assembler: use common to match registers

assembler/src/source/token_info.rs

@@ -1,3 +1,5 @@
+use common::prelude::Register;
+
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct SymbolToken {
     pub name: String,
@@ -15,7 +17,14 @@ pub struct DirectiveToken {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct RegisterToken {
-    pub name: String,
+    pub reg: Register,
+}
+
+impl RegisterToken {
+    /// Returns the name of a valid [`Register`]
+    pub fn name(&self) -> String {
+        self.reg.to_string()
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]