cf99fb40c9
Squashed commit of the following:
libs/libxx: Fix some confusing in naming. If the directory is called libxx, then the library must be libxx.a (unless perhaps LIBCXX is selected).
libs/: Fix paths in moved library directories.
libs: Brute force move of libc, libnx, and libxx to libs. Cannot yet build it in that configuration.
122 lines
4.7 KiB
C
122 lines
4.7 KiB
C
/****************************************************************************
|
|
* libs/libc/math/__cos.c
|
|
*
|
|
* Ported to NuttX from FreeBSD by Alan Carvalho de Assis:
|
|
*
|
|
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
|
|
*
|
|
* Developed at SunSoft, a Sun Microsystems, Inc. business.
|
|
* Permission to use, copy, modify, and distribute this
|
|
* software is freely granted, provided that this notice
|
|
* is preserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/* __sin( x, y, iy)
|
|
*
|
|
* kernel sin function on ~[-pi/4, pi/4] (except on -0), pi/4 ~ 0.7854
|
|
* Input x is assumed to be bounded by ~pi/4 in magnitude.
|
|
* Input y is the tail of x.
|
|
* Input iy indicates whether y is 0. (if iy=0, y assume to be 0).
|
|
*
|
|
* Algorithm
|
|
* 1. Since sin(-x) = -sin(x), we need only to consider positive x.
|
|
* 2. Callers must return sin(-0) = -0 without calling here since our
|
|
* odd polynomial is not evaluated in a way that preserves -0.
|
|
* Callers may do the optimization sin(x) ~ x for tiny x.
|
|
* 3. sin(x) is approximated by a polynomial of degree 13 on
|
|
* [0,pi/4]
|
|
* 3 13
|
|
* sin(x) ~ x + S1*x + ... + S6*x
|
|
* where
|
|
*
|
|
* |sin(x) 2 4 6 8 10 12 | -58
|
|
* |----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x +S6*x )| <= 2
|
|
* | x |
|
|
*
|
|
* 4. sin(x+y) = sin(x) + sin'(x')*y
|
|
* ~ sin(x) + (1-x*x/2)*y
|
|
* For better accuracy, let
|
|
* 3 2 2 2 2
|
|
* r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6))))
|
|
* then 3 2
|
|
* sin(x) = x + (S1*x + (x *(r-y/2)+y))
|
|
*/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
#include <nuttx/compiler.h>
|
|
|
|
#include <sys/types.h>
|
|
#include <math.h>
|
|
|
|
#ifdef CONFIG_HAVE_DOUBLE
|
|
|
|
/****************************************************************************
|
|
* Private Data
|
|
****************************************************************************/
|
|
|
|
static const double g_s1 = -1.66666666666666324348e-01; /* 0xbfc55555, 0x55555549 */
|
|
static const double g_s2 = 8.33333333332248946124e-03; /* 0x3f811111, 0x1110f8a6 */
|
|
static const double g_s3 = -1.98412698298579493134e-04; /* 0xbf2a01a0, 0x19c161d5 */
|
|
static const double g_s4 = 2.75573137070700676789e-06; /* 0x3ec71de3, 0x57b1fe7d */
|
|
static const double g_s5 = -2.50507602534068634195e-08; /* 0xbe5ae5e6, 0x8a2b9ceb */
|
|
static const double g_s6 = 1.58969099521155010221e-10; /* 0x3de5d93a, 0x5acfd57c */
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
double __sin(double x, double y, int iy)
|
|
{
|
|
double z;
|
|
double r;
|
|
double v;
|
|
double w;
|
|
|
|
z = x * x;
|
|
w = z * z;
|
|
r = g_s2 + z * (g_s3 + z * g_s4) + z * w * (g_s5 + z * g_s6);
|
|
v = z * x;
|
|
|
|
if (iy == 0)
|
|
{
|
|
return x + v * (g_s1 + z * r);
|
|
}
|
|
else
|
|
{
|
|
return x - ((z * (0.5 * y - v * r) - y) - v * g_s1);
|
|
}
|
|
}
|
|
#endif
|