filter_ma_fast_q12.c revision c55a96383497a772a307b346368133960b02ad03 
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 "signal_processing_library.h"
19
20void WebRtcSpl_FilterMAFastQ12(WebRtc_Word16* in_ptr,
21                               WebRtc_Word16* out_ptr,
22                               WebRtc_Word16* B,
23                               WebRtc_Word16 B_length,
24                               WebRtc_Word16 length)
25{
26    WebRtc_Word32 o;
27    int i, j;
28    for (i = 0; i < length; i++)
29    {
30        G_CONST WebRtc_Word16* b_ptr = &B[0];
31        G_CONST WebRtc_Word16* x_ptr = &in_ptr[i];
32
33        o = (WebRtc_Word32)0;
34
35        for (j = 0; j < B_length; j++)
36        {
37            o += WEBRTC_SPL_MUL_16_16(*b_ptr++, *x_ptr--);
38        }
39
40        // If output is higher than 32768, saturate it. Same with negative side
41        // 2^27 = 134217728, which corresponds to 32768 in Q12
42
43        // Saturate the output
44        o = WEBRTC_SPL_SAT((WebRtc_Word32)134215679, o, (WebRtc_Word32)-134217728);
45
46        *out_ptr++ = (WebRtc_Word16)((o + (WebRtc_Word32)2048) >> 12);
47    }
48    return;
49}
50