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/* 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.
* ====================================================
*/
#if defined(LIBM_SCCS) && !defined(lint)
static char rcsid[] = "$NetBSD: s_rint.c,v 1.8 1995/05/10 20:48:04 jtc Exp $";
#endif
/*
* 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_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;
int32_t i0, j0, sx;
double w, t;
GET_HIGH_WORD (i0, x);
sx = (i0 >> 31) & 1;
j0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
if (j0 < 52)
{
if (j0 < 0)
{
libc_feholdexcept (&env);
w = TWO52[sx] + math_opt_barrier (x);
t = w - TWO52[sx];
math_force_eval (t);
libc_fesetenv (&env);
GET_HIGH_WORD (i0, t);
SET_HIGH_WORD (t, (i0 & 0x7fffffff) | (sx << 31));
return t;
}
}
else
{
if (j0 == 0x400)
return x + x; /* inf or NaN */
else
return x; /* x is integral */
}
libc_feholdexcept (&env);
w = TWO52[sx] + math_opt_barrier (x);
t = w - TWO52[sx];
math_force_eval (t);
libc_fesetenv (&env);
return t;
}
libm_alias_double (__nearbyint, nearbyint)
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