Assert CPU paused when switching disk images

src/disk.c

@@ -740,6 +740,10 @@ void disk6_init(void) {
 
 const char *disk6_eject(int drive) {
 
+#if !TESTING
+    assert(cpu_isPaused() && "CPU must be paused for disk ejection");
+#endif
+
     const char *err = NULL;
 
     if (disk6.disk[drive].fd > 0) {
@@ -799,6 +803,10 @@ const char *disk6_eject(int drive) {
 
 const char *disk6_insert(int drive, const char * const raw_file_name, int readonly) {
 
+#if !TESTING
+    assert(cpu_isPaused() && "CPU must be paused for disk insertion");
+#endif
+
     disk6_eject(drive);
 
     disk6.disk[drive].file_name = STRDUP(raw_file_name);

src/misc.c

@@ -298,8 +298,6 @@ void emulator_start(void) {
 
 void emulator_shutdown(void) {
     emulatorShuttingDown = true;
-    disk6_eject(0);
-    disk6_eject(1);
     video_shutdown();
     prefs_shutdown();
     timing_stopCPU();

src/timing.c

@@ -509,6 +509,9 @@ static void *cpu_thread(void *dummyptr) {
     cpu_thread_id = 0;
     cpu_pause();
 
+    disk6_eject(0);
+    disk6_eject(1);
+
     return NULL;
 }