MdePkg/Library/BaseMemoryLibOptDxe/Ia32/CompareMem.nasm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ; Module Name:
   7 ;
   8 ;   CompareMem.Asm
   9 ;
  10 ; Abstract:
  11 ;
  12 ;   CompareMem function
  13 ;
  14 ; Notes:
  15 ;
  16 ;   The following BaseMemoryLib instances contain the same copy of this file:
  17 ;
  18 ;       BaseMemoryLibRepStr
  19 ;       BaseMemoryLibMmx
  20 ;       BaseMemoryLibSse2
  21 ;       BaseMemoryLibOptDxe
  22 ;       BaseMemoryLibOptPei
  23 ;
  24 ;------------------------------------------------------------------------------
  25
  26     SECTION .text
  27
  28 ;------------------------------------------------------------------------------
  29 ; INTN
  30 ; EFIAPI
  31 ; InternalMemCompareMem (
  32 ;   IN      CONST VOID                *DestinationBuffer,
  33 ;   IN      CONST VOID                *SourceBuffer,
  34 ;   IN      UINTN                     Length
  35 ;   );
  36 ;------------------------------------------------------------------------------
  37 global ASM_PFX(InternalMemCompareMem)
  38 ASM_PFX(InternalMemCompareMem):
  39     push    esi
  40     push    edi
  41     mov     esi, [esp + 12]
  42     mov     edi, [esp + 16]
  43     mov     ecx, [esp + 20]
  44     repe    cmpsb
  45     movzx   eax, byte [esi - 1]
  46     movzx   edx, byte [edi - 1]
  47     sub     eax, edx
  48     pop     edi
  49     pop     esi
  50     ret
  51