1 #ifndef _FIXP_ARITH_H
2 #define _FIXP_ARITH_H
3
4 /*
5 * Simplistic fixed-point arithmetics.
6 * Hmm, I'm probably duplicating some code :(
7 *
8 * Copyright (c) 2002 Johann Deneux
9 */
10
11 /*
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
16 *
17 */
18
19 #include <linux/types.h>
20
21 static const s32 sin_table[] = {
22 0x00000000, 0x023be165, 0x04779632, 0x06b2f1d2, 0x08edc7b6, 0x0b27eb5c,
23 0x0d61304d, 0x0f996a26, 0x11d06c96, 0x14060b67, 0x163a1a7d, 0x186c6ddd,
24 0x1a9cd9ac, 0x1ccb3236, 0x1ef74bf2, 0x2120fb82, 0x234815ba, 0x256c6f9e,
25 0x278dde6e, 0x29ac379f, 0x2bc750e8, 0x2ddf003f, 0x2ff31bdd, 0x32037a44,
26 0x340ff241, 0x36185aee, 0x381c8bb5, 0x3a1c5c56, 0x3c17a4e7, 0x3e0e3ddb,
27 0x3fffffff, 0x41ecc483, 0x43d464fa, 0x45b6bb5d, 0x4793a20f, 0x496af3e1,
28 0x4b3c8c11, 0x4d084650, 0x4ecdfec6, 0x508d9210, 0x5246dd48, 0x53f9be04,
29 0x55a6125a, 0x574bb8e5, 0x58ea90c2, 0x5a827999, 0x5c135399, 0x5d9cff82,
30 0x5f1f5ea0, 0x609a52d1, 0x620dbe8a, 0x637984d3, 0x64dd894f, 0x6639b039,
31 0x678dde6d, 0x68d9f963, 0x6a1de735, 0x6b598ea1, 0x6c8cd70a, 0x6db7a879,
32 0x6ed9eba0, 0x6ff389de, 0x71046d3c, 0x720c8074, 0x730baeec, 0x7401e4bf,
33 0x74ef0ebb, 0x75d31a5f, 0x76adf5e5, 0x777f903b, 0x7847d908, 0x7906c0af,
34 0x79bc384c, 0x7a6831b8, 0x7b0a9f8c, 0x7ba3751c, 0x7c32a67c, 0x7cb82884,
35 0x7d33f0c8, 0x7da5f5a3, 0x7e0e2e31, 0x7e6c924f, 0x7ec11aa3, 0x7f0bc095,
36 0x7f4c7e52, 0x7f834ecf, 0x7fb02dc4, 0x7fd317b3, 0x7fec09e1, 0x7ffb025e,
37 0x7fffffff
38 };
39
40 /**
41 * __fixp_sin32() returns the sin of an angle in degrees
42 *
43 * @degrees: angle, in degrees, from 0 to 360.
44 *
45 * The returned value ranges from -0x7fffffff to +0x7fffffff.
46 */
__fixp_sin32(int degrees)47 static inline s32 __fixp_sin32(int degrees)
48 {
49 s32 ret;
50 bool negative = false;
51
52 if (degrees > 180) {
53 negative = true;
54 degrees -= 180;
55 }
56 if (degrees > 90)
57 degrees = 180 - degrees;
58
59 ret = sin_table[degrees];
60
61 return negative ? -ret : ret;
62 }
63
64 /**
65 * fixp_sin32() returns the sin of an angle in degrees
66 *
67 * @degrees: angle, in degrees. The angle can be positive or negative
68 *
69 * The returned value ranges from -0x7fffffff to +0x7fffffff.
70 */
fixp_sin32(int degrees)71 static inline s32 fixp_sin32(int degrees)
72 {
73 degrees = (degrees % 360 + 360) % 360;
74
75 return __fixp_sin32(degrees);
76 }
77
78 /* cos(x) = sin(x + 90 degrees) */
79 #define fixp_cos32(v) fixp_sin32((v) + 90)
80
81 /*
82 * 16 bits variants
83 *
84 * The returned value ranges from -0x7fff to 0x7fff
85 */
86
87 #define fixp_sin16(v) (fixp_sin32(v) >> 16)
88 #define fixp_cos16(v) (fixp_cos32(v) >> 16)
89
90 #endif
91