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      1 ;------------------------------------------------------------------------------
      2 ;
      3 ; Copyright (c) 2006, 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 ;   CopyMem.nasm
     15 ;
     16 ; Abstract:
     17 ;
     18 ;   CopyMem function
     19 ;
     20 ; Notes:
     21 ;
     22 ;------------------------------------------------------------------------------
     23 
     24     SECTION .text
     25 
     26 ;------------------------------------------------------------------------------
     27 ;  VOID *
     28 ;  EFIAPI
     29 ;  InternalMemCopyMem (
     30 ;    IN VOID   *Destination,
     31 ;    IN VOID   *Source,
     32 ;    IN UINTN  Count
     33 ;    );
     34 ;------------------------------------------------------------------------------
     35 global ASM_PFX(InternalMemCopyMem)
     36 ASM_PFX(InternalMemCopyMem):
     37     push    esi
     38     push    edi
     39     mov     esi, [esp + 16]             ; esi <- Source
     40     mov     edi, [esp + 12]             ; edi <- Destination
     41     mov     edx, [esp + 20]             ; edx <- Count
     42     lea     eax, [esi + edx - 1]        ; eax <- End of Source
     43     cmp     esi, edi
     44     jae     .0
     45     cmp     eax, edi                    ; Overlapped?
     46     jae     @CopyBackward               ; Copy backward if overlapped
     47 .0:
     48     mov     ecx, edx
     49     and     edx, 7
     50     shr     ecx, 3                      ; ecx <- # of Qwords to copy
     51     jz      @CopyBytes
     52     push    eax
     53     push    eax
     54     movq    [esp], mm0                  ; save mm0
     55 .1:
     56     movq    mm0, [esi]
     57     movq    [edi], mm0
     58     add     esi, 8
     59     add     edi, 8
     60     loop    .1
     61     movq    mm0, [esp]                  ; restore mm0
     62     pop     ecx                         ; stack cleanup
     63     pop     ecx                         ; stack cleanup
     64     jmp     @CopyBytes
     65 @CopyBackward:
     66     mov     esi, eax                    ; esi <- Last byte in Source
     67     lea     edi, [edi + edx - 1]        ; edi <- Last byte in Destination
     68     std
     69 @CopyBytes:
     70     mov     ecx, edx
     71     rep     movsb
     72     cld
     73     mov     eax, [esp + 12]
     74     pop     edi
     75     pop     esi
     76     ret
     77 
     78