DelayMix_16x16.c revision d918324d44aa48b3b064ea9b87d0c520c38f15a9
1/*
2 * Copyright (C) 2004-2010 NXP Software
3 * Copyright (C) 2010 The Android Open Source Project
4 *
5 * Licensed under the Apache License, Version 2.0 (the "License");
6 * you may not use this file except in compliance with the License.
7 * You may obtain a copy of the License at
8 *
9 *      http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18/**********************************************************************************
19   INCLUDE FILES
20***********************************************************************************/
21
22#include "VectorArithmetic.h"
23
24/**********************************************************************************
25   FUNCTION DelayMix_16x16
26***********************************************************************************/
27
28void DelayMix_16x16(const LVM_INT16 *src,           /* Source 1, to be delayed */
29                          LVM_INT16 *delay,         /* Delay buffer */
30                          LVM_INT16 size,           /* Delay size */
31                          LVM_INT16 *dst,           /* Source/destination */
32                          LVM_INT16 *pOffset,       /* Delay offset */
33                          LVM_INT16 n)              /* Number of stereo samples */
34{
35    LVM_INT16   i;
36    LVM_INT16   Offset  = *pOffset;
37    LVM_INT16   temp;
38
39    for (i=0; i<n; i++)
40    {
41        /* Left channel */
42        temp            = (LVM_INT16)((LVM_UINT32)((LVM_INT32)(*dst) + (LVM_INT32)delay[Offset]) >> 1);
43        *dst            = temp;
44        dst++;
45
46        delay[Offset] = *src;
47        Offset++;
48        src++;
49
50
51        /* Right channel */
52        temp            = (LVM_INT16)((LVM_UINT32)((LVM_INT32)(*dst) - (LVM_INT32)delay[Offset]) >> 1);
53        *dst            = temp;
54        dst++;
55
56        delay[Offset] = *src;
57        Offset++;
58        src++;
59
60        /* Make the reverb delay buffer a circular buffer */
61        if (Offset >= size)
62        {
63            Offset = 0;
64        }
65    }
66
67    /* Update the offset */
68    *pOffset = Offset;
69
70    return;
71}
72
73/**********************************************************************************/
74