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Annotation of OpenXM_contrib/gmp/mpfr/set_f.c, Revision 1.1.1.2

1.1       maekawa     1: /* mpfr_set_f -- set a MPFR number from a GNU MPF number
                      2:
1.1.1.2 ! ohara       3: Copyright 1999, 2000, 2001 Free Software Foundation, Inc.
1.1       maekawa     4:
                      5: This file is part of the MPFR Library.
                      6:
                      7: The MPFR Library is free software; you can redistribute it and/or modify
1.1.1.2 ! ohara       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 MPFR 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 ! ohara      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 ! ohara      17: You should have received a copy of the GNU Lesser General Public License
1.1       maekawa    18: along with the MPFR 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 <stdio.h>
                     23: #include "gmp.h"
                     24: #include "gmp-impl.h"
                     25: #include "longlong.h"
                     26: #include "mpfr.h"
1.1.1.2 ! ohara      27: #include "mpfr-impl.h"
1.1       maekawa    28:
1.1.1.2 ! ohara      29: int
        !            30: mpfr_set_f (mpfr_ptr y, mpf_srcptr x, mp_rnd_t rnd_mode)
1.1       maekawa    31: {
1.1.1.2 ! ohara      32:   mp_limb_t *my, *mx, *tmp;
        !            33:   unsigned long cnt, sx, sy;
        !            34:   int inexact;
1.1       maekawa    35:   TMP_DECL(marker);
                     36:
1.1.1.2 ! ohara      37:   if (SIZ(x) * MPFR_SIGN(y) < 0)
        !            38:     MPFR_CHANGE_SIGN (y);
1.1       maekawa    39:
1.1.1.2 ! ohara      40:   MPFR_CLEAR_FLAGS (y);
1.1       maekawa    41:
1.1.1.2 ! ohara      42:   sx = ABS(SIZ(x)); /* number of limbs of the mantissa of x */
        !            43:   sy = 1 + (MPFR_PREC(y) - 1) / BITS_PER_MP_LIMB;
        !            44:   my = MPFR_MANT(y);
        !            45:   mx = PTR(x);
1.1       maekawa    46:
1.1.1.2 ! ohara      47:   if (sx == 0) /* x is zero */
        !            48:     {
        !            49:       MPFR_SET_ZERO(y);
        !            50:       return 0; /* 0 is exact */
        !            51:     }
        !            52:
        !            53:   count_leading_zeros(cnt, mx[sx - 1]);
1.1       maekawa    54:
1.1.1.2 ! ohara      55:   if (sy <= sx) /* we may have to round even when sy = sx */
1.1       maekawa    56:     {
                     57:       unsigned long xprec = sx * BITS_PER_MP_LIMB;
                     58:
1.1.1.2 ! ohara      59:       TMP_MARK(marker);
1.1       maekawa    60:       tmp = (mp_limb_t*) TMP_ALLOC(xprec);
1.1.1.2 ! ohara      61:       if (cnt)
        !            62:        mpn_lshift(tmp, mx, sx, cnt);
        !            63:       else
        !            64:        MPN_COPY(tmp, mx, sx);
        !            65:       mpfr_round_raw (my, tmp, xprec, (SIZ(x)<0), MPFR_PREC(y), rnd_mode,
        !            66:                      &inexact);
        !            67:       TMP_FREE(marker);
1.1       maekawa    68:     }
                     69:   else
                     70:     {
1.1.1.2 ! ohara      71:       if (cnt)
        !            72:        mpn_lshift(my + sy - sx, mx, sx, cnt);
        !            73:       else
        !            74:        MPN_COPY(my + sy - sx, mx, sy);
1.1       maekawa    75:       MPN_ZERO(my, sy - sx);
                     76:       /* no rounding necessary, since y has a larger mantissa */
1.1.1.2 ! ohara      77:       inexact = 0;
1.1       maekawa    78:     }
                     79:
1.1.1.2 ! ohara      80:   MPFR_EXP(y) = EXP(x) * BITS_PER_MP_LIMB - cnt;
1.1       maekawa    81:
1.1.1.2 ! ohara      82:   return inexact;
1.1       maekawa    83: }