1 files changed, 19 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Ebc/Synchronization.c b/MdePkg/Library/BaseLib/Ebc/Synchronization.c
index ef3fa62d89..cb5d1f3450 100644
--- a/MdePkg/Library/BaseLib/Ebc/Synchronization.c
+++ b/MdePkg/Library/BaseLib/Ebc/Synchronization.c
@@ -12,6 +12,25 @@
 
 **/
 
+/**
+  Performs an atomic compare exchange operation on a 32-bit
+  unsigned integer.
+
+  Performs an atomic compare exchange operation on the 32-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 32-bit value for the
+                        compare exchange operation.
+  @param  CompareValue  32-bit value used in compare operation.
+  @param  ExchangeValue 32-bit value used in exchange operation.
+
+  @return The original *Value before exchange.
+
+**/
 UINT32
 EFIAPI
 InternalSyncCompareExchange32 (