boredos_mirror/docs/build/toolchain.md
2026-05-11 19:54:00 +03:00

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# Build Toolchain
BoredOS is built cross-compiled from a host system (such as macOS or Linux) to target the generic `x86_64-elf` platform.
## Prerequisites
To build BoredOS, you need the following tools:
1. **x86_64 ELF GCC Cross-Compiler**:
- `x86_64-elf-gcc`: The C compiler targeting the freestanding overarching ELF environment.
- `x86_64-elf-ld`: The linker to combine object files into the final `boredos.elf` kernel and userland binaries.
2. **NASM**:
- Required to compile the `.asm` files in `src/arch/` and `src/userland/crt0.asm`. It formats the output as `elf64` objects to be linked alongside the C code.
3. **xorriso**:
- A specialized tool to create ISO 9660 filesystem images.
- *Why?* `xorriso` packages the compiled kernel, Limine bootloader, and asset files (fonts, images, userland binaries) into the final bootable `boredos.iso` CD-ROM image.
4. **QEMU** (Optional but highly recommended for testing):
- `qemu-system-x86_64` is used to virtualize the OS for testing or to mess around.
## WSL2 Unconfigured support
BoredOS supports WSL2 but unconfigured for x86-64-elf-ld, to use it you can run "make unsafe" but you need to install the following packages:
sudo apt install build-essential nasm xorriso qemu-system-x86 gcc-x86-64-linux-gnu
This is implemented as because downloading that package isn't as easy as doing "sudo apt install x86_64_elf or sum""
It should also properly build TCC files
## Building the Cross-Compiler on Linux
### Availability Issue
On most Linux distributions, the `x86_64-elf-gcc` cross-compiler binary is **not pre-packaged** in standard repositories. The only notable exception is **Arch Linux** and Arch-based distributions (Manjaro, EndeavourOS, etc.), where it can be installed via `pacman`:
```bash
pacman -S x86_64-elf-gcc x86_64-elf-binutils
```
For all other Linux distributions (Debian, Ubuntu, Fedora, openSUSE, etc.), you **must build the cross-compiler from source**.
### Building from Source
To build the x86_64-ELF GCC cross-compiler:
1. **Download prerequisites**:
- GNU Binutils source
- GCC source
2. **Configure and build Binutils**:
```bash
../binutils-*/configure --target=x86_64-elf --prefix=/usr/local/cross
make && make install
```
3. **Configure and build GCC**:
```bash
../gcc-*/configure --target=x86_64-elf --prefix=/usr/local/cross \
--without-headers --enable-languages=c
make all-gcc && make install-gcc
```
4. **Add to PATH**:
```bash
export PATH="/usr/local/cross/bin:$PATH"
```
Verify the installation:
```bash
x86_64-elf-gcc --version
```
> **Note**: Building the cross-compiler can take 20-30 minutes depending on system performance. This is a one-time setup cost.