feat: PCI-e, APIC timer

kernel/src/Timekeeping/ApicTimer.hpp

@@ -0,0 +1,22 @@
+/*
+    * ApicTimer.hpp
+    * Local APIC timer for periodic tick interrupts and timekeeping
+    * Copyright (c) 2025 Daniel Hammer
+*/
+
+#pragma once
+#include <cstdint>
+
+namespace Timekeeping {
+    // Initialize the APIC timer: calibrate against PIT, start periodic interrupts
+    void ApicTimerInitialize();
+
+    // Get the monotonic tick count (increments on each timer interrupt)
+    uint64_t GetTicks();
+
+    // Get elapsed milliseconds since timer initialization
+    uint64_t GetMilliseconds();
+
+    // Busy-wait sleep for the given number of milliseconds
+    void Sleep(uint64_t ms);
+};