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/* mpz_sqrtrem(root,rem,x) -- Set ROOT to floor(sqrt(X)) and REM
to the remainder, i.e. X - ROOT**2.
Copyright 1991, 1993, 1994, 1996, 2000, 2001, 2005 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 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 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 Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
#include <stdio.h> /* for NULL */
#include "gmp.h"
#include "gmp-impl.h"
#ifdef BERKELEY_MP
#include "mp.h"
#endif
void
#ifndef BERKELEY_MP
mpz_sqrtrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr op)
#else /* BERKELEY_MP */
msqrt (mpz_srcptr op, mpz_ptr root, mpz_ptr rem)
#endif /* BERKELEY_MP */
{
mp_size_t op_size, root_size, rem_size;
mp_ptr root_ptr, op_ptr;
mp_ptr free_me = NULL;
mp_size_t free_me_size;
TMP_DECL;
TMP_MARK;
op_size = op->_mp_size;
if (op_size <= 0)
{
if (op_size < 0)
SQRT_OF_NEGATIVE;
SIZ(root) = 0;
SIZ(rem) = 0;
return;
}
if (rem->_mp_alloc < op_size)
_mpz_realloc (rem, op_size);
/* 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
(*__gmp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB);
root->_mp_alloc = root_size;
root_ptr = (mp_ptr) (*__gmp_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);
}
}
rem_size = mpn_sqrtrem (root_ptr, rem->_mp_d, op_ptr, op_size);
root->_mp_size = root_size;
/* Write remainder size last, to enable us to define this function to
give only the square root remainder, if the user calls if with
ROOT == REM. */
rem->_mp_size = rem_size;
if (free_me != NULL)
(*__gmp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
TMP_FREE;
}
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