1 files changed, 44 insertions, 0 deletions
diff --git a/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange64.c b/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange64.c
new file mode 100644
index 00000000..9c0572ce
--- /dev/null
+++ b/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange64.c
@@ -0,0 +1,44 @@
+/** @file
+  InterlockedCompareExchange64 function
+
+  Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+
+
+
+/**
+  Performs an atomic compare exchange operation on a 64-bit unsigned integer.
+
+  Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
+  by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
+  CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
+  The compare exchange operation must be performed using MP safe mechanisms.
+
+  @param  Value         A pointer to the 64-bit value for the compare exchange
+                        operation.
+  @param  CompareValue  A 64-bit value used in a compare operation.
+  @param  ExchangeValue A 64-bit value used in an exchange operation.
+
+  @return The original *Value before exchange.
+
+**/
+UINT64
+EFIAPI
+InternalSyncCompareExchange64 (
+  IN      volatile UINT64           *Value,
+  IN      UINT64                    CompareValue,
+  IN      UINT64                    ExchangeValue
+  )
+{
+  _asm {
+    mov     esi, Value
+    mov     eax, dword ptr [CompareValue + 0]
+    mov     edx, dword ptr [CompareValue + 4]
+    mov     ebx, dword ptr [ExchangeValue + 0]
+    mov     ecx, dword ptr [ExchangeValue + 4]
+    lock    cmpxchg8b   qword ptr [esi]
+  }
+}