Asterisk - The Open Source Telephony Project GIT-master-f36a736
random.c
Go to the documentation of this file.
1/*
2
3$Log$
4Revision 1.15 2004/06/26 03:50:14 markster
5Merge source cleanups (bug #1911)
6
7Revision 1.14 2003/02/12 13:59:15 matteo
8mer feb 12 14:56:57 CET 2003
9
10Revision 1.1.1.1 2003/02/12 13:59:15 matteo
11mer feb 12 14:56:57 CET 2003
12
13Revision 1.2 2000/01/05 08:20:39 markster
14Some 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
38extern 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
93integer 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_ */
integer
INT32 integer
Definition: lpc10.h:80
shortint
INT16 shortint
Definition: lpc10.h:82
random_
integer random_(struct lpc10_decoder_state *st)
Definition: random.c:93
lpc10_decoder_state
Definition: lpc10.h:149
lpc10_decoder_state::y
shortint y[5]
Definition: lpc10.h:189
lpc10_decoder_state::j
integer j
Definition: lpc10.h:187
lpc10_decoder_state::k
integer k
Definition: lpc10.h:188
Generated on Wed Dec 18 2024 20:04:15 for Asterisk - The Open Source Telephony Project by doxygen 1.9.4