[fsbl] add fsbl for cv181x/cv180x

Change-Id: I6809bc5016d4bc148f62be2ed3f8e928ec111f19

fsbl/lib/libtommath/bn_mp_count_bits.c

@@ -0,0 +1,41 @@
+#include "tommath_private.h"
+#ifdef BN_MP_COUNT_BITS_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
+ */
+
+/* returns the number of bits in an int */
+int mp_count_bits(const mp_int *a)
+{
+   int     r;
+   mp_digit q;
+
+   /* shortcut */
+   if (a->used == 0) {
+      return 0;
+   }
+
+   /* get number of digits and add that */
+   r = (a->used - 1) * DIGIT_BIT;
+
+   /* take the last digit and count the bits in it */
+   q = a->dp[a->used - 1];
+   while (q > (mp_digit)0) {
+      ++r;
+      q >>= (mp_digit)1;
+   }
+   return r;
+}
+#endif
+
+/* ref:         $Format:%D$ */
+/* git commit:  $Format:%H$ */
+/* commit time: $Format:%ai$ */