Make a Hello World! OS

src/lib.rs

@@ -5,10 +5,21 @@ extern crate rlibc;
 
 #[no_mangle]
 pub extern fn rust_main() {
-    let x = ["Hello", " ", "World", "!"];
-    let test = (0..3).flat_map(|x| 0..x).zip(0..);
-    let mut a = ("hello", 42);
-    a.1 += 1;
+    // ATTENTION: we have a very small stack and no guard page
+
+    let hello = b"Hello World!";
+    let color_byte = 0x1f; // white foreground, blue background
+
+    let mut hello_colored = [color_byte; 24];
+    for (i, char_byte) in hello.into_iter().enumerate() {
+        hello_colored[i*2] = *char_byte;
+    }
+
+    // write `Hello World!` to the center of the VGA text buffer
+    let buffer_ptr = (0xb8000 + 1988) as *mut _;
+    unsafe { *buffer_ptr = hello_colored };
+
+    loop{}
 }
 
 #[lang = "eh_personality"] extern fn eh_personality() {}