text: /*
   * Copyright (C) 2010 The Android Open Source Project
   *
   * 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
   *
   *      http://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 "helloneon-intrinsics.h"
  #include <arm_neon.h>
  
  /* this source file should only be compiled by Android.mk when targeting
   * the armeabi-v7a ABI, and should be built in NEON mode
   */
  void
  fir_filter_neon_intrinsics(short *output, const short* input, const short* kernel, int width, int kernelSize)
  {
  #if 1
     int nn, offset = -kernelSize/2;
  
     for (nn = 0; nn < width; nn++)
     {
          int mm, sum = 0;
          int32x4_t sum_vec = vdupq_n_s32(0);
          for(mm = 0; mm < kernelSize/4; mm++)
          {
              int16x4_t  kernel_vec = vld1_s16(kernel + mm*4);
              int16x4_t  input_vec = vld1_s16(input + (nn+offset+mm*4));
              sum_vec = vmlal_s16(sum_vec, kernel_vec, input_vec);
          }
  
          sum += vgetq_lane_s32(sum_vec, 0);
          sum += vgetq_lane_s32(sum_vec, 1);
          sum += vgetq_lane_s32(sum_vec, 2);
          sum += vgetq_lane_s32(sum_vec, 3);
  
          if(kernelSize & 3)
          {
              for(mm = kernelSize - (kernelSize & 3); mm < kernelSize; mm++)
                  sum += kernel[mm] * input[nn+offset+mm];
          }
  
          output[nn] = (short)((sum + 0x8000) >> 16);
      }
  #else /* for comparison purposes only */
      int nn, offset = -kernelSize/2;
      for (nn = 0; nn < width; nn++) {
          int sum = 0;
          int mm;
          for (mm = 0; mm < kernelSize; mm++) {
              sum += kernel[mm]*input[nn+offset+mm];
          }
          output[n] = (short)((sum + 0x8000) >> 16);
      }
  #endif
  }
  