67 lines
1.7 KiB
Rust
67 lines
1.7 KiB
Rust
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use core::fmt::{Error, Write};
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pub struct Uart {}
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impl Uart {
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pub fn new() -> Uart {
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Uart {}
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}
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pub fn putc(&self, c: u8) {
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let ptr = 0xE000_1800 as *mut u32;
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unsafe {
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while ptr.add(1).read_volatile() == 0 {}
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ptr.add(0).write_volatile(c as u32);
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}
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}
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fn get(&self, base_addr: usize) -> Option<u8> {
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let ptr = 0xE000_1800 as *mut u32;
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unsafe {
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if ptr.add(2).read_volatile() == 0 {
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Some(ptr.add(0).read_volatile() as u8)
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} else {
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None
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}
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}
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}
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}
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// This is a slightly different syntax. Write is this "trait", meaning it is much like
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// an interface where we're just guaranteeing a certain function signature. In the Write
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// trait, one is absolutely required to be implemented, which is write_str. There are other
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// functions, but they all rely on write_str(), so their default implementation is OK for now.
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impl Write for Uart {
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// The trait Write expects us to write the function write_str
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// which looks like:
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fn write_str(&mut self, s: &str) -> Result<(), Error> {
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for c in s.bytes() {
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self.putc(c);
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}
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// Return that we succeeded.
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Ok(())
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}
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}
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#[macro_export]
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macro_rules! print
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{
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($($args:tt)+) => ({
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use core::fmt::Write;
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let _ = write!(crate::uart::Uart::new(), $($args)+);
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});
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}
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#[macro_export]
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macro_rules! println
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{
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() => ({
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print!("\r\n")
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});
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($fmt:expr) => ({
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print!(concat!($fmt, "\r\n"))
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});
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($fmt:expr, $($args:tt)+) => ({
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print!(concat!($fmt, "\r\n"), $($args)+)
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});
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}
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