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/* @(#)s_rint.c 5.1 93/09/24 */
/*
* ====================================================
* 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 <math.h>
#include <math_private.h>
static const double
TWO52[2] = {
4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */
-4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */
};
double
__rint (double x)
{
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)
{
w = TWO52[sx] + x;
t = w - TWO52[sx];
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 */
}
w = TWO52[sx] + x;
return w - TWO52[sx];
}
#ifndef __rint
weak_alias (__rint, rint)
# ifdef NO_LONG_DOUBLE
strong_alias (__rint, __rintl)
weak_alias (__rint, rintl)
# endif
#endif
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