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nemu/src/device/device.cc

@@ -40,9 +40,12 @@ static void timer_sig_handler(int signum) {
   Assert(ret == 0, "Can not set timer");
 }
 
-void device_update() {} // Now an independent thread will do it.
-
 void device_update_impl() {
+    // async
+    if(device_update_flag)
+        device_update_flag = false;
+    else
+        return;
   if (update_screen_flag) {
     update_screen();
     update_screen_flag = false;
@@ -72,6 +75,8 @@ void device_update_impl() {
   }
 }
 
+void device_update() {device_update_impl();}
+
 static void device_update_thread_daemon() {
   while(true) {
     if(device_update_flag.exchange(false)) {
@@ -104,7 +109,7 @@ void init_device() {
   ret = setitimer(ITIMER_VIRTUAL, &it, NULL);
   Assert(ret == 0, "Can not set timer");
 
-  std::thread(device_update_thread_daemon).detach();
+  // std::thread(device_update_thread_daemon).detach();
 }
 #else