diff --git a/MdePkg/Library/BaseMemoryLibMmx/BaseMemoryLibMmx.inf b/MdePkg/Library/BaseMemoryLibMmx/BaseMemoryLibMmx.inf
index f3ffc1cb79..00c68d0223 100644
--- a/MdePkg/Library/BaseMemoryLibMmx/BaseMemoryLibMmx.inf
+++ b/MdePkg/Library/BaseMemoryLibMmx/BaseMemoryLibMmx.inf
@@ -108,6 +108,7 @@
   X64/ScanMem8.asm
   X64/CompareMem.nasm
   X64/CompareMem.asm
+  X64/SetMem64.nasm
   X64/SetMem64.asm
   X64/SetMem32.asm
   X64/SetMem16.asm
@@ -123,6 +124,7 @@
   X64/ScanMem8.S
   X64/CompareMem.nasm
   X64/CompareMem.S
+  X64/SetMem64.nasm
   X64/SetMem64.S
   X64/SetMem32.S
   X64/SetMem16.S
diff --git a/MdePkg/Library/BaseMemoryLibMmx/X64/SetMem64.nasm b/MdePkg/Library/BaseMemoryLibMmx/X64/SetMem64.nasm
new file mode 100644
index 0000000000..8b076c5899
--- /dev/null
+++ b/MdePkg/Library/BaseMemoryLibMmx/X64/SetMem64.nasm
@@ -0,0 +1,46 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
+; This program and the accompanying materials
+; are licensed and made available under the terms and conditions of the BSD License
+; which accompanies this distribution.  The full text of the license may be found at
+; http://opensource.org/licenses/bsd-license.php.
+;
+; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+;
+; Module Name:
+;
+;   SetMem64.nasm
+;
+; Abstract:
+;
+;   SetMem64 function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+    DEFAULT REL
+    SECTION .text
+
+;------------------------------------------------------------------------------
+;  VOID *
+;  InternalMemSetMem64 (
+;    IN VOID   *Buffer,
+;    IN UINTN  Count,
+;    IN UINT64 Value
+;    )
+;------------------------------------------------------------------------------
+global ASM_PFX(InternalMemSetMem64)
+ASM_PFX(InternalMemSetMem64):
+    DB      0x49, 0xf, 0x6e, 0xc0         ; movd mm0, r8 (Value)
+    mov     rax, rcx                    ; rax <- Buffer
+    xchg    rcx, rdx                    ; rcx <- Count
+.0:
+    DB      0xf, 0xe7, 0x2              ; movntq  [rdx], mm0
+    add     rdx, 8
+    loop    .0
+    mfence
+    ret
+