make println!

Cargo.lock

@@ -13,4 +13,34 @@ name = "donald"
 version = "0.1.0"
 dependencies = [
  "bootloader",
+ "lazy_static",
+ "spin 0.5.2",
+ "volatile",
 ]
+
+[[package]]
+name = "lazy_static"
+version = "1.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bbd2bcb4c963f2ddae06a2efc7e9f3591312473c50c6685e1f298068316e66fe"
+dependencies = [
+ "spin 0.9.8",
+]
+
+[[package]]
+name = "spin"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
+
+[[package]]
+name = "spin"
+version = "0.9.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
+
+[[package]]
+name = "volatile"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f6b06ad3ed06fef1713569d547cdbdb439eafed76341820fb0e0344f29a41945"

Cargo.toml

@@ -14,3 +14,9 @@ build-std = ["core", "compiler_builtins"]
 
 [dependencies]
 bootloader = "0.9"
+volatile = "0.2.6"
+spin = "0.5.2"
+
+[dependencies.lazy_static]
+version = "1.0"
+features = ["spin_no_std"]

src/main.rs

@@ -9,11 +9,11 @@ fn panic(_info: &PanicInfo) -> ! {
     loop {}
 }
 
-static HELLO: &[u8] = b"Hello World!";
 
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
-    vga_buffer::print_something();  
+    println!("Hello World!");
+
 
     loop {}
 }

src/vga_buffer.rs

@@ -1,5 +1,15 @@
 // Handles VGA text printing
 
+use volatile::Volatile;
+use core::fmt;
+
+impl fmt::Write for Writer {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        self.write_string(s);
+        Ok(())
+    }
+}
+
 #[allow(dead_code)]
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 #[repr(u8)]
@@ -44,7 +54,7 @@ const BUFFER_WIDTH: usize = 80;
 
 #[repr(transparent)]
 struct Buffer {
-    chars: [[ScreenChar; BUFFER_WIDTH]; BUFFER_HEIGHT],
+    chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
 }
 
 pub struct Writer {
@@ -66,10 +76,10 @@ impl Writer {
                 let col = self.column_position;
 
                 let color_code = self.color_code;
-                self.buffer.chars[row][col] = ScreenChar {
+                self.buffer.chars[row][col].write(ScreenChar {
                     ascii_character: byte,
                     color_code,
-                };
+                });
                 self.column_position += 1;
             }
         }
@@ -85,17 +95,50 @@ impl Writer {
         }
     }
 
-    fn new_line(&mut self) {/*TODO */}
+    fn new_line(&mut self) {
+        for row in 1..BUFFER_HEIGHT {
+            for col in 0..BUFFER_WIDTH {
+                let character = self.buffer.chars[row][col].read();
+                self.buffer.chars[row - 1][col].write(character);
+            }
+        }
+        self.clear_row(BUFFER_HEIGHT - 1);
+        self.column_position = 0;
+    }
+    fn clear_row(&mut self, row: usize) {
+        let blank = ScreenChar {
+            ascii_character: b' ',
+            color_code: self.color_code,
+        };
+        for col in 0..BUFFER_WIDTH {
+            self.buffer.chars[row][col].write(blank);
+        }
+    }
 }
 
-pub fn print_something() {
-    let mut writer = Writer {
+use lazy_static::lazy_static;
+use spin::Mutex;
+lazy_static! {
+    pub static ref WRITER: Mutex<Writer> = Mutex::new(Writer {
         column_position: 0,
         color_code: ColorCode::new(Color::Yellow, Color::Black),
         buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
-    };
+    });
+}
 
-    writer.write_byte(b'H');
-    writer.write_string("ello ");
-    writer.write_string("World!")
+#[macro_export]
+macro_rules! print {
+    ($($arg:tt)*) => ($crate::vga_buffer::_print(format_args!($($arg)*)));
+}
+
+#[macro_export]
+macro_rules! println {
+    () => ($crate::print!("\n"));
+    ($($arg:tt)*) => ($crate::print!("{}\n", format_args!($($arg)*)));
+}
+
+#[doc(hidden)]
+pub fn _print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    WRITER.lock().write_fmt(args).unwrap();
 }