EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/EfiCopyMemRep1.asm

   1 ;/*++
   2 ;
   3 ;Copyright (c) 2007, 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 ;  EfiCopyMemRep1.asm
  15 ;
  16 ;Abstract:
  17 ;
  18 ;  This is the code that uses rep movsb CopyMem service
  19 ;
  20 ;--*/
  21 ;
  22 ;---------------------------------------------------------------------------
  23     .686
  24     .model  flat,C
  25     .code
  26
  27 ;---------------------------------------------------------------------------
  28 ;#include "Tiano.h"
  29 ;
  30 ;VOID
  31 ;EfiCommonLibCopyMem (
  32 ;  IN VOID   *Destination,
  33 ;  IN VOID   *Source,
  34 ;  IN UINTN  Count
  35 ;  )
  36 ;/*++
  37 ;
  38 ;Routine Description:
  39 ;
  40 ;  Copy Length bytes from Source to Destination.
  41 ;
  42 ;Arguments:
  43 ;
  44 ;  Destination - Target of copy
  45 ;
  46 ;  Source      - Place to copy from
  47 ;
  48 ;  Length      - Number of bytes to copy
  49 ;
  50 ;Returns:
  51 ;
  52 ;  None
  53 ;
  54 ;--*/
  55 EfiCommonLibCopyMem PROC
  56     push    ebp
  57     mov     ebp, esp
  58     push    esi
  59     push    edi
  60     mov     esi, dword ptr[ebp + 0Ch]    ; esi <- Source
  61     mov     edi, dword ptr[ebp + 8]      ; edi <- Destination
  62     mov     edx, dword ptr[ebp + 10h]    ; edx <- Count
  63     cmp     esi, edi
  64     je      _CopyDone
  65     cmp     edx, 0
  66     je      _CopyDone
  67     lea     eax, [esi + edx - 1]         ; eax <- End of Source
  68     cmp     esi, edi
  69     jae     _CopyBytes
  70     cmp     eax, edi
  71     jb      _CopyBytes                   ; Copy backward if overlapped
  72     mov     esi, eax                     ; esi <- End of Source
  73     lea     edi, [edi + edx - 1]         ; edi <- End of Destination
  74     std
  75 _CopyBytes:
  76     mov     ecx, edx
  77     rep     movsb                        ; Copy bytes backward
  78     cld
  79 _CopyDone:
  80     pop     edi
  81     pop     esi
  82     pop     ebp
  83     ret
  84 EfiCommonLibCopyMem ENDP
  85         END
  86