updated the kernel with initial functionality but used stub code

src/kernel/kernel.c

@@ -1,12 +1,73 @@
-#include "kernel.h"
-
-void kernel_main() {
-    // Your kernel code here
-    // Example: Print a message to the screen
-    print_string("Welcome to ClassicOS!");
-
-    // Infinite loop to keep the kernel running
-    while (1) {
-        // Your kernel code here
-    }
-}
+#include "kernel.h"
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
+#define VGA_ADDRESS 0xB8000
+#define VGA_WIDTH 80
+#define VGA_HEIGHT 25
+#define VGA_COLOR_BLACK 0x0
+#define VGA_COLOR_WHITE 0xF
+
+uint16_t* const VGA_MEMORY = (uint16_t*) VGA_ADDRESS;
+
+void clear_screen() {
+    for (int i = 0; i < VGA_WIDTH * VGA_HEIGHT; i++) {
+        VGA_MEMORY[i] = ((uint16_t)VGA_COLOR_BLACK << 8) | ' ';
+    }
+}
+
+void print(const char* message) {
+    static int row = 0;
+    static int col = 0;
+    for (size_t i = 0; message[i] != '\0'; i++) {
+        if (col >= VGA_WIDTH || message[i] == '\n') {
+            row++;
+            col = 0;
+        }
+        if (row >= VGA_HEIGHT) {
+            clear_screen();
+            row = 0;
+        }
+        if (message[i] != '\n') {
+            VGA_MEMORY[row * VGA_WIDTH + col] = ((uint16_t)VGA_COLOR_WHITE << 8) | message[i];
+            col++;
+        }
+    }
+}
+
+void init_memory_management() {
+    // Placeholder for actual implementation
+}
+
+void init_devices() {
+    // Placeholder for actual implementation
+}
+
+void kernel_main() {
+    clear_screen();
+    print("Welcome to ClassicOS!");
+
+    // Initialize memory management
+    init_memory_management();
+
+    // Initialize devices
+    init_devices();
+
+    // Infinite loop to keep the kernel running
+    while (1) {
+        // Handle any pending interrupts
+        handle_interrupts();
+
+        // Schedule the next process to run
+        schedule_next_process();
+
+        // Perform deferred work from interrupts or system calls
+        process_deferred_work();
+
+        // Handle system calls from user-space applications
+        handle_system_calls();
+    }
+}
+