summaryrefslogtreecommitdiff
path: root/libtommath/bn_mp_reduce_setup.c
diff options
context:
space:
mode:
authorMatt Johnston <matt@ucc.asn.au>2007-01-11 03:14:55 +0000
committerMatt Johnston <matt@ucc.asn.au>2007-01-11 03:14:55 +0000
commit68efaf4fb3d1cca475eee7ff15d6abb71a48cf88 (patch)
tree6dacbff2e9f5c60a1568382db55c72dd6d2ce925 /libtommath/bn_mp_reduce_setup.c
parent0e9e709195eb6421f80d4c62fe66e43ae3ac2422 (diff)
parent4ebcb4da9b179c9bc735698414524ccda5932568 (diff)
downloaddropbear-68efaf4fb3d1cca475eee7ff15d6abb71a48cf88.tar.gz
propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 2af95f00ebd5bb7a28b3817db1218442c935388e)
to branch 'au.asn.ucc.matt.dropbear' (head ecd779509ef23a8cdf64888904fc9b31d78aa933)
Diffstat (limited to 'libtommath/bn_mp_reduce_setup.c')
-rw-r--r--libtommath/bn_mp_reduce_setup.c34
1 files changed, 34 insertions, 0 deletions
diff --git a/libtommath/bn_mp_reduce_setup.c b/libtommath/bn_mp_reduce_setup.c
new file mode 100644
index 0000000..5085af0
--- /dev/null
+++ b/libtommath/bn_mp_reduce_setup.c
@@ -0,0 +1,34 @@
+#include <tommath.h>
+#ifdef BN_MP_REDUCE_SETUP_C
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://math.libtomcrypt.com
+ */
+
+/* pre-calculate the value required for Barrett reduction
+ * For a given modulus "b" it calulates the value required in "a"
+ */
+int mp_reduce_setup (mp_int * a, mp_int * b)
+{
+ int res;
+
+ if ((res = mp_2expt (a, b->used * 2 * DIGIT_BIT)) != MP_OKAY) {
+ return res;
+ }
+ return mp_div (a, b, a, NULL);
+}
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_reduce_setup.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */