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/*
Copyright (C) 2012 Fredrik Johansson
This file is part of Arb.
Arb is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version. See <http://www.gnu.org/licenses/>.
*/
#include "flint/double_extras.h"
#include "fmpr.h"
void
fmpr_set_d(fmpr_t x, double v)
{
#if FLINT_BITS == 64
mp_limb_t h, sign, exp, frac;
slong real_exp, real_man;
union { double uf; mp_limb_t ul; } u;
u.uf = v;
h = u.ul;
sign = h >> 63;
exp = (h << 1) >> 53;
frac = (h << 12) >> 12;
if (exp == 0 && frac == 0)
{
fmpr_zero(x);
return;
}
else if (exp == 0x7ff)
{
if (frac == 0)
{
if (sign)
fmpr_neg_inf(x);
else
fmpr_pos_inf(x);
}
else
{
fmpr_nan(x);
}
return;
}
/* handle subnormals */
if (exp == 0 && frac != 0)
{
int exp2;
v = frexp(v, &exp2);
u.uf = v;
h = u.ul;
sign = h >> 63;
exp = (h << 1) >> 53;
frac = (h << 12) >> 12;
exp += exp2;
}
real_exp = exp - 1023 - 52;
frac |= (UWORD(1) << 52);
real_man = sign ? (-frac) : frac;
fmpr_set_si_2exp_si(x, real_man, real_exp);
#else
mpfr_t t;
mp_limb_t tmp[2];
t->_mpfr_prec = 53;
t->_mpfr_sign = 1;
t->_mpfr_exp = 0;
t->_mpfr_d = tmp;
mpfr_set_d(t, v, MPFR_RNDD);
fmpr_set_mpfr(x, t);
#endif
}
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