mirror of https://github.com/acidanthera/audk.git
81 lines
2.8 KiB
NASM
81 lines
2.8 KiB
NASM
;------------------------------------------------------------------------------
|
|
;
|
|
; Copyright (c) 2007, 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:
|
|
;
|
|
; memcpy function
|
|
;
|
|
; Notes:
|
|
;
|
|
;------------------------------------------------------------------------------
|
|
|
|
.code
|
|
|
|
;------------------------------------------------------------------------------
|
|
; VOID *
|
|
; memcpy (
|
|
; OUT VOID *DestinationBuffer,
|
|
; IN CONST VOID *SourceBuffer,
|
|
; IN UINTN Length
|
|
; );
|
|
;------------------------------------------------------------------------------
|
|
memcpy PROC USES rsi rdi
|
|
mov rax, rcx ; rax <- Destination as return value
|
|
cmp rdx, rcx ; if Source == Destination, do nothing
|
|
je @CopyMemDone
|
|
cmp r8, 0 ; if Count == 0, do nothing
|
|
je @CopyMemDone
|
|
mov rsi, rdx ; rsi <- Source
|
|
mov rdi, rcx ; rdi <- Destination
|
|
lea r9, [rsi + r8 - 1] ; r9 <- Last byte of Source
|
|
cmp rsi, rdi
|
|
jae @F ; Copy forward if Source > Destination
|
|
cmp r9, rdi ; Overlapped?
|
|
jae @CopyBackward ; Copy backward if overlapped
|
|
@@:
|
|
xor rcx, rcx
|
|
sub rcx, rdi ; rcx <- -rdi
|
|
and rcx, 15 ; rcx + rsi should be 16 bytes aligned
|
|
jz @F ; skip if rcx == 0
|
|
cmp rcx, r8
|
|
cmova rcx, r8
|
|
sub r8, rcx
|
|
rep movsb
|
|
@@:
|
|
mov rcx, r8
|
|
and r8, 15
|
|
shr rcx, 4 ; rcx <- # of DQwords to copy
|
|
jz @CopyBytes
|
|
@@:
|
|
movdqu xmm0, [rsi] ; rsi may not be 16-byte aligned
|
|
movdqa [rdi], xmm0 ; rdi should be 16-byte aligned
|
|
add rsi, 16
|
|
add rdi, 16
|
|
loop @B
|
|
jmp @CopyBytes ; copy remaining bytes
|
|
@CopyBackward:
|
|
mov rsi, r9 ; rsi <- Last byte of Source
|
|
lea rdi, [rdi + r8 - 1] ; rdi <- Last byte of Destination
|
|
std
|
|
@CopyBytes:
|
|
mov rcx, r8
|
|
rep movsb
|
|
cld
|
|
@CopyMemDone:
|
|
ret
|
|
memcpy ENDP
|
|
|
|
END
|