diff --git a/src/asm.rs b/src/asm.rs
index 14ab476..f9e3836 100644
--- a/src/asm.rs
+++ b/src/asm.rs
@@ -16,9 +16,5 @@ macro_rules! instruction {
 
 
 /// Priviledged ISA Instructions
-instruction!(ecall, "ecall");
 instruction!(ebreak, "ebreak");
-instruction!(uret, "uret");
-instruction!(sret, "sret");
-instruction!(mret, "mret");
 instruction!(wfi, "wfi");