Add stupid first serial output

src/kernel/console.cpp

@@ -1,4 +1,5 @@
 #include "console.h"
+#include "io.h"
 
 const char digits[] = "0123456789abcdef";
 
@@ -80,6 +81,18 @@ console::console(const font &f, const screen &s, void *scratch, size_t len) :
 		default_console = this;
 }
 
+static bool
+serial_ready()
+{
+	return (inb(COM1 + 5) & 0x20) != 0;
+}
+
+static void
+serial_write(char c) {
+	while (!serial_ready());
+	outb(COM1, c);
+}
+
 char *
 console::line_pointer(unsigned line)
 {
@@ -171,6 +184,7 @@ console::puts(const char *message)
 			break;
 
 		case '\n':
+			serial_write('\r');
 			m_pos.x = 0;
 			m_pos.y++;
 			break;
@@ -191,6 +205,7 @@ console::puts(const char *message)
 			scroll(1);
 			line = line_pointer(m_pos.y);
 		}
+		serial_write(c);
 	}
 
 	return count;

src/kernel/io.cpp

@@ -0,0 +1,16 @@
+#include "io.h"
+
+uint8_t
+inb(uint16_t port)
+{
+	uint8_t val;
+	__asm__ __volatile__ ( "inb %1, %0" : "=a"(val) : "Nd"(port) );
+	return val;
+}
+
+void
+outb(uint16_t port, uint8_t val)
+{
+	__asm__ __volatile__ ( "outb %0, %1" :: "a"(val), "Nd"(port) );
+}
+

src/kernel/io.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <stdint.h>
+
+extern "C" {
+
+/// Read a byte from an IO port.
+/// \arg port  The address of the IO port
+/// \returns   One byte read from the port
+uint8_t inb(uint16_t port);
+
+/// Write a byte to an IO port.
+/// \arg port  The addres of the IO port
+/// \arg val   The byte to write
+void outb(uint16_t port, uint8_t val);
+
+}
+
+const uint16_t COM1 = 0x03f8;