glibc/sysdeps/ieee754/flt-32/s_sincosf.c

/* Compute sine and cosine of argument.
   Copyright (C) 1997-2013 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <math.h>

#include <math_private.h>

#ifndef SINCOSF
# define SINCOSF_FUNC __sincosf
#else
# define SINCOSF_FUNC SINCOSF
#endif

void
SINCOSF_FUNC (float x, float *sinx, float *cosx)
{
  int32_t ix;

  /* High word of x. */
  GET_FLOAT_WORD (ix, x);

  /* |x| ~< pi/4 */
  ix &= 0x7fffffff;
  if (ix <= 0x3f490fd8)
    {
      *sinx = __kernel_sinf (x, 0.0, 0);
      *cosx = __kernel_cosf (x, 0.0);
    }
  else if (ix>=0x7f800000)
    {
      /* sin(Inf or NaN) is NaN */
      *sinx = *cosx = x - x;
    }
  else
    {
      /* Argument reduction needed.  */
      float y[2];
      int n;

      n = __ieee754_rem_pio2f (x, y);
      switch (n & 3)
	{
	case 0:
	  *sinx = __kernel_sinf (y[0], y[1], 1);
	  *cosx = __kernel_cosf (y[0], y[1]);
	  break;
	case 1:
	  *sinx = __kernel_cosf (y[0], y[1]);
	  *cosx = -__kernel_sinf (y[0], y[1], 1);
	  break;
	case 2:
	  *sinx = -__kernel_sinf (y[0], y[1], 1);
	  *cosx = -__kernel_cosf (y[0], y[1]);
	  break;
	default:
	  *sinx = -__kernel_cosf (y[0], y[1]);
	  *cosx = __kernel_sinf (y[0], y[1], 1);
	  break;
	}
    }
}

#ifndef SINCOSF
weak_alias (__sincosf, sincosf)
#endif