writing this while following the post from Philipp Opperman
As we won't use the standar library we have to create a Panic function to deal with possible panics in our program.
We don't have as well a Runtime to rely on, so we create a new start declaring the lang item "start" on the function.
It must have the same name and an additional #[no_mangle]
to guarantee the
BIOS know which function to call when starting the OS