MdePkg/Library/BaseLib/Ia32/SwapBytes64.c

   1 /** @file
   2   Implementation of 64-bit swap bytes
   3
   4   Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 /**
  10   Switches the endianess of a 64-bit integer.
  11
  12   This function swaps the bytes in a 64-bit unsigned value to switch the value
  13   from little endian to big endian or vice versa. The byte swapped value is
  14   returned.
  15
  16   @param  Operand A 64-bit unsigned value.
  17
  18   @return The byte swaped Operand.
  19
  20 **/
  21 UINT64
  22 EFIAPI
  23 InternalMathSwapBytes64 (
  24   IN      UINT64  Operand
  25   )
  26 {
  27   _asm {
  28     mov     eax, dword ptr [Operand + 4]
  29     mov     edx, dword ptr [Operand + 0]
  30     bswap   eax
  31     bswap   edx
  32   }
  33 }