MdePkg/Library/BaseLib/Ia32/RShiftU64.c

   1 /** @file
   2   64-bit logical right shift function for IA-32
   3
   4   Copyright (c) 2006, Intel Corporation<BR>
   5   All rights reserved. This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #if _MSC_EXTENSIONS
  16
  17 UINT64
  18 EFIAPI
  19 InternalMathRShiftU64 (
  20   IN      UINT64                    Operand,
  21   IN      UINTN                     Count
  22   )
  23 {
  24   _asm {
  25     mov     cl, byte ptr [Count]
  26     xor     edx, edx
  27     mov     eax, dword ptr [Operand + 4]
  28     test    cl, 32
  29     cmovz   edx, eax
  30     cmovz   eax, dword ptr [Operand + 0]
  31     shrd    eax, edx, cl
  32     shr     edx, cl
  33   }
  34 }
  35
  36 #endif