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db_include/port/atomics/generic-msvc.h

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+/*-------------------------------------------------------------------------
+ *
+ * generic-msvc.h
+ *	  Atomic operations support when using MSVC
+ *
+ * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * NOTES:
+ *
+ * Documentation:
+ * * Interlocked Variable Access
+ *   http://msdn.microsoft.com/en-us/library/ms684122%28VS.85%29.aspx
+ *
+ * src/include/port/atomics/generic-msvc.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#include <intrin.h>
+
+/* intentionally no include guards, should only be included by atomics.h */
+#ifndef INSIDE_ATOMICS_H
+#error "should be included via atomics.h"
+#endif
+
+#pragma intrinsic(_ReadWriteBarrier)
+#define pg_compiler_barrier_impl()	_ReadWriteBarrier()
+
+#ifndef pg_memory_barrier_impl
+#define pg_memory_barrier_impl()	MemoryBarrier()
+#endif
+
+#if defined(HAVE_ATOMICS)
+
+#define PG_HAVE_ATOMIC_U32_SUPPORT
+typedef struct pg_atomic_uint32
+{
+	volatile uint32 value;
+} pg_atomic_uint32;
+
+#define PG_HAVE_ATOMIC_U64_SUPPORT
+typedef struct __declspec(align(8)) pg_atomic_uint64
+{
+	volatile uint64 value;
+} pg_atomic_uint64;
+
+
+#define PG_HAVE_ATOMIC_COMPARE_EXCHANGE_U32
+static inline bool
+pg_atomic_compare_exchange_u32_impl(volatile pg_atomic_uint32 *ptr,
+									uint32 *expected, uint32 newval)
+{
+	bool	ret;
+	uint32	current;
+	current = InterlockedCompareExchange(&ptr->value, newval, *expected);
+	ret = current == *expected;
+	*expected = current;
+	return ret;
+}
+
+#define PG_HAVE_ATOMIC_FETCH_ADD_U32
+static inline uint32
+pg_atomic_fetch_add_u32_impl(volatile pg_atomic_uint32 *ptr, int32 add_)
+{
+	return InterlockedExchangeAdd(&ptr->value, add_);
+}
+
+/*
+ * The non-intrinsics versions are only available in vista upwards, so use the
+ * intrinsic version. Only supported on >486, but we require XP as a minimum
+ * baseline, which doesn't support the 486, so we don't need to add checks for
+ * that case.
+ */
+#pragma intrinsic(_InterlockedCompareExchange64)
+
+#define PG_HAVE_ATOMIC_COMPARE_EXCHANGE_U64
+static inline bool
+pg_atomic_compare_exchange_u64_impl(volatile pg_atomic_uint64 *ptr,
+									uint64 *expected, uint64 newval)
+{
+	bool	ret;
+	uint64	current;
+	current = _InterlockedCompareExchange64(&ptr->value, newval, *expected);
+	ret = current == *expected;
+	*expected = current;
+	return ret;
+}
+
+/* Only implemented on itanium and 64bit builds */
+#ifdef _WIN64
+#pragma intrinsic(_InterlockedExchangeAdd64)
+
+#define PG_HAVE_ATOMIC_FETCH_ADD_U64
+static inline uint64
+pg_atomic_fetch_add_u64_impl(volatile pg_atomic_uint64 *ptr, int64 add_)
+{
+	return _InterlockedExchangeAdd64(&ptr->value, add_);
+}
+#endif /* _WIN64 */
+
+#endif /* HAVE_ATOMICS */