/* s_cosf.c -- float version of s_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 <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)