audk/MdePkg/Library/BaseMemoryLibMmx/Ia32/CopyMem.asm

78 lines
2.3 KiB
NASM

;------------------------------------------------------------------------------
;
; Copyright (c) 2006, 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:
;
; CopyMem function
;
; Notes:
;
;------------------------------------------------------------------------------
.686
.model flat,C
.mmx
.code
;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; InternalMemCopyMem (
; IN VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
InternalMemCopyMem PROC USES esi edi
mov esi, [esp + 16] ; esi <- Source
mov edi, [esp + 12] ; edi <- Destination
mov edx, [esp + 20] ; edx <- Count
lea eax, [esi + edx - 1] ; eax <- End of Source
cmp esi, edi
jae @F
cmp eax, edi ; Overlapped?
jae @CopyBackward ; Copy backward if overlapped
@@:
mov ecx, edx
and edx, 7
shr ecx, 3 ; ecx <- # of Qwords to copy
jz @CopyBytes
push eax
push eax
movq [esp], mm0 ; save mm0
@@:
movq mm0, [esi]
movq [edi], mm0
add esi, 8
add edi, 8
loop @B
movq mm0, [esp] ; restore mm0
pop ecx ; stack cleanup
pop ecx ; stack cleanup
jmp @CopyBytes
@CopyBackward:
mov esi, eax ; esi <- Last byte in Source
lea edi, [edi + edx - 1] ; edi <- Last byte in Destination
std
@CopyBytes:
mov ecx, edx
rep movsb
cld
mov eax, [esp + 12]
ret
InternalMemCopyMem ENDP
END