diff options
| author | Anssi Hannula <anssi.hannula@gmail.com> | 2006-06-05 00:18:43 -0400 |
|---|---|---|
| committer | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-06-05 00:18:43 -0400 |
| commit | 3cbd5b32cb625f5c0f1b1476d154fac873dd49ce (patch) | |
| tree | 836110c370fc6b87746c77d15a3e09277d3817aa /drivers | |
| parent | fe65b97a5885a84baa103d7213754ff29e8f872f (diff) | |
Input: fix accuracy of fixp-arith.h
Add the value of cos(90) = 0 to the table. This also moves the results so
that sin(x) == sin(180-x) is true as expected.
Signed-off-by: Anssi Hannula <anssi.hannula@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/input/fixp-arith.h | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/drivers/usb/input/fixp-arith.h b/drivers/usb/input/fixp-arith.h index b44d398de07..ed3d2da0c48 100644 --- a/drivers/usb/input/fixp-arith.h +++ b/drivers/usb/input/fixp-arith.h @@ -2,8 +2,6 @@ #define _FIXP_ARITH_H /* - * $$ - * * Simplistic fixed-point arithmetics. * Hmm, I'm probably duplicating some code :( * @@ -31,20 +29,20 @@ #include <linux/types.h> -// The type representing fixed-point values +/* 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[45] = { +/* 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 + 0x002C, 0x0023, 0x001A, 0x0011, 0x0008, 0x0000 }; @@ -68,9 +66,8 @@ 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 = 89 - i; - } + if (quadrant == 1 || quadrant == 3) + i = 90 - i; i >>= 1; |