diff --git a/src/vga_buffer.rs b/src/vga_buffer.rs new file mode 100644 index 00000000..1de07433 --- /dev/null +++ b/src/vga_buffer.rs @@ -0,0 +1,133 @@ +const BUFFER_HEIGHT: usize = 25; +const BUFFER_WIDTH: usize = 80; + +#[macro_export] +macro_rules! print { + ($($arg:tt)*) => ($crate::vga_buffer::_print(format_args!($($arg)*))); +} + +#[macro_export] +macro_rules! println { + ($fmt:expr) => (print!(concat!($fmt, "\n"))); + ($fmt:expr, $($arg:tt)*) => (print!(concat!($fmt, "\n"), $($arg)*)); +} + +pub fn clear_screen() { + for _ in 0..BUFFER_HEIGHT { + println!(""); + } +} + +pub fn _print(fmt: ::core::fmt::Arguments) { + use core::fmt::Write; + static mut WRITER: Writer = Writer::new(Color::LightGreen, Color::Black); + let _ = unsafe{WRITER.write_fmt(fmt)}; +} + +pub struct Writer { + column_position: usize, + color_code: ColorCode, +} + +impl Writer { + pub const fn new(foreground: Color, background: Color) -> Writer { + Writer { + column_position: 0, + color_code: ColorCode::new(foreground, background), + } + } + + pub fn write_byte(&mut self, byte: u8) { + const NEWLINE: u8 = b'\n'; + + match byte { + NEWLINE => self.new_line(), + byte => { + if self.column_position >= BUFFER_WIDTH { + self.new_line() + } + let row = BUFFER_HEIGHT - 1; + let col = self.column_position; + + Self::buffer().chars[row][col] = ScreenChar { + ascii_character: byte, + color_code: self.color_code, + }; + self.column_position += 1; + } + } + } + + fn buffer() -> &'static mut Buffer { + const BUFFER: *mut Buffer = 0xb8000 as *mut _; + unsafe{&mut *BUFFER} + } + + fn new_line(&mut self) { + let buffer = Self::buffer(); + for row in 0..(BUFFER_HEIGHT-1) { + buffer.chars[row] = buffer.chars[row + 1] + } + self.clear_row(BUFFER_HEIGHT-1); + self.column_position = 0; + } + + fn clear_row(&mut self, row: usize) { + let blank = ScreenChar { + ascii_character: ' ' as u8, + color_code: self.color_code, + }; + Self::buffer().chars[row] = [blank; BUFFER_WIDTH]; + } +} + +impl ::core::fmt::Write for Writer { + fn write_str(&mut self, s: &str) -> ::core::fmt::Result { + for byte in s.bytes() { + self.write_byte(byte) + } + Ok(()) + } +} + +#[derive(Clone, Copy)] +#[allow(dead_code)] +#[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)] +struct ColorCode(u8); + +impl ColorCode { + const fn new(foreground: Color, background: Color) -> ColorCode { + ColorCode((background as u8) << 4 | (foreground as u8)) + } +} + +#[derive(Clone, Copy)] +#[repr(packed)] +struct ScreenChar { + ascii_character: u8, + color_code: ColorCode, +} + +struct Buffer { + chars: [[ScreenChar; BUFFER_WIDTH]; BUFFER_HEIGHT], +}