1 /** @file
2 Implementation of the EfiSetMem routine. This function is broken
3 out into its own source file so that it can be excluded from a
4 build for a particular platform easily if an optimized version
5 is desired.
6
7 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
8 Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
9 Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
10
11 This program and the accompanying materials
12 are licensed and made available under the terms and conditions of the BSD License
13 which accompanies this distribution. The full text of the license may be found at
14 http://opensource.org/licenses/bsd-license.php.
15
16 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
17 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
18
19 **/
20
21
22
23
24 #include "MemLibInternals.h"
25
26 /**
27 Set Buffer to Value for Size bytes.
28
29 @param Buffer The memory to set.
30 @param Length The number of bytes to set.
31 @param Value The value of the set operation.
32
33 @return Buffer
34
35 **/
36 VOID *
37 EFIAPI
InternalMemSetMem(OUT VOID * Buffer,IN UINTN Length,IN UINT8 Value)38 InternalMemSetMem (
39 OUT VOID *Buffer,
40 IN UINTN Length,
41 IN UINT8 Value
42 )
43 {
44 //
45 // Declare the local variables that actually move the data elements as
46 // volatile to prevent the optimizer from replacing this function with
47 // the intrinsic memset()
48 //
49 volatile UINT8 *Pointer8;
50 volatile UINT32 *Pointer32;
51 volatile UINT64 *Pointer64;
52 UINT32 Value32;
53 UINT64 Value64;
54
55 if ((((UINTN)Buffer & 0x7) == 0) && (Length >= 8)) {
56 // Generate the 64bit value
57 Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
58 Value64 = LShiftU64 (Value32, 32) | Value32;
59
60 Pointer64 = (UINT64*)Buffer;
61 while (Length >= 8) {
62 *(Pointer64++) = Value64;
63 Length -= 8;
64 }
65
66 // Finish with bytes if needed
67 Pointer8 = (UINT8*)Pointer64;
68 } else if ((((UINTN)Buffer & 0x3) == 0) && (Length >= 4)) {
69 // Generate the 32bit value
70 Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
71
72 Pointer32 = (UINT32*)Buffer;
73 while (Length >= 4) {
74 *(Pointer32++) = Value32;
75 Length -= 4;
76 }
77
78 // Finish with bytes if needed
79 Pointer8 = (UINT8*)Pointer32;
80 } else {
81 Pointer8 = (UINT8*)Buffer;
82 }
83 while (Length-- > 0) {
84 *(Pointer8++) = Value;
85 }
86 return Buffer;
87 }
88