Added Counter() function to CPU

Core/CPU.cpp

@@ -240,6 +240,24 @@ namespace CPU
 			trace("Features for BSP initialized.");
 #elif defined(__i386__)
 #elif defined(__aarch64__)
+#endif
+	}
+
+	uint64_t Counter()
+	{
+		// TODO: Get the counter from the x2APIC or any other timer that is available. (TSC is not available on all CPUs)
+#if defined(__amd64__)
+		uint64_t counter;
+		asmv("rdtsc"
+			 : "=A"(counter));
+		return counter;
+#elif defined(__i386__)
+		return 0;
+#elif defined(__aarch64__)
+		uint64_t counter;
+		asmv("mrs %0, cntvct_el0"
+			 : "=r"(counter));
+		return counter;
 #endif
 	}
 }

include/cpu.hpp

@@ -203,6 +203,9 @@ namespace CPU
     /** @brief To be used only once. */
     void InitializeFeatures();
 
+    /** @brief Get CPU counter value. */
+    uint64_t Counter();
+
     namespace MemBar
     {
         __attribute__((no_stack_protector)) static inline void Barrier()