Added serial output support to the kernel

CMakeLists.txt

@@ -12,6 +12,8 @@ set(LIMINE_DIR ${CMAKE_BINARY_DIR}/limine)
 
 file(GLOB_RECURSE KERNEL_SOURCES CONFIGURE_DEPENDS
         kernel/*.cpp
+        include/*.h
+        include/*.hpp
 )
 
 find_program(LLD_LINKER NAMES ld.lld REQUIRED)
@@ -52,7 +54,9 @@ add_custom_command(
         -T ${CMAKE_SOURCE_DIR}/linker.ld
         -o ${KERNEL_ELF}
         $<TARGET_OBJECTS:avery_objects>
-        DEPENDS avery_objects ${CMAKE_SOURCE_DIR}/linker.ld
+        DEPENDS
+        $<TARGET_OBJECTS:avery_objects>
+        ${CMAKE_SOURCE_DIR}/linker.ld
         COMMAND_EXPAND_LISTS
         VERBATIM
 )

include/io/io.h

@@ -0,0 +1,36 @@
+/*
+* io.h
+* As part of the Avery project
+* Created by Max Van den Eynde in 2026
+* --------------------------------------
+* Description: I/O Mapping and writing functions
+* Copyright (c) 2026 Max Van den Eynde
+*/
+
+#ifndef AVERY_IO_H
+#define AVERY_IO_H
+#include "../types.h"
+
+namespace io {
+    inline void outb(u16 port, u8 value) {
+        asm volatile(
+            "outb %0, %1"
+            :
+            : "a"(value), "Nd"(port)
+        );
+    }
+
+    inline u8 inb(u16 port) {
+        u8 val;
+
+        asm volatile(
+            "inb %1, %0"
+            : "=a"(val)
+            : "Nd"(port)
+        );
+
+        return val;
+    }
+}
+
+#endif //AVERY_IO_H

include/io/serial.h

@@ -0,0 +1,19 @@
+/*
+* serial.h
+* As part of the Avery project
+* Created by Max Van den Eynde in 2026
+* --------------------------------------
+* Description: The serial output for Avery
+* Copyright (c) 2026 Max Van den Eynde
+*/
+
+#ifndef AVERY_SERIAL_H
+#define AVERY_SERIAL_H
+#include "../types.h"
+
+namespace io {
+    void serialWriteChar(char c);
+    void serialWrite(string input);
+}
+
+#endif //AVERY_SERIAL_H

include/types.h

@@ -0,0 +1,27 @@
+/*
+* types.h
+* As part of the Avery project
+* Created by Max Van den Eynde in 2026
+* --------------------------------------
+* Description: Type definition for the Avery Kernel
+* Copyright (c) 2026 Max Van den Eynde
+*/
+
+#ifndef AVERY_TYPES_H
+#define AVERY_TYPES_H
+
+using u8 = unsigned char;
+using u16 = unsigned short;
+using u32 = unsigned int;
+using u64 = unsigned long long;
+using usize = decltype(sizeof(0));
+
+using i8 = char;
+using i16 = short;
+using i32 = int;
+using i64 = long long;
+
+using string = const char*;
+
+
+#endif //AVERY_TYPES_H

kernel/io/serial.cpp

@@ -0,0 +1,23 @@
+/*
+* serial.cpp
+* As part of the Avery project
+* Created by Max Van den Eynde in 2026
+* --------------------------------------
+* Description: Serial implementation
+* Copyright (c) 2026 Max Van den Eynde
+*/
+
+#include "types.h"
+#include "io/serial.h"
+#include "io/io.h"
+
+void io::serialWriteChar(char c) {
+    outb(0xE9, static_cast<u8>(c));
+}
+
+void io::serialWrite(string input) {
+    while (*input) {
+        serialWriteChar(*input);
+        input++;
+    }
+}

kernel/main.cpp

@@ -1,5 +1,7 @@
 #include <limine.h>
 
+#include "io/serial.h"
+
 __attribute__((used, section(".limine_requests")))
 static volatile uint64_t limine_base_revision[] = LIMINE_BASE_REVISION(6);
 
@@ -17,6 +19,8 @@ __attribute__((used, section(".limine_requests_end")))
 static volatile uint64_t limine_requests_end_marker[] = LIMINE_REQUESTS_END_MARKER;
 
 extern "C" [[noreturn]] void _start() {
+    io::serialWrite("Hello, World!");
+
     if (LIMINE_BASE_REVISION_SUPPORTED(limine_base_revision) == false) {
         while (true) {
             asm("hlt");