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...).

5 files changed, 23 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 82555a4..9962ecc 100644
--- a/Makefile
+++ b/Makefile
@@ -93,14 +93,14 @@ clean:
 	rm -f build/*
 
 qemu: bootdisk.iso
-	qemu-system-x86_64 -drive file=./bootdisk.iso,format=raw -k en-us
+	qemu-system-x86_64 -drive file=./bootdisk.iso,format=raw -k en-us -serial mon:stdio
 
 gdb:
 	gdb -x /tmp/gdbcommands.$(shell id -u) build/kernel
 
 qemu-gdb: bootdisk.iso
 	@echo "target remote localhost:$(shell echo $$(( $$(id -u) % (65536 - 1024) + 1024 )))" > /tmp/gdbcommands.$(shell id -u)
-	@qemu-system-x86_64 -drive file=bootdisk.iso,format=raw -k en-us -S -gdb tcp::$(shell echo $$(( $$(id -u) % (65536 - 1024) + 1024 )))
+	@qemu-system-x86_64 -drive file=bootdisk.iso,format=raw -k en-us -S -gdb tcp::$(shell echo $$(( $$(id -u) % (65536 - 1024) + 1024 ))) -serial mon:stdio
 
 test:
 	@echo "---BUILD DIR---"
diff --git a/src/lib.rs b/src/lib.rs
index 99478be..185014d 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -9,7 +9,6 @@ mod ds;
 mod io;
 mod machine;
 mod mm;
-use crate::machine::key::Modifiers;
 mod proc;
 extern crate alloc;
 use alloc::vec::Vec;
@@ -19,7 +18,9 @@ use arch::x86_64::interrupt::pic_8259::PicDeviceInt;
 use core::panic::PanicInfo;
 use defs::*;
 use machine::cgascr::CGAScreen;
+use machine::key::Modifiers;
 use machine::multiboot;
+use machine::serial::Serial;
 
 #[cfg(not(test))]
 #[panic_handler]
@@ -61,6 +62,7 @@ pub extern "C" fn _entry() -> ! {
 	for s in test_vec.iter() {
 		println!("{s}");
 	}
+	Serial::print("hello from serial");
 	loop {
 		io::KBCTL_GLOBAL.lock().fetch_key();
 		if let Some(k) = io::KBCTL_GLOBAL.lock().consume_key() {
diff --git a/src/machine/device_io.rs b/src/machine/device_io.rs
index 2a0c907..9a530f1 100644
--- a/src/machine/device_io.rs
+++ b/src/machine/device_io.rs
@@ -4,7 +4,7 @@ pub use crate::arch::x86_64::io_port::*;
 // either use the io functions directly, or via a IOPort instance.
 pub struct IOPort(u16);
 impl IOPort {
-	pub fn new(port: u16) -> Self {
+	pub const fn new(port: u16) -> Self {
 		Self(port)
 	}
 	pub fn inw(&self) -> u16 {
diff --git a/src/machine/mod.rs b/src/machine/mod.rs
index a2cf730..b2b026f 100644
--- a/src/machine/mod.rs
+++ b/src/machine/mod.rs
@@ -5,5 +5,6 @@ pub mod key;
 pub mod keyctrl;
 pub mod mem;
 pub mod multiboot;
+pub mod serial;
 
 // TODO: this module *should* be arch independent.
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);
+		}
+	}
+}