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_FilterARFastQ12().
14 * The description header can be found in signal_processing_library.h
15 *
16 */
17
18 #include "signal_processing_library.h"
19
WebRtcSpl_FilterARFastQ12(WebRtc_Word16 * in,WebRtc_Word16 * out,WebRtc_Word16 * A,WebRtc_Word16 A_length,WebRtc_Word16 length)20 void WebRtcSpl_FilterARFastQ12(WebRtc_Word16 *in, WebRtc_Word16 *out, WebRtc_Word16 *A,
21 WebRtc_Word16 A_length, WebRtc_Word16 length)
22 {
23 WebRtc_Word32 o;
24 int i, j;
25
26 WebRtc_Word16 *x_ptr = &in[0];
27 WebRtc_Word16 *filtered_ptr = &out[0];
28
29 for (i = 0; i < length; i++)
30 {
31 // Calculate filtered[i]
32 G_CONST WebRtc_Word16 *a_ptr = &A[0];
33 WebRtc_Word16 *state_ptr = &out[i - 1];
34
35 o = WEBRTC_SPL_MUL_16_16(*x_ptr++, *a_ptr++);
36
37 for (j = 1; j < A_length; j++)
38 {
39 o -= WEBRTC_SPL_MUL_16_16(*a_ptr++,*state_ptr--);
40 }
41
42 // Saturate the output
43 o = WEBRTC_SPL_SAT((WebRtc_Word32)134215679, o, (WebRtc_Word32)-134217728);
44
45 *filtered_ptr++ = (WebRtc_Word16)((o + (WebRtc_Word32)2048) >> 12);
46 }
47
48 return;
49 }
50