version 0.3.33

[fms.git] / libs / libtommath / bn_mp_reduce_is_2k_l.c

diff --git a/libs/libtommath/bn_mp_reduce_is_2k_l.c b/libs/libtommath/bn_mp_reduce_is_2k_l.c
new file mode 100644 (file)
index 0000000..c4b42c9
--- /dev/null
+++ b/libs/libtommath/bn_mp_reduce_is_2k_l.c
@@ -0,0 +1,44 @@
+#include <tommath.h>
+#ifdef BN_MP_REDUCE_IS_2K_L_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@gmail.com, http://math.libtomcrypt.com
+ */
+
+/* determines if reduce_2k_l can be used */
+int mp_reduce_is_2k_l(mp_int *a)
+{
+   int ix, iy;
+   
+   if (a->used == 0) {
+      return MP_NO;
+   } else if (a->used == 1) {
+      return MP_YES;
+   } else if (a->used > 1) {
+      /* if more than half of the digits are -1 we're sold */
+      for (iy = ix = 0; ix < a->used; ix++) {
+          if (a->dp[ix] == MP_MASK) {
+              ++iy;
+          }
+      }
+      return (iy >= (a->used/2)) ? MP_YES : MP_NO;
+      
+   }
+   return MP_NO;
+}
+
+#endif
+
+/* $Source: /cvs/libtom/libtommath/bn_mp_reduce_is_2k_l.c,v $ */
+/* $Revision: 1.3 $ */
+/* $Date: 2006/03/31 14:18:44 $ */