MdePkg/Library/BaseMemoryLibOptPei/Ia32/CompareMem.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, 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 # Module Name:
  13 #
  14 #   CompareMem.S
  15 #
  16 # Abstract:
  17 #
  18 #   CompareMem function
  19 #
  20 # Notes:
  21 #
  22 #   The following BaseMemoryLib instances contain the same copy of this file:
  23 #
  24 #       BaseMemoryLibRepStr
  25 #       BaseMemoryLibMmx
  26 #       BaseMemoryLibSse2
  27 #       BaseMemoryLibOptDxe
  28 #       BaseMemoryLibOptPei
  29 #
  30 #------------------------------------------------------------------------------
  31
  32 ASM_GLOBAL ASM_PFX(InternalMemCompareMem)
  33
  34 #------------------------------------------------------------------------------
  35 # INTN
  36 # EFIAPI
  37 # InternalMemCompareMem (
  38 #   IN      CONST VOID                *DestinationBuffer,
  39 #   IN      CONST VOID                *SourceBuffer,
  40 #   IN      UINTN                     Length
  41 #   );
  42 #------------------------------------------------------------------------------
  43 ASM_PFX(InternalMemCompareMem):
  44     push    %esi
  45     push    %edi
  46     movl    12(%esp), %esi
  47     movl    16(%esp), %edi
  48     movl    20(%esp), %ecx
  49     repe    cmpsb
  50     movzbl  -1(%esi), %eax
  51     movzbl  -1(%edi), %edx
  52     subl    %edx, %eax
  53     pop     %edi
  54     pop     %esi
  55     ret