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Annotation of OpenXM_contrib/gmp/mpf/sqrt.c, Revision 1.1.1.3

1.1       maekawa     1: /* mpf_sqrt -- Compute the square root of a float.
                      2:
1.1.1.3 ! ohara       3: Copyright 1993, 1994, 1996, 2000, 2001 Free Software Foundation, Inc.
1.1       maekawa     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
1.1.1.2   maekawa     8: it under the terms of the GNU Lesser General Public License as published by
                      9: the Free Software Foundation; either version 2.1 of the License, or (at your
1.1       maekawa    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
1.1.1.2   maekawa    14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
1.1       maekawa    15: License for more details.
                     16:
1.1.1.2   maekawa    17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    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:
1.1.1.2   maekawa    22: #include <stdio.h> /* for NULL */
1.1       maekawa    23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25:
                     26: void
                     27: mpf_sqrt (mpf_ptr r, mpf_srcptr u)
                     28: {
                     29:   mp_size_t usize;
                     30:   mp_ptr up, tp;
                     31:   mp_size_t prec;
                     32:   mp_exp_t tsize, rexp;
                     33:   TMP_DECL (marker);
                     34:
                     35:   usize = u->_mp_size;
                     36:   if (usize <= 0)
                     37:     {
1.1.1.2   maekawa    38:       if (usize < 0)
                     39:         SQRT_OF_NEGATIVE;
                     40:       r->_mp_size = 0;
1.1       maekawa    41:       r->_mp_exp = 0;
                     42:       return;
                     43:     }
                     44:
                     45:   TMP_MARK (marker);
                     46:
                     47:   prec = r->_mp_prec;
                     48:   rexp = (u->_mp_exp + 1) >> 1;        /* round towards -inf */
                     49:   tsize = 2 * prec + (u->_mp_exp & 1);
                     50:
                     51:   up = u->_mp_d;
                     52:   tp = (mp_ptr) TMP_ALLOC (tsize * BYTES_PER_MP_LIMB);
                     53:
                     54:   if (usize > tsize)
                     55:     {
                     56:       up += usize - tsize;
                     57:       usize = tsize;
                     58:       MPN_COPY (tp, up, tsize);
                     59:     }
                     60:   else
                     61:     {
                     62:       MPN_ZERO (tp, tsize - usize);
                     63:       MPN_COPY (tp + (tsize - usize), up, usize);
                     64:     }
                     65:
                     66:   mpn_sqrtrem (r->_mp_d, NULL, tp, tsize);
                     67:
                     68:   r->_mp_size = (tsize + 1) / 2;
                     69:   r->_mp_exp = rexp;
                     70:   TMP_FREE (marker);
                     71: }