MdePkg/Library/BaseMemoryLibOptDxe/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.Asm
  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     push    rcx       ; push Buffer
  38     xor     rax, rax  ; rax = 0
  39     mov     rdi, rcx  ; rdi = Buffer
  40     mov     rcx, rdx  ; rcx = Count
  41     shr     rcx, 3    ; rcx = rcx / 8
  42     and     rdx, 7    ; rdx = rdx & 7
  43     cld
  44     rep     stosq
  45     mov     rcx, rdx  ; rcx = rdx
  46     rep     stosb
  47     pop     rax       ; rax = Buffer
  48     pop     rdi
  49     ret
  50