1#------------------------------------------------------------------------------
2#
3# Copyright (c) 2006 - 2008, 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
24ASM_GLOBAL ASM_PFX(InternalMemCopyMem)
25
26#------------------------------------------------------------------------------
27#  VOID *
28#  EFIAPI
29#  InternalMemCopyMem (
30#    IN VOID   *Destination,
31#    IN VOID   *Source,
32#    IN UINTN  Count
33#    );
34#------------------------------------------------------------------------------
35ASM_PFX(InternalMemCopyMem):
36    push    %esi
37    push    %edi
38    movl    16(%esp), %esi              # esi <- Source
39    movl    12(%esp), %edi              # edi <- Destination
40    movl    20(%esp), %edx              # edx <- Count
41    leal    -1(%esi, %edx), %eax        # eax <- End of Source
42    cmpl    %edi, %esi
43    jae     L0
44    cmpl    %edi, %eax
45    jae     L_CopyBackward              # Copy backward if overlapped
46L0:
47    movl    %edx, %ecx
48    andl    $3, %edx
49    shrl    $2, %ecx
50    rep
51    movsl                               # Copy as many Dwords as possible
52    jmp     L_CopyBytes
53L_CopyBackward:
54    movl    %eax, %esi                  # esi <- End of Source
55    leal    -1(%edi, %edx), %edi        # edi <- End of Destination
56    std
57L_CopyBytes:
58    movl    %edx, %ecx
59    rep
60    movsb                               # Copy bytes backward
61    cld
62    movl    12(%esp), %eax              # eax <- Destination as return value
63    pop     %edi
64    pop     %esi
65    ret
66