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

87 lines
2.4 KiB
NASM

;/*++
;
;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:
;
; EfiCopyMemRep1.asm
;
;Abstract:
;
; This is the code that uses rep movsb CopyMem service
;
;--*/
;
;---------------------------------------------------------------------------
.686
.model flat,C
.code
;---------------------------------------------------------------------------
;#include "Tiano.h"
;
;VOID
;EfiCommonLibCopyMem (
; IN VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; )
;/*++
;
;Routine Description:
;
; Copy Length bytes from Source to Destination.
;
;Arguments:
;
; Destination - Target of copy
;
; Source - Place to copy from
;
; Length - Number of bytes to copy
;
;Returns:
;
; None
;
;--*/
EfiCommonLibCopyMem PROC
push ebp
mov ebp, esp
push esi
push edi
mov esi, dword ptr[ebp + 0Ch] ; esi <- Source
mov edi, dword ptr[ebp + 8] ; edi <- Destination
mov edx, dword ptr[ebp + 10h] ; 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 _CopyBytes
cmp eax, edi
jb _CopyBytes ; Copy backward if overlapped
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:
pop edi
pop esi
pop ebp
ret
EfiCommonLibCopyMem ENDP
END