MdePkg/Library/BaseMemoryLibMmx/CompareMemWrapper.c

   1 /** @file
   2   CompareMem() implementation.
   3
   4   Copyright (c) 2006, 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   Module Name:  CompareMemWrapper.c
  14
  15   The following BaseMemoryLib instances share the same version of this file:
  16
  17     BaseMemoryLib
  18     BaseMemoryLibMmx
  19     BaseMemoryLibSse2
  20     BaseMemoryLibRepStr
  21     PeiMemoryLib
  22     UefiMemoryLib
  23
  24 **/
  25
  26 #include "MemLibInternals.h"
  27
  28 /**
  29   Compares two memory buffers of a given length.
  30
  31   This function compares Length bytes of SourceBuffer to Length bytes of
  32   DestinationBuffer. If all Length bytes of the two buffers are identical, then
  33   0 is returned. Otherwise, the value returned is the first mismatched byte in
  34   SourceBuffer subtracted from the first mismatched byte in DestinationBuffer.
  35
  36   If DestinationBuffer is NULL and Length > 0, then ASSERT().
  37   If SourceBuffer is NULL and Length > 0, then ASSERT().
  38   If Length is greater than (MAX_ADDRESS - DestinationBuffer + 1), then
  39   ASSERT().
  40   If Length is greater than (MAX_ADDRESS - SourceBuffer + 1), then ASSERT().
  41
  42   @param  DestinationBuffer First memory buffer
  43   @param  SourceBuffer      Second memory buffer
  44   @param  Length            Length of DestinationBuffer and SourceBuffer memory
  45                             regions to compare
  46
  47   @retval 0         if DestinationBuffer == SourceBuffer
  48   @retval Non-zero  if DestinationBuffer != SourceBuffer
  49
  50 **/
  51 INTN
  52 EFIAPI
  53 CompareMem (
  54   IN      CONST VOID                *DestinationBuffer,
  55   IN      CONST VOID                *SourceBuffer,
  56   IN      UINTN                     Length
  57   )
  58 {
  59   ASSERT (DestinationBuffer != NULL);
  60   ASSERT (SourceBuffer != NULL);
  61   ASSERT (Length <= MAX_ADDRESS - (UINTN)DestinationBuffer + 1);
  62   ASSERT (Length <= MAX_ADDRESS - (UINTN)SourceBuffer + 1);
  63   if (Length == 0) {
  64     return 0;
  65   }
  66   return InternalMemCompareMem (DestinationBuffer, SourceBuffer, Length);
  67 }