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authorKevin Ferrare <kevin@rockbox.org>2007-07-31 04:59:03 +0000
committerKevin Ferrare <kevin@rockbox.org>2007-07-31 04:59:03 +0000
commitdf4f56b2b0a5343fb40cc749b24897f239c76be7 (patch)
treef324668f9b4c718649db29b6c7f9025bf115d309 /apps/plugins/lib
parent4e8b171fc4cc3b62a1656ae67e92944ff855dcd3 (diff)
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plugins code cleanup : moved the duplicated fixed point table loockup based sinus/cosinus functions to fixedpoint.c, removed the bmp size definition in the clock.c|-(useless as the size is already defined in a .h generated with every bitmaps ...)
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@14087 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'apps/plugins/lib')
-rw-r--r--apps/plugins/lib/fixedpoint.c66
-rw-r--r--apps/plugins/lib/fixedpoint.h3
2 files changed, 68 insertions, 1 deletions
diff --git a/apps/plugins/lib/fixedpoint.c b/apps/plugins/lib/fixedpoint.c
index 56597c1..cf69d9c 100644
--- a/apps/plugins/lib/fixedpoint.c
+++ b/apps/plugins/lib/fixedpoint.c
@@ -60,6 +60,21 @@ static const unsigned long atan_table[] = {
0x00000000, /* +0.000000000 */
};
+/* Precalculated sine and cosine * 16384 (2^14) (fixed point 18.14) */
+static const short sin_table[91] =
+{
+ 0, 285, 571, 857, 1142, 1427, 1712, 1996, 2280, 2563,
+ 2845, 3126, 3406, 3685, 3963, 4240, 4516, 4790, 5062, 5334,
+ 5603, 5871, 6137, 6401, 6663, 6924, 7182, 7438, 7691, 7943,
+ 8191, 8438, 8682, 8923, 9161, 9397, 9630, 9860, 10086, 10310,
+ 10531, 10748, 10963, 11173, 11381, 11585, 11785, 11982, 12175, 12365,
+ 12550, 12732, 12910, 13084, 13254, 13420, 13582, 13740, 13894, 14043,
+ 14188, 14329, 14466, 14598, 14725, 14848, 14967, 15081, 15190, 15295,
+ 15395, 15491, 15582, 15668, 15749, 15825, 15897, 15964, 16025, 16082,
+ 16135, 16182, 16224, 16261, 16294, 16321, 16344, 16361, 16374, 16381,
+ 16384
+};
+
/**
* Implements sin and cos using CORDIC rotation.
*
@@ -136,3 +151,54 @@ long fsqrt(long a, unsigned int fracbits)
return b;
}
+/**
+ * Fixed point sinus using a lookup table
+ * don't forget to divide the result by 16384 to get the actual sinus value
+ * @param val sinus argument in degree
+ * @return sin(val)*16384
+ */
+long sin_int(int val)
+{
+ val = (val+360)%360;
+ if (val < 181)
+ {
+ if (val < 91)/* phase 0-90 degree */
+ return (long)sin_table[val];
+ else/* phase 91-180 degree */
+ return (long)sin_table[180-val];
+ }
+ else
+ {
+ if (val < 271)/* phase 181-270 degree */
+ return -(long)sin_table[val-180];
+ else/* phase 270-359 degree */
+ return -(long)sin_table[360-val];
+ }
+ return 0;
+}
+
+/**
+ * Fixed point cosinus using a lookup table
+ * don't forget to divide the result by 16384 to get the actual cosinus value
+ * @param val sinus argument in degree
+ * @return cos(val)*16384
+ */
+long cos_int(int val)
+{
+ val = (val+360)%360;
+ if (val < 181)
+ {
+ if (val < 91)/* phase 0-90 degree */
+ return (long)sin_table[90-val];
+ else/* phase 91-180 degree */
+ return -(long)sin_table[val-90];
+ }
+ else
+ {
+ if (val < 271)/* phase 181-270 degree */
+ return -(long)sin_table[270-val];
+ else/* phase 270-359 degree */
+ return (long)sin_table[val-270];
+ }
+ return 0;
+}
diff --git a/apps/plugins/lib/fixedpoint.h b/apps/plugins/lib/fixedpoint.h
index ff773cb..c587989 100644
--- a/apps/plugins/lib/fixedpoint.h
+++ b/apps/plugins/lib/fixedpoint.h
@@ -21,4 +21,5 @@
long fsincos(unsigned long phase, long *cos);
long fsqrt(long a, unsigned int fracbits);
-
+long cos_int(int val);
+long sin_int(int val);