MdePkg/Library/BaseMemoryLibSse2/X64/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     DEFAULT REL
  33     SECTION .text
  34
  35 ;------------------------------------------------------------------------------
  36 ; INTN
  37 ; EFIAPI
  38 ; InternalMemCompareMem (
  39 ;   IN      CONST VOID                *DestinationBuffer,
  40 ;   IN      CONST VOID                *SourceBuffer,
  41 ;   IN      UINTN                     Length
  42 ;   );
  43 ;------------------------------------------------------------------------------
  44 global ASM_PFX(InternalMemCompareMem)
  45 ASM_PFX(InternalMemCompareMem):
  46     push    rsi
  47     push    rdi
  48     mov     rsi, rcx
  49     mov     rdi, rdx
  50     mov     rcx, r8
  51     repe    cmpsb
  52     movzx   rax, byte [rsi - 1]
  53     movzx   rdx, byte [rdi - 1]
  54     sub     rax, rdx
  55     pop     rdi
  56     pop     rsi
  57     ret
  58