The very first step to working on SnowflakeOS again was to setup the environment: download the sources and the tools to build them. Here’s a quick rundown.

Gathering the dependencies

Packages

I run Archlinux, so if you want to follow along you’ll have to grab the corresponding packages for your distro.
After cloning the repository, I installed the dependencies listed in the README:

• libisoburn
• mtools
• qemu
• grub

Cross-compiler

Things here get a bit hairier, but basically all that’s needed is explained on OSDev’s wiki on cross-compilation. Still, I’ll detail the process.

• export the following environnement variables:

  export PREFIX="$HOME/opt/cross"
  export TARGET=i686-elf
  export PATH="$PREFIX/bin:$PATH"
  

• download the latest versions of binutils and gcc
• build them out-of-tree, with a clean outer directory:

  ./binutils-x.y.z/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
  make
  make install
  

  and in another, clean directory above gcc-x.y.z,

  ./gcc-x.y.z/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers
  make all-gcc
  make all-target-libgcc
  make install-gcc
  make install-target-libgcc
  

  I recommend running make with at least -j2, otherwise compiling gcc might take long.

• Add ~/opt/cross/bin to your path and you’re set!

Compile & Run

Updated on 19/12/19 to match the new buildsystem

All that’s left to do is compiling the kernel and running it. You can do both in one command with

make qemu

I won’t detail the build system too much; it was heavily inspired by the wiki’s and that of other hobby OSes.
The gist of it is that submakefiles are called first to copy their headers to an LFS-looking environment (the sysroot directory), and then in a second pass to build their respective projects and copy binaries, while respecting the dependencies listed in the root Makefile.