Eric Lee / smarc-fsl-linux-kernel

Download as
Browse Code ยป

Commit 3cbd5b32cb625f5c0f1b1476d154fac873dd49ce

Authored by Anssi Hannula
Committed by Dmitry Torokhov
1 parent fe65b97a58

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>

Showing 1 changed file with 6 additions and 9 deletions Side-by-side Diff

drivers/usb/input/fixp-arith.h
Diff comments   View file @ 3cbd5b3
... ... @@ -2,8 +2,6 @@
2 2 #define _FIXP_ARITH_H
3 3  
4 4 /*
5   - * $$
6   - *
7 5 * Simplistic fixed-point arithmetics.
8 6 * Hmm, I'm probably duplicating some code :(
9 7 *
10 8  
11 9  
... ... @@ -31,20 +29,20 @@
31 29  
32 30 #include <linux/types.h>
33 31  
34   -// The type representing fixed-point values
  32 +/* The type representing fixed-point values */
35 33 typedef s16 fixp_t;
36 34  
37 35 #define FRAC_N 8
38 36 #define FRAC_MASK ((1<<FRAC_N)-1)
39 37  
40   -// Not to be used directly. Use fixp_{cos,sin}
41   -static const fixp_t cos_table[45] = {
  38 +/* Not to be used directly. Use fixp_{cos,sin} */
  39 +static const fixp_t cos_table[46] = {
42 40 0x0100, 0x00FF, 0x00FF, 0x00FE, 0x00FD, 0x00FC, 0x00FA, 0x00F8,
43 41 0x00F6, 0x00F3, 0x00F0, 0x00ED, 0x00E9, 0x00E6, 0x00E2, 0x00DD,
44 42 0x00D9, 0x00D4, 0x00CF, 0x00C9, 0x00C4, 0x00BE, 0x00B8, 0x00B1,
45 43 0x00AB, 0x00A4, 0x009D, 0x0096, 0x008F, 0x0087, 0x0080, 0x0078,
46 44 0x0070, 0x0068, 0x005F, 0x0057, 0x004F, 0x0046, 0x003D, 0x0035,
47   - 0x002C, 0x0023, 0x001A, 0x0011, 0x0008
  45 + 0x002C, 0x0023, 0x001A, 0x0011, 0x0008, 0x0000
48 46 };
49 47  
50 48  
... ... @@ -68,9 +66,8 @@
68 66 int quadrant = (degrees / 90) & 3;
69 67 unsigned int i = degrees % 90;
70 68  
71   - if (quadrant == 1 || quadrant == 3) {
72   - i = 89 - i;
73   - }
  69 + if (quadrant == 1 || quadrant == 3)
  70 + i = 90 - i;
74 71  
75 72 i >>= 1;
76 73