1 files changed, 46 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Ia32/RShiftU64.asm b/MdePkg/Library/BaseLib/Ia32/RShiftU64.asm
new file mode 100644
index 0000000000..faa4e96771
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Ia32/RShiftU64.asm
@@ -0,0 +1,46 @@
+;------------------------------------------------------------------------------
+;
+; 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:
+;
+;   RShiftU64.asm
+;
+; Abstract:
+;
+;   64-bit logical right shift function for IA-32
+;
+;------------------------------------------------------------------------------
+
+    .686
+    .model  flat,C
+    .code
+
+;------------------------------------------------------------------------------
+; UINT64
+; EFIAPI
+; InternalMathRShiftU64 (
+;   IN      UINT64                    Operand,
+;   IN      UINTN                     Count
+;   );
+;------------------------------------------------------------------------------
+InternalMathRShiftU64   PROC
+    mov     cl, [esp + 12]              ; cl <- Count
+    xor     edx, edx
+    mov     eax, [esp + 8]
+    test    cl, 32                      ; Count >= 32?
+    cmovz   edx, eax
+    cmovz   eax, [esp + 4]
+    shrd    eax, edx, cl
+    shr     edx, cl
+    ret
+InternalMathRShiftU64   ENDP
+
+    END