Rename the src directory to kernel.

kernel/arch/x86_64/serial.rs

@@ -0,0 +1,39 @@
+use core::fmt;
+use super::io::{Io, Pio};
+
+pub struct SerialConsole {
+    status: Pio<u8>,
+    data: Pio<u8>
+}
+
+impl SerialConsole {
+    pub fn new() -> SerialConsole {
+        SerialConsole {
+            status: Pio::new(0x3F8 + 5),
+            data: Pio::new(0x3F8)
+        }
+    }
+
+    pub fn write(&mut self, bytes: &[u8]) {
+        for byte in bytes.iter() {
+            while !self.status.readf(0x20) {}
+            self.data.write(*byte);
+
+            if *byte == 8 {
+                while !self.status.readf(0x20) {}
+                self.data.write(0x20);
+
+                while !self.status.readf(0x20) {}
+                self.data.write(8);
+            }
+        }
+    }
+}
+
+impl fmt::Write for SerialConsole {
+    fn write_str(&mut self, s: &str) -> Result<(), fmt::Error> {
+        self.write(s.as_bytes());
+
+        Ok(())
+    }
+}