TartOS is a bare-metal operating system for the RPi3, written in Zig. It is inspired by bztsrc's bare metal tutorial and draws heavily from it. If you're familiar with it already, the code in this repo should seem very familiar. The goals of this project are to:
- Achieve the same level of functionality as the bare metal tutorial
- Use Zig features to make hardware interaction nicer
- Should serve as a nice base for writing a bare metal program
Building requires the following utils (which may be installed from a package manager):
- Zig 0.11.0
- make
- llvm (for llvm-objcopy)
To start, check that Zig is correctly setup:
# This should make an ELF file under zig-out/bin
$ make appelf
$ file zig-out/bin/app
zig-out/bin/app: ELF 64-bit LSB executable, ARM aarch64, version 1 (SYSV), statically linked, with debug_info, not strippedNext, check that llvm-objcopy can create the image file, or use another solution to do so:
# This should make an image file under artifacts/ called app.img
$ make appIf you have QEMU installed, you can run the OS directly, but keep in mind that emulation is limited in features:
$ make run- Tutorial - Individual tutorials for kickstarting bare metal development on the Raspberry Pi 3.
- BCM2835 SoC Peripherals - Peripheral manual for the Broadcom SoC. Introduced in Raspberry Pi, but peripheral architecture is identical for Raspberry Pi 2/3.
- BCM2836 ARM-Local Peripherals - ARM-Local peripheral documentation. Introduced in Raspberry Pi 2 to accommodate quad-core architecture. Architecture is identical for Raspberry Pi 3.
- ARM Cortex-A53 - Documentation for the CPU core on the Raspberry Pi 3.
- ARMv8-A Architecture Registers - Summary of special registers on the ARMv8-A architecture.
- ARMv8-A Programmer's Guide - Programmers reference guide for the ARMv8-A architecture.
- ARMv8-A Address Translation Primer - Good intro to understand the MMU and required registers.
- Boot Code Examples - Example ASM boot code for the ARMv8-A architecture. Notably: the transition of exception levels.