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// Example: Hello World!
//
// This is an example UEFI application that prints "Hello World!", then waits
// for key input before it exits. It serves as base example how to write UEFI
// applications without any helper modules other than the UEFI protocol
// definitions.
//
// This example builds upon the `freestanding.rs` example, using the same setup
// and rust integration. See there for details on the panic-handler and entry
// point configuration.
//
// Note that UEFI uses UTF-16 strings. Since rust literals are UTF-8, we have
// to use an open-coded, zero-terminated, UTF-16 array as argument to
// `output_string()`. Similarly to the panic handler, real applications should
// rather use UTF-16 modules.
#![no_main]
#![no_std]
use r_efi::efi;
#[panic_handler]
fn panic_handler(_info: &core::panic::PanicInfo) -> ! {
loop {}
}
#[export_name = "efi_main"]
pub extern "C" fn main(_h: efi::Handle, st: *mut efi::SystemTable) -> efi::Status {
let s = [
0x0048u16, 0x0065u16, 0x006cu16, 0x006cu16, 0x006fu16, // "Hello"
0x0020u16, // " "
0x0057u16, 0x006fu16, 0x0072u16, 0x006cu16, 0x0064u16, // "World"
0x0021u16, // "!"
0x000au16, // "\n"
0x0000u16, // NUL
];
// Print "Hello World!".
let r =
unsafe { ((*(*st).con_out).output_string)((*st).con_out, s.as_ptr() as *mut efi::Char16) };
if r.is_error() {
return r;
}
// Wait for key input, by waiting on the `wait_for_key` event hook.
let r = unsafe {
let mut x: usize = 0;
((*(*st).boot_services).wait_for_event)(1, &mut (*(*st).con_in).wait_for_key, &mut x)
};
if r.is_error() {
return r;
}
efi::Status::SUCCESS
}
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