added vga buffer

.cargo/config.toml

@@ -3,4 +3,7 @@ build-std-features = ["compiler-builtins-mem"]
 build-std = ["core", "compiler_builtins"]
 
 [build]
-target = "x86_64-rust_os.json"
+target = "x86_64-rust_os.json"
+
+[target.'cfg(target_os = "none")']
+runner = "bootimage runner"

src/main.rs

@@ -1,7 +1,8 @@
 #![no_std] // don't link the Rust standard library
 #![no_main] // disable all Rust-level entry points
-#![allow(unused_imports)]
-// #![feature(custom_test_frameworks)]
+            // #![feature(custom_test_frameworks)]
+
+mod vga_buffer;
 
 use core::panic::PanicInfo;
 

src/vga_buffer.rs

@@ -0,0 +1,45 @@
+#[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: [[ScreenChar; BUFFER_WIDTH]; BUFFER_HEIGHT],
+}