1 /*
2  *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "common_audio/signal_processing/dot_product_with_scale.h"
12 
13 #include "rtc_base/numerics/safe_conversions.h"
14 
WebRtcSpl_DotProductWithScale(const int16_t * vector1,const int16_t * vector2,size_t length,int scaling)15 int32_t WebRtcSpl_DotProductWithScale(const int16_t* vector1,
16                                       const int16_t* vector2,
17                                       size_t length,
18                                       int scaling) {
19   int64_t sum = 0;
20   size_t i = 0;
21 
22   /* Unroll the loop to improve performance. */
23   for (i = 0; i + 3 < length; i += 4) {
24     sum += (vector1[i + 0] * vector2[i + 0]) >> scaling;
25     sum += (vector1[i + 1] * vector2[i + 1]) >> scaling;
26     sum += (vector1[i + 2] * vector2[i + 2]) >> scaling;
27     sum += (vector1[i + 3] * vector2[i + 3]) >> scaling;
28   }
29   for (; i < length; i++) {
30     sum += (vector1[i] * vector2[i]) >> scaling;
31   }
32 
33   return rtc::saturated_cast<int32_t>(sum);
34 }
35