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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:
;
; memcpyRep1.asm
;
; Abstract:
;
; CopyMem function
;
; Notes:
;
;------------------------------------------------------------------------------
.code
;------------------------------------------------------------------------------
; VOID
; memcpy (
; OUT VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
memcpy PROC USES rsi rdi
mov rax, rcx
cmp rdx, rcx ; if Source == Destination, do nothing
je @CopyMemDone
cmp r8, 0 ; if Count == 0, do nothing
je @CopyMemDone
mov rsi, rdx ; rsi <- Source
mov rdi, rcx ; rdi <- Destination
lea r9, [rsi + r8 - 1] ; r9 <- End of Source
cmp rsi, rdi
jae @F
cmp r9, rdi
jb @F ; Copy backward if overlapped
mov rsi, r9 ; rsi <- End of Source
lea rdi, [rdi + r8 - 1] ; esi <- End of Destination
std ; set direction flag
@@:
mov rcx, r8
rep movsb ; Copy bytes backward
cld
@CopyMemDone:
ret
memcpy ENDP
END
|
