Red Screen of Death

Check it out!

That beautiful red screen is brought to you by the NedOS boot loader, and the NedOS kernel (which is currently just a rep stosq and an infinite loop).

I was able to fit all the boot loader functionality into one 512 B sector.

It has to:

1. Retrieve the memory map from the BIOS
2. Enable A20
3. Get a list of video modes, pick one, and set it
4. Transition the system into 64 bit paged mode

The memory map code is kind of a hog. Together with the logic for picking a video mode, the boot loader is nearly 500 B. That is after a lot of effort to minimize code size.

That is too big for a harddrive boot sector (which has 64 B of partition tables and a 2 B signature). I have a version where I strip out all the error checking, that brings the size of the memory map code down significantly. Still, it is currently 433 B - leaving about 10 B to actually load something. Not enough to walk the partition table and figure out on its own what to load. I will have to load something from a hard coded location.

I'd like to be able to draw a text window, and put some text in it...