CloverBootloader/MdePkg/Library/BaseMemoryLibMmx/Ia32/CopyMem.nasm
SergeySlice 6b33696c93 kext and kernel patches will be part of LOADER_ENTRY class
Signed-off-by: SergeySlice <sergey.slice@gmail.com>
2020-05-01 19:26:28 +03:00

72 lines
2.0 KiB
NASM

;------------------------------------------------------------------------------
;
; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
; CopyMem.nasm
;
; Abstract:
;
; CopyMem function
;
; Notes:
;
;------------------------------------------------------------------------------
SECTION .text
;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; InternalMemCopyMem(
; IN VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemCopyMem)
ASM_PFX(InternalMemCopyMem):
push esi
push 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 .0
cmp eax, edi ; Overlapped?
jae @CopyBackward ; Copy backward if overlapped
.0:
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
.1:
movq mm0, [esi]
movq [edi], mm0
add esi, 8
add edi, 8
loop .1
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]
pop edi
pop esi
ret