More traits

We derived the Debug trait. It would be useful to implement a few more traits too.

use core::fmt::{self, Write};

impl Write for Uart {
    fn write_str(&mut self, s: &str) -> fmt::Result {
        for c in s.as_bytes() {

// SAFETY: `Uart` just contains a pointer to device memory, which can be
// accessed from any context.
unsafe impl Send for Uart {}
  • Implementing Write lets us use the write! and writeln! macros with our Uart type.
  • Run the example in QEMU with make qemu_minimal under src/bare-metal/aps/examples.