;
      }
  
      /* Tail */
      blkCnt = blockSize & 0x3;
  
      if (blkCnt > 0U)
      {
          mve_pred16_t p0 = vctp32q(blkCnt);
          vec1 = vld1q((float32_t const *) pSrc);
          vstrwq_p(pDst, vmulq(vec1, scale), p0);
      }
  
  
  }
  
  #else
  void arm_scale_f32(
    const float32_t *pSrc,
          float32_t scale,
          float32_t *pDst,
          uint32_t blockSize)
  {
    uint32_t blkCnt;                               /* Loop counter */
  #if defined(ARM_MATH_NEON_EXPERIMENTAL)
      f32x4_t vec1;
      f32x4_t res;
  
      /* Compute 4 outputs at a time */
      blkCnt = blockSize >> 2U;
  
      while (blkCnt > 0U)
      {
          /* C = A * scale */
  
      	/* Scale the input and then store the results in the destination buffer. */
          vec1 = vld1q_f32(pSrc);
          res = vmulq_f32(vec1, vdupq_n_f32(scale));
          vst1q_f32(pDst, res);
  
          /* Increment pointers */
          pSrc += 4; 
          pDst += 4;
          
          /* Decrement the loop counter */
          blkCnt--;
      }
  
      /* Tail */
      blkCnt = blockSize & 0x3;
  
  #else
  #if defined (ARM_MATH_LOOPUNROLL)
  
    /* Loop unrolling: Compute 4 outputs at a time */
    blkCnt = blockSize >> 2U;
  
    while (blkCnt > 0U)
    {
      float32_t in1, in2, in3, in4;
  
      /* C = A * scale */
  
      /* Scale input and store result in destination buffer. */
      in1 = (*pSrc++) * scale;
  
      in2 = (*pSrc++) * scale;
  
      in3 = (*pSrc++) * scale;
  
      in4 = (*pSrc++) * scale;
  
      *pDst++ = in1;
      *pDst++ = in2;
      *pDst++ = in3;
      *pDst++ = in4;
  
      /* Decrement loop counter */
      blkCnt--;
    }
  
    /* Loop unrolling: Compute remaining outputs */
    blkCnt = blockSize % 0x4U;
  
  #else
  
    /* Initialize blkCnt with number of samples */
    blkCnt = blockSize;
  
  #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
  #endif /* #if defined(ARM_MATH_NEON_EXPERIMENTAL) */
  
    while (blkCnt > 0U)
    {
      /* C = A * scale */
  
      /* Scale input and store result in destination buffer. */
      *pDst++ = (*pSrc++) * scale;
  
      /* Decrement loop counter */
      blkCnt--;
    }
  
  }
  #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
  
  /**
    @} end of BasicScale group
   */
  