YAOS

Yet Another Operating System

Getting Started

1. apt install nasm g++ xorriso qemu-system-i386 for compilation
2. apt install clang clang-format for auto formatting with Visual Studio Code
3. make

Building a Cross Compiler

To compile XOS, a cross compiler is needed (see Why cross compiler are necessary). The complete article can be found on osdev.org.

Alternatively, you can view a list of pre-built cross compilers at https://wiki.osdev.org/GCC_Cross-Compiler#Prebuilt_Toolchains (not tested).

Preparation

sudo apt install bison make texinfo libgmp3-dev libmpfr-dev libmpc-dev 

mkdir -p $HOME/opt/cross/{bin,build,src}

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

cd $HOME/opt/cross

Building Binutils

Binutils can be downloaded at https://ftp.gnu.org/gnu/binutils/binutils-2.39.tar.gz, or you can browse all available versions at https://ftp.gnu.org/gnu/binutils.

The below commands compile binutils (assembler, disassembler, and various other useful stuff), handling code in the format specified by $TARGET.

tar xf ~/Downloads/binutils-2.39.tar.gz -C $PREFIX/src

mkdir -p $PREFIX/build/binutils-2.39
cd $PREFIX/build/binutils-2.39

$PREFIX/src/binutils-2.39/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
make
make install

The above process will take about 2 - 3 minutes.

Building GCC

GCC can be downloaded at https://ftp.gnu.org/gnu/gcc/gcc-9.4.0/gcc-9.4.0.tar.gz, or you can browse all available versions at https://ftp.gnu.org/gnu/gcc/.

tar xf ~/Downloads/gcc-9.4.0.tar.gz -C $PREFIX/src

mkdir -p $PREFIX/build/gcc-9.4.0
cd $PREFIX/build/gcc-9.4.0
 
# The $PREFIX/bin dir must be in PATH. We did that above.
which -- $TARGET-as || echo "$TARGET-as is not in PATH"

$PREFIX/src/gcc-9.4.0/configure --target=$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

The above process will take about 20 - 25 minutes.

To be able to use the newly compiled gcc globally, add export PATH=$PATH:$HOME/opt/cross/bin to your .bashrc file.