rt 0.19.0

A real-time operating system capable of full preemption
Documentation 
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use core::{fmt::Write, panic::PanicInfo};

#[inline]
fn panic(m: &str) -> ! {
    unsafe { crate::bindings::rt_panic(m.as_ptr().cast()) }
}

struct PanicBuf<const N: usize> {
    cursor: usize,
    buf: [u8; N],
}

impl<const N: usize> PanicBuf<N> {
    const fn new() -> PanicBuf<N> {
        PanicBuf {
            cursor: 0,
            buf: [0; N],
        }
    }

    const fn as_str(&self) -> &str {
        unsafe { core::str::from_utf8_unchecked(&self.buf) }
    }
}

impl<const N: usize> core::fmt::Write for PanicBuf<N> {
    fn write_str(&mut self, s: &str) -> core::fmt::Result {
        for &b in s.as_bytes() {
            if let Some(e) = self.buf.get_mut(self.cursor) {
                *e = b;
                self.cursor += 1;
            } else {
                break;
            }
        }
        Ok(())
    }
}

#[panic_handler]
fn panic_handler(panic_info: &PanicInfo) -> ! {
    use crate::panic::PanicBuf;

    let mut panic_buf: PanicBuf<128> = PanicBuf::new();
    let _ = core::write!(panic_buf, "{}", panic_info);
    panic(panic_buf.as_str())
}