diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
index 1976720ac6..bd98a5aebf 100644
--- a/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
+++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/GccInline.c
@@ -115,11 +115,10 @@ InternalSyncCompareExchange16 (
 {
   __asm__ __volatile__ (
     "lock                 \n\t"
-    "cmpxchgw    %1, %2   \n\t"
-    : "=a" (CompareValue)       // %0
-    : "q"  (ExchangeValue),     // %1
-      "m"  (*Value),            // %2
-      "0"  (CompareValue)       // %3
+    "cmpxchgw    %2, %1   \n\t"
+    : "+a" (CompareValue),      // %0
+      "+m" (*Value)             // %1
+    : "q"  (ExchangeValue)      // %2
     : "memory",
       "cc"
     );
diff --git a/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c b/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c
index 0212798d7a..4338fb8e65 100644
--- a/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c
+++ b/MdePkg/Library/BaseSynchronizationLib/X64/GccInline.c
@@ -115,12 +115,10 @@ InternalSyncCompareExchange16 (
 {
   __asm__ __volatile__ (
     "lock                 \n\t"
-    "cmpxchgw    %3, %1   \n\t"
-    : "=a" (CompareValue),      // %0
-      "=m" (*Value)             // %1
-    : "a"  (CompareValue),      // %2
-      "r"  (ExchangeValue),     // %3
-      "m"  (*Value)             // %4
+    "cmpxchgw    %2, %1   \n\t"
+    : "+a" (CompareValue),      // %0
+      "+m" (*Value)             // %1
+    : "r"  (ExchangeValue)      // %2
     : "memory",
       "cc"
     );