example code for a very minimalistic x64 BIOS bootloader providing a memory map, page table, long mode and an example c program which gets executed by it.
compile.sh to compile (requires nasm, gcc and ld)
run.sh to run in qemu (will not work on any system since the qemu executable names differ)
I still need to document this way better when i have time. If you need help, feel free to contact me tho.