1 files changed, 12 insertions, 1 deletions
diff --git a/src/Language/Fiddle/Ast/Internal/SyntaxTree.hs b/src/Language/Fiddle/Ast/Internal/SyntaxTree.hs
index 0d0bc32..b597a25 100644
--- a/src/Language/Fiddle/Ast/Internal/SyntaxTree.hs
+++ b/src/Language/Fiddle/Ast/Internal/SyntaxTree.hs
@@ -18,6 +18,7 @@ module Language.Fiddle.Ast.Internal.SyntaxTree
     FieldSpan (..),
     QRegMetadata (..),
     QBitsMetadata (..),
+    RegSz(..),
     -- Witness Types
     Witness (..),
     -- AST Types
@@ -50,6 +51,7 @@ module Language.Fiddle.Ast.Internal.SyntaxTree
     EnumConstantDecl (..),
     PackageBody (..),
     -- Helper Functions
+    regSzToBits,
     mapDirected,
     mapDirectedM,
     asDirected,
@@ -105,6 +107,15 @@ deriving instance
   (FromJSON (When s (FieldSpan Bytes))) =>
   FromJSON (QRegMetadata s)
 
+data RegSz = RegSz8 | RegSz16 | RegSz32  | RegSz64
+  deriving (Eq, Ord, Show, Enum, Generic, ToJSON, FromJSON)
+
+regSzToBits :: RegSz -> N Bits
+regSzToBits RegSz8 = 8
+regSzToBits RegSz16 = 16
+regSzToBits RegSz32 = 32
+regSzToBits RegSz64 = 64
+
 data QBitsMetadata (checkStage :: Bool) where
   QBitsMetadata ::
     { bitsSpan :: When checkStage (FieldSpan Bits),
@@ -520,7 +531,7 @@ data ObjTypeDecl stage f a where
       -- doesn't exist.
       regIdent :: Guaranteed (stage .>= Qualified) (Identifier f a),
       -- | Size of the register.
-      regSize :: Expression Bits stage f a,
+      regSize :: Variant (stage .>= Qualified) RegSz (Expression Bits stage f a),
       -- | Optional register body.
       regBody :: Maybe (RegisterBody stage f a),
       -- | Annotation for the register declaration.