version 0.3.33

[fms.git] / libs / libtommath / bn_mp_invmod.c

diff --git a/libs/libtommath/bn_mp_invmod.c b/libs/libtommath/bn_mp_invmod.c
new file mode 100644 (file)
index 0000000..3f5791f
--- /dev/null
+++ b/libs/libtommath/bn_mp_invmod.c
@@ -0,0 +1,43 @@
+#include <tommath.h>
+#ifdef BN_MP_INVMOD_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
+ */
+
+/* hac 14.61, pp608 */
+int mp_invmod (mp_int * a, mp_int * b, mp_int * c)
+{
+  /* b cannot be negative */
+  if (b->sign == MP_NEG || mp_iszero(b) == 1) {
+    return MP_VAL;
+  }
+
+#ifdef BN_FAST_MP_INVMOD_C
+  /* if the modulus is odd we can use a faster routine instead */
+  if (mp_isodd (b) == 1) {
+    return fast_mp_invmod (a, b, c);
+  }
+#endif
+
+#ifdef BN_MP_INVMOD_SLOW_C
+  return mp_invmod_slow(a, b, c);
+#endif
+
+  return MP_VAL;
+}
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_invmod.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */