1 /*
2 ** Copyright 2003-2010, VisualOn, Inc.
3 **
4 ** Licensed under the Apache License, Version 2.0 (the "License");
5 ** you may not use this file except in compliance with the License.
6 ** You may obtain a copy of the License at
7 **
8 ** http://www.apache.org/licenses/LICENSE-2.0
9 **
10 ** Unless required by applicable law or agreed to in writing, software
11 ** distributed under the License is distributed on an "AS IS" BASIS,
12 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 ** See the License for the specific language governing permissions and
14 ** limitations under the License.
15 */
16
17 /***********************************************************************
18 * File: residu.c *
19 * *
20 * Description: Compute the LPC residual by filtering *
21 * the input speech through A(z) *
22 * *
23 ************************************************************************/
24
25 #include "typedef.h"
26 #include "basic_op.h"
27
Residu(Word16 a[],Word16 x[],Word16 y[],Word16 lg)28 void Residu(
29 Word16 a[], /* (i) Q12 : prediction coefficients */
30 Word16 x[], /* (i) : speech (values x[-m..-1] are needed */
31 Word16 y[], /* (o) x2 : residual signal */
32 Word16 lg /* (i) : size of filtering */
33 )
34 {
35 Word16 i,*p1, *p2;
36 Word32 s;
37 for (i = 0; i < lg; i++)
38 {
39 p1 = a;
40 p2 = &x[i];
41 s = vo_mult32((*p1++), (*p2--));
42 s += vo_mult32((*p1++), (*p2--));
43 s += vo_mult32((*p1++), (*p2--));
44 s += vo_mult32((*p1++), (*p2--));
45 s += vo_mult32((*p1++), (*p2--));
46 s += vo_mult32((*p1++), (*p2--));
47 s += vo_mult32((*p1++), (*p2--));
48 s += vo_mult32((*p1++), (*p2--));
49 s += vo_mult32((*p1++), (*p2--));
50 s += vo_mult32((*p1++), (*p2--));
51 s += vo_mult32((*p1++), (*p2--));
52 s += vo_mult32((*p1++), (*p2--));
53 s += vo_mult32((*p1++), (*p2--));
54 s += vo_mult32((*p1++), (*p2--));
55 s += vo_mult32((*p1++), (*p2--));
56 s += vo_mult32((*p1++), (*p2--));
57 s += vo_mult32((*p1), (*p2));
58
59 s = L_shl2(s, 5);
60 y[i] = extract_h(L_add(s, 0x8000));
61 }
62
63 return;
64 }
65
66
67
68