1/* mpf_ui_div -- Divide an unsigned integer with a float.
2
3Copyright 1993-1996, 2000-2002, 2004, 2005, 2012 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library.
6
7The GNU MP Library is free software; you can redistribute it and/or modify
8it under the terms of either:
9
10  * the GNU Lesser General Public License as published by the Free
11    Software Foundation; either version 3 of the License, or (at your
12    option) any later version.
13
14or
15
16  * the GNU General Public License as published by the Free Software
17    Foundation; either version 2 of the License, or (at your option) any
18    later version.
19
20or both in parallel, as here.
21
22The GNU MP Library is distributed in the hope that it will be useful, but
23WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
25for more details.
26
27You should have received copies of the GNU General Public License and the
28GNU Lesser General Public License along with the GNU MP Library.  If not,
29see https://www.gnu.org/licenses/.  */
30
31#include <stdio.h>  /* for NULL */
32#include "gmp-impl.h"
33#include "longlong.h"
34
35
36void
37mpf_ui_div (mpf_ptr r, unsigned long int u, mpf_srcptr v)
38{
39  mp_srcptr vp;
40  mp_ptr rp, tp, remp, new_vp;
41  mp_size_t vsize;
42  mp_size_t rsize, prospective_rsize, zeros, tsize, high_zero;
43  mp_size_t sign_quotient;
44  mp_size_t prec;
45  mp_exp_t rexp;
46  TMP_DECL;
47
48  vsize = v->_mp_size;
49  sign_quotient = vsize;
50
51  if (UNLIKELY (vsize == 0))
52    DIVIDE_BY_ZERO;
53
54  if (UNLIKELY (u == 0))
55    {
56      r->_mp_size = 0;
57      r->_mp_exp = 0;
58      return;
59    }
60
61  vsize = ABS (vsize);
62  prec = r->_mp_prec;
63
64  TMP_MARK;
65  rexp = 1 - v->_mp_exp + 1;
66
67  rp = r->_mp_d;
68  vp = v->_mp_d;
69
70  prospective_rsize = 1 - vsize + 1;    /* quot from using given u,v sizes */
71  rsize = prec + 1;                     /* desired quot size */
72
73  zeros = rsize - prospective_rsize;    /* padding u to give rsize */
74  tsize = 1 + zeros;                    /* u with zeros */
75
76  if (WANT_TMP_DEBUG)
77    {
78      /* separate alloc blocks, for malloc debugging */
79      remp = TMP_ALLOC_LIMBS (vsize);
80      tp = TMP_ALLOC_LIMBS (tsize);
81      new_vp = NULL;
82      if (rp == vp)
83        new_vp = TMP_ALLOC_LIMBS (vsize);
84    }
85  else
86    {
87      /* one alloc with calculated size, for efficiency */
88      mp_size_t size = vsize + tsize + (rp == vp ? vsize : 0);
89      remp = TMP_ALLOC_LIMBS (size);
90      tp = remp + vsize;
91      new_vp = tp + tsize;
92    }
93
94  /* ensure divisor doesn't overlap quotient */
95  if (rp == vp)
96    {
97      MPN_COPY (new_vp, vp, vsize);
98      vp = new_vp;
99    }
100
101  MPN_ZERO (tp, tsize-1);
102
103  tp[tsize - 1] = u & GMP_NUMB_MASK;
104#if BITS_PER_ULONG > GMP_NUMB_BITS
105  if (u > GMP_NUMB_MAX)
106    {
107      /* tsize-vsize+1 == rsize, so tsize >= rsize.  rsize == prec+1 >= 2,
108         so tsize >= 2, hence there's room for 2-limb u with nails */
109      ASSERT (tsize >= 2);
110      tp[tsize - 1] = u >> GMP_NUMB_BITS;
111      tp[tsize - 2] = u & GMP_NUMB_MASK;
112      rexp++;
113    }
114#endif
115
116  ASSERT (tsize-vsize+1 == rsize);
117  mpn_tdiv_qr (rp, remp, (mp_size_t) 0, tp, tsize, vp, vsize);
118
119  /* strip possible zero high limb */
120  high_zero = (rp[rsize-1] == 0);
121  rsize -= high_zero;
122  rexp -= high_zero;
123
124  r->_mp_size = sign_quotient >= 0 ? rsize : -rsize;
125  r->_mp_exp = rexp;
126  TMP_FREE;
127}
128