rt 0.19.1

A real-time operating system capable of full preemption
Documentation 
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#![no_main]
#![cfg_attr(target_os = "none", no_std)]

use core::sync::atomic::{AtomicUsize, Ordering};

rt::queue!(QUEUE, u32, 10);

fn pusher(mut i: u32) {
    rt::task::drop_privilege();
    loop {
        QUEUE.push(i);
        i += 1;
    }
}

const NPUSHERS: usize = 2;
const TASK_INC: u32 = 0x1000000;

static NUM_POPPED: AtomicUsize = AtomicUsize::new(0);

fn popper() {
    rt::task::drop_privilege();
    let mut max_elems = [0u32; NPUSHERS];
    loop {
        let x = QUEUE.peek();
        let y = QUEUE.pop();
        assert!(x == y, "peeked and popped value don't match");
        NUM_POPPED.fetch_add(1, Ordering::Relaxed);
        let task = x / TASK_INC;
        let elem = x % TASK_INC;
        if let Some(max_elem) = max_elems.get_mut(task as usize) {
            assert!(
                elem >= *max_elem,
                "queue elements were received out of order"
            );
            *max_elem = elem;
        }
    }
}

fn timeout() {
    rt::task::drop_privilege();
    rt::task::sleep(1000);
    rt::exit();
}

const STACK_SIZE: usize = rt::stack::MIN * 8;

rt::task!(pusher(0), STACK_SIZE, 1);
rt::task!(pusher(TASK_INC), STACK_SIZE, 1);
rt::task!(popper, STACK_SIZE, 1);
rt::task!(timeout, rt::stack::MIN, 0);