chiark / gitweb /
progs/perftest.c: Use from Glibc syscall numbers.
[catacomb] / math / mp-exp.c
CommitLineData
f4535c64 1/* -*-c-*-
f4535c64 2 *
3 * Exponentiation for large integers
4 *
5 * (c) 2004 Straylight/Edgeware
6 */
7
45c0fd36 8/*----- Licensing notice --------------------------------------------------*
f4535c64 9 *
10 * This file is part of Catacomb.
11 *
12 * Catacomb is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU Library General Public License as
14 * published by the Free Software Foundation; either version 2 of the
15 * License, or (at your option) any later version.
45c0fd36 16 *
f4535c64 17 * Catacomb is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU Library General Public License for more details.
45c0fd36 21 *
f4535c64 22 * You should have received a copy of the GNU Library General Public
23 * License along with Catacomb; if not, write to the Free
24 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
25 * MA 02111-1307, USA.
26 */
27
28/*----- Header files ------------------------------------------------------*/
29
30#include <assert.h>
31
32#include "mp.h"
33#include "mp-exp.h"
34
35/*----- Main code ---------------------------------------------------------*/
36
37/* --- @mp_exp@ --- *
38 *
39 * Arguments: @mp *d@ = fake destination
40 * @mp *a@ = base
41 * @mp *e@ = exponent
42 *
43 * Returns: Result, %$a^e$%.
44 */
45
46mp *mp_exp(mp *d, mp *a, mp *e)
47{
48 mp *x = MP_ONE;
49 mp *spare = (e->f & MP_BURN) ? MP_NEWSEC : MP_NEW;
50 assert(!MP_NEGP(e));
51
52 MP_COPY(a);
53 if (MP_ZEROP(e))
54 ;
55 else if (MP_LEN(e) < EXP_THRESH)
56 EXP_SIMPLE(x, a, e);
57 else
58 EXP_WINDOW(x, a, e);
59 mp_drop(d);
60 mp_drop(spare);
61 mp_drop(a);
62 return (x);
63}
64
65/*----- That's all, folks -------------------------------------------------*/