rust-raspberrypi-OS-tutorials/03_hacky_hello_world/README.md

Tutorial 03 - Hacky Hello World

tl;dr

Introducing global print!() macros to enable "printf debugging" at the earliest; To keep tutorial length reasonable, printing functions for now "abuse" a QEMU property that lets us use the RPi's UART without setting it up properly; Using the real hardware UART is enabled step-by-step in following tutorials.

Notable additions

• src/console.rs introduces interface Traits for console commands.
• src/bsp/rpi.rs implements the interface for QEMU's emulated UART.
• The panic handler makes use of the new print!() to display user error messages.

Test it

QEMU is no longer running in assembly mode. It will from now on show the output of the console.

$ make qemu
[...]
Hello from Rust!

Kernel panic: Stopping here.

Diff to previous