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|
use super::*;
use crate::sync::interface::Mutex;
use crate::sync::NullLock;
use core::fmt;
use volatile::Volatile;
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(C)]
struct ScreenChar {
ascii_character: u8,
color_code: ColorCode,
}
const BUFFER_HEIGHT: usize = 25;
const BUFFER_WIDTH: usize = 80;
#[repr(transparent)]
struct Buffer {
chars: [[Volatile<ScreenChar>; BUFFER_WIDTH]; BUFFER_HEIGHT],
}
pub struct VgaWriter {
column_position: usize,
color_code: ColorCode,
buffer: Option<&'static mut Buffer>,
}
impl VgaWriter {
pub fn write_byte(&mut self, byte: u8) {
match byte {
b'\n' => self.new_line(),
byte => {
if self.column_position >= BUFFER_WIDTH {
self.new_line();
}
let row = BUFFER_HEIGHT - 1;
let col = self.column_position;
let color_code = self.color_code;
if let Some(buffer) = &mut self.buffer {
buffer.chars[row][col].write(ScreenChar {
ascii_character: byte,
color_code,
});
}
self.column_position += 1;
}
}
}
fn new_line(&mut self) {
for row in 1..BUFFER_HEIGHT {
for col in 0..BUFFER_WIDTH {
if let Some(buffer) = &mut self.buffer {
let character = buffer.chars[row][col].read();
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 {
if let Some(buffer) = &mut self.buffer {
buffer.chars[row][col].write(blank);
}
}
}
pub fn write_string(&mut self, s: &str) {
for byte in s.bytes() {
match byte {
// printable ASCII byte or newline
0x20..=0x7e | b'\n' => self.write_byte(byte),
// not part of printable ASCII range
_ => self.write_byte(0xfe),
}
}
}
}
impl fmt::Write for VgaWriter {
fn write_str(&mut self, s: &str) -> fmt::Result {
self.write_string(s);
Ok(())
}
}
impl crate::sync::interface::Initializable for VgaWriter {
fn init(&mut self) {
self.buffer = Some(unsafe { &mut *(0xb8000 as *mut Buffer) });
}
}
#[doc(hidden)]
pub fn _print(args: fmt::Arguments) {
use core::fmt::Write;
WRITER.lock(|writer| {
writer.write_fmt(args).unwrap();
});
}
#[macro_export]
macro_rules! print {
($($arg:tt)*) => ($crate::vga::_print(format_args!($($arg)*)));
}
#[macro_export]
macro_rules! println {
() => (print!("\n"));
($($arg:tt)*) => (print!("{}\n", format_args!($($arg)*)));
}
pub static WRITER: NullLock<VgaWriter> = NullLock::new(VgaWriter {
column_position: 0,
color_code: ColorCode::new(Color::LightBlue, Color::Black),
buffer: None,
});
#[test_case]
fn test_println_simple() {
println!("test_println_simple output");
}
#[test_case]
fn test_println_many() {
for _ in 0..200 {
println!("test_println_many output");
}
}
#[test_case]
fn test_println_output() {
let s = "Some test string that fits on a single line";
println!("{}", s);
for (i, c) in s.chars().enumerate() {
let screen_char = WRITER.lock(|writer| {
if let Some(buffer) = &writer.buffer {
return buffer.chars[BUFFER_HEIGHT - 2][i].read();
} else {
return ScreenChar {
ascii_character: b' ',
color_code: ColorCode::new(Color::LightBlue, Color::Black),
};
}
});
assert_eq!(char::from(screen_char.ascii_character), c);
}
}
|
