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Annotation of OpenXM_contrib/gmp/mpfr/set_ui.c, Revision 1.1.1.1

1.1       ohara       1: /* mpfr_set_ui -- set a MPFR number from a machine unsigned integer
                      2:
                      3: Copyright 1999, 2000, 2001 Free Software Foundation.
                      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
                      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
                     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
                     14: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     15: License for more details.
                     16:
                     17: You should have received a copy of the GNU Lesser General Public License
                     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 "gmp.h"
                     23: #include "gmp-impl.h"
                     24: #include "longlong.h"
                     25: #include "mpfr.h"
                     26: #include "mpfr-impl.h"
                     27:
                     28: int
                     29: mpfr_set_ui (mpfr_ptr x, unsigned long i, mp_rnd_t rnd_mode)
                     30: {
                     31:   int inex = 0;
                     32:
                     33:   MPFR_CLEAR_FLAGS(x);
                     34:   if (i == 0)
                     35:     MPFR_SET_ZERO(x);  /* the sign will be set later */
                     36:   else
                     37:     {
                     38:       mp_size_t xn;
                     39:       unsigned int cnt, nbits;
                     40:       mp_limb_t *xp;
                     41:
                     42:       xn = (MPFR_PREC(x)-1)/BITS_PER_MP_LIMB;
                     43:       count_leading_zeros(cnt, (mp_limb_t) i);
                     44:
                     45:       xp = MPFR_MANT(x);
                     46:       xp[xn] = ((mp_limb_t) i) << cnt;
                     47:       /* don't forget to put zero in lower limbs */
                     48:       MPN_ZERO(xp, xn);
                     49:
                     50:       MPFR_EXP(x) = nbits = BITS_PER_MP_LIMB - cnt;
                     51:       inex = mpfr_check_range(x, rnd_mode);
                     52:       if (inex)
                     53:         return inex; /* underflow or overflow */
                     54:
                     55:       /* round if MPFR_PREC(x) smaller than length of i */
                     56:       if (MPFR_PREC(x) < nbits)
                     57:         {
                     58:           int carry;
                     59:           carry = mpfr_round_raw(xp+xn, xp+xn, nbits, 0, MPFR_PREC(x),
                     60:                                  rnd_mode, &inex);
                     61:           if (carry)
                     62:             {
                     63:               mp_exp_t exp = MPFR_EXP(x);
                     64:
                     65:               if (exp == __mpfr_emax)
                     66:                 return mpfr_set_overflow(x, rnd_mode, 1);
                     67:
                     68:               MPFR_EXP(x)++;
                     69:               xp[xn] = GMP_LIMB_HIGHBIT;
                     70:             }
                     71:         }
                     72:     }
                     73:
                     74:   MPFR_SET_POS(x);
                     75:
                     76:   MPFR_RET(inex);
                     77: }