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 
DelayMix_16x16(const LVM_INT16 * src,LVM_INT16 * delay,LVM_INT16 size,LVM_INT16 * dst,LVM_INT16 * pOffset,LVM_INT16 n)28 void 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