diff --git a/src/vm/instruction.rs b/src/vm/instruction.rs
index 316dc5a..63e7d28 100644
--- a/src/vm/instruction.rs
+++ b/src/vm/instruction.rs
@@ -4,6 +4,7 @@
 
 use crate::vm::VM;
 
+#[derive(Debug)]
 enum OpCode {
     // branch
     BR = 0,
@@ -44,23 +45,23 @@ enum OpCode {
 fn get_opcode(instruction: u16) -> OpCode {
     // the opcode is stored in the left 4 bits
     match instruction >> 12 {
-         0 => OpCode::BR,
-         1 => OpCode::ADD,
-         2 => OpCode::LD,
-         3 => OpCode::ST,
-         4 => OpCode::JSR,
-         5 => OpCode::AND,
-         6 => OpCode::LDR,
-         7 => OpCode::STR,
-         8 => OpCode::RTI,
-         9 => OpCode::NOT,
+        0 => OpCode::BR,
+        1 => OpCode::ADD,
+        2 => OpCode::LD,
+        3 => OpCode::ST,
+        4 => OpCode::JSR,
+        5 => OpCode::AND,
+        6 => OpCode::LDR,
+        7 => OpCode::STR,
+        8 => OpCode::RTI,
+        9 => OpCode::NOT,
         10 => OpCode::LDI,
         11 => OpCode::STI,
         12 => OpCode::JMP,
         13 => OpCode::RES,
         14 => OpCode::LEA,
         15 => OpCode::TRAP,
-         _ => OpCode::NOOP,
+        _ => OpCode::NOOP,
     }
 }
 
@@ -69,21 +70,21 @@ pub fn execute_instruction(vm: &mut VM) {
     let opcode = get_opcode(instruction);
 
     match opcode {
-        OpCode::BR   => no_op(vm),
-        OpCode::ADD  => no_op(vm),
-        OpCode::LD   => no_op(vm),
-        OpCode::ST   => no_op(vm),
-        OpCode::JSR  => no_op(vm),
-        OpCode::AND  => no_op(vm),
-        OpCode::LDR  => no_op(vm),
-        OpCode::STR  => no_op(vm),
-        OpCode::RTI  => no_op(vm),
-        OpCode::NOT  => no_op(vm),
-        OpCode::LDI  => no_op(vm),
-        OpCode::STI  => no_op(vm),
-        OpCode::JMP  => no_op(vm),
-        OpCode::RES  => no_op(vm),
-        OpCode::LEA  => no_op(vm),
+        OpCode::BR => no_op(vm),
+        OpCode::ADD => no_op(vm),
+        OpCode::LD => no_op(vm),
+        OpCode::ST => no_op(vm),
+        OpCode::JSR => no_op(vm),
+        OpCode::AND => no_op(vm),
+        OpCode::LDR => no_op(vm),
+        OpCode::STR => no_op(vm),
+        OpCode::RTI => no_op(vm),
+        OpCode::NOT => no_op(vm),
+        OpCode::LDI => no_op(vm),
+        OpCode::STI => no_op(vm),
+        OpCode::JMP => no_op(vm),
+        OpCode::RES => no_op(vm),
+        OpCode::LEA => no_op(vm),
         OpCode::TRAP => no_op(vm),
         OpCode::NOOP => no_op(vm),
     }