EhlOS is a simple OS designed to be virtualized. EhlOS is buildt using C and the GNU development tools for operating systems.
The source code of most packages can be found here
Preparation
Please run this in your current terminal:
sudo apt install libgmp3-dev
sudo apt install libmpc-dev
sudo apt install libmpfr-dev
sudo apt install texinfo
sudo apt install bison
sudo apt install flex
export PREFIX="$HOME/opt/cross"
export TARGET=i686-elf
export PATH="$PREFIX/bin:$PATH"
Binutils
cd $HOME/src
mkdir build-binutils
cd build-binutils
../binutils-x.y.z/configure --target=$TARGET --prefix="$PREFIX" --with-sysroot --disable-nls --disable-werror
make
make install
GDB
../gdb.x.y.z/configure --target=$TARGET --prefix="$PREFIX" --disable-werror
make all-gdb
make install-gdb
GCC
cd $HOME/src
# The $PREFIX/bin dir _must_ be in the PATH. We did that above.
which -- $TARGET-as || echo $TARGET-as is not in the PATH
mkdir build-gcc
cd build-gcc
../gcc-x.y.z/configure --target=$TARGET --prefix="$PREFIX" --disable-nls --enable-languages=c,c++ --without-headers
make all-gcc
make all-target-libgcc
make install-gcc
make install-target-libgcc
Adding to PATH
Please add export PATH="$HOME/opt/cross/bin:$PATH" to ~/.profile.
The command used to assemble boot.s is i686-elf-as boot.s -o boot.o
This command uses the boot assembler we created earlier in How to install tools for OS work
You can compile the kernel by running i686-elf-gcc -c kernel.c -o kernel.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra
The kernel can then be linked to the bootloader by running i686-elf-gcc -T linker.ld -o ehlos.bin -ffreestanding -O2 -nostdlib boot.o kernel.o -lgcc
You can verify that ehlos.bin is multiboot compliant by moving to the src directory and running ./check-multiboot.sh
To create the ISO, run grub-mkrescue -o ehlos.iso iso from the root directory of this repo
To run a virtual version of the system, run the following command: qemu-system-i386 -cdrom ehlos.iso
IMPORTANT: QEMU must be configured to boot things from BIOS, not just UEFI