AK: Add atomic free functions

This allows for using atomic operations on any variables,
not only those wrapped in AK::Atomic<T>

AK/Atomic.h

@@ -39,6 +39,63 @@ enum MemoryOrder {
  memory_order_seq_cst = __ATOMIC_SEQ_CST
 };
 
+template <typename T>
+static inline T atomic_exchange(volatile T* var, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_exchange_n(var, desired, order);
+}
+
+template <typename T>
+static inline bool atomic_compare_exchange_strong(volatile T* var, T& expected, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ if (order == memory_order_acq_rel || order == memory_order_release)
+ return __atomic_compare_exchange_n(var, &expected, desired, false, memory_order_release, memory_order_acquire);
+ else
+ return __atomic_compare_exchange_n(var, &expected, desired, false, order, order);
+}
+
+template <typename T>
+static inline T atomic_fetch_add(volatile T* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_fetch_add(var, val, order);
+}
+
+template <typename T>
+static inline T atomic_fetch_sub(volatile T* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_fetch_sub(var, val, order);
+}
+
+template <typename T>
+static inline T atomic_fetch_and(volatile T* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_fetch_and(var, val, order);
+}
+
+template <typename T>
+static inline T atomic_fetch_or(volatile T* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_fetch_or(var, val, order);
+}
+
+template <typename T>
+static inline T atomic_fetch_xor(volatile T* var, T val, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_fetch_xor(var, val, order);
+}
+
+template <typename T>
+static inline T atomic_load(volatile T* var, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ return __atomic_load_n(var, order);
+}
+
+template <typename T>
+static inline void atomic_store(volatile T* var, T desired, MemoryOrder order = memory_order_seq_cst) noexcept
+{
+ __atomic_store_n(var, desired, order);
+}
+
 template<typename T>
 class Atomic {
  T m_value { 0 };
@@ -53,6 +110,11 @@ class Atomic {
  {
  }
 
+ volatile T* ptr()
+ {
+ return &m_value;
+ }
+
  T exchange(T desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
  {
  return __atomic_exchange_n(&m_value, desired, order);
@@ -177,6 +239,11 @@ class Atomic<T*> {
  {
  }
 
+ volatile T** ptr()
+ {
+ return &m_value;
+ }
+
  T* exchange(T* desired, MemoryOrder order = memory_order_seq_cst) volatile noexcept
  {
  return __atomic_exchange_n(&m_value, desired, order);