MdePkg/Library/BaseMemoryLibMmx/X64/CompareMem.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006, Intel Corporation
   4 # All rights reserved. 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 #------------------------------------------------------------------------------
  33 # INTN
  34 # EFIAPI
  35 # InternalMemCompareMem (
  36 #   IN      CONST VOID                *DestinationBuffer,
  37 #   IN      CONST VOID                *SourceBuffer,
  38 #   IN      UINTN                     Length
  39 #   );
  40 #------------------------------------------------------------------------------
  41 .global _InternalMemCompareMem;
  42 _InternalMemCompareMem:
  43     push    %rsi
  44     push    %rdi
  45     mov     %rcx, %rsi
  46     mov     %rdx, %rdi
  47     mov     %r8, %rcx
  48     repe    cmpsb
  49     movzbq  -1(%rsi), %rax
  50     movzbq  -1(%rdi), %rdx
  51     sub     %rdx, %rax
  52     pop     %rdi
  53     pop     %rsi
  54     ret