arb/mag/get_d.c

52 lines
1.5 KiB
C

/*=============================================================================
This file is part of ARB.
ARB is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
ARB 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with ARB; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
=============================================================================*/
/******************************************************************************
Copyright (C) 2014 Fredrik Johansson
******************************************************************************/
#include "double_extras.h"
#include "mag.h"
double
mag_get_d(const mag_t z)
{
if (mag_is_zero(z))
{
return 0.0;
}
else if (mag_is_inf(z))
{
return D_INF;
}
else if (MAG_EXP(z) < -1000 || MAG_EXP(z) > 1000)
{
if (fmpz_sgn(MAG_EXPREF(z)) < 0)
return ldexp(1.0, -1000);
else
return D_INF;
}
else
{
return ldexp(MAG_MAN(z), MAG_EXP(z) - MAG_BITS);
}
}