Print available memory areas

src/lib.rs

@@ -17,6 +17,16 @@ pub extern fn rust_main(multiboot_information_address: usize) {
     vga_buffer::clear_screen();
     println!("Hello World{}", "!");
 
+    let boot_info = unsafe{ multiboot2::load(multiboot_information_address) };
+    let memory_map_tag = boot_info.memory_map_tag()
+        .expect("Memory map tag required");
+
+    println!("memory areas:");
+    for area in memory_map_tag.memory_areas() {
+        println!("    start: 0x{:x}, length: 0x{:x}",
+            area.base_addr, area.length);
+    }
+
     loop{}
 }