diff --git a/src/isr.pas b/src/isr.pas
index c83c4723..71af0a99 100644
--- a/src/isr.pas
+++ b/src/isr.pas
@@ -25,7 +25,7 @@ end;
 
 procedure init();
 begin
-    idt.set_gate(0, uint32(@isr0), $08, $8E);
+    idt.set_gate(0, uint32(@isr0), $08, ISR_RING_0);
 end;
 
 end.
\ No newline at end of file
diff --git a/src/system.pas b/src/system.pas
index f29fd1fa..2b77946b 100644
--- a/src/system.pas
+++ b/src/system.pas
@@ -2,6 +2,12 @@ unit system;
 
 interface
 
+const
+     ISR_RING_0 = $8E;
+     ISR_RING_1 = $AE;
+     ISR_RING_2 = $CE;
+     ISR_RING_3 = $EE;
+
 type
     //internal types
     cardinal = 0..$FFFFFFFF;