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      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 }
     85