Asterisk - The Open Source Telephony Project  18.5.0
random.c
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1 /*
2 
3 $Log$
4 Revision 1.15 2004/06/26 03:50:14 markster
5 Merge source cleanups (bug #1911)
6 
7 Revision 1.14 2003/02/12 13:59:15 matteo
8 mer feb 12 14:56:57 CET 2003
9 
10 Revision 1.1.1.1 2003/02/12 13:59:15 matteo
11 mer feb 12 14:56:57 CET 2003
12 
13 Revision 1.2 2000/01/05 08:20:39 markster
14 Some OSS fixes and a few lpc changes to make it actually work
15 
16  * Revision 1.2 1996/08/20 20:41:32 jaf
17  * Removed all static local variables that were SAVE'd in the Fortran
18  * code, and put them in struct lpc10_decoder_state that is passed as an
19  * argument.
20  *
21  * Removed init function, since all initialization is now done in
22  * init_lpc10_decoder_state().
23  *
24  * Revision 1.1 1996/08/19 22:30:49 jaf
25  * Initial revision
26  *
27 
28 */
29 
30 /* -- translated by f2c (version 19951025).
31  You must link the resulting object file with the libraries:
32  -lf2c -lm (in that order)
33 */
34 
35 #include "f2c.h"
36 
37 #ifdef P_R_O_T_O_T_Y_P_E_S
38 extern integer random_(struct lpc10_decoder_state *st);
39 #endif
40 
41 /* ********************************************************************** */
42 
43 /* RANDOM Version 49 */
44 
45 /* $Log$
46  * Revision 1.15 2004/06/26 03:50:14 markster
47  * Merge source cleanups (bug #1911)
48  *
49  * Revision 1.14 2003/02/12 13:59:15 matteo
50  * mer feb 12 14:56:57 CET 2003
51  *
52  * Revision 1.1.1.1 2003/02/12 13:59:15 matteo
53  * mer feb 12 14:56:57 CET 2003
54  *
55  * Revision 1.2 2000/01/05 08:20:39 markster
56  * Some OSS fixes and a few lpc changes to make it actually work
57  *
58  * Revision 1.2 1996/08/20 20:41:32 jaf
59  * Removed all static local variables that were SAVE'd in the Fortran
60  * code, and put them in struct lpc10_decoder_state that is passed as an
61  * argument.
62  *
63  * Removed init function, since all initialization is now done in
64  * init_lpc10_decoder_state().
65  *
66  * Revision 1.1 1996/08/19 22:30:49 jaf
67  * Initial revision
68  * */
69 /* Revision 1.3 1996/03/20 16:13:54 jaf */
70 /* Rearranged comments a little bit, and added comments explaining that */
71 /* even though there is local state here, there is no need to create an */
72 /* ENTRY for reinitializing it. */
73 
74 /* Revision 1.2 1996/03/14 22:25:29 jaf */
75 /* Just rearranged the comments and local variable declarations a bit. */
76 
77 /* Revision 1.1 1996/02/07 14:49:01 jaf */
78 /* Initial revision */
79 
80 
81 /* ********************************************************************* */
82 
83 /* Pseudo random number generator based on Knuth, Vol 2, p. 27. */
84 
85 /* Function Return: */
86 /* RANDOM - Integer variable, uniformly distributed over -32768 to 32767 */
87 
88 /* This subroutine maintains local state from one call to the next. */
89 /* In the context of the LPC10 coder, there is no reason to reinitialize */
90 /* this local state when switching between audio streams, because its */
91 /* results are only used to generate noise for unvoiced frames. */
92 
93 integer random_(struct lpc10_decoder_state *st)
94 {
95  /* Initialized data */
96 
97  integer *j;
98  integer *k;
99  shortint *y;
100 
101  /* System generated locals */
102  integer ret_val;
103 
104 /* Parameters/constants */
105 /* Local state */
106 /* The following is a 16 bit 2's complement addition, */
107 /* with overflow checking disabled */
108 
109  j = &(st->j);
110  k = &(st->k);
111  y = &(st->y[0]);
112 
113  y[*k - 1] += y[*j - 1];
114  ret_val = y[*k - 1];
115  --(*k);
116  if (*k <= 0) {
117  *k = 5;
118  }
119  --(*j);
120  if (*j <= 0) {
121  *j = 5;
122  }
123  return ret_val;
124 } /* random_ */
lpc10_decoder_state::y
shortint y[5]
Definition: lpc10.h:189
lpc10_decoder_state::k
integer k
Definition: lpc10.h:188
random_
integer random_(struct lpc10_decoder_state *st)
Definition: random.c:93
lpc10_decoder_state::j
integer j
Definition: lpc10.h:187
lpc10_decoder_state
Definition: lpc10.h:149
shortint
INT16 shortint
Definition: lpc10.h:82
integer
INT32 integer
Definition: lpc10.h:80
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