MdePkg/Library/BaseMemoryLibOptDxe/X64/SetMem.S

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2006 - 2008, 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 #   SetMem.S
  15 #
  16 # Abstract:
  17 #
  18 #   SetMem function
  19 #
  20 # Notes:
  21 #
  22 #------------------------------------------------------------------------------
  23 #------------------------------------------------------------------------------
  24 #  VOID *
  25 #  EFIAPI
  26 #  InternalMemSetMem (
  27 #    IN VOID   *Buffer,
  28 #    IN UINTN  Count,
  29 #    IN UINT8  Value
  30 #    )
  31 #------------------------------------------------------------------------------
  32 .intel_syntax noprefix
  33 .globl ASM_PFX(InternalMemSetMem)
  34 ASM_PFX(InternalMemZeroMem):
  35     push    rdi
  36     push    rbx
  37     push    rcx         # push Buffer
  38     mov     rax, r8     # rax = Value
  39     and     rax, 0xff   # rax = lower 8 bits of r8, upper 56 bits are 0
  40     mov     ah,  al     # ah  = al
  41     mov     bx,  ax     # bx  = ax
  42     shl     rax, 0x10   # rax = ax << 16
  43     mov     ax,  bx     # ax  = bx
  44     mov     rbx, rax    # ebx = eax
  45     shl     rax, 0x20   # rax = rax << 32
  46     or      rax, rbx    # eax = ebx
  47     mov     rdi, rcx    # rdi = Buffer
  48     mov     rcx, rdx    # rcx = Count
  49     shr     rcx, 3      # rcx = rcx / 8
  50     cld
  51     rep     stosq
  52     mov     rcx, rdx    # rcx = rdx
  53     and     rcx, 7      # rcx = rcx & 7
  54     rep     stosb
  55     pop     rax         # rax = Buffer
  56     pop     rbx
  57     pop     rdi
  58     ret