1 /* mpz_sqrt(root, u) -- Set ROOT to floor(sqrt(U)).
3 Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
5 This file is part of the GNU MP Library.
7 The GNU MP Library is free software; you can redistribute it and/or modify
8 it under the terms of the GNU Library General Public License as published by
9 the Free Software Foundation; either version 2 of the License, or (at your
10 option) any later version.
12 The GNU MP Library is distributed in the hope that it will be useful, but
13 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
14 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
15 License for more details.
17 You should have received a copy of the GNU Library General Public License
18 along with the GNU MP Library; see the file COPYING.LIB. If not, write to
19 the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
20 MA 02111-1307, USA. */
27 mpz_sqrt (mpz_ptr root, mpz_srcptr op)
34 mp_size_t op_size, root_size;
35 mp_ptr root_ptr, op_ptr;
36 mp_ptr free_me = NULL;
37 mp_size_t free_me_size;
41 op_size = op->_mp_size;
43 op_size = 1 / (op_size > 0); /* Divide by zero for negative OP. */
45 /* The size of the root is accurate after this simple calculation. */
46 root_size = (op_size + 1) / 2;
48 root_ptr = root->_mp_d;
51 if (root->_mp_alloc < root_size)
53 if (root_ptr == op_ptr)
56 free_me_size = root->_mp_alloc;
59 (*_mp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB);
61 root->_mp_alloc = root_size;
62 root_ptr = (mp_ptr) (*_mp_allocate_func) (root_size * BYTES_PER_MP_LIMB);
63 root->_mp_d = root_ptr;
67 /* Make OP not overlap with ROOT. */
68 if (root_ptr == op_ptr)
70 /* ROOT and OP are identical. Allocate temporary space for OP. */
71 op_ptr = (mp_ptr) TMP_ALLOC (op_size * BYTES_PER_MP_LIMB);
72 /* Copy to the temporary space. Hack: Avoid temporary variable
74 MPN_COPY (op_ptr, root_ptr, op_size);
78 mpn_sqrtrem (root_ptr, NULL, op_ptr, op_size);
80 root->_mp_size = root_size;
83 (*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);