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

1.1       maekawa     1: /* mpz_sqrtrem(root,rem,x) -- Set ROOT to floor(sqrt(X)) and REM
                      2:    to the remainder, i.e. X - ROOT**2.
                      3:
                      4: Copyright (C) 1991, 1993, 1994, 1996 Free Software Foundation, Inc.
                      5:
                      6: This file is part of the GNU MP Library.
                      7:
                      8: The GNU MP Library is free software; you can redistribute it and/or modify
                      9: it under the terms of the GNU Library General Public License as published by
                     10: the Free Software Foundation; either version 2 of the License, or (at your
                     11: option) any later version.
                     12:
                     13: The GNU MP Library is distributed in the hope that it will be useful, but
                     14: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     15: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
                     16: License for more details.
                     17:
                     18: You should have received a copy of the GNU Library General Public License
                     19: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     20: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     21: MA 02111-1307, USA. */
                     22:
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26: #ifndef BERKELEY_MP
                     27: void
                     28: #if __STDC__
                     29: mpz_sqrtrem (mpz_ptr root, mpz_ptr rem, mpz_srcptr op)
                     30: #else
                     31: mpz_sqrtrem (root, rem, op)
                     32:      mpz_ptr root;
                     33:      mpz_ptr rem;
                     34:      mpz_srcptr op;
                     35: #endif
                     36: #else /* BERKELEY_MP */
                     37: void
                     38: #if __STDC__
                     39: msqrt (mpz_srcptr op, mpz_ptr root, mpz_ptr rem)
                     40: #else
                     41: msqrt (op, root, rem)
                     42:      mpz_srcptr op;
                     43:      mpz_ptr root;
                     44:      mpz_ptr rem;
                     45: #endif
                     46: #endif /* BERKELEY_MP */
                     47: {
                     48:   mp_size_t op_size, root_size, rem_size;
                     49:   mp_ptr root_ptr, op_ptr;
                     50:   mp_ptr free_me = NULL;
                     51:   mp_size_t free_me_size;
                     52:   TMP_DECL (marker);
                     53:
                     54:   TMP_MARK (marker);
                     55:   op_size = op->_mp_size;
                     56:   if (op_size < 0)
                     57:     op_size = 1 / (op_size > 0); /* Divide by zero for negative OP.  */
                     58:
                     59:   if (rem->_mp_alloc < op_size)
                     60:     _mpz_realloc (rem, op_size);
                     61:
                     62:   /* The size of the root is accurate after this simple calculation.  */
                     63:   root_size = (op_size + 1) / 2;
                     64:
                     65:   root_ptr = root->_mp_d;
                     66:   op_ptr = op->_mp_d;
                     67:
                     68:   if (root->_mp_alloc < root_size)
                     69:     {
                     70:       if (root_ptr == op_ptr)
                     71:        {
                     72:          free_me = root_ptr;
                     73:          free_me_size = root->_mp_alloc;
                     74:        }
                     75:       else
                     76:        (*_mp_free_func) (root_ptr, root->_mp_alloc * BYTES_PER_MP_LIMB);
                     77:
                     78:       root->_mp_alloc = root_size;
                     79:       root_ptr = (mp_ptr) (*_mp_allocate_func) (root_size * BYTES_PER_MP_LIMB);
                     80:       root->_mp_d = root_ptr;
                     81:     }
                     82:   else
                     83:     {
                     84:       /* Make OP not overlap with ROOT.  */
                     85:       if (root_ptr == op_ptr)
                     86:        {
                     87:          /* ROOT and OP are identical.  Allocate temporary space for OP.  */
                     88:          op_ptr = (mp_ptr) TMP_ALLOC (op_size * BYTES_PER_MP_LIMB);
                     89:          /* Copy to the temporary space.  Hack: Avoid temporary variable
                     90:             by using ROOT_PTR.  */
                     91:          MPN_COPY (op_ptr, root_ptr, op_size);
                     92:        }
                     93:     }
                     94:
                     95:   rem_size = mpn_sqrtrem (root_ptr, rem->_mp_d, op_ptr, op_size);
                     96:
                     97:   root->_mp_size = root_size;
                     98:
                     99:   /* Write remainder size last, to enable us to define this function to
                    100:      give only the square root remainder, if the user calls if with
                    101:      ROOT == REM.  */
                    102:   rem->_mp_size = rem_size;
                    103:
                    104:   if (free_me != NULL)
                    105:     (*_mp_free_func) (free_me, free_me_size * BYTES_PER_MP_LIMB);
                    106:   TMP_FREE (marker);
                    107: }