glibc/sysdeps/ieee754/dbl-64/mpn2dbl.c
Andreas Jaeger 41bdb6e20c Update to LGPL v2.1.
2001-07-06  Paul Eggert  <eggert@twinsun.com>

	* manual/argp.texi: Remove ignored LGPL copyright notice; it's
	not appropriate for documentation anyway.
	* manual/libc-texinfo.sh: "Library General Public License" ->
	"Lesser General Public License".

2001-07-06  Andreas Jaeger  <aj@suse.de>

	* All files under GPL/LGPL version 2: Place under LGPL version
	2.1.
2001-07-06 04:58:11 +00:00

47 lines
1.6 KiB
C

/* Copyright (C) 1995, 1996, 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include "gmp.h"
#include "gmp-impl.h"
#include <ieee754.h>
#include <float.h>
/* Convert a multi-precision integer of the needed number of bits (53 for
double) and an integral power of two to a `double' in IEEE754 double-
precision format. */
double
__mpn_construct_double (mp_srcptr frac_ptr, int expt, int negative)
{
union ieee754_double u;
u.ieee.negative = negative;
u.ieee.exponent = expt + IEEE754_DOUBLE_BIAS;
#if BITS_PER_MP_LIMB == 32
u.ieee.mantissa1 = frac_ptr[0];
u.ieee.mantissa0 = frac_ptr[1] & ((1 << (DBL_MANT_DIG - 32)) - 1);
#elif BITS_PER_MP_LIMB == 64
u.ieee.mantissa1 = frac_ptr[0] & ((1L << 32) - 1);
u.ieee.mantissa0 = (frac_ptr[0] >> 32) & ((1 << (DBL_MANT_DIG - 32)) - 1);
#else
#error "mp_limb size " BITS_PER_MP_LIMB "not accounted for"
#endif
return u.d;
}