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/* mpf_sqrt -- Compute the square root of a float.
Copyright (C) 1993, 1994, 1996, 2000 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_sqrt (mpf_ptr r, mpf_srcptr u)
#else
mpf_sqrt (r, u)
mpf_ptr r;
mpf_srcptr u;
#endif
{
mp_size_t usize;
mp_ptr up, tp;
mp_size_t prec;
mp_exp_t tsize, rexp;
TMP_DECL (marker);
usize = u->_mp_size;
if (usize <= 0)
{
if (usize < 0)
SQRT_OF_NEGATIVE;
r->_mp_size = 0;
r->_mp_exp = 0;
return;
}
TMP_MARK (marker);
prec = r->_mp_prec;
rexp = (u->_mp_exp + 1) >> 1; /* round towards -inf */
tsize = 2 * prec + (u->_mp_exp & 1);
up = u->_mp_d;
tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
if (usize > tsize)
{
up += usize - tsize;
usize = tsize;
MPN_COPY (tp, up, tsize);
}
else
{
MPN_ZERO (tp, tsize - usize);
MPN_COPY (tp + (tsize - usize), up, usize);
}
mpn_sqrtrem (r->_mp_d, NULL, tp, tsize);
r->_mp_size = (tsize + 1) / 2;
r->_mp_exp = rexp;
TMP_FREE (marker);
}
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