Make state print when just running dependent on a flag

src/main.rs

@@ -65,6 +65,9 @@ struct Args {
     /// Just run the CPU instad of starting a REPL
     #[clap(short, long)]
     run: bool,
+    /// If not using a REPL, print the state of the CPU on halt
+    #[clap(short, long, requires("run"))]
+    print_state: bool,
 }
 
 fn main() -> Result<(), anyhow::Error> {
@@ -91,7 +94,9 @@ fn main() -> Result<(), anyhow::Error> {
         while !state.cpu.stopped {
             state.cpu.step();
         }
+        if args.print_state {
             println!("CPU stopped at PC {:#x}\n{}", state.cpu.pc(), state.cpu);
+        }
         return Ok(());
     }
     Repl::<_, anyhow::Error>::new(state)