1  /* mpf_div_ui -- Divide a float with an unsigned integer.
       2  
       3  Copyright 1993, 1994, 1996, 2000-2002, 2004, 2005, 2012 Free Software
       4  Foundation, Inc.
       5  
       6  This file is part of the GNU MP Library.
       7  
       8  The GNU MP Library is free software; you can redistribute it and/or modify
       9  it under the terms of either:
      10  
      11    * the GNU Lesser General Public License as published by the Free
      12      Software Foundation; either version 3 of the License, or (at your
      13      option) any later version.
      14  
      15  or
      16  
      17    * the GNU General Public License as published by the Free Software
      18      Foundation; either version 2 of the License, or (at your option) any
      19      later version.
      20  
      21  or both in parallel, as here.
      22  
      23  The GNU MP Library is distributed in the hope that it will be useful, but
      24  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
      25  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
      26  for more details.
      27  
      28  You should have received copies of the GNU General Public License and the
      29  GNU Lesser General Public License along with the GNU MP Library.  If not,
      30  see https://www.gnu.org/licenses/.  */
      31  
      32  #include "gmp-impl.h"
      33  #include "longlong.h"
      34  
      35  void
      36  mpf_div_ui (mpf_ptr r, mpf_srcptr u, unsigned long int v)
      37  {
      38    mp_srcptr up;
      39    mp_ptr rp, tp, rtp;
      40    mp_size_t usize;
      41    mp_size_t rsize, tsize;
      42    mp_size_t sign_quotient;
      43    mp_size_t prec;
      44    mp_limb_t q_limb;
      45    mp_exp_t rexp;
      46    TMP_DECL;
      47  
      48  #if BITS_PER_ULONG > GMP_NUMB_BITS  /* avoid warnings about shift amount */
      49    if (v > GMP_NUMB_MAX)
      50      {
      51        mpf_t vf;
      52        mp_limb_t vl[2];
      53        SIZ(vf) = 2;
      54        EXP(vf) = 2;
      55        PTR(vf) = vl;
      56        vl[0] = v & GMP_NUMB_MASK;
      57        vl[1] = v >> GMP_NUMB_BITS;
      58        mpf_div (r, u, vf);
      59        return;
      60      }
      61  #endif
      62  
      63    if (UNLIKELY (v == 0))
      64      DIVIDE_BY_ZERO;
      65  
      66    usize = u->_mp_size;
      67  
      68    if (usize == 0)
      69      {
      70        r->_mp_size = 0;
      71        r->_mp_exp = 0;
      72        return;
      73      }
      74  
      75    sign_quotient = usize;
      76    usize = ABS (usize);
      77    prec = r->_mp_prec;
      78  
      79    TMP_MARK;
      80  
      81    rp = r->_mp_d;
      82    up = u->_mp_d;
      83  
      84    tsize = 1 + prec;
      85    tp = TMP_ALLOC_LIMBS (tsize + 1);
      86  
      87    if (usize > tsize)
      88      {
      89        up += usize - tsize;
      90        usize = tsize;
      91        rtp = tp;
      92      }
      93    else
      94      {
      95        MPN_ZERO (tp, tsize - usize);
      96        rtp = tp + (tsize - usize);
      97      }
      98  
      99    /* Move the dividend to the remainder.  */
     100    MPN_COPY (rtp, up, usize);
     101  
     102    mpn_divmod_1 (rp, tp, tsize, (mp_limb_t) v);
     103    q_limb = rp[tsize - 1];
     104  
     105    rsize = tsize - (q_limb == 0);
     106    rexp = u->_mp_exp - (q_limb == 0);
     107    r->_mp_size = sign_quotient >= 0 ? rsize : -rsize;
     108    r->_mp_exp = rexp;
     109    TMP_FREE;
     110  }