rCore-Tutorial-v3-tests/os/src/main.rs

#![no_std]
#![no_main]
#![feature(global_asm)]
#![feature(llvm_asm)]
#![feature(panic_info_message)]

#[macro_use]
mod console;
mod lang_items;
mod sbi;
mod syscall;
mod trap;

global_asm!(include_str!("entry.asm"));
global_asm!(include_str!("link_app.S"));

fn clear_bss() {
    extern "C" {
        fn sbss();
        fn ebss();
    }
    (sbss as usize..ebss as usize).for_each(|a| {
        unsafe { (a as *mut u8).write_volatile(0) }
    });
}

#[no_mangle]
pub fn rust_main() -> ! {
    clear_bss();
    println!("Hello, world!");
    extern "C" {
        fn _num_app();
    }
    let num_app_ptr = _num_app as usize as *const usize;
    let num_app = unsafe { num_app_ptr.read_volatile() };
    println!("num_app = {}", num_app);
    let app_start: &[usize] = unsafe {
        core::slice::from_raw_parts(num_app_ptr.add(1), num_app + 1)
    };
    for i in 0..num_app {
        println!("app_{} [{:#x}, {:#x})", i, app_start[i], app_start[i + 1]);
    }
    panic!("Shutdown machine!");
}