MdePkg/Library/BaseLib/Ia32/RShiftU64.c

   1 /** @file
   2   64-bit logical right shift function for IA-32
   3
   4   Copyright (c) 2006 - 2007, 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 //
  16 // Include common header file for this module.
  17 //
  18
  19
  20 UINT64
  21 EFIAPI
  22 InternalMathRShiftU64 (
  23   IN      UINT64                    Operand,
  24   IN      UINTN                     Count
  25   )
  26 {
  27   _asm {
  28     mov     cl, byte ptr [Count]
  29     xor     edx, edx
  30     mov     eax, dword ptr [Operand + 4]
  31     test    cl, 32
  32     cmovz   edx, eax
  33     cmovz   eax, dword ptr [Operand + 0]
  34     shrd    eax, edx, cl
  35     shr     edx, cl
  36   }
  37 }
  38