Make it API compatible with the existing vga crate.

Cargo.toml

@@ -4,3 +4,4 @@ version = "0.1.0"
 authors = ["Steve Klabnik <[email protected]>"]
 
 [dependencies]
+spin = "0.4.2"

src/lib.rs

@@ -1,11 +1,18 @@
 #![no_std]
+#![feature(const_fn)]
+
+extern crate spin;
 
 use core::fmt;
 use core::fmt::Write;
 
 mod color;
 use color::Color;
 
+mod print;
+
+use spin::Mutex;
+
 const ROWS: usize = 25;
 const COLS: usize = 80;
 const COL_BYTES: usize = COLS * 2;
@@ -16,6 +23,8 @@ pub struct Vga {
     position: usize,
 }
 
+unsafe impl Send for Vga {}
+
 impl Vga {
     pub unsafe fn new(location: *mut u8) -> Vga {
         Vga {
@@ -80,6 +89,14 @@ impl Write for Vga {
     }
 }
 
+pub static BUFFER: Mutex<Vga> = Mutex::new(
+    Vga {
+        location: 0xb8000 as *mut u8,
+        buffer: [0; ROWS * COL_BYTES],
+        position: 0,
+    }
+);
+
 #[cfg(test)]
 mod tests {
     use Vga;

src/print.rs

@@ -0,0 +1,29 @@
+/// Prints something to the screen, with a trailing newline.
+///
+/// # Examples
+///
+/// ```ignore
+/// kprintln!("Hello, world!");
+/// ```
+#[macro_export]
+macro_rules! kprintln {
+    ($fmt:expr) => (kprint!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => (kprint!(concat!($fmt, "\n"), $($arg)*));
+}
+
+/// Prints something to the screen.
+///
+/// # Examples
+///
+/// ```ignore
+/// kprint!("Hello, world!");
+/// ```
+#[macro_export]
+macro_rules! kprint {
+    ($($arg:tt)*) => ({
+        use core::fmt::Write;
+        let mut b = $crate::BUFFER.lock();
+        b.write_fmt(format_args!($($arg)*)).unwrap();
+        b.flush();
+    });
+}