CMSIS-DSP/Source/BasicMathFunctions/arm_clip_f32.c

/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_clip_f32.c
 * Description:  Floating-point vector addition
 *
 * $Date:        23 April 2021
 * $Revision:    V1.9.0
 *
 * Target Processor: Cortex-M and Cortex-A cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2021 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 "dsp/basic_math_functions.h"

/**
  @ingroup groupMath
 */

/**
  @defgroup BasicClip Elementwise clipping

  Element-by-element clipping of a value.

  The value is constrained between 2 bounds.

  There are separate functions for floating-point, Q7, Q15, and Q31 data types.
 */

/**
  @addtogroup BasicClip
  @{
 */

/**
  @brief         Elementwise floating-point clipping
  @param[in]     pSrc          points to input values
  @param[out]    pDst          points to output clipped values
  @param[in]     low           lower bound
  @param[in]     high          higher bound
  @param[in]     numSamples    number of samples to clip
 */
#if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)

#include "arm_helium_utils.h"

void arm_clip_f32(const float32_t * pSrc, 
  float32_t * pDst, 
  float32_t low, 
  float32_t high, 
  uint32_t numSamples)
{
    uint32_t  blkCnt;
    f32x4_t curVec0, curVec1;
    f32x4_t vecLow, vecHigh;

    vecLow = vdupq_n_f32(low);
    vecHigh = vdupq_n_f32(high);

    curVec0 = vld1q(pSrc);
    pSrc += 4;
    /*
     * unrolled x 2 to allow
     * vldr/vstr/vmin/vmax
     * stall free interleaving
     */
    blkCnt = numSamples >> 3;
    while (blkCnt--)
    {
        curVec0 = vmaxnmq(curVec0, vecLow);
        curVec1 = vld1q(pSrc);
        pSrc += 4;
        curVec0 = vminnmq(curVec0, vecHigh);
        vst1q(pDst, curVec0);
        pDst += 4;
        curVec1 = vmaxnmq(curVec1, vecLow);
        curVec0 = vld1q(pSrc);
        pSrc += 4;
        curVec1 = vminnmq(curVec1, vecHigh);
        vst1q(pDst, curVec1);
        pDst += 4;
    }
    /*
     * Tail handling
     */
    blkCnt = numSamples - ((numSamples >> 3) << 3);
    if (blkCnt >= 4)
    {
        curVec0 = vmaxnmq(curVec0, vecLow);
        curVec0 = vminnmq(curVec0, vecHigh);
        vst1q(pDst, curVec0);
        pDst += 4;
        curVec0 = vld1q(pSrc);
        pSrc += 4;
    }

    if (blkCnt > 0)
    {
        mve_pred16_t p0 = vctp32q(blkCnt & 3);
        curVec0 = vmaxnmq(curVec0, vecLow);
        curVec0 = vminnmq(curVec0, vecHigh);
        vstrwq_p(pDst, curVec0, p0);
    }
}

#else
void arm_clip_f32(const float32_t * pSrc, 
  float32_t * pDst, 
  float32_t low, 
  float32_t high, 
  uint32_t numSamples)
{
    uint32_t i;
    for (i = 0; i < numSamples; i++)
    {                                        
        if (pSrc[i] > high)                  
            pDst[i] = high;                  
        else if (pSrc[i] < low)              
            pDst[i] = low;                   
        else                                 
            pDst[i] = pSrc[i];               
    }
}
#endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */

/**
  @} end of BasicClip group
 */