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/* k_cosf.c -- float version of k_cos.c
Copyright (C) 2011-2018 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));
}
}
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