I've been interested for a while now in learning about Bare Metal OSes and found this wonderful GitHub by Eugene Obrezkov that gives a basic text shell that works in QEMU. I could not get it to run in VirtualBox though.
https://github.com/ghaiklor/ghaiklor-os-gcc
I want to extend upon it and add a simple boot up splash screen that runs in say 1024x768x24bpp. What is the standard method of doing so on modern computers?
This question though is like asking a few questions. :(
Should I be reading about VBE3? I have a document that I'm reading here:
https://pdos.csail.mit.edu/6.828/2011/readings/hardware/vbe3.pdf
I also took a look at this SE, which says not to use VBE3, which covers a little about graphics mode in UEFI, is it applicable though to a Bare Metal OS that I would test in QEMU or VirtualBox?
Assembly - How to set graphics mode in UEFI (No VGA, No BIOS, Nothing deprecated)
If the answer based on Eugene's initial source is either to use VBE3 or UEFI, which mode do I need to be in among real, protected, or long? This is what I found about switching between modes:
https://www.codeproject.com/Articles/45788/The-Real-Protected-Long-mode-assembly-tutorial-for
Windows uses drivers that directly access the graphics card. However, this assumes that you have different drivers for different graphics cards. Without special drivers for a certain graphics card, the maximum is 640x480x16.
More recent Linux versions can either use special drivers or VESA BIOS. For a long time VESA BIOS was the default.