A (very early-stage) 64-bit OS, for fun.
Comprised for now almost exclusively of a bootloader, which:
- Sets up the MBR
- Sets up a basic flat-model GDT
- Elevates from real mode to protected mode
- Sets up identity paging
- Elevates from protected mode to long mode
- Calls the
_start()function in the kernel
- Writing a Simple Operating System — from Scratch: although it doesn't cover long mode, it has a lot of great information on computer architecture and covers well the 16-bit/32-bit parts of the bootloader.
- Poncho's OS dev series: great to actually see someone writing the code from scratch while explaining.
- 64-bit OS tutorial: the code is divided in chapters that incrementally build the bootloader, and goes beyond it to the kernel, with a much simpler build implementation than every other ressource I could find, using LLVM instead of cross-compiling GCC and writing a linker script.
- OSDev wiki: tentacular and full of extensive articles about very specific topics that help getting those bits of info you can't find anywhere else.