Vga buffer + test for it

This commit is contained in:
greg 2019-07-10 02:25:12 -07:00
parent be54882fe2
commit 0e9bff7bff
2 changed files with 100 additions and 10 deletions

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@ -1,6 +1,8 @@
#![no_std]
#![no_main]
mod vga_buffer;
use core::panic::PanicInfo;
#[panic_handler]
@ -8,19 +10,11 @@ fn panic(_info: &PanicInfo) -> !{
loop {}
}
static GREETING: &[u8] = b"Gamarjoba, munde";
#[no_mangle]
pub extern "C" fn _start() -> ! {
let vga_buffer = 0xb8000 as *mut u8;
for (i, &byte) in GREETING.iter().enumerate() {
unsafe {
*vga_buffer.offset(i as isize * 2) = byte;
*vga_buffer.offset(i as isize * 2 + 1) = 0xb; //light cyan
}
}
vga_buffer::yolo();
loop {}
}

96
src/vga_buffer.rs Normal file
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@ -0,0 +1,96 @@
#[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_char: u8,
color_code: ColorCode,
}
const BUFFER_WIDTH: usize = 80;
const BUFFER_HEIGHT: usize = 25;
#[repr(transparent)]
struct Buffer {
chars: [[ScreenChar; BUFFER_WIDTH]; BUFFER_HEIGHT],
}
pub struct Writer {
column_position: usize,
color_code: ColorCode,
buffer: &'static mut Buffer,
}
impl Writer {
pub fn write_string(&mut self, s: &str) {
for byte in s.bytes() {
match byte {
0x20..=0x7e | b'\n' => self.write_byte(byte),
_ => self.write_byte(0xfe), // a ■
}
}
}
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] = ScreenChar {
ascii_char: byte, color_code,
};
self.column_position += 1;
}
}
}
fn new_line(&mut self) {
}
}
pub fn yolo() {
let mut writer = Writer {
column_position: 0, color_code: ColorCode::new(Color::Yellow, Color::Black),
buffer: unsafe { &mut *(0xb8000 as *mut Buffer) },
};
writer.write_string("Gamarjoba, munde\n");
writer.write_string("Hella bro");
writer.write_string("sore は");
}