io: add serial output through port 0x3f8 (qemu)

not yet wrapped with fmt macros because I want some thing stateless.
(i.e. I don't want to pass `&mut self` to write_str...).

1 files changed, 16 insertions, 0 deletions

diff --git a/src/machine/serial.rs b/src/machine/serial.rs
new file mode 100644
index 0000000..edb18c0
--- /dev/null
+++ b/src/machine/serial.rs
@@ -0,0 +1,16 @@
+use crate::machine::device_io::IOPort;
+use core::{fmt, str};
+/// serial output through port 3f8 (qemu), stateless, not thread safe.
+pub struct Serial {}
+impl Serial {
+	const PORT: IOPort = IOPort::new(0x3f8);
+	pub fn putchar(ch: char) {
+		Self::PORT.outb(ch as u8);
+	}
+
+	pub fn print(s: &str) {
+		for c in s.bytes() {
+			Self::putchar(c as char);
+		}
+	}
+}