Mercurial > dropbear

annotate bn_mp_reduce_setup.c @ 385:fa7a368e12b1 libtommath-dropbear

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Refer to local headers locally with #include "" not #include <>. Required now that we've got rid of the libtomcrypt variants that were 'accidentally' being included in the -I path
author Matt Johnston <matt@ucc.asn.au>
date Thu, 11 Jan 2007 03:09:09 +0000
parents 91fbc376f010
children 97db060d0ef5
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
282
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
1 #include <tommath.h>
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
2 #ifdef BN_MP_REDUCE_SETUP_C
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
3 /* LibTomMath, multiple-precision integer library -- Tom St Denis
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
4 *
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
5 * LibTomMath is a library that provides multiple-precision
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
6 * integer arithmetic as well as number theoretic functionality.
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
7 *
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
8 * The library was designed directly after the MPI library by
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
9 * Michael Fromberger but has been written from scratch with
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
10 * additional optimizations in place.
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
11 *
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
12 * The library is free for all purposes without any express
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
13 * guarantee it works.
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
14 *
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
15 * Tom St Denis, [email protected], http://math.libtomcrypt.org
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
16 */
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
17
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
18 /* pre-calculate the value required for Barrett reduction
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
19 * For a given modulus "b" it calulates the value required in "a"
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
20 */
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
21 int mp_reduce_setup (mp_int * a, mp_int * b)
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
22 {
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
23 int res;
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
24
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
25 if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) {
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
26 return res;
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
27 }
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
28 return mp_div (a, b, a, NULL);
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
29 }
91fbc376f010 Import of libtommath 0.35
Matt Johnston <matt@ucc.asn.au>
parents:
diff changeset
30 #endif