bern-kernel 0.3.1

Preemptive real-time kernel for microcontrollers.
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use crate::exec::process::{Process, ProcessMemory};
use crate::exec::thread::Thread;
use crate::stack::Stack;
use core::sync::atomic::{compiler_fence, Ordering};

extern "C" {
    static mut __smprocess_default_idle: usize;
    static mut __emprocess_default_idle: usize;
    static __siprocess_default_idle: usize;
}

#[no_mangle]
#[link_section = ".kernel.process"]
static BERN_DEFAULT_IDLE: Process = Process::new(unsafe {
    ProcessMemory {
        size: 256,

        data_start: (&__smprocess_default_idle) as *const _ as *const u8,
        data_end: (&__emprocess_default_idle) as *const _ as *const u8,
        data_load: (&__siprocess_default_idle) as *const _ as *const u8,

        heap_start: 1 as *const u8,
        heap_end: 1 as *const u8,
    }
});

#[link_section = ".process.default_idle"]
static mut STACK: [u8; 256] = [0; 256];

pub(crate) fn init() {
    crate::log::trace!("Init idle thread");
    BERN_DEFAULT_IDLE
        .init(|c| {
            Thread::new(c)
                .idle_task()
                .stack(unsafe { Stack::new(&mut STACK, STACK.len()) })
                .spawn(|| loop {
                    compiler_fence(Ordering::SeqCst);
                });
        })
        .ok();
}