[fsbl] add fsbl for cv181x/cv180x

Change-Id: I6809bc5016d4bc148f62be2ed3f8e928ec111f19

fsbl/lib/libtommath/bn_mp_abs.c

@@ -0,0 +1,39 @@
+#include "tommath_private.h"
+#ifdef BN_MP_ABS_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
+ */
+
+/* b = |a|
+ *
+ * Simple function copies the input and fixes the sign to positive
+ */
+int mp_abs(const mp_int *a, mp_int *b)
+{
+   int     res;
+
+   /* copy a to b */
+   if (a != b) {
+      if ((res = mp_copy(a, b)) != MP_OKAY) {
+         return res;
+      }
+   }
+
+   /* force the sign of b to positive */
+   b->sign = MP_ZPOS;
+
+   return MP_OKAY;
+}
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */