/* Adapted for use as nearbyint by Ulrich Drepper <drepper@cygnus.com>.  */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

/*

 * rint(x)

 * Return x rounded to integral value according to the prevailing

 * rounding mode.

 * Method:

 *	Using floating addition.

 * Exception:

 *	Inexact flag raised if x not equal to rint(x).

 */

#include <fenv.h>

#include <math.h>

#include <math-barriers.h>

#include <math_private.h>

#include <libm-alias-double.h>

static const double

TWO52[2]={

  4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */

 -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */

};

double

__nearbyint(double x)

{

	fenv_t env;

	int64_t i0,sx;

	int32_t j0;

	EXTRACT_WORDS64(i0,x);

	sx = (i0>>63)&1;

	j0 = ((i0>>52)&0x7ff)-0x3ff;

	if(__builtin_expect(j0<52, 1)) {

	    if(j0<0) {

		libc_feholdexcept (&env;;

		double w = TWO52[sx] + math_opt_barrier (x);

		double t =  w-TWO52[sx];

		math_force_eval (t);

		libc_fesetenv (&env;;

		return __copysign (t, x);

	    }

	} else {

	    if(j0==0x400) return x+x;	/* inf or NaN */

	    else return x;		/* x is integral */

	}

	libc_feholdexcept (&env;;

	double w = TWO52[sx] + math_opt_barrier (x);

	double t = w-TWO52[sx];

	math_force_eval (t);

	libc_fesetenv (&env;;

	return t;

}

libm_alias_double (__nearbyint, nearbyint)