--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tomsfastmath/src/bit/fp_count_bits.c	Wed Nov 23 18:10:20 2011 +0700
@@ -0,0 +1,36 @@
+/* TomsFastMath, a fast ISO C bignum library.
+ * 
+ * This project is meant to fill in where LibTomMath
+ * falls short.  That is speed ;-)
+ *
+ * This project is public domain and free for all purposes.
+ * 
+ * Tom St Denis, [email protected]
+ */
+#include <tfm.h>
+
+int fp_count_bits (fp_int * a)
+{
+  int     r;
+  fp_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 > ((fp_digit) 0)) {
+    ++r;
+    q >>= ((fp_digit) 1);
+  }
+  return r;
+}
+
+/* $Source$ */
+/* $Revision$ */
+/* $Date$ */