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comparison libtwamr/syn_filt.c @ 394:2af94ba0c075

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libtwamr: integrate syn_filt.c
author Mychaela Falconia <falcon@freecalypso.org>
date Mon, 06 May 2024 18:49:17 +0000
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393:a2351f2ad4f8 394:2af94ba0c075
1 /*
2 ********************************************************************************
3 *
4 * GSM AMR-NB speech codec R98 Version 7.6.0 December 12, 2001
5 * R99 Version 3.3.0
6 * REL-4 Version 4.1.0
7 *
8 ********************************************************************************
9 *
10 * File : syn_filt.c
11 * Purpose : Perform synthesis filtering through 1/A(z).
12 *
13 ********************************************************************************
14 */
15 /*
16 ********************************************************************************
17 * MODULE INCLUDE FILE AND VERSION ID
18 ********************************************************************************
19 */
20 #include "namespace.h"
21 #include "syn_filt.h"
22
23 /*
24 ********************************************************************************
25 * INCLUDE FILES
26 ********************************************************************************
27 */
28 #include "typedef.h"
29 #include "basic_op.h"
30 #include "no_count.h"
31 #include "cnst.h"
32
33 /*
34 ********************************************************************************
35 * LOCAL VARIABLES AND TABLES
36 ********************************************************************************
37 */
38 /*
39 *--------------------------------------*
40 * Constants (defined in cnst.h *
41 *--------------------------------------*
42 * M : LPC order *
43 *--------------------------------------*
44 */
45
46 /*
47 ********************************************************************************
48 * PUBLIC PROGRAM CODE
49 ********************************************************************************
50 */
51 void Syn_filt (
52 Word16 a[], /* (i) : a[M+1] prediction coefficients (M=10) */
53 Word16 x[], /* (i) : input signal */
54 Word16 y[], /* (o) : output signal */
55 Word16 lg, /* (i) : size of filtering */
56 Word16 mem[], /* (i/o) : memory associated with this filtering. */
57 Word16 update /* (i) : 0=no update, 1=update of memory. */
58 )
59 {
60 Word16 i, j;
61 Word32 s;
62 Word16 tmp[80]; /* This is usually done by memory allocation (lg+M) */
63 Word16 *yy;
64
65 /* Copy mem[] to yy[] */
66
67 yy = tmp; move16 ();
68
69 for (i = 0; i < M; i++)
70 {
71 *yy++ = mem[i]; move16 ();
72 }
73
74 /* Do the filtering. */
75
76 for (i = 0; i < lg; i++)
77 {
78 s = L_mult (x[i], a[0]);
79 for (j = 1; j <= M; j++)
80 {
81 s = L_msu (s, a[j], yy[-j]);
82 }
83 s = L_shl (s, 3);
84 *yy++ = round (s); move16 ();
85 }
86
87 for (i = 0; i < lg; i++)
88 {
89 y[i] = tmp[i + M]; move16 ();
90 }
91
92 /* Update of memory if update==1 */
93
94 test ();
95 if (update != 0)
96 {
97 for (i = 0; i < M; i++)
98 {
99 mem[i] = y[lg - M + i]; move16 ();
100 }
101 }
102 return;
103 }