diff --git a/pac_encoder.hh b/pac_encoder.hh
index d2f63ee..c3ab9c0 100644
--- a/pac_encoder.hh
+++ b/pac_encoder.hh
@@ -20,12 +20,19 @@ class PACEncoder
 	}
 	static bool conv(int *state, bool input)
 	{
+#if 0
 		bool b1 = (*state >> 1) & 1;
 		bool b3 = (*state >> 3) & 1;
 		bool b4 = (*state >> 4) & 1;
 		bool b6 = (*state >> 6) & 1;
 		bool output = input ^ b1 ^ b3 ^ b4 ^ b6;
 		*state = ((*state & 126) << 1) | (input ? 2 : 0) | (output ? 1 : 0);
+#else
+		bool s1 = *state & 1;
+		bool s2 = *state & 2;
+		bool output = input ^ s1 ^ s2;
+		*state = (s1 << 1) | output;
+#endif
 		return output;
 	}
 public:
diff --git a/pac_list_decoder.hh b/pac_list_decoder.hh
index 10dd82f..2e55df5 100644
--- a/pac_list_decoder.hh
+++ b/pac_list_decoder.hh
@@ -19,12 +19,19 @@ struct PACListLeaf
 	typedef typename PH::MAP MAP;
 	static bool conv(int *state, bool input)
 	{
+#if 0
 		bool b1 = (*state >> 1) & 1;
 		bool b3 = (*state >> 3) & 1;
 		bool b4 = (*state >> 4) & 1;
 		bool b6 = (*state >> 6) & 1;
 		bool output = input ^ b1 ^ b3 ^ b4 ^ b6;
 		*state = ((*state & 126) << 1) | (input ? 2 : 0) | (output ? 1 : 0);
+#else
+		bool s1 = *state & 1;
+		bool s2 = *state & 2;
+		bool output = input ^ s1 ^ s2;
+		*state = (s1 << 1) | output;
+#endif
 		return output;
 	}
 	static MAP rate0(PATH *metric, int *state, TYPE *hard, TYPE *soft)