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;------------------------------------------------------------------------------
;
; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Module Name:
;
; CopyMem.Asm
;
; Abstract:
;
; CopyMem function
;
; Notes:
;
;------------------------------------------------------------------------------
DEFAULT REL
SECTION .text
;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; InternalMemCopyMem (
; IN VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; )
;------------------------------------------------------------------------------
global ASM_PFX(InternalMemCopyMem)
ASM_PFX(InternalMemCopyMem):
push rsi
push rdi
mov rsi, rdx ; rsi <- Source
mov rdi, rcx ; rdi <- Destination
lea r9, [rsi + r8 - 1] ; r9 <- End of Source
cmp rsi, rdi
mov rax, rdi ; rax <- Destination as return value
jae .0
cmp r9, rdi
jae @CopyBackward ; Copy backward if overlapped
.0:
mov rcx, r8
and r8, 7
shr rcx, 3
rep movsq ; Copy as many Qwords as possible
jmp @CopyBytes
@CopyBackward:
mov rsi, r9 ; rsi <- End of Source
lea rdi, [rdi + r8 - 1] ; esi <- End of Destination
std ; set direction flag
@CopyBytes:
mov rcx, r8
rep movsb ; Copy bytes backward
cld
pop rdi
pop rsi
ret
|
