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Annotation of OpenXM_contrib/gmp/mpf/get_d.c, Revision 1.1

1.1     ! maekawa     1: /* double mpf_get_d (mpf_t src) -- Return the double approximation to SRC.
        !             2:
        !             3: Copyright (C) 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: double
        !            26: #if __STDC__
        !            27: mpf_get_d (mpf_srcptr src)
        !            28: #else
        !            29: mpf_get_d (src)
        !            30:      mpf_srcptr src;
        !            31: #endif
        !            32: {
        !            33:   double res;
        !            34:   mp_size_t size, i, n_limbs_to_use;
        !            35:   int negative;
        !            36:   mp_ptr qp;
        !            37:
        !            38:   size = SIZ(src);
        !            39:   if (size == 0)
        !            40:     return 0.0;
        !            41:
        !            42:   negative = size < 0;
        !            43:   size = ABS (size);
        !            44:   qp = PTR(src);
        !            45:
        !            46:   res = qp[size - 1];
        !            47:   n_limbs_to_use = MIN (LIMBS_PER_DOUBLE, size);
        !            48:   for (i = 2; i <= n_limbs_to_use; i++)
        !            49:     res = res * MP_BASE_AS_DOUBLE + qp[size - i];
        !            50:
        !            51:   res = __gmp_scale2 (res, (EXP(src) - n_limbs_to_use) * BITS_PER_MP_LIMB);
        !            52:
        !            53:   return negative ? -res : res;
        !            54: }