EdkCompatibilityPkg/Foundation/Library/EfiCommonLib/Ia32/EfiZeroMemRep4.c

   1 /*++
   2
   3 Copyright (c) 2007, 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   EfiZeroMemRep4.c
  15
  16 Abstract:
  17
  18   This is the code that uses rep stosd ZeroMem service
  19
  20 --*/
  21
  22 #include "Tiano.h"
  23
  24 VOID
  25 EfiCommonLibZeroMem (
  26   IN VOID   *Buffer,
  27   IN UINTN  Count
  28   )
  29 /*++
  30
  31 Input:  VOID   *Buffer - Pointer to buffer to clear
  32         UINTN  Count  - Number of bytes to clear
  33
  34 Output: None.
  35
  36 Saves:
  37
  38 Modifies:
  39
  40 Description:  This function uses rep stosd to zero memory.
  41
  42 --*/
  43 {
  44   __asm {
  45     mov         ecx, Count
  46     test        ecx, ecx
  47     je          Exit
  48     xor         eax, eax
  49     mov         edi, Buffer
  50     mov         edx, ecx
  51     shr         ecx, 2
  52     and         edx, 3
  53     rep         stosd
  54     mov         ecx, edx
  55     rep         stosb
  56 Exit:
  57   }
  58 }
  59