Toolchain
What NULLos is built with today – until it builds itself.
What you need
| What | What for | Version¹ |
|---|
| Apple clang (Xcode / Command Line Tools) | Build the tools for the Mac (make host), the compiler cc and the libc, GNU make | 21.0.0, make 3.81 |
llvm (Homebrew) | clang for the kernel (ELF) and bootloader (PE/UEFI) | 23.1.4 |
lld | ld.lld (kernel, programs for NULLos), lld-link (bootloader) | 23.1.4 |
qemu | Run NULLos; brings the UEFI firmware along (edk2/OVMF, edk2-x86_64-code.fd) | 11.1.2 |
coreutils | timeout for the boot test make check | 9.12 |
| Rosetta 2 | Run cc's x86_64 test programs on the ARM Mac | – |
bash 5 (Homebrew) | Cross-check for the shell tests (without it: stored results) | 5.3.20 |
python3 | Abgleich (status of all tools), checksum in the boot test | 3.15.2 |
mtools | FAT32 for the download images and the disk boot test (mformat, mcopy) – until fs takes over | 4.0.49 |
xorriso | the live ISO | 1.5.8 |
nasm | is in the install list, not used anywhere yet | 3.02 |
¹ As installed on Max's Mac (macOS 27.0.1, Apple Silicon), checked with brew info and
--version on 28.10.2026. Other versions probably work too – only these are tested.
Fresh Mac – from zero to prompt
xcode-select --install # Apple clang, make, git
softwareupdate --install-rosetta # for the cc tests
# install Homebrew from brew.sh, then:
brew install llvm lld qemu nasm mtools xorriso coreutils bash
git clone … nullos && cd nullos # the repo is still private
make nullos-tools && make run
The paths are at the top of the Makefile (LLVM, LLD, QEMU,
OVMF) and can be overridden, e.g. make run LLVM=/pfad/zu/llvm/bin, if Homebrew lives somewhere else.
All make targets
| Target | What |
|---|
make nullos-tools | tools against the NULLos libc, end up in /bin |
make os | bootloader + kernel + init.img, boot partition in the build folder |
make run | build + start in QEMU (window + serial console in the terminal) |
make check | boot without a window, type commands, check the answers |
make host | all tools for the Mac |
make test | all tool tests |
make clean | delete the build folder |
make -C cc … | test stage2 stage3 tools as-cmp kernel test-arm64 stage3-arm64 test-qemu-arm64 test-qemu-riscv64 fuzz test-clang check clean |
make -C libc … | tools test-tools, with TARGET=nullos for NULLos |
Later: only our own tools
Our own compiler cc has a built-in assembler and ELF linker and already builds all of NULLos by itself –
kernel, libc, 280 tools (make -C cc kernel). It even runs on NULLos and compiles itself there.
Only archives (.a) are still written by llvm-ar. Our own mk already understands the Makefile
(mk -n host = make -n host). Goal: NULLos builds itself on NULLos. coming soon