blog_os/src/bin/test-basic-boot.rs

#![no_std] // don't link the Rust standard library
#![cfg_attr(not(test), no_main)] // disable all Rust-level entry points
#![cfg_attr(test, allow(dead_code, unused_macros, unused_imports))]

use blog_os::{exit_qemu, serial_println};
use core::panic::PanicInfo;

/// This function is the entry point, since the linker looks for a function
/// named `_start` by default.
#[cfg(not(test))]
#[no_mangle] // don't mangle the name of this function
pub extern "C" fn _start() -> ! {
    serial_println!("ok");

    unsafe {
        exit_qemu();
    }
    loop {}
}

/// This function is called on panic.
#[cfg(not(test))]
#[panic_handler]
fn panic(info: &PanicInfo) -> ! {
    serial_println!("failed");

    serial_println!("{}", info);

    unsafe {
        exit_qemu();
    }
    loop {}
}