# ByOS Toy operative system for x86 coded in Assembly and C.

How is this working?

boot/boot.asm -> Bootloader

boot/kernel.c -> Kernel

boot/16/ -> Libraries and functions for 16 bits Real Mode.

boot/32/ -> Libraries and functions for 32 bits Protected Mode.

boot/globals/ -> Libraries to switch from 16 bits Real Mode to 32 bits Protected Mode.

The boot.bin (assembled from boot/boot.asm) file loads kernel.bin (compiled from boot/kernel.c) into memory, then jumps to it and starts executing code. This two files are joined together into os.img. The folders boot/16/ and boot/32/ contain some files not used in the bootloader, but they can be used in other projects. The folder drivers/ hasn't been used yet.

Linux

For Linux users, is just needed to have NASM (https://www.nasm.us/) and QEMU (just for emulation, not obligatory) (https://www.qemu.org/); since all coreutils and binutils are already downloaded.

Windows

Step 1º: Change to Linux

Step 2º: In case step 1 didn't work, try again :)

Good luck

How to build?

Run make build to create the os.img file, then make clean to clean not-needed bin files, and then make run to run os.img via qemu-system-i386. You can just run makeor make all, which is equivalent to make build, make clean and make run, in that order.

ATENTION: This booloader will only compile and run on computers having x86 architecture. If you try it on other architecture (e.g ARM), the result is unexpected, at least from the part of the kernel compiling.

License

All the code is licensed under the GNU Public License v3.0 https://www.gnu.org/licenses/gpl-3.0.html