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authorpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2012-10-28 18:42:09 +0000
committerpatacongo <patacongo@42af7a65-404d-4744-a932-0658087f49c3>2012-10-28 18:42:09 +0000
commit2e745de2f7768f4932e365f0a49edbe15a448818 (patch)
tree73b8411e1d00ef6df3dd5fa2ed717241174ae14b /nuttx/lib/math/lib_sinl.c
parent83edd56f6581555c199f3cc3a96ed80f58554c1a (diff)
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lib/math files not follow coding standard; float, double, and long double versions in separate files to reduce size of dumb link
git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5270 42af7a65-404d-4744-a932-0658087f49c3
Diffstat (limited to 'nuttx/lib/math/lib_sinl.c')
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1 files changed, 114 insertions, 0 deletions
diff --git a/nuttx/lib/math/lib_sinl.c b/nuttx/lib/math/lib_sinl.c
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+/************************************************************************
+ * lib/math/lib_sinl.c
+ *
+ * This file is a part of NuttX:
+ *
+ * Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ * Ported by: Darcy Gong
+ *
+ * It derives from the Rhombs OS math library by Nick Johnson which has
+ * a compatibile, MIT-style license:
+ *
+ * Copyright (C) 2009-2011 Nick Johnson <nickbjohnson4224 at gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ ************************************************************************/
+
+/************************************************************************
+ * Included Files
+ ************************************************************************/
+
+#include <nuttx/config.h>
+#include <nuttx/compiler.h>
+
+#include <sys/types.h>
+#include <math.h>
+
+#if CONFIG_HAVE_LONG_DOUBLE
+
+/************************************************************************
+ * Private Data
+ ************************************************************************/
+
+static long double _ldbl_inv_fact[] =
+{
+ 1.0 / 1.0, // 1 / 1!
+ 1.0 / 6.0, // 1 / 3!
+ 1.0 / 120.0, // 1 / 5!
+ 1.0 / 5040.0, // 1 / 7!
+ 1.0 / 362880.0, // 1 / 9!
+ 1.0 / 39916800.0, // 1 / 11!
+ 1.0 / 6227020800.0, // 1 / 13!
+ 1.0 / 1307674368000.0, // 1 / 15!
+ 1.0 / 355687428096000.0, // 1 / 17!
+ 1.0 / 121645100408832000.0, // 1 / 19!
+};
+
+/************************************************************************
+ * Public Functions
+ ************************************************************************/
+
+long double sinl(long double x)
+{
+ long double x_squared;
+ long double sin_x;
+ size_t i;
+
+ /* Move x to [-pi, pi) */
+
+ x = fmodl(x, 2 * M_PI);
+ if (x >= M_PI)
+ {
+ x -= 2 * M_PI;
+ }
+
+ if (x < -M_PI)
+ {
+ x += 2 * M_PI;
+ }
+
+ /* Move x to [-pi/2, pi/2) */
+
+ if (x >= M_PI_2)
+ {
+ x = M_PI - x;
+ }
+
+ if (x < -M_PI_2)
+ {
+ x = -M_PI - x;
+ }
+
+ x_squared = x * x;
+ sin_x = 0.0;
+
+ /* Perform Taylor series approximation for sin(x) with ten terms */
+
+ for (i = 0; i < 10; i++)
+ {
+ if (i % 2 == 0)
+ {
+ sin_x += x * _ldbl_inv_fact[i];
+ }
+ else
+ {
+ sin_x -= x * _ldbl_inv_fact[i];
+ }
+
+ x *= x_squared;
+ }
+
+ return sin_x;
+}
+#endif