diff --git a/bs/TagEngine.bs b/bs/TagEngine.bs
index d168ed4..cb21845 100644
--- a/bs/TagEngine.bs
+++ b/bs/TagEngine.bs
@@ -1,10 +1,51 @@
 package TagEngine() where
 
+import Vector
 import Util
 
+#define UIntLog2N(n) (UInt (TLog n))
+
+data Tag a
+    = Next (UInt a)
+    | Empty
+    deriving (Bits, Eq, FShow)
+
+initTagNext :: Integer -> Module(Reg (Tag a))
+initTagNext i = do
+    t :: Reg (Tag a)
+    t <- mkReg (Next (fromInteger i))
+    return t
+
+initTagEmpty :: Integer -> Module(Reg (Tag a))
+initTagEmpty i = do
+    t :: Reg (Tag a)
+    t <- mkReg Empty
+    return t
+
 interface (TagEngine :: # -> *) numTags =
-    requestTag :: ActionValue (UInt (TLog numTags))
-    retireTag  :: UInt (TLog numTags) -> Action
+    requestTag :: ActionValue UIntLog2N(numTags)
+    retireTag  :: UIntLog2N(numTags) -> Action
+
+
+mkTagEngine :: Module (TagEngine numTags)
+mkTagEngine =
+    do
+        let v :: Vector numTags Integer = genVector
+        -- placeholder
+        counter <- mkReg(0 :: UIntLog2N(numTags))
+        return $
+          interface TagEngine
+            requestTag :: ActionValue UIntLog2N(numTags)
+            requestTag = do
+                -- placeholder
+                counter := counter + 1
+                return counter
+            retireTag :: UIntLog2N(numTags) -> Action
+            retireTag tag = do
+                -- placeholder
+                counter := 0
+    where
+        a = "Hello"
 
 a :: Integer
-a = 3
\ No newline at end of file
+a = 3