Here is a small novelty I made over the past few days. It's a retro TV effect that works when you switch off your calculator.

Here's a Youtube video of it in action:



Unfortunately, at the moment it only works on the CX model running OS 3.1.

I'm still looking around for a better hooking address but apart from that it works okay-ish. More details in the README if anyone is interested in improving it.

Source and downloads

awesome, great job

how, very nice effect , i love it

That looks pretty cool.

Nice
You may be interested by Ndless's new builtin function nl_set_resident() (on the SVN trunk, to yet upload as a release): http://hackspire.unsads.com/wiki/index.php/Ndless_features_and_limitations#Resident_programs

I'm planning to extend the support for hooks by Ndless, any ideas are welcome. It would include:
 - Hook installation detection (something similar to your is_already_hooked())
 - Standard hook points, to avoid programs having to include themselves the hook adresses (switch on/switch off would be one of them)
 - Multiple hooks at this point
 - Hook uninstallation

Thanks. I did have a look at it but it seems that the calculator crashes when it is called.

Otherwise, I'm very pleased to see a lot of new features in the newer Ndless releases!

On the hook points, I'm curious as to your method to finding hook addresses. My method was to create a custom emulator that enters debug mode when a certain register is written to (i.e. to turn off the screen), make a memory dump and backtrace it using IDA. It is hard to tell however, where is the best place to install the hook  - most of it comes down to trial and error.

Do you have a better way?

This is in C, right? How did you edit memory values to add the hook?

The source code is included if you want to poke around with it. However, I believe the hooking macros are all defined in common.h in the Ndless SDK. You can check out a copy of Ndless source code and look how it's implemented.

Make it quit in a diamond shape instead of just a line.