diff --git a/src/emulator/instructions/arithmetic.rs b/src/emulator/instructions/arithmetic.rs
index d8dc7d6..e0eaf4a 100644
--- a/src/emulator/instructions/arithmetic.rs
+++ b/src/emulator/instructions/arithmetic.rs
@@ -13,3 +13,9 @@ pub fn add(register: Register, state: &mut EmulatorState) {
     set_cc(state, result);
     state.a = (result & 0xff) as u8;
 }
+
+pub fn adi(byte: u8, state: &mut EmulatorState) {
+    let result = state.a as u16 + byte as u16;
+    set_cc(state, result);
+    state.a = result as u8;
+}
diff --git a/src/emulator/main.rs b/src/emulator/main.rs
index 75da473..b324297 100644
--- a/src/emulator/main.rs
+++ b/src/emulator/main.rs
@@ -1,5 +1,5 @@
 use std::{fs, env};
-use instructions::arithmetic::add;
+use instructions::arithmetic;
 
 mod instructions;
 
@@ -34,6 +34,7 @@ pub struct ConditionCodes {
     ac: bool,
 }
 
+#[derive(PartialEq)]
 pub enum Register {
     B, C, D, E,
     H, L, M, A,
@@ -120,9 +121,10 @@ fn tick(state: &mut EmulatorState) {
     };
 
     match instruction {
-        0x0  => {} // NOP
-        0x80..=0x87 => add(register_from_num(instruction & 0xf), state), // ADD
-        _ => not_implemented(state),
+        0x00        => {} // NOP
+        0x80..=0x87 => arithmetic::add(register_from_num(instruction & 0xf), state), // ADD
+        0xc6        => arithmetic::adi(next_byte(), state), // ADI
+        _           => not_implemented(state),
     }
 
     state.pc += 1;