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#ifndef _FIXP_ARITH_H
#define _FIXP_ARITH_H
 
/*
 * Simplistic fixed-point arithmetics.
 * Hmm, I'm probably duplicating some code :(
 *
 * Copyright (c) 2002 Johann Deneux
 */
 
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * Should you need to contact me, the author, you can do so by
 * e-mail - mail your message to <johann.deneux@gmail.com>
 */
 
#include <linux/types.h>
 
/* The type representing fixed-point values */
typedef s16 fixp_t;
 
#define FRAC_N 8
#define FRAC_MASK ((1<<FRAC_N)-1)
 
/* Not to be used directly. Use fixp_{cos,sin} */
static const fixp_t cos_table[46] = {
        0x0100, 0x00FF, 0x00FF, 0x00FE, 0x00FD, 0x00FC, 0x00FA, 0x00F8,
        0x00F6, 0x00F3, 0x00F0, 0x00ED, 0x00E9, 0x00E6, 0x00E2, 0x00DD,
        0x00D9, 0x00D4, 0x00CF, 0x00C9, 0x00C4, 0x00BE, 0x00B8, 0x00B1,
        0x00AB, 0x00A4, 0x009D, 0x0096, 0x008F, 0x0087, 0x0080, 0x0078,
        0x0070, 0x0068, 0x005F, 0x0057, 0x004F, 0x0046, 0x003D, 0x0035,
        0x002C, 0x0023, 0x001A, 0x0011, 0x0008, 0x0000
};
 
 
/* a: 123 -> 123.0 */
static inline fixp_t fixp_new(s16 a)
{
        return a<<FRAC_N;
}
 
/* a: 0xFFFF -> -1.0
      0x8000 -> 1.0
      0x0000 -> 0.0
*/
static inline fixp_t fixp_new16(s16 a)
{
        return ((s32)a)>>(16-FRAC_N);
}
 
static inline fixp_t fixp_cos(unsigned int degrees)
{
        int quadrant = (degrees / 90) & 3;
        unsigned int i = degrees % 90;
 
        if (quadrant == 1 || quadrant == 3)
                i = 90 - i;
 
        i >>= 1;
 
        return (quadrant == 1 || quadrant == 2)? -cos_table[i] : cos_table[i];
}
 
static inline fixp_t fixp_sin(unsigned int degrees)
{
        return -fixp_cos(degrees + 90);
}
 
static inline fixp_t fixp_mult(fixp_t a, fixp_t b)
{
        return ((s32)(a*b))>>FRAC_N;
}
 
#endif

Line No.	Rev	Author	Line
1	62	marcus.erl	`#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			`* This program is distributed in the hope that it will be useful,`
18			`* but WITHOUT ANY WARRANTY; without even the implied warranty of`
19			`* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the`
20			`* GNU General Public License for more details.`
21			`*`
22			`* You should have received a copy of the GNU General Public License`
23			`* along with this program; if not, write to the Free Software`
24			`* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA`
25			`*`
26			`* Should you need to contact me, the author, you can do so by`
27			`* e-mail - mail your message to <johann.deneux@gmail.com>`
28			`*/`
29
30			`#include <linux/types.h>`
31
32			`/* The type representing fixed-point values */`
33			`typedef s16 fixp_t;`
34
35			`#define FRAC_N 8`
36			`#define FRAC_MASK ((1<<FRAC_N)-1)`
37
38			`/* Not to be used directly. Use fixp_{cos,sin} */`
39			`static const fixp_t cos_table[46] = {`
40			`0x0100, 0x00FF, 0x00FF, 0x00FE, 0x00FD, 0x00FC, 0x00FA, 0x00F8,`
41			`0x00F6, 0x00F3, 0x00F0, 0x00ED, 0x00E9, 0x00E6, 0x00E2, 0x00DD,`
42			`0x00D9, 0x00D4, 0x00CF, 0x00C9, 0x00C4, 0x00BE, 0x00B8, 0x00B1,`
43			`0x00AB, 0x00A4, 0x009D, 0x0096, 0x008F, 0x0087, 0x0080, 0x0078,`
44			`0x0070, 0x0068, 0x005F, 0x0057, 0x004F, 0x0046, 0x003D, 0x0035,`
45			`0x002C, 0x0023, 0x001A, 0x0011, 0x0008, 0x0000`
46			`};`
47
48
49			`/* a: 123 -> 123.0 */`
50			`static inline fixp_t fixp_new(s16 a)`
51			`{`
52			`return a<<FRAC_N;`
53			`}`
54
55			`/* a: 0xFFFF -> -1.0`
56			`0x8000 -> 1.0`
57			`0x0000 -> 0.0`
58			`*/`
59			`static inline fixp_t fixp_new16(s16 a)`
60			`{`
61			`return ((s32)a)>>(16-FRAC_N);`
62			`}`
63
64			`static inline fixp_t fixp_cos(unsigned int degrees)`
65			`{`
66			`int quadrant = (degrees / 90) & 3;`
67			`unsigned int i = degrees % 90;`
68
69			`if (quadrant == 1 \|\| quadrant == 3)`
70			`i = 90 - i;`
71
72			`i >>= 1;`
73
74			`return (quadrant == 1 \|\| quadrant == 2)? -cos_table[i] : cos_table[i];`
75			`}`
76
77			`static inline fixp_t fixp_sin(unsigned int degrees)`
78			`{`
79			`return -fixp_cos(degrees + 90);`
80			`}`
81
82			`static inline fixp_t fixp_mult(fixp_t a, fixp_t b)`
83			`{`
84			`return ((s32)(a*b))>>FRAC_N;`
85			`}`
86
87			`#endif`

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[/] [test_project/] [trunk/] [linux_sd_driver/] [drivers/] [input/] [fixp-arith.h] - Blame information for rev 65