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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>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#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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