diff --git a/src/assemble.rs b/src/assemble.rs
index c229a45..3e8043e 100644
--- a/src/assemble.rs
+++ b/src/assemble.rs
@@ -77,7 +77,6 @@ pub fn assemble(code: Vec<String>, output: String) {
     println!("{}", line_split.len() - 1);
 
     append_hex(&mut output_file, instruction);
-    sleep(Duration::from_millis(1));
     inc_progress_bar();
   }
 
@@ -87,9 +86,9 @@ pub fn assemble(code: Vec<String>, output: String) {
 }
 
 fn append_hex(file: &mut File, instruction: Instruction) {
-  for (field, val) in instruction.iter() {
-    file
-      .write_all(&[*val.downcast_ref::<u8>().unwrap()])
-      .unwrap();
-  }
+  file.write_all(&[instruction.opt_code]).unwrap();
+  file.write_all(&[instruction.arg1]).unwrap();
+  file.write_all(&[instruction.arg2]).unwrap();
+  file.write_all(&[instruction.arg3]).unwrap();
+  file.write_all(&[instruction.arg4]).unwrap();
 }