summaryrefslogtreecommitdiff
path: root/source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c
diff options
context:
space:
mode:
authorMatthieu Patou <mat@matws.net>2010-08-15 18:31:28 +0400
committerAndrew Bartlett <abartlet@samba.org>2010-10-03 01:15:04 +0000
commitab6e3fce040f9ad27cbce44e9038a24f15b601c8 (patch)
treeab99a431c9610927b5d0d26335d2712b509fd6dc /source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c
parent197a1514d62494cc8b862d169c841a26e04b8925 (diff)
downloadsamba-ab6e3fce040f9ad27cbce44e9038a24f15b601c8.tar.gz
samba-ab6e3fce040f9ad27cbce44e9038a24f15b601c8.tar.bz2
samba-ab6e3fce040f9ad27cbce44e9038a24f15b601c8.zip
s4:heimdal: import lorikeet-heimdal-201009250123 (commit 42cabfb5b683dbcb97d583c397b897507689e382)
I based this on Matthieu's import of lorikeet-heimdal, and then updated it to this commit. Andrew Bartlett
Diffstat (limited to 'source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c')
-rw-r--r--source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c b/source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c
new file mode 100644
index 0000000000..f5015cce45
--- /dev/null
+++ b/source4/heimdal/lib/hcrypto/libtommath/bn_mp_sub.c
@@ -0,0 +1,59 @@
+#include <tommath.h>
+#ifdef BN_MP_SUB_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://libtom.org
+ */
+
+/* high level subtraction (handles signs) */
+int
+mp_sub (mp_int * a, mp_int * b, mp_int * c)
+{
+ int sa, sb, res;
+
+ sa = a->sign;
+ sb = b->sign;
+
+ if (sa != sb) {
+ /* subtract a negative from a positive, OR */
+ /* subtract a positive from a negative. */
+ /* In either case, ADD their magnitudes, */
+ /* and use the sign of the first number. */
+ c->sign = sa;
+ res = s_mp_add (a, b, c);
+ } else {
+ /* subtract a positive from a positive, OR */
+ /* subtract a negative from a negative. */
+ /* First, take the difference between their */
+ /* magnitudes, then... */
+ if (mp_cmp_mag (a, b) != MP_LT) {
+ /* Copy the sign from the first */
+ c->sign = sa;
+ /* The first has a larger or equal magnitude */
+ res = s_mp_sub (a, b, c);
+ } else {
+ /* The result has the *opposite* sign from */
+ /* the first number. */
+ c->sign = (sa == MP_ZPOS) ? MP_NEG : MP_ZPOS;
+ /* The second has a larger magnitude */
+ res = s_mp_sub (b, a, c);
+ }
+ }
+ return res;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_sub.c,v $ */
+/* $Revision: 1.4 $ */
+/* $Date: 2006/12/28 01:25:13 $ */