MdePkg/Library/BaseLib/Ia32/LShiftU64.c

   1 /** @file
   2   64-bit left 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 UINT64
  16 EFIAPI
  17 InternalMathLShiftU64 (
  18   IN      UINT64                    Operand,
  19   IN      UINTN                     Count
  20   )
  21 {
  22   _asm {
  23     mov     cl, byte ptr [Count]
  24     xor     eax, eax
  25     mov     edx, dword ptr [Operand + 0]
  26     test    cl, 32                      // Count >= 32?
  27     cmovz   eax, edx
  28     cmovz   edx, dword ptr [Operand + 4]
  29     shld    edx, eax, cl
  30     shl     eax, cl
  31   }
  32 }
  33