diff --git a/src/main.rs b/src/main.rs
index cf576fb..9edc3c3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -171,7 +171,14 @@ fn main() -> Result<(), anyhow::Error> {
                                 let pc = state.cpu.pc();
                                 out += &disas_fmt(&mut state.cpu, pc, &state.symbol_tables).0;
                             }
-                            state.cpu.step();
+                            match state.cpu.step() {
+                                Ok(_) => (),
+                                Err(bus_error) => {
+                                    println!("{bus_error}");
+                                    state.cpu.stopped=true;
+                                    break;
+                                }
+                            }
                         }
                         if args.get_flag("print_regs") {
                             out += &format!("{}\n", state.cpu);
@@ -214,7 +221,14 @@ fn main() -> Result<(), anyhow::Error> {
                                         let pc = state.cpu.pc();
                                         out += &disas_fmt(&mut state.cpu, pc, &state.symbol_tables).0;
                                     }
-                                    state.cpu.step();
+                                    match state.cpu.step() {
+                                        Ok(_) => (),
+                                        Err(bus_error) => {
+                                            println!("{bus_error}");
+                                            state.cpu.stopped=true;
+                                            break;
+                                        }
+                                    }
                                 }
                                 out += &format!("{}\n", state.cpu);
                                 let pc = state.cpu.pc();