1 files changed, 52 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseMemoryLibOptDxe/x64/CompareMem.asm b/MdePkg/Library/BaseMemoryLibOptDxe/x64/CompareMem.asm
new file mode 100644
index 0000000000..554bc07c64
--- /dev/null
+++ b/MdePkg/Library/BaseMemoryLibOptDxe/x64/CompareMem.asm
@@ -0,0 +1,52 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, Intel Corporation
+; All rights reserved. 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:
+;
+;   CompareMem.Asm
+;
+; Abstract:
+;
+;   CompareMem function
+;
+; Notes:
+;
+;   The following BaseMemoryLib instances share the same version of this file:
+;
+;       BaseMemoryLibRepStr
+;       BaseMemoryLibMmx
+;       BaseMemoryLibSse2
+;
+;------------------------------------------------------------------------------
+
+    .code
+
+;------------------------------------------------------------------------------
+; INTN
+; EFIAPI
+; InternalMemCompareMem (
+;   IN      CONST VOID                *DestinationBuffer,
+;   IN      CONST VOID                *SourceBuffer,
+;   IN      UINTN                     Length
+;   );
+;------------------------------------------------------------------------------
+InternalMemCompareMem   PROC    USES    rsi rdi
+    mov     rsi, rcx
+    mov     rdi, rdx
+    mov     rcx, r8
+    repe    cmpsb
+    movzx   rax, byte ptr [rsi - 1]
+    movzx   rdx, byte ptr [rdi - 1]
+    sub     rax, rdx
+    ret
+InternalMemCompareMem   ENDP
+
+    END