diff --git a/litex/gen/common.py b/litex/gen/common.py
index 604cec853..81c2fca88 100644
--- a/litex/gen/common.py
+++ b/litex/gen/common.py
@@ -19,10 +19,6 @@ def colorer(s, color="bright"):
     trailer = "\x1b[0m"
     return header + str(s) + trailer
 
-# Signals ------------------------------------------------------------------------------------------
-
-class Open(Signal) : pass
-
 # Bit/Bytes Reversing ------------------------------------------------------------------------------
 
 def reverse_bits(s):
@@ -34,6 +30,20 @@ def reverse_bytes(s):
     return Cat(*[s[i*8:min((i + 1)*8, len(s))]
         for i in reversed(range(n))])
 
+# Signals ------------------------------------------------------------------------------------------
+
+class Open(Signal): pass
+
+class Unsigned(Signal):
+    def __init__(self, bits=1, *args, **kwargs):
+        assert isinstance(bits, int)
+        Signal.__init__(self, bits_sign=(bits, 0), *args, **kwargs)
+
+class Signed(Signal):
+    def __init__(self, bits=1, *args, **kwargs):
+        assert isinstance(bits, int)
+        Signal.__init__(self, bits_sign=(bits, 1), *args, **kwargs)
+
 # Reduction ----------------------------------------------------------------------------------------
 
 from functools import reduce