EdkCompatibilityPkg/Foundation/Library/EdkIIGlueLib/Library/BaseMemoryLib/Ebc/CopyMem.c

   1 /*++
   2
   3 Copyright (c) 2004 - 2006, Intel Corporation. All rights reserved.<BR>
   4 This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12
  13 Module Name:
  14
  15   CopyMem.c
  16
  17 Abstract:
  18
  19   Internal CopyMem
  20
  21 --*/
  22
  23 #include "BaseMemoryLibInternal.h"
  24
  25 /**
  26   Copy Length bytes from Source to Destination.
  27
  28   @param  Destination Target of copy
  29   @param  Source Place to copy from
  30   @param  Length Number of bytes to copy
  31
  32   @return Destination
  33
  34 **/
  35 VOID *
  36 EFIAPI
  37 InternalMemCopyMem (
  38   OUT     VOID                      *Destination,
  39   IN      CONST VOID                *Source,
  40   IN      UINTN                     Length
  41   )
  42 {
  43   //
  44   // Declare the local variables that actually move the data elements as
  45   // volatile to prevent the optimizer from replacing this function with
  46   // the intrinsic memcpy()
  47   //
  48   volatile UINT8                    *Destination8;
  49   CONST UINT8                       *Source8;
  50
  51   if (Source > Destination) {
  52     Destination8 = (UINT8*)Destination;
  53     Source8 = (CONST UINT8*)Source;
  54     while (Length-- != 0) {
  55       *(Destination8++) = *(Source8++);
  56     }
  57   } else if (Source < Destination) {
  58     Destination8 = (UINT8*)Destination + Length;
  59     Source8 = (CONST UINT8*)Source + Length;
  60     while (Length-- != 0) {
  61       *(--Destination8) = *(--Source8);
  62     }
  63   }
  64   return Destination;
  65 }