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
+   An add-in that returns from its main() function automatically exits to the
-   using OS-dependent settings, it cannot be started again unless another
+   OS' main menu. However, when this happens the OS does not allow the add-in
-   application is launched first.
+   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
+   This function enables a gint trick where after main() returns the add-in
-   of exiting. This can give a proper illusion of restarting if used correctly.
+   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
+static int start2(int isappli, int optnum)
-   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)
 {
 	/* 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
@@ -179,8 +175,6 @@ 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)) {
@@ -191,10 +185,6 @@ int start(int isappli, int optnum)
 		callarray(&bdtors, &edtors);
 	}
 
-		if(!gint_restart) break;
-		gint_osmenu();
-	}
-
 	/* Before leaving the application, we need to clean everything we
 	   changed to hardware settings and peripheral modules. The OS is bound
 	   to be confused (and hang, or crash, or any other kind of giving up)
@@ -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)
 {