Add VGA text-mode console driver

Cargo.lock

@@ -3,6 +3,8 @@ name = "sparkle_os"
 version = "0.1.0"
 dependencies = [
  "rlibc 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "spin 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)",
+ "volatile 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "x86 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -179,6 +181,16 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "spin"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "volatile"
+version = "0.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
 name = "x86"
 version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -214,4 +226,6 @@ dependencies = [
 "checksum serde 0.6.15 (registry+https://github.com/rust-lang/crates.io-index)" = "c97b18e9e53de541f11e497357d6c5eaeb39f0cb9c8734e274abe4935f6991fa"
 "checksum serde_json 0.6.1 (registry+https://github.com/rust-lang/crates.io-index)" = "b5aaee47e038bf9552d30380d3973fff2593ee0a76d81ad4c581f267cdcadf36"
 "checksum siphasher 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "0df90a788073e8d0235a67e50441d47db7c8ad9debd91cbf43736a2a92d36537"
+"checksum spin 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)" = "1d16a26e2b789f86aabddbe91cb82ee2e822beb8a59840d631941b625ef77e53"
+"checksum volatile 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6633c5250f16598f92b48272265ce9f8179447f702f0ba0cb640c5be6537b0c0"
 "checksum x86 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "ada1976e1004a0b5999beb7403541af96637e8f439b97d86c8c9abef2e0e7d19"

Cargo.toml

@@ -8,4 +8,6 @@ crate-type = ["staticlib"]
 
 [dependencies]
 rlibc = "1.0"
-x86 = "0.8"
+spin = "0.4.5"
+volatile = "0.2"
+x86 = "0.8"

src/arch/mod.rs

@@ -0,0 +1 @@
+pub mod x86_64;

src/arch/x86_64/device/mod.rs

@@ -0,0 +1 @@
+pub mod vga_console;

src/arch/x86_64/device/vga_console.rs

@@ -0,0 +1,155 @@
+use core::fmt;
+use core::ptr::Unique;
+use spin::Mutex;
+use volatile::Volatile;
+
+pub static WRITER: Mutex<Writer> = Mutex::new(Writer {
+    column_pos: 0, row_pos: 0,
+    style: CharStyle::new(Color::Cyan, Color::DarkGray),
+    buffer: unsafe {Unique::new(0xb8000 as *mut _)},
+});
+
+#[allow(dead_code)]
+#[derive(Clone, Copy, Debug)]
+#[repr(u8)]
+pub enum Color {
+    Black      = 0,
+    Blue       = 1,
+    Green      = 2,
+    Cyan       = 3,
+    Red        = 4,
+    Magenta    = 5,
+    Brown      = 6,
+    LightGray  = 7,
+    DarkGray   = 8,
+    LightBlue  = 9,
+    LightGreen = 10,
+    LightCyan  = 11,
+    LightRed   = 12,
+    Pink       = 13,
+    Yellow     = 14,
+    White      = 15,
+}
+
+#[derive(Clone, Copy, Debug)]
+pub struct CharStyle(u8);
+impl CharStyle {
+    const fn new(foreground: Color, background: Color) -> CharStyle {
+        CharStyle((background as u8) << 4 | (foreground as u8))
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+#[repr(C)]
+struct VgaChar {
+    ascii_char: u8,
+    style: CharStyle,
+}
+
+const BUFFER_HEIGHT: usize = 25;
+const BUFFER_WIDTH: usize = 80;
+
+/// Shadows the actual VGA text-mode buffer at 0xb8000.
+struct Buffer {
+    chars: [[Volatile<VgaChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
+}
+
+/// Abstraction layer used to write into the VGA text buffer
+pub struct Writer {
+    /// Current position of the 'write cursor'
+    row_pos: usize, column_pos: usize,
+    /// Current style we're writing with
+    style: CharStyle,
+    /// This is set up on initialization to shadow `0xb8000`, the VGA text-mode buffer.
+    buffer: Unique<Buffer>,
+}
+
+#[allow(dead_code)]
+impl Writer {
+    pub fn write_byte(&mut self, byte: u8) {
+        match byte {
+            b'\n' => self.new_line(),
+            byte => {
+                if self.column_pos >= BUFFER_WIDTH {self.new_line();}
+
+                let row = self.row_pos;
+                let col = self.column_pos;
+                let style = self.style;
+
+                self.buffer().chars[row][col].write(VgaChar {
+                    ascii_char: byte,
+                    style: style,
+                });
+
+                self.column_pos += 1;
+            }
+        }
+    }
+
+    pub fn write_byte_at(&mut self, byte: u8, row: usize, col: usize) {
+        self.row_pos = row; self.column_pos = col;
+        let style = self.style;
+
+        self.buffer().chars[row][col].write(VgaChar {ascii_char: byte, style: style});
+    }
+
+    pub fn clear_screen(&mut self) {
+        let clear_style = VgaChar {ascii_char:  b' ', style: self.style};
+        for row in 0..BUFFER_HEIGHT {
+            for col in 0..BUFFER_WIDTH {
+                self.buffer().chars[row][col].write(clear_style);
+            }
+        }
+    }
+
+    pub fn set_style(&mut self, style: CharStyle) {
+        self.style = style;
+    }
+
+    pub fn get_style(&self) -> CharStyle {
+        self.style
+    }
+
+    fn new_line(&mut self) {
+        self.column_pos = 0;
+        self.row_pos += 1;
+
+        if self.row_pos >= BUFFER_HEIGHT {
+            self.scroll();
+        }
+    }
+
+    fn clear_row(&mut self, row: usize) {
+        let clear_style = VgaChar {ascii_char:  b' ', style: self.style};
+        for col in 0..BUFFER_WIDTH {
+            self.buffer().chars[row][col].write(clear_style);
+        }
+    }
+
+    fn scroll(&mut self){
+        for row in 0..(BUFFER_HEIGHT - 1) {
+            for col in 0..BUFFER_WIDTH {
+                let c = self.buffer().chars[row + 1][col].read();
+                self.buffer().chars[row][col].write(c);
+            }
+        }
+
+        self.clear_row(BUFFER_HEIGHT - 1);
+        self.column_pos = 0;
+        self.row_pos = BUFFER_HEIGHT - 1;
+    }
+
+    fn buffer(&mut self) -> &mut Buffer {
+        unsafe { self.buffer.as_mut() }
+    }
+}
+
+impl fmt::Write for Writer {
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        for byte in s.bytes() {
+            self.write_byte(byte);
+        }
+
+        Ok(())
+    }
+}

src/arch/x86_64/mod.rs

@@ -0,0 +1 @@
+pub mod device;

src/macros.rs

@@ -0,0 +1,20 @@
+use core::fmt;
+
+#[macro_export]
+macro_rules! print {
+    ($($arg:tt)*) => ({
+        $crate::macros::print(format_args!($($arg)*));
+    });
+}
+
+pub fn print(args: fmt::Arguments) {
+    use core::fmt::Write;
+    let _ = ::arch::x86_64::device::vga_console::WRITER.lock().write_fmt(args);
+}
+
+#[macro_export]
+macro_rules! println {
+    () => (print!("\n"));
+    ($fmt:expr) => (print!(concat!($fmt, "\n")));
+    ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*));
+}