EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/EfiCompareMem.c

   1 /*++
   2
   3 Copyright (c) 2004, Intel Corporation
   4 All rights reserved. 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 Module Name:
  13
  14   EfiCompareMem.c
  15
  16 Abstract:
  17
  18   Generic compare-memory routine.
  19
  20 --*/
  21
  22 #include "Tiano.h"
  23 #include "EfiDriverLib.h"
  24
  25
  26 INTN
  27 EfiCompareMem (
  28   IN VOID     *MemOne,
  29   IN VOID     *MemTwo,
  30   IN UINTN    Length
  31   )
  32 /*++
  33
  34 Routine Description:
  35
  36   Compares two memory buffers of a given length.
  37
  38 Arguments:
  39
  40   MemOne - First memory buffer
  41
  42   MemTwo - Second memory buffer
  43
  44   Len    - Length of Mem1 and Mem2 memory regions to compare
  45
  46 Returns:
  47
  48   = 0     if MemOne == MemTwo
  49
  50 --*/
  51 {
  52   INTN ReturnValue;
  53
  54   if (!(EFI_UINTN_ALIGNED (MemOne) || EFI_UINTN_ALIGNED (MemTwo) || EFI_UINTN_ALIGNED (Length))) {
  55     //
  56     // If Destination/Source/Length are aligned do UINTN conpare
  57     //
  58     for (; Length > 0; Length -= sizeof (INTN), MemOne = (VOID *)((UINTN)MemOne + sizeof (INTN)), MemTwo = (VOID *)((UINTN)MemTwo + sizeof (INTN))) {
  59       if (*(INTN *)MemOne != *(INTN *)MemTwo) {
  60         break;
  61       }
  62     }
  63   }
  64
  65   //
  66   // If Destination/Source/Length not aligned do byte compare
  67   //
  68   for (; Length > 0; Length--, MemOne = (VOID *)((UINTN)MemOne + 1), MemTwo = (VOID *)((UINTN)MemTwo + 1)) {
  69     ReturnValue = (INTN)(*(INT8 *)MemOne - *(INT8 *)MemTwo);
  70     if (ReturnValue != 0) {
  71       return ReturnValue;
  72     }
  73   }
  74
  75   return 0;
  76 }