/** @file | |
Implementation of the InternalMemCopyMem 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 - 2016, 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" | |
/** | |
Copy Length bytes from Source to Destination. | |
@param DestinationBuffer The target of the copy request. | |
@param SourceBuffer The place to copy from. | |
@param Length The number of bytes to copy. | |
@return Destination | |
**/ | |
VOID * | |
EFIAPI | |
InternalMemCopyMem ( | |
OUT VOID *DestinationBuffer, | |
IN CONST VOID *SourceBuffer, | |
IN UINTN Length | |
) | |
{ | |
// | |
// Declare the local variables that actually move the data elements as | |
// volatile to prevent the optimizer from replacing this function with | |
// the intrinsic memcpy() | |
// | |
volatile UINT8 *Destination8; | |
CONST UINT8 *Source8; | |
volatile UINT32 *Destination32; | |
CONST UINT32 *Source32; | |
volatile UINT64 *Destination64; | |
CONST UINT64 *Source64; | |
UINTN Alignment; | |
if ((((UINTN)DestinationBuffer & 0x7) == 0) && (((UINTN)SourceBuffer & 0x7) == 0) && (Length >= 8)) { | |
if (SourceBuffer > DestinationBuffer) { | |
Destination64 = (UINT64 *)DestinationBuffer; | |
Source64 = (CONST UINT64 *)SourceBuffer; | |
while (Length >= 8) { | |
*(Destination64++) = *(Source64++); | |
Length -= 8; | |
} | |
// Finish if there are still some bytes to copy | |
Destination8 = (UINT8 *)Destination64; | |
Source8 = (CONST UINT8 *)Source64; | |
while (Length-- != 0) { | |
*(Destination8++) = *(Source8++); | |
} | |
} else if (SourceBuffer < DestinationBuffer) { | |
Destination64 = (UINT64 *)((UINTN)DestinationBuffer + Length); | |
Source64 = (CONST UINT64 *)((UINTN)SourceBuffer + Length); | |
// Destination64 and Source64 were aligned on a 64-bit boundary | |
// but if length is not a multiple of 8 bytes then they won't be | |
// anymore. | |
Alignment = Length & 0x7; | |
if (Alignment != 0) { | |
Destination8 = (UINT8 *)Destination64; | |
Source8 = (CONST UINT8 *)Source64; | |
while (Alignment-- != 0) { | |
*(--Destination8) = *(--Source8); | |
--Length; | |
} | |
Destination64 = (UINT64 *)Destination8; | |
Source64 = (CONST UINT64 *)Source8; | |
} | |
while (Length > 0) { | |
*(--Destination64) = *(--Source64); | |
Length -= 8; | |
} | |
} | |
} else if ((((UINTN)DestinationBuffer & 0x3) == 0) && (((UINTN)SourceBuffer & 0x3) == 0) && (Length >= 4)) { | |
if (SourceBuffer > DestinationBuffer) { | |
Destination32 = (UINT32 *)DestinationBuffer; | |
Source32 = (CONST UINT32 *)SourceBuffer; | |
while (Length >= 4) { | |
*(Destination32++) = *(Source32++); | |
Length -= 4; | |
} | |
// Finish if there are still some bytes to copy | |
Destination8 = (UINT8 *)Destination32; | |
Source8 = (CONST UINT8 *)Source32; | |
while (Length-- != 0) { | |
*(Destination8++) = *(Source8++); | |
} | |
} else if (SourceBuffer < DestinationBuffer) { | |
Destination32 = (UINT32 *)((UINTN)DestinationBuffer + Length); | |
Source32 = (CONST UINT32 *)((UINTN)SourceBuffer + Length); | |
// Destination32 and Source32 were aligned on a 32-bit boundary | |
// but if length is not a multiple of 4 bytes then they won't be | |
// anymore. | |
Alignment = Length & 0x3; | |
if (Alignment != 0) { | |
Destination8 = (UINT8 *)Destination32; | |
Source8 = (CONST UINT8 *)Source32; | |
while (Alignment-- != 0) { | |
*(--Destination8) = *(--Source8); | |
--Length; | |
} | |
Destination32 = (UINT32 *)Destination8; | |
Source32 = (CONST UINT32 *)Source8; | |
} | |
while (Length > 0) { | |
*(--Destination32) = *(--Source32); | |
Length -= 4; | |
} | |
} | |
} else { | |
if (SourceBuffer > DestinationBuffer) { | |
Destination8 = (UINT8 *)DestinationBuffer; | |
Source8 = (CONST UINT8 *)SourceBuffer; | |
while (Length-- != 0) { | |
*(Destination8++) = *(Source8++); | |
} | |
} else if (SourceBuffer < DestinationBuffer) { | |
Destination8 = (UINT8 *)DestinationBuffer + (Length - 1); | |
Source8 = (CONST UINT8 *)SourceBuffer + (Length - 1); | |
while (Length-- != 0) { | |
*(Destination8--) = *(Source8--); | |
} | |
} | |
} | |
return DestinationBuffer; | |
} |