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/* mpf_set_d -- Assign a float from a IEEE double.
Copyright (C) 1993, 1994, 1995 Free Software Foundation, Inc.
This file is part of the GNU MP Library.
The GNU MP Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
The GNU MP 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 Library General Public
License for more details.
You should have received a copy of the GNU Library General Public License
along with the GNU MP Library; see the file COPYING.LIB. 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"
void
#if __STDC__
mpf_set_d (mpf_ptr r, double d)
#else
mpf_set_d (r, d)
mpf_ptr r;
double d;
#endif
{
mp_ptr rp;
mp_size_t size;
mp_exp_t exp;
mp_limb_t manh, manl;
mp_limb_t man2, man1, man0;
union ieee_double_extract x;
unsigned sc;
/* ??? This needs more work since it assumes that limbs are 32 bits.
See mpz/set_d for ideas on how to handle 64-bit machines. */
if (d == 0)
{
r->_mp_exp = 0;
r->_mp_size = 0;
return;
}
rp = r->_mp_d;
x.d = d;
exp = x.s.exp;
sc = (unsigned) (exp + 2) % BITS_PER_MP_LIMB;
manh = 0x80000000 | (x.s.manh << 11) | (x.s.manl >> 21);
manl = x.s.manl << 11;
if (sc != 0)
{
man2 = manh >> (BITS_PER_MP_LIMB - sc);
man1 = (manl >> (BITS_PER_MP_LIMB - sc)) | (manh << sc);
man0 = manl << sc;
}
else
{
man2 = manh;
man1 = manl;
man0 = 0;
}
if (man0 == 0)
{
if (man1 == 0)
{
size = 1;
rp[0] = man2;
}
else
{
size = 2;
rp[1] = man2;
rp[0] = man1;
}
}
else
{
size = 3;
rp[2] = man2;
rp[1] = man1;
rp[0] = man0;
}
r->_mp_exp = (exp + 1) / BITS_PER_MP_LIMB - 1024 / BITS_PER_MP_LIMB + 1;
r->_mp_size = x.s.sig == 0 ? size : -size;
}
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