Added macros print! and println!

uefi-services/src/lib.rs

@@ -28,6 +28,7 @@ extern crate log;
 extern crate uefi;
 
 use core::ffi::c_void;
+use core::fmt::Write;
 use core::ptr::NonNull;
 
 use cfg_if::cfg_if;
@@ -95,6 +96,51 @@ pub fn init(st: &mut SystemTable<Boot>) -> Result {
     }
 }
 
+// Interal function for print macros
+#[doc(hidden)]
+pub fn _print(args: core::fmt::Arguments) {
+    unsafe {
+        if let Some(st) = &mut SYSTEM_TABLE {
+            st.stdout().write_fmt(args).expect("Failed to write to stdout");
+        } else {
+            panic!("SYSTEM_TABLE is None");
+        }
+    }
+}
+
+/// Prints to the standard output
+/// 
+/// # Panics
+/// Will panic if SYSTEM_TABLE is None (Before [init] and after [exit_boot_services])
+/// 
+/// # Examples
+/// ```
+/// print!("");
+/// print!("Hello World\n");
+/// print!("Hello {}", "World");
+/// ```
+#[macro_export]
+macro_rules! print {
+    ($($arg:tt)*) => ($crate::_print(core::format_args!($($arg)*)));
+}
+
+/// Prints to the standard output, with a newline
+/// 
+/// # Panics
+/// Will panic if SYSTEM_TABLE is None (Before [init] and after [exit_boot_services])
+/// 
+/// # Examples
+/// ```
+/// println!();
+/// println!("Hello World");
+/// println!("Hello {}", "World");
+/// ```
+#[macro_export]
+macro_rules! println {
+    () => ($crate::print!("\n"));
+    ($($arg:tt)*) => ($crate::_print(core::format_args!("{}{}", core::format_args!($($arg)*), "\n")));
+}
+
 /// Set up logging
 ///
 /// This is unsafe because you must arrange for the logger to be reset with