MdePkg/Library/BaseMemoryLibSse2/X64/ZeroMem.nasm

   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 ;   ZeroMem.nasm
  15 ;
  16 ; Abstract:
  17 ;
  18 ;   ZeroMem function
  19 ;
  20 ; Notes:
  21 ;
  22 ;------------------------------------------------------------------------------
  23
  24     DEFAULT REL
  25     SECTION .text
  26
  27 ;------------------------------------------------------------------------------
  28 ;  VOID *
  29 ;  InternalMemZeroMem (
  30 ;    IN VOID   *Buffer,
  31 ;    IN UINTN  Count
  32 ;    )
  33 ;------------------------------------------------------------------------------
  34 global ASM_PFX(InternalMemZeroMem)
  35 ASM_PFX(InternalMemZeroMem):
  36     push    rdi
  37     mov     rdi, rcx
  38     xor     rcx, rcx
  39     xor     eax, eax
  40     sub     rcx, rdi
  41     and     rcx, 15
  42     mov     r8, rdi
  43     jz      .0
  44     cmp     rcx, rdx
  45     cmova   rcx, rdx
  46     sub     rdx, rcx
  47     rep     stosb
  48 .0:
  49     mov     rcx, rdx
  50     and     edx, 15
  51     shr     rcx, 4
  52     jz      @ZeroBytes
  53     pxor    xmm0, xmm0
  54 .1:
  55     movntdq [rdi], xmm0                 ; rdi should be 16-byte aligned
  56     add     rdi, 16
  57     loop    .1
  58     mfence
  59 @ZeroBytes:
  60     mov     ecx, edx
  61     rep     stosb
  62     mov     rax, r8
  63     pop     rdi
  64     ret
  65