MdePkg/Library/BaseMemoryLibSse2/X64/ZeroMem.nasm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006, Intel Corporation. All rights reserved.<BR>
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ; Module Name:
   7 ;
   8 ;   ZeroMem.nasm
   9 ;
  10 ; Abstract:
  11 ;
  12 ;   ZeroMem function
  13 ;
  14 ; Notes:
  15 ;
  16 ;------------------------------------------------------------------------------
  17
  18     DEFAULT REL
  19     SECTION .text
  20
  21 ;------------------------------------------------------------------------------
  22 ;  VOID *
  23 ;  InternalMemZeroMem (
  24 ;    IN VOID   *Buffer,
  25 ;    IN UINTN  Count
  26 ;    )
  27 ;------------------------------------------------------------------------------
  28 global ASM_PFX(InternalMemZeroMem)
  29 ASM_PFX(InternalMemZeroMem):
  30     push    rdi
  31     mov     rdi, rcx
  32     xor     rcx, rcx
  33     xor     eax, eax
  34     sub     rcx, rdi
  35     and     rcx, 15
  36     mov     r8, rdi
  37     jz      .0
  38     cmp     rcx, rdx
  39     cmova   rcx, rdx
  40     sub     rdx, rcx
  41     rep     stosb
  42 .0:
  43     mov     rcx, rdx
  44     and     edx, 15
  45     shr     rcx, 4
  46     jz      @ZeroBytes
  47     pxor    xmm0, xmm0
  48 .1:
  49     movntdq [rdi], xmm0                 ; rdi should be 16-byte aligned
  50     add     rdi, 16
  51     loop    .1
  52     mfence
  53 @ZeroBytes:
  54     mov     ecx, edx
  55     rep     stosb
  56     mov     rax, r8
  57     pop     rdi
  58     ret
  59