View source for TestMode

{{syscall
| name = TestMode
| header = fxcg/system.h
| index = 0x0EA7
| signature = void TestMode(int vram)
| synopsis = Opens an hidden OS menu, the Test Mode, where some OS functionality can be tested and a look into the OS internals can be taken.
| parameters = * '''vram''' - Whether to restore the previous VRAM when exiting the Test Mode.
}}
== Functionality ==
Functionality includes:
* [[File_System#Main_Memory|MCS]] browser ("Valiable Manager" (''sic''));
* Memory viewer (but not editor) (F4 and F5 in the "Valiable Manager");
* Font and character code checking, including for "GB codes" (Chinese codes plus alternatives to some Latin ones), probably a reference to the GB 18030 character set;
* [[Setup]] visualizer (opens a menu like the ones seen when pressing Shift+Menu in different built-in apps, but showing all possible settings);
* [[GetFKeyPtr|Function key bitmap]] visualizer;
* Ability to set function key label color and screen frame color;
* [[File_System#Storage_Memory|Fugue FAT File System]] and [[:Category:Syscalls:Bfile|Bfile]] testing functions;
* Memory usage visualizer for the [[heap]], the main process [[stack]] and the child stack;
* Disabled function to dump flash data over USB.

Some of this functionality is present and extended in Simon Lothar's Insight add-in.

== How to access ==
Besides calling the corresponding syscall (something the Insight add-in lets one do), there's also the key combination used for entering the diagnostics mode: on the "Delete all data" screen (which doesn't delete anything), one can quickly type 5963 to open the Test Mode. So the key combination becomes as follows:

[OPTN]+[EXP]+[AC/ON], then quickly type 5963.

More key combinations can be found [[Secret_Key_Combinations|here]].