This commit is contained in:
Timothy Warren 2019-09-24 10:20:27 -04:00
parent b91cab1d91
commit 8e83ca2f19
4 changed files with 179 additions and 11 deletions

24
Cargo.lock generated
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@ -5,6 +5,9 @@ name = "blog_os"
version = "0.1.0" version = "0.1.0"
dependencies = [ dependencies = [
"bootloader 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)", "bootloader 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
"lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
"spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
"volatile 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
] ]
[[package]] [[package]]
@ -12,5 +15,26 @@ name = "bootloader"
version = "0.8.1" version = "0.8.1"
source = "registry+https://github.com/rust-lang/crates.io-index" source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "lazy_static"
version = "1.4.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
"spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)",
]
[[package]]
name = "spin"
version = "0.5.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
[[package]]
name = "volatile"
version = "0.2.6"
source = "registry+https://github.com/rust-lang/crates.io-index"
[metadata] [metadata]
"checksum bootloader 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "45dd858bd74a742ec0fe887722952c263abd0825aa8d33a3704917a97d7bd41e" "checksum bootloader 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)" = "45dd858bd74a742ec0fe887722952c263abd0825aa8d33a3704917a97d7bd41e"
"checksum lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
"checksum spin 0.5.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6e63cff320ae2c57904679ba7cb63280a3dc4613885beafb148ee7bf9aa9042d"
"checksum volatile 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)" = "6af0edf5b4faacc31fc51159244d78d65ec580f021afcef7bd53c04aeabc7f29"

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@ -8,6 +8,12 @@ edition = "2018"
[dependencies] [dependencies]
bootloader = "0.8.1" bootloader = "0.8.1"
spin = "0.5.2"
volatile = "0.2.6"
[dependencies.lazy_static]
version = "1.4.0"
features = ["spin_no_std"]
[profile.dev] [profile.dev]
panic = "abort" panic = "abort"

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@ -3,24 +3,18 @@
use core::panic::PanicInfo; use core::panic::PanicInfo;
mod vga_buffer;
/// This function is called on panic. /// This function is called on panic.
#[panic_handler] #[panic_handler]
fn panic(_info: &PanicInfo) -> ! { fn panic(info: &PanicInfo) -> ! {
println!("{}", info);
loop {} loop {}
} }
static HELLO: &[u8] = b"Hello World!";
#[no_mangle] #[no_mangle]
pub extern "C" fn _start() -> ! { pub extern "C" fn _start() -> ! {
let vga_buffer = 0xb8000 as *mut u8; panic!("Some panic message");
for (i, &byte) in HELLO.iter().enumerate() {
unsafe {
*vga_buffer.offset(i as isize * 2) = byte;
*vga_buffer.offset(i as isize * 2 + 1) = 0xb;
}
}
loop {} loop {}
} }

144
src/vga_buffer.rs Normal file
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@ -0,0 +1,144 @@
use core::fmt;
use lazy_static::lazy_static;
use spin::Mutex;
use volatile::Volatile;
#[allow(dead_code)]
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
#[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(Debug, Clone, Copy, PartialEq, Eq)]
#[repr(transparent)]
struct ColorCode(u8);
impl ColorCode {
fn new(foreground: Color, background: Color) -> ColorCode {
ColorCode((background as u8) << 4 | (foreground as u8))
}
}
#[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 Writer {
column_position: usize,
color_code: ColorCode,
buffer: &'static mut Buffer,
}
impl Writer {
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;
self.buffer.chars[row][col].write(ScreenChar {
ascii_character: byte,
color_code,
});
self.column_position += 1;
}
}
}
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),
}
}
}
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);
}
}
}
impl fmt::Write for Writer {
fn write_str(&mut self, s: &str) -> fmt::Result {
self.write_string(s);
Ok(())
}
}
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) },
});
}
#[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();
}