Return to sqrt.c CVS log

Up to [local] / OpenXM_contrib / gmp / mpz

Annotation of OpenXM_contrib/gmp/mpz/sqrt.c, Revision 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: }