mirror of https://github.com/acidanthera/audk.git
149 lines
4.7 KiB
C
149 lines
4.7 KiB
C
/** @file
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Implementation of the InternalMemCopyMem routine. This function is broken
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out into its own source file so that it can be excluded from a build for a
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particular platform easily if an optimized version is desired.
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Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
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Copyright (c) 2012 - 2013, ARM Ltd. All rights reserved.<BR>
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Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
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SPDX-License-Identifier: BSD-2-Clause-Patent
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**/
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#include "MemLibInternals.h"
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/**
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Copy Length bytes from Source to Destination.
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@param DestinationBuffer The target of the copy request.
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@param SourceBuffer The place to copy from.
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@param Length The number of bytes to copy.
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@return Destination
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**/
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VOID *
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EFIAPI
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InternalMemCopyMem (
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OUT VOID *DestinationBuffer,
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IN CONST VOID *SourceBuffer,
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IN UINTN Length
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)
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{
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//
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// Declare the local variables that actually move the data elements as
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// volatile to prevent the optimizer from replacing this function with
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// the intrinsic memcpy()
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//
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volatile UINT8 *Destination8;
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CONST UINT8 *Source8;
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volatile UINT32 *Destination32;
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CONST UINT32 *Source32;
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volatile UINT64 *Destination64;
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CONST UINT64 *Source64;
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UINTN Alignment;
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if ((((UINTN)DestinationBuffer & 0x7) == 0) && (((UINTN)SourceBuffer & 0x7) == 0) && (Length >= 8)) {
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if (SourceBuffer > DestinationBuffer) {
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Destination64 = (UINT64 *)DestinationBuffer;
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Source64 = (CONST UINT64 *)SourceBuffer;
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while (Length >= 8) {
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*(Destination64++) = *(Source64++);
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Length -= 8;
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}
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// Finish if there are still some bytes to copy
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Destination8 = (UINT8 *)Destination64;
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Source8 = (CONST UINT8 *)Source64;
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while (Length-- != 0) {
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*(Destination8++) = *(Source8++);
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}
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} else if (SourceBuffer < DestinationBuffer) {
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Destination64 = (UINT64 *)((UINTN)DestinationBuffer + Length);
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Source64 = (CONST UINT64 *)((UINTN)SourceBuffer + Length);
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// Destination64 and Source64 were aligned on a 64-bit boundary
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// but if length is not a multiple of 8 bytes then they won't be
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// anymore.
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Alignment = Length & 0x7;
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if (Alignment != 0) {
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Destination8 = (UINT8 *)Destination64;
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Source8 = (CONST UINT8 *)Source64;
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while (Alignment-- != 0) {
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*(--Destination8) = *(--Source8);
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--Length;
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}
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Destination64 = (UINT64 *)Destination8;
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Source64 = (CONST UINT64 *)Source8;
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}
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while (Length > 0) {
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*(--Destination64) = *(--Source64);
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Length -= 8;
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}
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}
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} else if ((((UINTN)DestinationBuffer & 0x3) == 0) && (((UINTN)SourceBuffer & 0x3) == 0) && (Length >= 4)) {
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if (SourceBuffer > DestinationBuffer) {
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Destination32 = (UINT32 *)DestinationBuffer;
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Source32 = (CONST UINT32 *)SourceBuffer;
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while (Length >= 4) {
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*(Destination32++) = *(Source32++);
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Length -= 4;
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}
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// Finish if there are still some bytes to copy
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Destination8 = (UINT8 *)Destination32;
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Source8 = (CONST UINT8 *)Source32;
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while (Length-- != 0) {
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*(Destination8++) = *(Source8++);
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}
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} else if (SourceBuffer < DestinationBuffer) {
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Destination32 = (UINT32 *)((UINTN)DestinationBuffer + Length);
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Source32 = (CONST UINT32 *)((UINTN)SourceBuffer + Length);
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// Destination32 and Source32 were aligned on a 32-bit boundary
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// but if length is not a multiple of 4 bytes then they won't be
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// anymore.
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Alignment = Length & 0x3;
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if (Alignment != 0) {
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Destination8 = (UINT8 *)Destination32;
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Source8 = (CONST UINT8 *)Source32;
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while (Alignment-- != 0) {
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*(--Destination8) = *(--Source8);
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--Length;
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}
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Destination32 = (UINT32 *)Destination8;
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Source32 = (CONST UINT32 *)Source8;
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}
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while (Length > 0) {
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*(--Destination32) = *(--Source32);
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Length -= 4;
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}
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}
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} else {
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if (SourceBuffer > DestinationBuffer) {
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Destination8 = (UINT8 *)DestinationBuffer;
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Source8 = (CONST UINT8 *)SourceBuffer;
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while (Length-- != 0) {
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*(Destination8++) = *(Source8++);
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}
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} else if (SourceBuffer < DestinationBuffer) {
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Destination8 = (UINT8 *)DestinationBuffer + (Length - 1);
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Source8 = (CONST UINT8 *)SourceBuffer + (Length - 1);
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while (Length-- != 0) {
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*(Destination8--) = *(Source8--);
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}
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}
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}
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return DestinationBuffer;
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}
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