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/** @file
Implementation of the EfiSetMem routine. This function is broken
out into its own source file so that it can be excluded from a
build for a particular platform easily if an optimized version
is desired.
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php.
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "MemLibInternals.h"
/**
Set Buffer to Value for Size bytes.
@param Buffer The memory to set.
@param Length The number of bytes to set.
@param Value The value of the set operation.
@return Buffer
**/
VOID *
EFIAPI
InternalMemSetMem (
OUT VOID *Buffer,
IN UINTN Length,
IN UINT8 Value
)
{
//
// Declare the local variables that actually move the data elements as
// volatile to prevent the optimizer from replacing this function with
// the intrinsic memset()
//
volatile UINT8 *Pointer8;
volatile UINT32 *Pointer32;
volatile UINT64 *Pointer64;
UINT32 Value32;
UINT64 Value64;
if ((((UINTN)Buffer & 0x7) == 0) && (Length >= 8)) {
// Generate the 64bit value
Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
Value64 = LShiftU64 (Value32, 32) | Value32;
Pointer64 = (UINT64*)Buffer;
while (Length >= 8) {
*(Pointer64++) = Value64;
Length -= 8;
}
// Finish with bytes if needed
Pointer8 = (UINT8*)Pointer64;
} else if ((((UINTN)Buffer & 0x3) == 0) && (Length >= 4)) {
// Generate the 32bit value
Value32 = (Value << 24) | (Value << 16) | (Value << 8) | Value;
Pointer32 = (UINT32*)Buffer;
while (Length >= 4) {
*(Pointer32++) = Value32;
Length -= 4;
}
// Finish with bytes if needed
Pointer8 = (UINT8*)Pointer32;
} else {
Pointer8 = (UINT8*)Buffer;
}
while (Length-- > 0) {
*(Pointer8++) = Value;
}
return Buffer;
}
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