audk/MdePkg/Library/BaseLib/Ia32/ARShiftU64.c

/** @file
  64-bit arithmetic right shift function for IA-32.

  Copyright (c) 2006 - 2008, Intel Corporation<BR>
  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.

**/




/**
  Shifts a 64-bit integer right between 0 and 63 bits. The high bits
  are filled with original integer's bit 63. The shifted value is returned.

  This function shifts the 64-bit value Operand to the right by Count bits. The
  high Count bits are set to bit 63 of Operand.  The shifted value is returned.

  @param  Operand The 64-bit operand to shift right.
  @param  Count   The number of bits to shift right.

  @return Operand arithmetically shifted right by Count

**/
UINT64
EFIAPI
InternalMathARShiftU64 (
  IN      UINT64                    Operand,
  IN      UINTN                     Count
  )
{
  _asm {
    mov     cl, byte ptr [Count]
    mov     eax, dword ptr [Operand + 4]
    cdq
    test    cl, 32
    cmovz   edx, eax
    cmovz   eax, dword ptr [Operand + 0]
    shrd    eax, edx, cl
    sar     edx, cl
  }
}