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/* $OpenBSD: s_lround.c,v 1.8 2016/09/12 19:47:02 guenther Exp $ */
/* $NetBSD: lround.c,v 1.2 2004/10/13 15:18:32 drochner Exp $ */
/*-
* Copyright (c) 2004
* Matthias Drochner. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
*/
#include <sys/types.h>
#include <sys/limits.h>
#include <float.h>
#include <math.h>
#include <ieeefp.h>
#include <machine/ieee.h>
#include "math_private.h"
#ifndef LROUNDNAME
#define LROUNDNAME lround
#define RESTYPE long int
#define RESTYPE_MIN LONG_MIN
#define RESTYPE_MAX LONG_MAX
#endif
#define RESTYPE_BITS (sizeof(RESTYPE) * 8)
RESTYPE
LROUNDNAME(double x)
{
u_int32_t i0, i1;
int e, s, shift;
RESTYPE res;
GET_HIGH_WORD(i0, x);
e = i0 >> DBL_FRACHBITS;
s = e >> DBL_EXPBITS;
e = (e & 0x7ff) - DBL_EXP_BIAS;
/* 1.0 x 2^-1 is the smallest number which can be rounded to 1 */
if (e < -1)
return (0);
/* 1.0 x 2^31 (or 2^63) is already too large */
if (e >= (int)RESTYPE_BITS - 1)
return (s ? RESTYPE_MIN : RESTYPE_MAX); /* ??? unspecified */
/* >= 2^52 is already an exact integer */
if (e < DBL_FRACBITS) {
/* add 0.5, extraction below will truncate */
x += (s ? -0.5 : 0.5);
}
EXTRACT_WORDS(i0, i1, x);
e = ((i0 >> DBL_FRACHBITS) & 0x7ff) - DBL_EXP_BIAS;
i0 &= 0xfffff;
i0 |= (1 << DBL_FRACHBITS);
shift = e - DBL_FRACBITS;
if (shift >=0)
res = (shift < RESTYPE_BITS ? (RESTYPE)i1 << shift : 0);
else
res = (shift > -RESTYPE_BITS ? (RESTYPE)i1 >> -shift : 0);
shift += 32;
if (shift >=0)
res |= (shift < RESTYPE_BITS ? (RESTYPE)i0 << shift : 0);
else
res |= (shift > -RESTYPE_BITS ? (RESTYPE)i0 >> -shift : 0);
return (s ? -res : res);
}
DEF_STD(LROUNDNAME);
LDBL_MAYBE_UNUSED_CLONE(LROUNDNAME);
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