diff --git a/src/instruction.rs b/src/instruction.rs
index 2b60044..b8c9eac 100644
--- a/src/instruction.rs
+++ b/src/instruction.rs
@@ -2,7 +2,9 @@
 
 mod opcode;
 
-use std::fmt::{self, Display, Formatter};
+use alloc::format;
+use alloc::string::String;
+use core::fmt::{self, Display, Formatter};
 
 /// Instruction
 #[derive(Debug)]
diff --git a/src/lib.rs b/src/lib.rs
index cfe71c8..e2946c5 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,6 +22,8 @@
 //! // --output--
 //! // addi t0, t0, -276
 //! ```
+#![cfg_attr(not(test), no_std)]
+extern crate alloc;
 
 pub mod decode;
 pub mod instruction;