first boot

src/kernel/kernel.cpp

@@ -0,0 +1,18 @@
+#include "../include/multiboot.h"
+#include "vga_console.h"
+
+typedef void(*constructor)();
+extern "C" constructor start_ctors;
+extern "C" constructor end_ctors;
+extern "C" void callConstructors()
+{
+    for (constructor* i = &start_ctors; i != &end_ctors; i++) {
+        (*i)();
+    }
+}
+
+extern "C" void kernelMain(multiboot_info* multibootInfo, unsigned int magicNumber) {
+    vgaPrint("Hello, world!");
+
+    while (true);
+}

src/kernel/vga_console.cpp

@@ -0,0 +1,13 @@
+#include "vga_console.h"
+
+void vgaPrint(char* string) {
+    static unsigned short* vgaVideoMemory = (unsigned short*)0xb8000;
+
+    for (unsigned int i = 0; string[i] != 0; i++) {
+        /*
+            The high byte in the VGA video memory contains colour info we don't want to overwrite.
+            So, we have to combine the high byte with the char we're writing.
+        */
+        vgaVideoMemory[i] = (vgaVideoMemory[i] & 0xFF00) | string[i];
+    }
+}

src/kernel/vga_console.h

@@ -0,0 +1,3 @@
+#pragma once
+
+void vgaPrint(char* string);