diff --git a/firepower-core/src/main/scala/com/htmlism/firepower/core/AssemblerOptions.scala b/firepower-core/src/main/scala/com/htmlism/firepower/core/AssemblerOptions.scala
index 0ce4cf3..cebb467 100644
--- a/firepower-core/src/main/scala/com/htmlism/firepower/core/AssemblerOptions.scala
+++ b/firepower-core/src/main/scala/com/htmlism/firepower/core/AssemblerOptions.scala
@@ -1,7 +1,10 @@
 package com.htmlism.firepower.core
 
-case class AssemblerOptions()
+case class AssemblerOptions(instructionCase: AssemblerOptions.InstructionCase, definitionsMode: AssemblerOptions.DefinitionsMode)
 
 object AssemblerOptions:
-  enum Definitions:
+  enum DefinitionsMode:
     case InlineDefinitions, UseDefinitions, UseDefinitionsWithMath
+
+  enum InstructionCase:
+    case Uppercase, Lowercase