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Diffstat (limited to 'apps/codecs/libmad/fixed.c')
-rw-r--r-- | apps/codecs/libmad/fixed.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/apps/codecs/libmad/fixed.c b/apps/codecs/libmad/fixed.c new file mode 100644 index 0000000000..d30f7a1219 --- /dev/null +++ b/apps/codecs/libmad/fixed.c | |||
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1 | /* | ||
2 | * libmad - MPEG audio decoder library | ||
3 | * Copyright (C) 2000-2004 Underbit Technologies, Inc. | ||
4 | * | ||
5 | * This program is free software; you can redistribute it and/or modify | ||
6 | * it under the terms of the GNU General Public License as published by | ||
7 | * the Free Software Foundation; either version 2 of the License, or | ||
8 | * (at your option) any later version. | ||
9 | * | ||
10 | * This program is distributed in the hope that it will be useful, | ||
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
13 | * GNU General Public License for more details. | ||
14 | * | ||
15 | * You should have received a copy of the GNU General Public License | ||
16 | * along with this program; if not, write to the Free Software | ||
17 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
18 | * | ||
19 | * $Id$ | ||
20 | */ | ||
21 | |||
22 | # ifdef HAVE_CONFIG_H | ||
23 | # include "config.h" | ||
24 | # endif | ||
25 | |||
26 | # include "global.h" | ||
27 | |||
28 | # include "fixed.h" | ||
29 | |||
30 | /* | ||
31 | * NAME: fixed->abs() | ||
32 | * DESCRIPTION: return absolute value of a fixed-point number | ||
33 | */ | ||
34 | mad_fixed_t mad_f_abs(mad_fixed_t x) | ||
35 | { | ||
36 | return x < 0 ? -x : x; | ||
37 | } | ||
38 | |||
39 | /* | ||
40 | * NAME: fixed->div() | ||
41 | * DESCRIPTION: perform division using fixed-point math | ||
42 | */ | ||
43 | mad_fixed_t mad_f_div(mad_fixed_t x, mad_fixed_t y) | ||
44 | { | ||
45 | mad_fixed_t q, r; | ||
46 | unsigned int bits; | ||
47 | |||
48 | q = mad_f_abs(x / y); | ||
49 | |||
50 | if (x < 0) { | ||
51 | x = -x; | ||
52 | y = -y; | ||
53 | } | ||
54 | |||
55 | r = x % y; | ||
56 | |||
57 | if (y < 0) { | ||
58 | x = -x; | ||
59 | y = -y; | ||
60 | } | ||
61 | |||
62 | if (q > mad_f_intpart(MAD_F_MAX) && | ||
63 | !(q == -mad_f_intpart(MAD_F_MIN) && r == 0 && (x < 0) != (y < 0))) | ||
64 | return 0; | ||
65 | |||
66 | for (bits = MAD_F_FRACBITS; bits && r; --bits) { | ||
67 | q <<= 1, r <<= 1; | ||
68 | if (r >= y) | ||
69 | r -= y, ++q; | ||
70 | } | ||
71 | |||
72 | /* round */ | ||
73 | if (2 * r >= y) | ||
74 | ++q; | ||
75 | |||
76 | /* fix sign */ | ||
77 | if ((x < 0) != (y < 0)) | ||
78 | q = -q; | ||
79 | |||
80 | return q << bits; | ||
81 | } | ||