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/* mpz_sqrt(root, u) -- Set ROOT to floor(sqrt(U)).
Copyright (C) 1991, 1993, 1994, 1996 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__
mpz_sqrt (mpz_ptr root, mpz_srcptr op)
#else
mpz_sqrt (root, op)
mpz_ptr root;
mpz_srcptr op;
#endif
{
mp_size_t op_size, root_size;
mp_ptr root_ptr, op_ptr;
mp_ptr free_me = NULL;
mp_size_t free_me_size;
TMP_DECL (marker);
TMP_MARK (marker);
op_size = op->_mp_size;
if (op_size < 0)
op_size = 1 / (op_size > 0); /* Divide by zero for negative OP. */
/* The size of the root is accurate after this simple calculation. */
root_size = (op_size + 1) / 2;
root_ptr = root->_mp_d;
op_ptr = op->_mp_d;
if (root->_mp_alloc < root_size)
{
if (root_ptr == op_ptr)
{
free_me = root_ptr;
free_me_size = root->_mp_alloc;
}
else
(*_mp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB);
root->_mp_alloc = root_size;
root_ptr = (mp_ptr) (*_mp_allocate_func) (root_size * BYTES_PER_MP_LIMB);
root->_mp_d = root_ptr;
}
else
{
/* Make OP not overlap with ROOT. */
if (root_ptr == op_ptr)
{
/* ROOT and OP are identical. Allocate temporary space for OP. */
op_ptr = (mp_ptr) TMP_ALLOC (op_size * BYTES_PER_MP_LIMB);
/* Copy to the temporary space. Hack: Avoid temporary variable
by using ROOT_PTR. */
MPN_COPY (op_ptr, root_ptr, op_size);
}
}
mpn_sqrtrem (root_ptr, NULL, op_ptr, op_size);
root->_mp_size = root_size;
if (free_me != NULL)
(*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
TMP_FREE (marker);
}
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