common: port ScopedPtrMT to std::atomic

v2: s/NULL/nullptr/
v3: tentative fix for MSVC
// ScopedPtrMT.h(91, 0): error C2593: 'operator ==' is ambiguous

common/include/Utilities/Dependencies.h

@@ -200,6 +200,7 @@ public:
 #include <list>
 #include <algorithm>
 #include <memory>
+#include <atomic>
 
 #include "Pcsx2Defs.h"
 

common/include/Utilities/ScopedPtrMT.h

@@ -27,25 +27,23 @@ class ScopedPtrMT
 {
 	DeclareNoncopyableObject(ScopedPtrMT);
 
-	typedef T* TPtr;
-
 protected:
-	volatile TPtr		m_ptr;
+	std::atomic<T*>		m_ptr;
 	Threading::Mutex	m_mtx;
 
 public:
 	typedef T element_type;
 
-	wxEXPLICIT ScopedPtrMT(T * ptr = NULL)
+	wxEXPLICIT ScopedPtrMT(T * ptr = nullptr)
 	{
 		m_ptr = ptr;
 	}
 
 	~ScopedPtrMT() throw() { _Delete_unlocked(); }
 
-	ScopedPtrMT& Reassign(T * ptr = NULL)
+	ScopedPtrMT& Reassign(T * ptr = nullptr)
 	{
-		TPtr doh = (TPtr)Threading::AtomicExchangePointer( m_ptr, ptr );
+		T* doh = m_ptr.exchange(ptr);
 		if ( ptr != doh ) delete doh;
 		return *this;
 	}
@@ -57,17 +55,15 @@ public:
 	}
 
 	// Removes the pointer from scoped management, but does not delete!
-	// (ScopedPtr will be NULL after this method)
+	// (ScopedPtr will be nullptr after this method)
 	T *DetachPtr()
 	{
 		ScopedLock lock( m_mtx );
 
-		T *ptr = m_ptr;
+		return m_ptr.exchange(nullptr);
-		m_ptr = NULL;
-		return ptr;
 	}
 
-	// Returns the managed pointer.  Can return NULL as a valid result if the ScopedPtrMT
+	// Returns the managed pointer.  Can return nullptr as a valid result if the ScopedPtrMT
 	// has no object in management.
 	T* GetPtr() const
 	{
@@ -77,6 +73,7 @@ public:
 	void SwapPtr(ScopedPtrMT& other)
 	{
 		ScopedLock lock( m_mtx );
+		m_ptr.exchange(other.m_ptr.exchange(m_ptr.load()));
 		T * const tmp = other.m_ptr;
 		other.m_ptr = m_ptr;
 		m_ptr = tmp;
@@ -91,7 +88,7 @@ public:
 
 	bool operator!() const throw()
 	{
-		return m_ptr == NULL;
+		return m_ptr.load() == nullptr;
 	}
 
 	// Equality
@@ -106,7 +103,7 @@ public:
 		return !operator==(pT);
 	}
 
-	// Convenient assignment operator.  ScopedPtrMT = NULL will issue an automatic deletion
+	// Convenient assignment operator.  ScopedPtrMT = nullptr will issue an automatic deletion
 	// of the managed pointer.
 	ScopedPtrMT& operator=( T* src )
 	{
@@ -120,16 +117,16 @@ public:
 	}
 
 	// Dereference operator, returns a handle to the managed pointer.
-	// Generates a debug assertion if the object is NULL!
+	// Generates a debug assertion if the object is nullptr!
 	T& operator*() const
 	{
-		pxAssert(m_ptr != NULL);
+		pxAssert(m_ptr != nullptr);
 		return *m_ptr;
 	}
 
 	T* operator->() const
 	{
-		pxAssert(m_ptr != NULL);
+		pxAssert(m_ptr != nullptr);
 		return m_ptr;
 	}
 	#endif
@@ -137,7 +134,6 @@ public:
 protected:
 	void _Delete_unlocked() throw()
 	{
-		delete m_ptr;
+		delete m_ptr.exchange(nullptr);
-		m_ptr = NULL;
 	}
 };

common/include/Utilities/Threading.h

@@ -192,12 +192,6 @@ namespace Threading
 	extern bool AtomicBitTestAndReset( volatile u32& bitset, u8 bit );
 	extern bool AtomicBitTestAndReset( volatile s32& bitset, u8 bit );
 
-	extern void* _AtomicExchangePointer( volatile uptr& target, uptr value );
-	extern void* _AtomicCompareExchangePointer( volatile uptr& target, uptr value, uptr comparand );
-
-#define AtomicExchangePointer( dest, src )				_AtomicExchangePointer( (uptr&)dest, (uptr)src )
-#define AtomicCompareExchangePointer( dest, comp, src )	_AtomicExchangePointer( (uptr&)dest, (uptr)comp, (uptr)src )
-
 	// pthread Cond is an evil api that is not suited for Pcsx2 needs.
 	// Let's not use it. Use mutexes and semaphores instead to create waits. (Air)
 #if 0

common/src/Utilities/ThreadTools.cpp

@@ -828,24 +828,6 @@ __fi s32 Threading::AtomicDecrement(volatile s32& Target) {
 	return _InterlockedExchangeAdd((volatile vol_t*)&Target, -1);
 }
 
-__fi void* Threading::_AtomicExchangePointer(volatile uptr& target, uptr value)
-{
-#ifdef _M_X86_64		// high-level atomic ops, please leave these 64 bit checks in place.
-	return (void*)_InterlockedExchange64((volatile s64*)&target, value);
-#else
-	return (void*)_InterlockedExchange((volatile vol_t*)&target, value);
-#endif
-}
-
-__fi void* Threading::_AtomicCompareExchangePointer(volatile uptr& target, uptr value, uptr comparand)
-{
-#ifdef _M_X86_64		// high-level atomic ops, please leave these 64 bit checks in place.
-	return (void*)_InterlockedCompareExchange64((volatile s64*)&target, value, comparand);
-#else
-	return (void*)_InterlockedCompareExchange((volatile vol_t*)&target, value, comparand);
-#endif
-}
-
 // --------------------------------------------------------------------------------------
 //  BaseThreadError
 // --------------------------------------------------------------------------------------