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Annotation of OpenXM_contrib/gmp/mpz/sqrt.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpz_sqrt(root, u) --  Set ROOT to floor(sqrt(U)).
                      2:
                      3: Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
                      4:
                      5: This file is part of the GNU MP Library.
                      6:
                      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.
                     11:
                     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.
                     16:
                     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. */
                     21:
                     22: #include "gmp.h"
                     23: #include "gmp-impl.h"
                     24:
                     25: void
                     26: #if __STDC__
                     27: mpz_sqrt (mpz_ptr root, mpz_srcptr op)
                     28: #else
                     29: mpz_sqrt (root, op)
                     30:      mpz_ptr root;
                     31:      mpz_srcptr op;
                     32: #endif
                     33: {
                     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;
                     38:   TMP_DECL (marker);
                     39:
                     40:   TMP_MARK (marker);
                     41:   op_size = op->_mp_size;
                     42:   if (op_size < 0)
                     43:     op_size = 1 / (op_size > 0); /* Divide by zero for negative OP.  */
                     44:
                     45:   /* The size of the root is accurate after this simple calculation.  */
                     46:   root_size = (op_size + 1) / 2;
                     47:
                     48:   root_ptr = root->_mp_d;
                     49:   op_ptr = op->_mp_d;
                     50:
                     51:   if (root->_mp_alloc < root_size)
                     52:     {
                     53:       if (root_ptr == op_ptr)
                     54:        {
                     55:          free_me = root_ptr;
                     56:          free_me_size = root->_mp_alloc;
                     57:        }
                     58:       else
                     59:        (*_mp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB);
                     60:
                     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;
                     64:     }
                     65:   else
                     66:     {
                     67:       /* Make OP not overlap with ROOT.  */
                     68:       if (root_ptr == op_ptr)
                     69:        {
                     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
                     73:             by using ROOT_PTR.  */
                     74:          MPN_COPY (op_ptr, root_ptr, op_size);
                     75:        }
                     76:     }
                     77:
                     78:   mpn_sqrtrem (root_ptr, NULL, op_ptr, op_size);
                     79:
                     80:   root->_mp_size = root_size;
                     81:
                     82:   if (free_me != NULL)
                     83:     (*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
                     84:   TMP_FREE (marker);
                     85: }