propagate from branch 'au.asn.ucc.matt.ltm.dropbear' (head 6c790cad5a7fa866ad062cb3a0c279f7ba788583)

            to branch 'au.asn.ucc.matt.dropbear' (head fff0894a0399405a9410ea1c6d118f342cf2aa64)

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extra : convert_revision : fdf4a7a3b97ae5046139915de7e40399cceb2c01

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diff --git a/libtommath/bn_mp_clamp.c b/libtommath/bn_mp_clamp.c
new file mode 100644
index 0000000..c172611
--- /dev/null
+++ b/libtommath/bn_mp_clamp.c
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+#include <tommath.h>
+#ifdef BN_MP_CLAMP_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@iahu.ca, http://math.libtomcrypt.org
+ */
+
+/* trim unused digits 
+ *
+ * This is used to ensure that leading zero digits are
+ * trimed and the leading "used" digit will be non-zero
+ * Typically very fast.  Also fixes the sign if there
+ * are no more leading digits
+ */
+void
+mp_clamp (mp_int * a)
+{
+  /* decrease used while the most significant digit is
+   * zero.
+   */
+  while (a->used > 0 && a->dp[a->used - 1] == 0) {
+    --(a->used);
+  }
+
+  /* reset the sign flag if used == 0 */
+  if (a->used == 0) {
+    a->sign = MP_ZPOS;
+  }
+}
+#endif