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;------------------------------------------------------------------------------
;
; Copyright (c) 2007, Intel Corporation
; All rights reserved. This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution. The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Module Name:
;
; CopyMem.asm
;
; Abstract:
;
; memcpy function
;
; Notes:
;
;------------------------------------------------------------------------------
.686
.model flat,C
.mmx
.code
;------------------------------------------------------------------------------
; VOID *
; memcpy (
; IN VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
memcpy PROC USES esi edi
mov esi, [esp + 16] ; esi <- Source
mov edi, [esp + 12] ; edi <- Destination
mov edx, [esp + 20] ; edx <- Count
cmp esi, edi
je @CopyDone
cmp edx, 0
je @CopyDone
lea eax, [esi + edx - 1] ; eax <- End of Source
cmp esi, edi
jae @F
cmp eax, edi
jae @CopyBackward ; Copy backward if overlapped
@@:
mov ecx, edx
and edx, 3
shr ecx, 2
rep movsd ; Copy as many Dwords as possible
jmp @CopyBytes
@CopyBackward:
mov esi, eax ; esi <- End of Source
lea edi, [edi + edx - 1] ; edi <- End of Destination
std
@CopyBytes:
mov ecx, edx
rep movsb ; Copy bytes backward
cld
@CopyDone:
mov eax, [esp + 12]
ret
memcpy ENDP
END
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