;------------------------------------------------------------------------------ | |
; | |
; 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 | |