diff --git a/riscv_config/constants.py b/riscv_config/constants.py
index 8e94fd2..c98e6e4 100644
--- a/riscv_config/constants.py
+++ b/riscv_config/constants.py
@@ -33,7 +33,7 @@
         "Zpn", "Zpsf"
 ] + Zve_extensions + Zvl_extensions
 
-S_extensions = ['Smrnmi','Svnapot','Svadu', 'Sdext', 'Ssqosid']
+S_extensions = ['Smrnmi','Svnapot','Svadu', 'Sdext', 'Ssqosid', 'Smstateen']
 
 sub_extensions = Z_extensions + S_extensions