No debugging unless the game is running

src/window/gdb.rs

@@ -3,7 +3,7 @@ use winit::event_loop::EventLoopProxy;
 
 use crate::{
     app::UserEvent,
-    emulator::{EmulatorClient, SimId},
+    emulator::{EmulatorClient, SimId, SimState},
     gdbserver::{GdbServer, GdbServerStatus},
 };
 
@@ -11,6 +11,7 @@ use super::AppWindow;
 
 pub struct GdbServerWindow {
     sim_id: SimId,
+    client: EmulatorClient,
     port_str: String,
     connected: bool,
     quit_on_disconnect: bool,
@@ -22,6 +23,7 @@ impl GdbServerWindow {
     pub fn new(sim_id: SimId, client: EmulatorClient, proxy: EventLoopProxy<UserEvent>) -> Self {
         Self {
             sim_id,
+            client: client.clone(),
             port_str: (8080 + sim_id.to_index()).to_string(),
             connected: false,
             quit_on_disconnect: false,
@@ -78,7 +80,9 @@ impl AppWindow for GdbServerWindow {
                     self.connected = false;
                 }
                 let start_button = Button::new("Start");
-                if ui.add_enabled(port_num.is_some(), start_button).clicked() {
+                let can_start =
+                    port_num.is_some() && self.client.sim_state(self.sim_id) == SimState::Ready;
+                if ui.add_enabled(can_start, start_button).clicked() {
                     let port = port_num.unwrap();
                     self.server.start(port);
                     self.connected = true;