kernel: make gint_setrestart() reset everything

include/gint/gint.h

@@ -59,14 +59,23 @@ void gint_world_sync(void);
    call to getkey(), but can also be called manually. */
 void gint_osmenu(void);
 
+/* gint_osmenu_native(): Like gint_osmenu() without the world switch
+   This is a replacement for gint_osmenu() which can be used when the current
+   kernel is already the native OS kernel. */
+void gint_osmenu_native(void);
+
 /* gint_setrestart(): Set whether to restart the add-in after exiting
 
-   An add-in that reaches the end of its code exits. On the calculator, except
-   using OS-dependent settings, it cannot be started again unless another
-   application is launched first.
+   An add-in that returns from its main() function automatically exits to the
+   OS' main menu. However, when this happens the OS does not allow the add-in
+   to be restarted unless another add-in is launched first. (This is because
+   the OS tries to *resume* the current add-in, which then proceeds to exit
+   again immediately.)
 
-   This setting allows the add-in to restart by calling gint_osmenu() instead
-   of exiting. This can give a proper illusion of restarting if used correctly.
+   This function enables a gint trick where after main() returns the add-in
+   will invoke the main menu with gint_osmenu() rather than exiting. If the
+   add-in is selected again, gint will jump back to the entry point, creating
+   the illusion that the add-in exited and was then restarted.
 
    @restart  0 to exit, 1 to restart by using gint_osmenu() */
 void gint_setrestart(int restart);

src/kernel/osmenu.c

@@ -23,7 +23,7 @@ static void __osmenu_handler(void)
 	__Timer_Deinstall(__osmenu_id);
 }
 
-static void __osmenu(void)
+void gint_osmenu_native(void)
 {
 	__ClearKeyBuffer();
 
@@ -70,5 +70,5 @@ static void __osmenu(void)
 /* gint_osmenu() - switch out of gint and call the calculator's main menu */
 void gint_osmenu(void)
 {
-	gint_world_switch(GINT_CALL(__osmenu));
+	gint_world_switch(GINT_CALL(gint_osmenu_native));
 }

src/kernel/start.c

@@ -94,11 +94,7 @@ static void callarray(void (**f)(void), void (**l)(void))
 	while(f < l) (*(*f++))();
 }
 
-/* start(): Where it all starts
-   Returns a status code. Invoking main menu is better than returning, see
-   gint_setrestart() for that. */
-GSECTION(".text.entry")
-int start(int isappli, int optnum)
+static int start2(int isappli, int optnum)
 {
 	/* We are currently in a dynamic userspace mapping of an add-in run
 	   from the storage memory. We are running in privileged mode with one
@@ -179,20 +175,14 @@ int start(int isappli, int optnum)
 	   hosted user application, which has its own constructors and
 	   destructors to work with. */
 
-	while(1)
-	{
-		/* Here, we use exit() to allow the standard library to do
-		   what it wants in exit() after main() finishes executing */
-		if(!setjmp(gint_exitbuf)) {
-			callarray(&bctors, &ectors);
-			exit(main(isappli, optnum));
-		}
-		else {
-			callarray(&bdtors, &edtors);
-		}
-
-		if(!gint_restart) break;
-		gint_osmenu();
+	/* Here, we use exit() to allow the standard library to do
+	   what it wants in exit() after main() finishes executing */
+	if(!setjmp(gint_exitbuf)) {
+		callarray(&bctors, &ectors);
+		exit(main(isappli, optnum));
+	}
+	else {
+		callarray(&bdtors, &edtors);
 	}
 
 	/* Before leaving the application, we need to clean everything we
@@ -206,6 +196,18 @@ int start(int isappli, int optnum)
 	return gint_exitcode;
 }
 
+GSECTION(".text.entry")
+int start(int isappli, int optnum)
+{
+	int rc;
+	while(1) {
+		rc = start2(isappli, optnum);
+		if(!gint_restart) break;
+		gint_osmenu_native();
+	}
+	return rc;
+}
+
 /* Standard _Exit, used by the fxlibc exit() to leave control */
 void _Exit(int rc)
 {