// Copyright 2015 Philipp Oppermann
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![feature(no_std, lang_items)]
#![feature(const_fn, unique, core_str_ext)]
#![no_std]

extern crate rlibc;
extern crate spin;

#[macro_use]
mod vga_buffer;

#[no_mangle]
pub extern fn rust_main() {
    // ATTENTION: we have a very small stack and no guard page
    println!("Hello World{}", "!");

    loop{}
}

#[cfg(not(test))]
#[lang = "eh_personality"]
extern fn eh_personality() {}

#[cfg(not(test))]
#[lang = "panic_fmt"]
extern fn panic_fmt() -> ! {loop{}}

// Copyright 2015 Philipp Oppermann
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//    http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#![feature(no_std, lang_items)]
#![feature(const_fn, unique, core_str_ext)]
#![no_std]

extern crate rlibc;
extern crate spin;

mod vga_buffer;

#[no_mangle]
pub extern fn rust_main() {
    // ATTENTION: we have a very small stack and no guard page

    let hello = b"Hello World!";
    let color_byte = 0x1f; // white foreground, blue background

    let mut hello_colored = [color_byte; 24];
    for (i, char_byte) in hello.into_iter().enumerate() {
        hello_colored[i*2] = *char_byte;
    }

    // write `Hello World!` to the center of the VGA text buffer
    let buffer_ptr = (0xb8000 + 1988) as *mut _;
    unsafe { *buffer_ptr = hello_colored };

    loop{}
}

#[cfg(not(test))]
#[lang = "eh_personality"]
extern fn eh_personality() {}

#[cfg(not(test))]
#[lang = "panic_fmt"]
extern fn panic_fmt() -> ! {loop{}}

--- 
+++ 
@@ -19,23 +19,13 @@
 extern crate rlibc;
 extern crate spin;
 
+#[macro_use]
 mod vga_buffer;
 
 #[no_mangle]
 pub extern fn rust_main() {
     // ATTENTION: we have a very small stack and no guard page
-
-    let hello = b"Hello World!";
-    let color_byte = 0x1f; // white foreground, blue background
-
-    let mut hello_colored = [color_byte; 24];
-    for (i, char_byte) in hello.into_iter().enumerate() {
-        hello_colored[i*2] = *char_byte;
-    }
-
-    // write `Hello World!` to the center of the VGA text buffer
-    let buffer_ptr = (0xb8000 + 1988) as *mut _;
-    unsafe { *buffer_ptr = hello_colored };
+    println!("Hello World{}", "!");
 
     loop{}
 }
Use `println!` to print the `Hello World!
