Allow IPv6 address entry in tools>ping - Loosens valid character check
[tomato/davidwu.git] / release / src / router / dropbear / libtommath / bn_mp_reduce_is_2k.c
blob0897b0a814ca072015d432078b40f07fb7abf0e6
1 #include <tommath.h>
2 #ifdef BN_MP_REDUCE_IS_2K_C
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
5 * LibTomMath is a library that provides multiple-precision
6 * integer arithmetic as well as number theoretic functionality.
8 * The library was designed directly after the MPI library by
9 * Michael Fromberger but has been written from scratch with
10 * additional optimizations in place.
12 * The library is free for all purposes without any express
13 * guarantee it works.
15 * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
18 /* determines if mp_reduce_2k can be used */
19 int mp_reduce_is_2k(mp_int *a)
21 int ix, iy, iw;
22 mp_digit iz;
24 if (a->used == 0) {
25 return MP_NO;
26 } else if (a->used == 1) {
27 return MP_YES;
28 } else if (a->used > 1) {
29 iy = mp_count_bits(a);
30 iz = 1;
31 iw = 1;
33 /* Test every bit from the second digit up, must be 1 */
34 for (ix = DIGIT_BIT; ix < iy; ix++) {
35 if ((a->dp[iw] & iz) == 0) {
36 return MP_NO;
38 iz <<= 1;
39 if (iz > (mp_digit)MP_MASK) {
40 ++iw;
41 iz = 1;
45 return MP_YES;
48 #endif
50 /* $Source: /cvs/libtom/libtommath/bn_mp_reduce_is_2k.c,v $ */
51 /* $Revision: 1.3 $ */
52 /* $Date: 2006/03/31 14:18:44 $ */