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/* mpfr_set -- copy of a floating-point number
Copyright 1999, 2001, 2002, 2003 Free Software Foundation.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR 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"
#include "mpfr.h"
#include "mpfr-impl.h"
/* set a to abs(b) * signb: a=b when signb = SIGN(b), a=abs(b) when signb=1 */
int
mpfr_set4 (mpfr_ptr a, mpfr_srcptr b, mp_rnd_t rnd_mode, int signb)
{
int inex;
if (MPFR_UNLIKELY( MPFR_IS_SINGULAR(b) ))
{
if (MPFR_IS_NAN(b))
{
MPFR_SET_NAN(a);
MPFR_RET_NAN;
}
else if (MPFR_IS_INF(b))
{
MPFR_CLEAR_FLAGS(a);
MPFR_SET_INF(a);
inex = 0;
}
else if (MPFR_IS_ZERO(b))
{
MPFR_SET_ZERO(a);
inex = 0;
}
else
/* Should never reach this code */
MPFR_ASSERTN(0);
}
else if (MPFR_LIKELY(MPFR_PREC(b) == MPFR_PREC(a)))
{
/* Same precision and b is not special:
* just copy the mantissa, and set the exponent and the sign */
MPFR_CLEAR_FLAGS(a);
MPN_COPY(MPFR_MANT(a), MPFR_MANT(b), MPFR_LIMB_SIZE(b));
MPFR_SET_SIGN(a, signb);
MPFR_SET_EXP(a, MPFR_GET_EXP(b));
MPFR_RET(0);
}
else
{
mp_limb_t *ap;
mp_prec_t aq;
int carry;
MPFR_CLEAR_FLAGS(a);
ap = MPFR_MANT(a);
aq = MPFR_PREC(a);
carry = mpfr_round_raw(ap, MPFR_MANT(b), MPFR_PREC(b),
MPFR_IS_NEG_SIGN(signb),
aq, rnd_mode, &inex);
/* FIXME: Carry is likely or not ? */
if (MPFR_UNLIKELY(carry))
{
mp_exp_t exp = MPFR_GET_EXP (b);
if (MPFR_UNLIKELY(exp == __gmpfr_emax))
return mpfr_set_overflow(a, rnd_mode, signb);
MPFR_SET_EXP(a, exp + 1);
ap[(MPFR_PREC(a)-1)/BITS_PER_MP_LIMB] = MPFR_LIMB_HIGHBIT;
}
else
MPFR_SET_EXP (a, MPFR_GET_EXP (b));
}
MPFR_SET_SIGN(a, signb);
MPFR_RET(inex);
}
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