Hello. Here is an small educational segmented kernel.
https://github.com/MaoKo/Segmented_Kernel
There is a kernel space and user space. In the user space, I implement a small shell.
You can switch between different "tty" with ctrl-b (backward) and ctrl-n (next).
Here I use TSS to fully exploit the isolation of the different tty with different address space (ldt) as well.
I use call gate for system call. I reserve empty slot in the GDT and LDTs to allow the kernel to be able to load dynamically without changing the gdt base.
If you have any recommendation, please tell me .

(Very nice kernel work, btw!)

Ha thanks you . Currently working on APIC/SMP stuff. Very interesting.

I like how your leveraging fasm to model the processor features. Makes it very readable and flexible, imho.

Yes thanks. I try to mimic the convention used in the old day of IAPX. At the time ASM286 was in use and I guess very readable code was primordial between team.
This is a sample of code found in the IAPX man:

Btw a very good man ;D