From: Jinoh Kang <jinoh.kang.kr@gmail.com>
Subject: [PATCH v2] include: Define atomic read/write helpers for 32-bit integers.
Message-Id: <1234ad61-ccfe-da1b-7c49-496573660a86@gmail.com>
Date: Mon, 6 Jun 2022 18:30:09 +0900

Based on the corresponding functions from Windows SDK header files.

Signed-off-by: Jinoh Kang <jinoh.kang.kr@gmail.com>
---
v1 -> v2: Remove *ULong* wrappers (not needed immediately)

 include/winnt.h | 92 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)

diff --git a/include/winnt.h b/include/winnt.h
index 87c4b4da92d..370ed3adce6 100644
--- a/include/winnt.h
+++ b/include/winnt.h
@@ -6475,6 +6475,61 @@ static FORCEINLINE void MemoryBarrier(void)
 
 #endif /* __i386__ */
 
+/* Since Visual Studio 2012, volatile accesses do not always imply acquire and
+ * release semantics.  We explicitly use ISO volatile semantics, manually
+ * placing barriers as appropriate.
+ */
+#if _MSC_VER >= 1700
+#pragma intrinsic(__iso_volatile_load32)
+#pragma intrinsic(__iso_volatile_store32)
+#define __WINE_ISO_VOLATILE_LOAD_32(src) (__iso_volatile_load32(src))
+#define __WINE_ISO_VOLATILE_STORE_32(dest, value) (__iso_volatile_store32(dest, value))
+#else  /* _MSC_VER >= 1700 */
+#define __WINE_ISO_VOLATILE_LOAD_32(src) (*(src))
+#define __WINE_ISO_VOLATILE_STORE_32(dest, value) ((void)(*(dest) = (value)))
+#endif  /* _MSC_VER >= 1700 */
+
+#if defined(__i386__) || defined(__x86_64__)
+#pragma intrinsic(_ReadWriteBarrier)
+void _ReadWriteBarrier(void);
+#endif  /* defined(__i386__) || defined(__x86_64__) */
+
+static void __wine_memory_barrier_acq_rel(void)
+{
+#if defined(__i386__) || defined(__x86_64__)
+#pragma warning(suppress:4996)
+    _ReadWriteBarrier();
+#elif defined(__arm__)
+    __dmb(_ARM_BARRIER_ISH);
+#elif defined(__aarch64__)
+    __dmb(_ARM64_BARRIER_ISH);
+#endif  /* defined(__i386__) || defined(__x86_64__) */
+}
+
+static FORCEINLINE LONG ReadAcquire( LONG const volatile *src )
+{
+    LONG value = __WINE_ISO_VOLATILE_LOAD_32( (int const volatile *)src );
+    __wine_memory_barrier_acq_rel();
+    return value;
+}
+
+static FORCEINLINE LONG ReadNoFence( LONG const volatile *src )
+{
+    LONG value = __WINE_ISO_VOLATILE_LOAD_32( (int const volatile *)src );
+    return value;
+}
+
+static FORCEINLINE void WriteRelease( LONG volatile *dest, LONG value )
+{
+    __wine_memory_barrier_acq_rel();
+    __WINE_ISO_VOLATILE_STORE_32( (int volatile *)dest, value );
+}
+
+static FORCEINLINE void WriteNoFence( LONG volatile *dest, LONG value )
+{
+    __WINE_ISO_VOLATILE_STORE_32( (int volatile *)dest, value );
+}
+
 #elif defined(__GNUC__)
 
 static FORCEINLINE BOOLEAN WINAPI BitScanForward(DWORD *index, DWORD mask)
@@ -6588,6 +6643,43 @@ static FORCEINLINE void MemoryBarrier(void)
     __sync_synchronize();
 }
 
+#if defined(__x86_64__) || defined(__i386__)
+/* On x86, Support old GCC with either no or buggy (GCC BZ#81316) __atomic_* support */
+#define __WINE_ATOMIC_LOAD_ACQUIRE(ptr, ret) do { *(ret) = *(ptr); __asm__ __volatile__( "" ::: "memory" ); } while (0)
+#define __WINE_ATOMIC_LOAD_RELAXED(ptr, ret) do { *(ret) = *(ptr); } while (0)
+#define __WINE_ATOMIC_STORE_RELEASE(ptr, val) do { __asm__ __volatile__( "" ::: "memory" ); *(ptr) = *(val); } while (0)
+#define __WINE_ATOMIC_STORE_RELAXED(ptr, val) do { *(ptr) = *(val); } while (0)
+#else
+#define __WINE_ATOMIC_LOAD_ACQUIRE(ptr, ret) __atomic_load(ptr, ret, __ATOMIC_ACQUIRE)
+#define __WINE_ATOMIC_LOAD_RELAXED(ptr, ret) __atomic_load(ptr, ret, __ATOMIC_RELAXED)
+#define __WINE_ATOMIC_STORE_RELEASE(ptr, val) __atomic_store(ptr, val, __ATOMIC_RELEASE)
+#define __WINE_ATOMIC_STORE_RELAXED(ptr, val) __atomic_store(ptr, val, __ATOMIC_RELAXED)
+#endif  /* defined(__x86_64__) || defined(__i386__) */
+
+static FORCEINLINE LONG ReadAcquire( LONG const volatile *src )
+{
+    LONG value;
+    __WINE_ATOMIC_LOAD_ACQUIRE( src, &value );
+    return value;
+}
+
+static FORCEINLINE LONG ReadNoFence( LONG const volatile *src )
+{
+    LONG value;
+    __WINE_ATOMIC_LOAD_RELAXED( src, &value );
+    return value;
+}
+
+static FORCEINLINE void WriteRelease( LONG volatile *dest, LONG value )
+{
+    __WINE_ATOMIC_STORE_RELEASE( dest, &value );
+}
+
+static FORCEINLINE void WriteNoFence( LONG volatile *dest, LONG value )
+{
+    __WINE_ATOMIC_STORE_RELAXED( dest, &value );
+}
+
 static FORCEINLINE DECLSPEC_NORETURN void __fastfail(unsigned int code)
 {
 #if defined(__x86_64__) || defined(__i386__)

-- 
2.35.3