MdePkg/Library/BaseMemoryLibRepStr/X64/CopyMem.S

   1 #
   2 # ConvertAsm.py: Automatically generated from CopyMem.asm
   3 #
   4 #------------------------------------------------------------------------------
   5 #
   6 # Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
   7 # This program and the accompanying materials
   8 # are licensed and made available under the terms and conditions of the BSD License
   9 # which accompanies this distribution.  The full text of the license may be found at
  10 # http://opensource.org/licenses/bsd-license.php
  11 #
  12 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  13 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  14 #
  15 # Module Name:
  16 #
  17 #   CopyMem.S
  18 #
  19 # Abstract:
  20 #
  21 #   CopyMem function
  22 #
  23 # Notes:
  24 #
  25 #------------------------------------------------------------------------------
  26
  27
  28 #------------------------------------------------------------------------------
  29 #  VOID *
  30 #  EFIAPI
  31 #  InternalMemCopyMem (
  32 #    IN VOID   *Destination,
  33 #    IN VOID   *Source,
  34 #    IN UINTN  Count
  35 #    )
  36 #------------------------------------------------------------------------------
  37 ASM_GLOBAL ASM_PFX(InternalMemCopyMem)
  38 ASM_PFX(InternalMemCopyMem):
  39     pushq   %rsi
  40     pushq   %rdi
  41     movq    %rdx, %rsi                  # rsi <- Source
  42     movq    %rcx, %rdi                  # rdi <- Destination
  43     leaq    -1(%rsi, %r8,), %r9         # r9 <- End of Source
  44     cmpq    %rdi, %rsi
  45     movq    %rdi, %rax                  # rax <- Destination as return value
  46     jae     L0
  47     cmpq    %rdi, %r9
  48     jae     L_CopyBackward               # Copy backward if overlapped
  49 L0:
  50     movq    %r8, %rcx
  51     andq    $7, %r8
  52     shrq    $3, %rcx
  53     rep     movsq                       # Copy as many Qwords as possible
  54     jmp     L_CopyBytes
  55 L_CopyBackward:
  56     movq    %r9, %rsi                   # rsi <- End of Source
  57     leaq    -1(%rdi, %r8),  %rdi        # esi <- End of Destination
  58     std                                 # set direction flag
  59 L_CopyBytes:
  60     movq    %r8, %rcx
  61     rep     movsb                       # Copy bytes backward
  62     cld
  63     popq    %rdi
  64     popq    %rsi
  65     ret
  66