MdePkg/Library/BaseMemoryLibMmx/X64/CopyMem.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006, Intel Corporation
   4 # All rights reserved. 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
  25 #------------------------------------------------------------------------------
  26 # VOID *
  27 # EFIAPI
  28 # InternalMemCopyMem (
  29 #   OUT     VOID                      *DestinationBuffer,
  30 #   IN      CONST VOID                *SourceBuffer,
  31 #   IN      UINTN                     Length
  32 #   );
  33 #------------------------------------------------------------------------------
  34 .global _InternalMemCopyMem;
  35 _InternalMemCopyMem:
  36     push    %rsi
  37     push    %rdi
  38     mov     %rdi, %rsi
  39     mov     %rcx, %rdi
  40     lea     -1(%r8,%rsi,1),%r9
  41     cmp     %rdi, %rsi
  42     mov     %rdi, %rax
  43     jae     L1
  44     cmp     %rdi, %r9
  45     jae     LCopyBackward               # Copy backward if overlapped
  46 L1:
  47     mov     %r8, %rcx
  48     and     $7, %r8
  49     shr     $3, %rcx
  50     jz      LCopyBytes
  51     movd    %mm0, %r10                  # (Save mm0 in r10)
  52 L2:
  53     movd    (%rsi), %mm0
  54     movntq  %mm0, (%rdi)
  55     add     $8, %rsi
  56     add     $8, %rdi
  57     loop    L2
  58     mfence
  59     movd    %r10, %mm0                  #(Restore mm0)
  60     jmp     LCopyBytes
  61 LCopyBackward:
  62     mov     %r9, %rsi
  63     lea     -1(%r8,%rdi,1),%rdi
  64     std                                 # set direction flag
  65 LCopyBytes:
  66     mov     %r8, %rcx
  67     rep
  68     movsb                               # Copy bytes backward
  69     cld
  70     pop     %rdi
  71     pop     %rsi
  72     ret