1 /*
2 * Copyright (c) 2011 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
12 /*
13 * This file contains the function WebRtcSpl_FilterMAFastQ12().
14 * The description header can be found in signal_processing_library.h
15 *
16 */
17
18 #include "common_audio/signal_processing/include/signal_processing_library.h"
19
20 #include "rtc_base/sanitizer.h"
21
WebRtcSpl_FilterMAFastQ12(const int16_t * in_ptr,int16_t * out_ptr,const int16_t * B,size_t B_length,size_t length)22 void WebRtcSpl_FilterMAFastQ12(const int16_t* in_ptr,
23 int16_t* out_ptr,
24 const int16_t* B,
25 size_t B_length,
26 size_t length)
27 {
28 size_t i, j;
29
30 rtc_MsanCheckInitialized(B, sizeof(B[0]), B_length);
31 rtc_MsanCheckInitialized(in_ptr - B_length + 1, sizeof(in_ptr[0]),
32 B_length + length - 1);
33
34 for (i = 0; i < length; i++)
35 {
36 int32_t o = 0;
37
38 for (j = 0; j < B_length; j++)
39 {
40 // Negative overflow is permitted here, because this is
41 // auto-regressive filters, and the state for each batch run is
42 // stored in the "negative" positions of the output vector.
43 o += B[j] * in_ptr[(ptrdiff_t) i - (ptrdiff_t) j];
44 }
45
46 // If output is higher than 32768, saturate it. Same with negative side
47 // 2^27 = 134217728, which corresponds to 32768 in Q12
48
49 // Saturate the output
50 o = WEBRTC_SPL_SAT((int32_t)134215679, o, (int32_t)-134217728);
51
52 *out_ptr++ = (int16_t)((o + (int32_t)2048) >> 12);
53 }
54 return;
55 }
56