diff --git a/src/system.pas b/src/system.pas
index 56d1ca37..25eeeae0 100644
--- a/src/system.pas
+++ b/src/system.pas
@@ -62,6 +62,8 @@ type
     UBit6 = 0..(1 shl 6) - 1;
     UBit7 = 0..(1 shl 7) - 1;
     UBit20 = 0..(1 shl 20) - 1;
+    UBit28 = 0..(1 shl 28) - 1;
+    UBit30 = 0..(1 shl 30) - 1;
 
 implementation