1;------------------------------------------------------------------------------
2;
3; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
4; This program and the accompanying materials
5; are licensed and made available under the terms and conditions of the BSD License
6; which accompanies this distribution.  The full text of the license may be found at
7; http://opensource.org/licenses/bsd-license.php.
8;
9; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
11;
12; Module Name:
13;
14;   CopyMem.Asm
15;
16; Abstract:
17;
18;   CopyMem function
19;
20; Notes:
21;
22;------------------------------------------------------------------------------
23
24    .code
25
26;------------------------------------------------------------------------------
27;  VOID *
28;  EFIAPI
29;  InternalMemCopyMem (
30;    IN VOID   *Destination,
31;    IN VOID   *Source,
32;    IN UINTN  Count
33;    )
34;------------------------------------------------------------------------------
35InternalMemCopyMem  PROC    USES    rsi rdi
36    mov     rsi, rdx                    ; rsi <- Source
37    mov     rdi, rcx                    ; rdi <- Destination
38    lea     r9, [rsi + r8 - 1]          ; r9 <- End of Source
39    cmp     rsi, rdi
40    mov     rax, rdi                    ; rax <- Destination as return value
41    jae     @F
42    cmp     r9, rdi
43    jae     @CopyBackward               ; Copy backward if overlapped
44@@:
45    mov     rcx, r8
46    and     r8, 7
47    shr     rcx, 3
48    rep     movsq                       ; Copy as many Qwords as possible
49    jmp     @CopyBytes
50@CopyBackward:
51    mov     rsi, r9                     ; rsi <- End of Source
52    lea     rdi, [rdi + r8 - 1]         ; esi <- End of Destination
53    std                                 ; set direction flag
54@CopyBytes:
55    mov     rcx, r8
56    rep     movsb                       ; Copy bytes backward
57    cld
58    ret
59InternalMemCopyMem  ENDP
60
61    END
62