enter protected mode and jump to rust binary

boot1/src/main.rs

@@ -10,9 +10,9 @@ const VGA_ADDR: usize = 0xb8000;
 
 const STR: &[u8] = b"the quick brown fox jumps over the lazy dog";
 
-extern "C" {
-  fn prelude() -> !;
-}
+// extern "C" {
+//   fn prelude() -> !;
+// }
 
 #[panic_handler]
 fn panic(_info: &PanicInfo) -> ! {
@@ -45,10 +45,7 @@ pub extern "C" fn _start() -> ! {
     vga_buf[i] = 0x1f00 | u16::from(b);
   }
 
-  vga_buf[0] = 0x1f02; //smiley
-
-  // hlt()
-  unsafe { prelude() };
+  hlt()
 }
 
 #[inline]