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1;------------------------------------------------------------------------------
2;
3; Copyright (c) 2007, 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; EfiCommonLibCopyMem (
30;   OUT     VOID                      *Destination,
31;   IN      VOID                      *Source,
32;   IN      UINTN                     Count
33;   );
34;------------------------------------------------------------------------------
35EfiCommonLibCopyMem  PROC    USES    rsi rdi
36    cmp     rdx, rcx                    ; if Source == Destination, do nothing
37    je      @CopyMemDone
38    cmp     r8, 0                       ; if Count == 0, do nothing
39    je      @CopyMemDone
40    mov     rsi, rdx                    ; rsi <- Source
41    mov     rdi, rcx                    ; rdi <- Destination
42    lea     r9, [rsi + r8 - 1]          ; r9 <- End of Source
43    cmp     rsi, rdi
44    mov     rax, rdi                    ; rax <- Destination as return value
45    jae     @F
46    cmp     r9, rdi
47    jae     @CopyBackward               ; Copy backward if overlapped
48@@:
49    mov     rcx, r8
50    and     r8, 7
51    shr     rcx, 3                      ; rcx <- # of Qwords to copy
52    jz      @CopyBytes
53    DB      49h, 0fh, 7eh, 0c2h         ; movd r10, mm0 (Save mm0 in r10)
54@@:
55    DB      0fh, 6fh, 06h               ; movd mm0, [rsi]
56    DB      48h, 0fh, 7eh, 07h          ; movd [rdi], mm0
57    add     rsi, 8
58    add     rdi, 8
59    loop    @B
60    DB      49h, 0fh, 6eh, 0c2h         ; movd mm0, r10 (Restore mm0)
61    jmp     @CopyBytes
62@CopyBackward:
63    mov     rsi, r9                     ; rsi <- End of Source
64    lea     rdi, [rdi + r8 - 1]         ; rdi <- End of Destination
65    std                                 ; set direction flag
66@CopyBytes:
67    mov     rcx, r8
68    rep     movsb                       ; Copy bytes backward
69    cld
70@CopyMemDone:
71    ret
72EfiCommonLibCopyMem  ENDP
73
74    END
75