examples/generics.rs


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//! examples/generics.rs

#![deny(unsafe_code)]
#![deny(warnings)]
#![no_main]
#![no_std]

extern crate panic_semihosting;

use cortex_m_semihosting::debug;
use lm3s6965::Interrupt;
use rtfm::{app, Mutex};

// NOTE: This convenience macro will appear in all the other examples and
// will always look the same
macro_rules! println {
    ($($tt:tt)*) => {
        if let Ok(mut stdout) = cortex_m_semihosting::hio::hstdout() {
            use core::fmt::Write;

            writeln!(stdout, $($tt)*).ok();
        }
    };
}

#[app(device = lm3s6965)]
const APP: () = {
    static mut SHARED: u32 = 0;

    #[init]
    fn init() {
        rtfm::pend(Interrupt::UART0);
        rtfm::pend(Interrupt::UART1);
    }

    #[interrupt(resources = [SHARED])]
    fn UART0() {
        static mut STATE: u32 = 0;

        println!("UART0(STATE = {})", *STATE);

        advance(STATE, resources.SHARED);

        rtfm::pend(Interrupt::UART1);

        debug::exit(debug::EXIT_SUCCESS);
    }

    #[interrupt(priority = 2, resources = [SHARED])]
    fn UART1() {
        static mut STATE: u32 = 0;

        println!("UART1(STATE = {})", *STATE);

        // just to show that `SHARED` can be accessed directly and ..
        *resources.SHARED += 0;
        // .. also through a (no-op) `lock`
        resources.SHARED.lock(|shared| *shared += 0);

        advance(STATE, resources.SHARED);
    }
};

fn advance(state: &mut u32, mut shared: impl Mutex<T = u32>) {
    *state += 1;

    let (old, new) = shared.lock(|shared| {
        let old = *shared;
        *shared += *state;
        (old, *shared)
    });

    println!("SHARED: {} -> {}", old, new);
}