/* mpfr_set_d -- convert a machine double precision float to
a multiple precision floating-point number
Copyright 1999-2004, 2006-2017 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.
This file is part of the GNU MPFR Library.
The GNU MPFR 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 3 of the License, or (at your
option) any later version.
The GNU MPFR 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 MPFR Library; see the file COPYING.LESSER. If not, see
http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include <float.h> /* For DOUBLE_ISINF and DOUBLE_ISNAN */
#define MPFR_NEED_LONGLONG_H
#include "mpfr-impl.h"
/* extracts the bits of d in rp[0..n-1] where n=ceil(53/GMP_NUMB_BITS).
Assumes d is neither 0 nor NaN nor Inf. */
static long
__gmpfr_extract_double (mpfr_limb_ptr rp, double d)
/* e=0 iff GMP_NUMB_BITS=32 and rp has only one limb */
{
long exp;
mp_limb_t manl;
#if GMP_NUMB_BITS == 32
mp_limb_t manh;
#endif
/* BUGS
1. Should handle Inf and NaN in IEEE specific code.
2. Handle Inf and NaN also in default code, to avoid hangs.
3. Generalize to handle all GMP_NUMB_BITS.
4. This lits is incomplete and misspelled.
*/
MPFR_ASSERTD(!DOUBLE_ISNAN(d));
MPFR_ASSERTD(!DOUBLE_ISINF(d));
MPFR_ASSERTD(d != 0.0);
#if _GMP_IEEE_FLOATS
{
union ieee_double_extract x;
x.d = d;
exp = x.s.exp;
if (exp)
{
#if GMP_NUMB_BITS >= 64
manl = ((MPFR_LIMB_ONE << 63)
| ((mp_limb_t) x.s.manh << 43) | ((mp_limb_t) x.s.manl << 11));
#else
manh = (MPFR_LIMB_ONE << 31) | (x.s.manh << 11) | (x.s.manl >> 21);
manl = x.s.manl << 11;
#endif
}
else /* subnormal number */
{
#if GMP_NUMB_BITS >= 64
manl = ((mp_limb_t) x.s.manh << 43) | ((mp_limb_t) x.s.manl << 11);
#else
manh = (x.s.manh << 11) /* high 21 bits */
| (x.s.manl >> 21); /* middle 11 bits */
manl = x.s.manl << 11; /* low 21 bits */
#endif
}
if (exp)
exp -= 1022;
else
exp = -1021;
}
#else /* _GMP_IEEE_FLOATS */
{
/* Unknown (or known to be non-IEEE) double format. */
exp = 0;
if (d >= 1.0)
{
MPFR_ASSERTN (d * 0.5 != d);
while (d >= 32768.0)
{
d *= (1.0 / 65536.0);
exp += 16;
}
while (d >= 1.0)
{
d *= 0.5;
exp += 1;
}
}
else if (d < 0.5)
{
while (d < (1.0 / 65536.0))
{
d *= 65536.0;
exp -= 16;
}
while (d < 0.5)
{
d *= 2.0;
exp -= 1;
}
}
d *= MP_BASE_AS_DOUBLE;
#if GMP_NUMB_BITS >= 64
manl = d;
#else
manh = (mp_limb_t) d;
manl = (mp_limb_t) ((d - manh) * MP_BASE_AS_DOUBLE);
#endif
}
#endif /* _GMP_IEEE_FLOATS */
#if GMP_NUMB_BITS >= 64
rp[0] = manl;
#else
rp[1] = manh;
rp[0] = manl;
#endif
return exp;
}
/* End of part included from gmp-2.0.2 */
int
mpfr_set_d (mpfr_ptr r, double d, mpfr_rnd_t rnd_mode)
{
int signd, inexact;
unsigned int cnt;
mp_size_t i, k;
mpfr_t tmp;
mp_limb_t tmpmant[MPFR_LIMBS_PER_DOUBLE];
MPFR_SAVE_EXPO_DECL (expo);
if (MPFR_UNLIKELY(DOUBLE_ISNAN(d)))
{
MPFR_SET_NAN(r);
MPFR_RET_NAN;
}
else if (MPFR_UNLIKELY(d == 0))
{
#if _GMP_IEEE_FLOATS
union ieee_double_extract x;
MPFR_SET_ZERO(r);
/* set correct sign */
x.d = d;
if (x.s.sig == 1)
MPFR_SET_NEG(r);
else
MPFR_SET_POS(r);
#else /* _GMP_IEEE_FLOATS */
MPFR_SET_ZERO(r);
{
/* This is to get the sign of zero on non-IEEE hardware
Some systems support +0.0, -0.0 and unsigned zero.
We can't use d==+0.0 since it should be always true,
so we check that the memory representation of d is the
same than +0.0. etc */
/* FIXME: consider the case where +0.0 or -0.0 may have several
representations. */
double poszero = +0.0, negzero = DBL_NEG_ZERO;
if (memcmp(&d, &poszero, sizeof(double)) == 0)
MPFR_SET_POS(r);
else if (memcmp(&d, &negzero, sizeof(double)) == 0)
MPFR_SET_NEG(r);
else
MPFR_SET_POS(r);
}
#endif
return 0; /* 0 is exact */
}
else if (MPFR_UNLIKELY(DOUBLE_ISINF(d)))
{
MPFR_SET_INF(r);
if (d > 0)
MPFR_SET_POS(r);
else
MPFR_SET_NEG(r);
return 0; /* infinity is exact */
}
/* now d is neither 0, nor NaN nor Inf */
MPFR_SAVE_EXPO_MARK (expo);
/* warning: don't use tmp=r here, even if SIZE(r) >= MPFR_LIMBS_PER_DOUBLE,
since PREC(r) may be different from PREC(tmp), and then both variables
would have same precision in the mpfr_set4 call below. */
MPFR_MANT(tmp) = tmpmant;
MPFR_PREC(tmp) = IEEE_DBL_MANT_DIG;
signd = (d < 0) ? MPFR_SIGN_NEG : MPFR_SIGN_POS;
d = ABS (d);
/* don't use MPFR_SET_EXP here since the exponent may be out of range */
MPFR_EXP(tmp) = __gmpfr_extract_double (tmpmant, d);
#ifdef MPFR_WANT_ASSERT
/* Failed assertion if the stored value is 0 (e.g., if the exponent range
has been reduced at the wrong moment and an underflow to 0 occurred).
Probably a bug in the C implementation if this happens. */
i = 0;
while (tmpmant[i] == 0)
{
i++;
MPFR_ASSERTN(i < MPFR_LIMBS_PER_DOUBLE);
}
#endif
/* determine the index i-1 of the most significant non-zero limb
and the number k of zero high limbs */
i = MPFR_LIMBS_PER_DOUBLE;
MPN_NORMALIZE_NOT_ZERO(tmpmant, i);
k = MPFR_LIMBS_PER_DOUBLE - i;
count_leading_zeros (cnt, tmpmant[i - 1]);
if (MPFR_LIKELY(cnt != 0))
mpn_lshift (tmpmant + k, tmpmant, i, cnt);
else if (k != 0)
MPN_COPY (tmpmant + k, tmpmant, i);
if (MPFR_UNLIKELY(k != 0))
MPN_ZERO (tmpmant, k);
/* don't use MPFR_SET_EXP here since the exponent may be out of range */
MPFR_EXP(tmp) -= (mpfr_exp_t) (cnt + k * GMP_NUMB_BITS);
/* tmp is exact since PREC(tmp)=53 */
inexact = mpfr_set4 (r, tmp, rnd_mode, signd);
MPFR_SAVE_EXPO_FREE (expo);
return mpfr_check_range (r, inexact, rnd_mode);
}