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comparison libtwamr/autocorr.c @ 253:54f6bc41ed10

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libtwamr: integrate a* modules
author Mychaela Falconia <falcon@freecalypso.org>
date Fri, 05 Apr 2024 06:08:15 +0000
parents
children 07f936338de1
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252:57b4053559ff 253:54f6bc41ed10
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 : autocorr.c
11 *
12 ********************************************************************************
13 */
14 /*
15 ********************************************************************************
16 * MODULE INCLUDE FILE AND VERSION ID
17 ********************************************************************************
18 */
19 #include "namespace.h"
20 #include "autocorr.h"
21 const char autocorr_id[] = "@(#)$Id $" autocorr_h;
22
23 /*
24 ********************************************************************************
25 * INCLUDE FILES
26 ********************************************************************************
27 */
28 #include "typedef.h"
29 #include "basic_op.h"
30 #include "oper_32b.h"
31 #include "no_count.h"
32 #include "cnst.h"
33
34 /*
35 ********************************************************************************
36 * LOCAL VARIABLES AND TABLES
37 ********************************************************************************
38 */
39
40 /*
41 ********************************************************************************
42 * PUBLIC PROGRAM CODE
43 ********************************************************************************
44 */
45 /*
46 **************************************************************************
47 *
48 * Function : autocorr
49 * Purpose : Compute autocorrelations of signal with windowing
50 *
51 **************************************************************************
52 */
53 Word16 Autocorr (
54 Word16 x[], /* (i) : Input signal (L_WINDOW) */
55 Word16 m, /* (i) : LPC order */
56 Word16 r_h[], /* (o) : Autocorrelations (msb) */
57 Word16 r_l[], /* (o) : Autocorrelations (lsb) */
58 const Word16 wind[] /* (i) : window for LPC analysis (L_WINDOW) */
59 )
60 {
61 Word16 i, j, norm;
62 Word16 y[L_WINDOW];
63 Word32 sum;
64 Word16 overfl, overfl_shft;
65
66 /* Windowing of signal */
67
68 for (i = 0; i < L_WINDOW; i++)
69 {
70 y[i] = mult_r (x[i], wind[i]); move16 ();
71 }
72
73 /* Compute r[0] and test for overflow */
74
75 overfl_shft = 0; move16 ();
76
77 do
78 {
79 overfl = 0; move16 ();
80 sum = 0L; move32 ();
81
82 for (i = 0; i < L_WINDOW; i++)
83 {
84 sum = L_mac (sum, y[i], y[i]);
85 }
86
87 /* If overflow divide y[] by 4 */
88
89 test ();
90 if (L_sub (sum, MAX_32) == 0L)
91 {
92 overfl_shft = add (overfl_shft, 4);
93 overfl = 1; move16 (); /* Set the overflow flag */
94
95 for (i = 0; i < L_WINDOW; i++)
96 {
97 y[i] = shr (y[i], 2); move16 ();
98 }
99 }
100 test ();
101 }
102 while (overfl != 0);
103
104 sum = L_add (sum, 1L); /* Avoid the case of all zeros */
105
106 /* Normalization of r[0] */
107
108 norm = norm_l (sum);
109 sum = L_shl (sum, norm);
110 L_Extract (sum, &r_h[0], &r_l[0]); /* Put in DPF format (see oper_32b) */
111
112 /* r[1] to r[m] */
113
114 for (i = 1; i <= m; i++)
115 {
116 sum = 0; move32 ();
117
118 for (j = 0; j < L_WINDOW - i; j++)
119 {
120 sum = L_mac (sum, y[j], y[j + i]);
121 }
122
123 sum = L_shl (sum, norm);
124 L_Extract (sum, &r_h[i], &r_l[i]);
125 }
126
127 norm = sub (norm, overfl_shft);
128
129 return norm;
130 }