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/* $NetBSD: floatunditf_ieee754.c,v 1.1 2014/01/30 15:06:18 joerg Exp $ */
/*-
* Copyright (c) 2014 Joerg Sonnenberger <joerg@NetBSD.org>.
* 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 COPYRIGHT HOLDERS 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
* COPYRIGHT HOLDERS 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/cdefs.h>
__RCSID("$NetBSD: floatunditf_ieee754.c,v 1.1 2014/01/30 15:06:18 joerg Exp $");
#include <math.h>
#include <machine/ieee.h>
#include <limits.h>
#ifdef __HAVE_LONG_DOUBLE
long double __floatunditf(uint64_t x);
/*
* Convert uint64_t to long double.
*/
long double
__floatunditf(uint64_t x)
{
int exponent, zeros;
union ieee_ext_u ux;
/* Use the easier conversion routine for uint32_t if possible. */
if (x <= UINT32_MAX)
return (long double)(uint32_t)x;
zeros = __builtin_clzll(x);
#ifdef LDBL_IMPLICIT_NBIT
exponent = 64 - zeros;
x <<= zeros + 1;
#else
exponent = 63 - zeros;
x <<= zeros;
#endif
ux.extu_exp = EXT_EXP_BIAS + exponent;
ux.extu_frach = (x >> (64 - EXT_FRACHBITS));
x <<= EXT_FRACHBITS;
#ifdef EXT_FRACHMBITS
ux.extu_frachm = (x >> (64 - EXT_FRACHMBITS));
x <<= EXT_FRACHMBITS;
#endif
#ifdef EXT_FRACLMBITS
ux.extu_fraclm = (x >> (64 - EXT_FRACLMBITS));
x <<= EXT_FRACLMBITS;
#endif
ux.extu_fracl = (x >> (64 - EXT_FRACLBITS));
ux.extu_sign = 0;
return ux.extu_ld;
}
#endif /* __HAVE_LONG_DOUBLE */
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