diff --git a/MdePkg/Library/BaseMemoryLibOptPei/BaseMemoryLibOptPei.inf b/MdePkg/Library/BaseMemoryLibOptPei/BaseMemoryLibOptPei.inf
index aad4cf191d..221dab9d20 100644
--- a/MdePkg/Library/BaseMemoryLibOptPei/BaseMemoryLibOptPei.inf
+++ b/MdePkg/Library/BaseMemoryLibOptPei/BaseMemoryLibOptPei.inf
@@ -54,6 +54,7 @@
   Ia32/SetMem16.S
   Ia32/SetMem.nasm
   Ia32/SetMem.S
+  Ia32/CopyMem.nasm
   Ia32/CopyMem.S
   Ia32/ScanMem64.nasm
   Ia32/ScanMem64.asm
@@ -75,6 +76,7 @@
   Ia32/SetMem16.asm
   Ia32/SetMem.nasm
   Ia32/SetMem.asm
+  Ia32/CopyMem.nasm
   Ia32/CopyMem.asm
   ScanMem64Wrapper.c
   ScanMem32Wrapper.c
diff --git a/MdePkg/Library/BaseMemoryLibOptPei/Ia32/CopyMem.nasm b/MdePkg/Library/BaseMemoryLibOptPei/Ia32/CopyMem.nasm
new file mode 100644
index 0000000000..d80f52b70b
--- /dev/null
+++ b/MdePkg/Library/BaseMemoryLibOptPei/Ia32/CopyMem.nasm
@@ -0,0 +1,62 @@
+;------------------------------------------------------------------------------
+;
+; 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:
+;
+;   CopyMem.Asm
+;
+; Abstract:
+;
+;   CopyMem function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+    SECTION .text
+
+;------------------------------------------------------------------------------
+;  VOID *
+;  InternalMemCopyMem (
+;    IN VOID   *Destination,
+;    IN VOID   *Source,
+;    IN UINTN  Count
+;    )
+;------------------------------------------------------------------------------
+global ASM_PFX(InternalMemCopyMem)
+ASM_PFX(InternalMemCopyMem):
+    push    esi
+    push    edi
+    mov     esi, [esp+16]                ; esi <- Source
+    mov     edi, [esp+12]                ; edi <- Destination
+    mov     edx, [esp+20]                ; edx <- Count
+    cmp     esi, edi
+    je      @CopyDone
+    cmp     edx, 0
+    je      @CopyDone
+    lea     eax, [esi + edx - 1]         ; eax <- End of Source
+    cmp     esi, edi
+    jae     @CopyBytes
+    cmp     eax, edi
+    jb      @CopyBytes                   ; Copy backward if overlapped
+    mov     esi, eax                     ; esi <- End of Source
+    lea     edi, [edi + edx - 1]         ; edi <- End of Destination
+    std
+@CopyBytes:
+    mov     ecx, edx
+    rep     movsb                        ; Copy bytes backward
+    cld
+@CopyDone:
+    mov     eax, [esp + 12]             ; eax <- Destination as return value
+    pop     edi
+    pop     esi
+    ret
+