[fsbl] add fsbl for cv181x/cv180x

Change-Id: I6809bc5016d4bc148f62be2ed3f8e928ec111f19

fsbl/lib/libtommath/bn_mp_dr_setup.c

@@ -0,0 +1,28 @@
+#include "tommath_private.h"
+#ifdef BN_MP_DR_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.
+ *
+ * SPDX-License-Identifier: Unlicense
+ */
+
+/* determines the setup value */
+void mp_dr_setup(const mp_int *a, mp_digit *d)
+{
+   /* the casts are required if DIGIT_BIT is one less than
+    * the number of bits in a mp_digit [e.g. DIGIT_BIT==31]
+    */
+   *d = (mp_digit)(((mp_word)1 << (mp_word)DIGIT_BIT) - (mp_word)a->dp[0]);
+}
+
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */