The Riku Operating System is a home-made, hobby operating system for Intel x64 architectures.

It is divided into two main components :

• loader, which is the x86 bootstrap code
• kern, which is the x64 kernel code

The userland stuff, such as the components of Michiru, the software stack built on top of Riku, is composed of two parts as well :

• libc, which is the source code of rLibC, the Riku's standard library implementation
  • rlibc is deprecated, Riku now partially supports newlib 2.5.0 as a standard library.
• michiru, which contains the userland stuff code

In order to compile and run Riku, some standard development environment is required :

• x86_64-elf-gcc toolchain (mandatory)
• grub2 (grub-mkrescue to be honest, to generate the riku.iso bootable image)
• nasm (my favourite assembler)
• qemu-system-x86_64 (a virtual machine to run the kernel on is always a good thing)
• GNU make (yep)
• libtool (for KConfig)
• Tons of coffee (don't tell me you don't need this, I won't believe you)

First you need to compile userland.

You can compile rLibC by entering the "libc" directory and running "make".

The userland can then be compiled by entering the "michiru" directory and running make in every sub-directory. You can also run the ./make_world.sh script in the "michiru" directory instead.

Clone riku-binutils, riku-gcc and riku-sysroot repositories.

• First follow the instructions in the riku-sysroot repository to compile newlib. Use /usr/x86_64-riku as sysroot.
• Then install riku-binutils.
• Finally, install riku-gcc.

Your cross-compilation toolchain should be installed in /usr/x86_64-riku. You can compile by running, for instance, /usr/x86_64-riku/bin/x86_64-riku-gcc main.c -o main.

Compile (only once) KConfig by running ./bootstrap, ./configure and make in the kconfig/ subfolder.

Configure the kernel by running make menuconfig and make config.

Compiling the kernel then should be as easy as running "make all".

Create a hard drive image by running make img (which is a shortcut to qemu-img create -f raw 4G). This image can be manipulated by mounting it as a loopback device on Linux hosts, by running make mount (or make umount to unmount it).

Run Riku in QEMU by running make run, or make debug to run QEMU alongside GDB for debugging.