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/* s_cosf.c -- float version of s_cos.c.
Copyright (C) 2011-2017 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 <errno.h>
#include <math.h>
#include <math_private.h>
#include <libm-alias-float.h>
static const float pio4 = 7.8539801e-1;
float
__cosf (float x)
{
float y[2], z = 0.0;
float ix;
int32_t n;
ix = __builtin_fabsf (x);
/* |x| ~< pi/4 */
if (ix <= pio4)
{
return __kernel_cosf (x, z);
/* cos(Inf or NaN) is NaN */
}
else if (isnanf (ix))
{
return x - x;
}
else if (isinff (ix))
{
__set_errno (EDOM);
return x - x;
}
/* argument reduction needed */
else
{
n = __ieee754_rem_pio2f (x, y);
switch (n & 3)
{
case 0:
return __kernel_cosf (y[0], y[1]);
case 1:
return -__kernel_sinf (y[0], y[1], 1);
case 2:
return -__kernel_cosf (y[0], y[1]);
default:
return __kernel_sinf (y[0], y[1], 1);
}
}
}
libm_alias_float (__cos, cos)
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