diff --git a/src/emulator/instructions/arithmetic.rs b/src/emulator/instructions/arithmetic.rs
index 6af8f5d..8b06d44 100644
--- a/src/emulator/instructions/arithmetic.rs
+++ b/src/emulator/instructions/arithmetic.rs
@@ -48,8 +48,8 @@ pub fn dad(register: Register, state: &mut EmulatorState) {
         _ => panic!("Cannot perform DAD on register {:?}", register),
     };
 
-    let result = num as u32 + u16::from_le_bytes([state.l, state.h]) as u32;
-    state.cc.c = result > 0xffff;
+    let (result, overflow) = num.overflowing_add(u16::from_le_bytes([state.l, state.h]));
+    state.cc.c = overflow;
     state.h = (result >> 8) as u8;
     state.l = result as u8;
 }