1 /* mpi-cmp.c - MPI functions
2 * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
3 *
4 * This file is part of GnuPG.
5 *
6 * GnuPG is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * GnuPG is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
19 */
20
21 #include "mpi-internal.h"
22
mpi_cmp_ui(MPI u,unsigned long v)23 int mpi_cmp_ui(MPI u, unsigned long v)
24 {
25 mpi_limb_t limb = v;
26
27 mpi_normalize(u);
28 if (!u->nlimbs && !limb)
29 return 0;
30 if (u->sign)
31 return -1;
32 if (u->nlimbs > 1)
33 return 1;
34
35 if (u->d[0] == limb)
36 return 0;
37 else if (u->d[0] > limb)
38 return 1;
39 else
40 return -1;
41 }
42 EXPORT_SYMBOL_GPL(mpi_cmp_ui);
43
do_mpi_cmp(MPI u,MPI v,int absmode)44 static int do_mpi_cmp(MPI u, MPI v, int absmode)
45 {
46 mpi_size_t usize;
47 mpi_size_t vsize;
48 int usign;
49 int vsign;
50 int cmp;
51
52 mpi_normalize(u);
53 mpi_normalize(v);
54
55 usize = u->nlimbs;
56 vsize = v->nlimbs;
57 usign = absmode ? 0 : u->sign;
58 vsign = absmode ? 0 : v->sign;
59
60 /* Compare sign bits. */
61
62 if (!usign && vsign)
63 return 1;
64 if (usign && !vsign)
65 return -1;
66
67 /* U and V are either both positive or both negative. */
68
69 if (usize != vsize && !usign && !vsign)
70 return usize - vsize;
71 if (usize != vsize && usign && vsign)
72 return vsize + usize;
73 if (!usize)
74 return 0;
75 cmp = mpihelp_cmp(u->d, v->d, usize);
76 if (!cmp)
77 return 0;
78 if ((cmp < 0?1:0) == (usign?1:0))
79 return 1;
80
81 return -1;
82 }
83
mpi_cmp(MPI u,MPI v)84 int mpi_cmp(MPI u, MPI v)
85 {
86 return do_mpi_cmp(u, v, 0);
87 }
88 EXPORT_SYMBOL_GPL(mpi_cmp);
89
mpi_cmpabs(MPI u,MPI v)90 int mpi_cmpabs(MPI u, MPI v)
91 {
92 return do_mpi_cmp(u, v, 1);
93 }
94 EXPORT_SYMBOL_GPL(mpi_cmpabs);
95