diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/usb/input/fixp-arith.h |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/usb/input/fixp-arith.h')
-rw-r--r-- | drivers/usb/input/fixp-arith.h | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/drivers/usb/input/fixp-arith.h b/drivers/usb/input/fixp-arith.h new file mode 100644 index 000000000000..26ca5b890a61 --- /dev/null +++ b/drivers/usb/input/fixp-arith.h | |||
@@ -0,0 +1,90 @@ | |||
1 | #ifndef _FIXP_ARITH_H | ||
2 | #define _FIXP_ARITH_H | ||
3 | |||
4 | /* | ||
5 | * $$ | ||
6 | * | ||
7 | * Simplistic fixed-point arithmetics. | ||
8 | * Hmm, I'm probably duplicating some code :( | ||
9 | * | ||
10 | * Copyright (c) 2002 Johann Deneux | ||
11 | */ | ||
12 | |||
13 | /* | ||
14 | * This program is free software; you can redistribute it and/or modify | ||
15 | * it under the terms of the GNU General Public License as published by | ||
16 | * the Free Software Foundation; either version 2 of the License, or | ||
17 | * (at your option) any later version. | ||
18 | * | ||
19 | * This program is distributed in the hope that it will be useful, | ||
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
22 | * GNU General Public License for more details. | ||
23 | * | ||
24 | * You should have received a copy of the GNU General Public License | ||
25 | * along with this program; if not, write to the Free Software | ||
26 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | ||
27 | * | ||
28 | * Should you need to contact me, the author, you can do so by | ||
29 | * e-mail - mail your message to <deneux@ifrance.com> | ||
30 | */ | ||
31 | |||
32 | #include <linux/types.h> | ||
33 | |||
34 | // The type representing fixed-point values | ||
35 | typedef s16 fixp_t; | ||
36 | |||
37 | #define FRAC_N 8 | ||
38 | #define FRAC_MASK ((1<<FRAC_N)-1) | ||
39 | |||
40 | // Not to be used directly. Use fixp_{cos,sin} | ||
41 | static fixp_t cos_table[45] = { | ||
42 | 0x0100, 0x00FF, 0x00FF, 0x00FE, 0x00FD, 0x00FC, 0x00FA, 0x00F8, | ||
43 | 0x00F6, 0x00F3, 0x00F0, 0x00ED, 0x00E9, 0x00E6, 0x00E2, 0x00DD, | ||
44 | 0x00D9, 0x00D4, 0x00CF, 0x00C9, 0x00C4, 0x00BE, 0x00B8, 0x00B1, | ||
45 | 0x00AB, 0x00A4, 0x009D, 0x0096, 0x008F, 0x0087, 0x0080, 0x0078, | ||
46 | 0x0070, 0x0068, 0x005F, 0x0057, 0x004F, 0x0046, 0x003D, 0x0035, | ||
47 | 0x002C, 0x0023, 0x001A, 0x0011, 0x0008 | ||
48 | }; | ||
49 | |||
50 | |||
51 | /* a: 123 -> 123.0 */ | ||
52 | static inline fixp_t fixp_new(s16 a) | ||
53 | { | ||
54 | return a<<FRAC_N; | ||
55 | } | ||
56 | |||
57 | /* a: 0xFFFF -> -1.0 | ||
58 | 0x8000 -> 1.0 | ||
59 | 0x0000 -> 0.0 | ||
60 | */ | ||
61 | static inline fixp_t fixp_new16(s16 a) | ||
62 | { | ||
63 | return ((s32)a)>>(16-FRAC_N); | ||
64 | } | ||
65 | |||
66 | static inline fixp_t fixp_cos(unsigned int degrees) | ||
67 | { | ||
68 | int quadrant = (degrees / 90) & 3; | ||
69 | unsigned int i = degrees % 90; | ||
70 | |||
71 | if (quadrant == 1 || quadrant == 3) { | ||
72 | i = 89 - i; | ||
73 | } | ||
74 | |||
75 | i >>= 1; | ||
76 | |||
77 | return (quadrant == 1 || quadrant == 2)? -cos_table[i] : cos_table[i]; | ||
78 | } | ||
79 | |||
80 | static inline fixp_t fixp_sin(unsigned int degrees) | ||
81 | { | ||
82 | return -fixp_cos(degrees + 90); | ||
83 | } | ||
84 | |||
85 | static inline fixp_t fixp_mult(fixp_t a, fixp_t b) | ||
86 | { | ||
87 | return ((s32)(a*b))>>FRAC_N; | ||
88 | } | ||
89 | |||
90 | #endif | ||