OSDev.org

Is Assemply code really needed for a OS?

For things like interrupt handler stubs and such, you really can't go without it unless you're using compiler specific methods.

Alrighty

Yes. There is no other language that can be used to call LIDT, LGDT, and other related functions. And these calls must be made to have a functioning operating system. However, these calls can be made from inline assembly within C files (at least, with a certain amount of messing around to get it play nice). A better question would be, do I really need to write assembly files (.asm) or can it all be put in other source files (.c, .cpp, etc)?