add hello world init program

src/main.rs

@@ -12,7 +12,6 @@ mod program;
 mod util;
 
 use core::panic::PanicInfo;
-use program::shell;
 
 use bootloader::{entry_point, BootInfo};
 use dev::memory;
@@ -25,7 +24,8 @@ fn kernel_main(boot_info: &'static BootInfo) -> ! {
 	int::init();
 	memory::init(boot_info.physical_memory_offset, &boot_info.memory_map);
 	println!("Finished initializations.");
-	shell::main();
+	program::shell::main();
+	// program::hello_world::main();
 	panic!("Exiting.")
 }
 

src/program/hello_world.rs

@@ -0,0 +1,6 @@
+use crate::{print, println, util::spin};
+
+pub fn main() -> ! {
+	println!("Hello World !");
+	spin()
+}

src/program/mod.rs

@@ -1 +1,2 @@
+pub mod hello_world;
 pub mod shell;