;------------------------------------------------------------------------------ | |
; | |
; Copyright (c) 2006 - 2022, Intel Corporation. All rights reserved.<BR> | |
; SPDX-License-Identifier: BSD-2-Clause-Patent | |
; | |
; Module Name: | |
; | |
; CopyMem.nasm | |
; | |
; Abstract: | |
; | |
; CopyMem function | |
; | |
; Notes: | |
; | |
;------------------------------------------------------------------------------ | |
DEFAULT REL | |
SECTION .text | |
;------------------------------------------------------------------------------ | |
; VOID * | |
; EFIAPI | |
; InternalMemCopyMem ( | |
; OUT VOID *DestinationBuffer, | |
; IN CONST VOID *SourceBuffer, | |
; IN UINTN Length | |
; ); | |
;------------------------------------------------------------------------------ | |
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 ; rcx <- # of Qwords to copy | |
jz @CopyBytes | |
movq r10, mm0 | |
.1: | |
movq mm0, [rsi] | |
movntq [rdi], mm0 | |
add rsi, 8 | |
add rdi, 8 | |
loop .1 | |
mfence | |
movq mm0, r10 | |
jmp @CopyBytes | |
@CopyBackward: | |
mov rsi, r9 ; rsi <- End of Source | |
lea rdi, [rdi + r8 - 1] ; rdi <- End of Destination | |
std ; set direction flag | |
@CopyBytes: | |
mov rcx, r8 | |
rep movsb ; Copy bytes backward | |
cld | |
pop rdi | |
pop rsi | |
ret | |