Add in the 1st version of ECP.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@2832 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/EfiCompareMem.c

@@ -0,0 +1,76 @@
+/*++
+
+Copyright (c) 2004, Intel Corporation                                                         
+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.             
+
+Module Name:
+
+  EfiCompareMem.c
+
+Abstract:
+
+  Generic compare-memory routine. 
+
+--*/
+
+#include "Tiano.h"
+#include "EfiDriverLib.h"
+
+
+INTN
+EfiCompareMem (
+  IN VOID     *MemOne,
+  IN VOID     *MemTwo,
+  IN UINTN    Length
+  )
+/*++
+
+Routine Description:
+
+  Compares two memory buffers of a given length.
+
+Arguments:
+
+  MemOne - First memory buffer
+
+  MemTwo - Second memory buffer
+
+  Len    - Length of Mem1 and Mem2 memory regions to compare
+
+Returns:
+
+  = 0     if MemOne == MemTwo
+
+--*/
+{
+  INTN ReturnValue;
+
+  if (!(EFI_UINTN_ALIGNED (MemOne) || EFI_UINTN_ALIGNED (MemTwo) || EFI_UINTN_ALIGNED (Length))) {
+    //
+    // If Destination/Source/Length are aligned do UINTN conpare
+    //
+    for (; Length > 0; Length -= sizeof (INTN), MemOne = (VOID *)((UINTN)MemOne + sizeof (INTN)), MemTwo = (VOID *)((UINTN)MemTwo + sizeof (INTN))) {
+      if (*(INTN *)MemOne != *(INTN *)MemTwo) {
+        break;
+      }
+    }
+  }
+
+  //
+  // If Destination/Source/Length not aligned do byte compare
+  //
+  for (; Length > 0; Length--, MemOne = (VOID *)((UINTN)MemOne + 1), MemTwo = (VOID *)((UINTN)MemTwo + 1)) {
+    ReturnValue = (INTN)(*(INT8 *)MemOne - *(INT8 *)MemTwo);
+    if (ReturnValue != 0) {
+      return ReturnValue;
+    }
+  }
+
+  return 0;
+}