diff --git a/src/correct_store_buffer.v b/src/correct_store_buffer.v
index c000ebf945f11846adac85e35f203dd4cb56e57b..7dd8dbc47c4714553166652323650b772b469793 100644
--- a/src/correct_store_buffer.v
+++ b/src/correct_store_buffer.v
@@ -2,17 +2,7 @@ Require Import Bool Lia List Nat PeanoNat.
 From StoreBuffer Require Import definitions utils.
 Import ListNotations.
 
-Variant sbStateT :=
-  | Empty
-  | NotEmpty
-  | Full.
-
-Scheme Equality for sbStateT.
-
 (* free and cycle functions. *)
-Definition busFree isSuUsed sbState :=
-  (sbStateT_beq sbState Empty) && (negb isSuUsed).
-
 Definition ready isSuUsed sbState (elt : instr_kind) :=
   match elt with
   | (Load, (Lsu, 0)) => busFree isSuUsed sbState
diff --git a/src/definitions.v b/src/definitions.v
index 3096c8746c0e85b777589b8b20162edb68c007a2..6f1ef36601cc7ae04fc6cdb351a175ce82b2154c 100644
--- a/src/definitions.v
+++ b/src/definitions.v
@@ -5,7 +5,7 @@
 Require Import Bool List Nat.
 Import ListNotations.
 
-(* Basic definitions: opcodes and stages. *)
+(* Basic definitions: opcodes, stages, store buffer state. *)
 Variant opcode :=
   | Load
   | Store.
@@ -97,6 +97,16 @@ Proof.
     reflexivity.
 Qed.
 
+Variant sbStateT :=
+  | Empty
+  | NotEmpty
+  | Full.
+
+Scheme Equality for sbStateT.
+
+Definition busFree isSuUsed sbState :=
+  (sbStateT_beq sbState Empty) && (negb isSuUsed).
+
 (* State of an instruction in the pipeline. *)
 Definition state := (stage * nat)%type.