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/* snarfed from BSD common_source/floor.c:
* Copyright (c) 1985, 1995 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)floor.c 5.7 (Berkeley) 10/9/90";
#endif /* not lint */
#include "mathimpl.h"
vc(L, 4503599627370496.0E0 ,0000,5c00,0000,0000, 55, 1.0) /* 2**55 */
ic(L, 4503599627370496.0E0, 52, 1.0) /* 2**52 */
#ifdef vccast
#define L vccast(L)
#endif
/*
* algorithm for rint(x) in pseudo-pascal form ...
*
* real rint(x): real x;
* ... delivers integer nearest x in direction of prevailing rounding
* ... mode
* const L = (last consecutive integer)/2
* = 2**55; for VAX D
* = 2**52; for IEEE 754 Double
* real s,t;
* begin
* if x != x then return x; ... NaN
* if |x| >= L then return x; ... already an integer
* s := copysign(L,x);
* t := x + s; ... = (x+s) rounded to integer
* return t - s
* end;
*
* Note: Inexact will be signaled if x is not an integer, as is
* customary for IEEE 754. No other signal can be emitted.
*/
double
__rint(x)
double x;
{
double s,t;
const double one = 1.0;
#if !defined(vax)&&!defined(tahoe)
if (x != x) /* NaN */
return (x);
#endif /* !defined(vax)&&!defined(tahoe) */
if (copysign(x,one) >= L) /* already an integer */
return (x);
s = copysign(L,x);
t = x + s; /* x+s rounded to integer */
return (t - s);
}
weak_alias (__rint, rint)
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