ArmPkg/Library/BaseMemoryLibStm/AArch64/SetMem.c

   1 /** @file
   2
   3   Copyright (c) 2012-2013, ARM Ltd. All rights reserved.<BR>
   4
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 #include "MemLibInternals.h"
  16
  17 /**
  18   Set Buffer to Value for Size bytes.
  19
  20   @param  Buffer   Memory to set.
  21   @param  Length   Number of bytes to set
  22   @param  Value    Value of the set operation.
  23
  24   @return Buffer
  25
  26 **/
  27 VOID *
  28 EFIAPI
  29 InternalMemSetMem (
  30   OUT     VOID                      *Buffer,
  31   IN      UINTN                     Length,
  32   IN      UINT8                     Value
  33   )
  34 {
  35   //
  36   // Declare the local variables that actually move the data elements as
  37   // volatile to prevent the optimizer from replacing this function with
  38   // the intrinsic memset()
  39   //
  40   volatile UINT8                    *Pointer8;
  41   volatile UINT32                   *Pointer32;
  42   volatile UINT64                   *Pointer64;
  43   UINT32                            Value32;
  44   UINT64                            Value64;
  45
  46   if ((((UINTN)Buffer & 0x7) == 0) && (Length >= 8)) {
  47     // Generate the 64bit value
  48     Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
  49     Value64 = (((UINT64)Value32) << 32) | Value32;
  50
  51     Pointer64 = (UINT64*)Buffer;
  52     while (Length >= 8) {
  53       *(Pointer64++) = Value64;
  54       Length -= 8;
  55     }
  56
  57     // Finish with bytes if needed
  58     Pointer8 = (UINT8*)Pointer64;
  59     while (Length-- > 0) {
  60       *(Pointer8++) = Value;
  61     }
  62   } else if ((((UINTN)Buffer & 0x3) == 0) && (Length >= 4)) {
  63     // Generate the 32bit value
  64     Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
  65
  66     Pointer32 = (UINT32*)Buffer;
  67     while (Length >= 4) {
  68       *(Pointer32++) = Value32;
  69       Length -= 4;
  70     }
  71
  72     // Finish with bytes if needed
  73     Pointer8 = (UINT8*)Pointer32;
  74     while (Length-- > 0) {
  75       *(Pointer8++) = Value;
  76     }
  77   } else {
  78     Pointer8 = (UINT8*)Buffer;
  79     while (Length-- > 0) {
  80       *(Pointer8++) = Value;
  81     }
  82   }
  83   return Buffer;
  84 }