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 <- Last byte of Source
39    cmp     rsi, rdi
40    mov     rax, rdi                    ; rax <- Destination as return value
41    jae     @F                          ; Copy forward if Source > Destination
42    cmp     r9, rdi                     ; Overlapped?
43    jae     @CopyBackward               ; Copy backward if overlapped
44@@:
45    xor     rcx, rcx
46    sub     rcx, rdi                    ; rcx <- -rdi
47    and     rcx, 15                     ; rcx + rsi should be 16 bytes aligned
48    jz      @F                          ; skip if rcx == 0
49    cmp     rcx, r8
50    cmova   rcx, r8
51    sub     r8, rcx
52    rep     movsb
53@@:
54    mov     rcx, r8
55    and     r8, 15
56    shr     rcx, 4                      ; rcx <- # of DQwords to copy
57    jz      @CopyBytes
58    movdqa  [rsp + 18h], xmm0           ; save xmm0 on stack
59@@:
60    movdqu  xmm0, [rsi]                 ; rsi may not be 16-byte aligned
61    movntdq [rdi], xmm0                 ; rdi should be 16-byte aligned
62    add     rsi, 16
63    add     rdi, 16
64    loop    @B
65    mfence
66    movdqa  xmm0, [rsp + 18h]           ; restore xmm0
67    jmp     @CopyBytes                  ; copy remaining bytes
68@CopyBackward:
69    mov     rsi, r9                     ; rsi <- Last byte of Source
70    lea     rdi, [rdi + r8 - 1]         ; rdi <- Last byte of Destination
71    std
72@CopyBytes:
73    mov     rcx, r8
74    rep     movsb
75    cld
76    ret
77InternalMemCopyMem  ENDP
78
79    END
80