MdePkg/Library/BaseMemoryLibRepStr/Ia32/CompareMem.nasm

   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.Asm
  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     SECTION .text
  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 global ASM_PFX(InternalMemCompareMem)
  44 ASM_PFX(InternalMemCompareMem):
  45     push    esi
  46     push    edi
  47     mov     esi, [esp + 12]
  48     mov     edi, [esp + 16]
  49     mov     ecx, [esp + 20]
  50     repe    cmpsb
  51     movzx   eax, byte [esi - 1]
  52     movzx   edx, byte [edi - 1]
  53     sub     eax, edx
  54     pop     edi
  55     pop     esi
  56     ret
  57