mirror of
https://sourceware.org/git/glibc.git
synced 2024-12-23 11:20:07 +00:00
66 lines
2.0 KiB
C
66 lines
2.0 KiB
C
/* k_cosf.c -- float version of k_cos.c
|
|
Copyright (C) 2011-2015 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Adhemerval Zanella <azanella@br.ibm.com>, 2011
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Library General Public License as
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If
|
|
not, see <http://www.gnu.org/licenses/>. */
|
|
|
|
#include <math.h>
|
|
#include <fenv.h>
|
|
#include <math_private.h>
|
|
|
|
static const float twom27 = 7.4505806e-09;
|
|
static const float dot3 = 3.0000001e-01;
|
|
static const float dot78125 = 7.8125000e-01;
|
|
|
|
static const float one = 1.0000000000e+00;
|
|
static const float C1 = 4.1666667908e-02;
|
|
static const float C2 = -1.3888889225e-03;
|
|
static const float C3 = 2.4801587642e-05;
|
|
static const float C4 = -2.7557314297e-07;
|
|
static const float C5 = 2.0875723372e-09;
|
|
static const float C6 = -1.1359647598e-11;
|
|
|
|
float
|
|
__kernel_cosf (float x, float y)
|
|
{
|
|
float a, hz, z, r, qx;
|
|
float ix;
|
|
ix = __builtin_fabsf (x);
|
|
if (ix < twom27)
|
|
{ /* |x| < 2**-27 */
|
|
__feraiseexcept (FE_INEXACT);
|
|
return one;
|
|
}
|
|
z = x * x;
|
|
r = z * (C1 + z * (C2 + z * (C3 + z * (C4 + z * (C5 + z * C6)))));
|
|
if (ix < dot3) /* if |x| < 0.3 */
|
|
return one - ((float) 0.5 * z - (z * r - x * y));
|
|
else
|
|
{
|
|
if (ix > dot78125)
|
|
{ /* x > 0.78125 */
|
|
qx = (float) 0.28125;
|
|
}
|
|
else
|
|
{
|
|
qx = ix / 4.0;
|
|
}
|
|
hz = (float) 0.5 *z - qx;
|
|
a = one - qx;
|
|
return a - (hz - (z * r - x * y));
|
|
}
|
|
}
|