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Annotation of OpenXM_contrib/gmp/mpf/urandomb.c, Revision 1.1.1.1

1.1       maekawa     1: /* mpf_urandomb (rop, state, nbits) -- Generate a uniform pseudorandom
                      2:    real number between 0 (inclusive) and 1 (exclusive) of size NBITS,
                      3:    using STATE as the random state previously initialized by a call to
                      4:    gmp_randinit().
                      5:
                      6: Copyright (C) 1999, 2000  Free Software Foundation, Inc.
                      7:
                      8: This file is part of the GNU MP Library.
                      9:
                     10: The GNU MP Library is free software; you can redistribute it and/or modify
                     11: it under the terms of the GNU Lesser General Public License as published by
                     12: the Free Software Foundation; either version 2.1 of the License, or (at your
                     13: option) any later version.
                     14:
                     15: The GNU MP Library is distributed in the hope that it will be useful, but
                     16: WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
                     17: or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
                     18: License for more details.
                     19:
                     20: You should have received a copy of the GNU Lesser General Public License
                     21: along with the GNU MP Library; see the file COPYING.LIB.  If not, write to
                     22: the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
                     23: MA 02111-1307, USA. */
                     24:
                     25: #include "gmp.h"
                     26: #include "gmp-impl.h"
                     27:
                     28: void
                     29: #if __STDC__
                     30: mpf_urandomb (mpf_t rop, gmp_randstate_t rstate, unsigned long int nbits)
                     31: #else
                     32: mpf_urandomb (rop, rstate, nbits)
                     33:      mpf_t rop;
                     34:      gmp_randstate_t rstate;
                     35:      unsigned long int nbits;
                     36: #endif
                     37: {
                     38:   mp_ptr rp;
                     39:   mp_size_t nlimbs;
                     40:   mp_exp_t exp;
                     41:
                     42:   rp = PTR (rop);
                     43:   nlimbs = (nbits + BITS_PER_MP_LIMB - 1) / BITS_PER_MP_LIMB;
                     44:
                     45:   _gmp_rand (rp, rstate, nbits);
                     46:
                     47:   /* If nbits isn't a multiple of BITS_PER_MP_LIMB, shift up.  */
                     48:   if (nlimbs != 0)
                     49:     {
                     50:       if (nbits % BITS_PER_MP_LIMB != 0)
                     51:        mpn_lshift (rp, rp, nlimbs,
                     52:                    BITS_PER_MP_LIMB - nbits % BITS_PER_MP_LIMB);
                     53:     }
                     54:
                     55:   exp = 0;
                     56:   while (nlimbs != 0 && rp[nlimbs - 1] == 0)
                     57:     {
                     58:       nlimbs--;
                     59:       exp--;
                     60:     }
                     61:   EXP (rop) = exp;
                     62:   SIZ (rop) = nlimbs;
                     63:
                     64: }