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|
;------------------------------------------------------------------------------
;
; Copyright (c) 2007, Intel Corporation. All rights reserved.<BR>
; 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:
;
; CopyMem function
;
; Notes:
;
;------------------------------------------------------------------------------
.code
;------------------------------------------------------------------------------
; VOID *
; EFIAPI
; EfiCommonLibCopyMem (
; OUT VOID *Destination,
; IN VOID *Source,
; IN UINTN Count
; );
;------------------------------------------------------------------------------
EfiCommonLibCopyMem PROC USES rsi rdi
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 <- End of Source
cmp rsi, rdi
mov rax, rdi ; rax <- Destination as return value
jae @F
cmp r9, rdi
jae @CopyBackward ; Copy backward if overlapped
@@:
mov rcx, r8
and r8, 7
shr rcx, 3 ; rcx <- # of Qwords to copy
jz @CopyBytes
DB 49h, 0fh, 7eh, 0c2h ; movd r10, mm0 (Save mm0 in r10)
@@:
DB 0fh, 6fh, 06h ; movd mm0, [rsi]
DB 48h, 0fh, 7eh, 07h ; movd [rdi], mm0
add rsi, 8
add rdi, 8
loop @B
DB 49h, 0fh, 6eh, 0c2h ; movd mm0, r10 (Restore mm0)
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
@CopyMemDone:
ret
EfiCommonLibCopyMem ENDP
END
|
