diff options
Diffstat (limited to 'Core/MdePkg/Library/BaseMemoryLib/CopyMem.c')
-rw-r--r-- | Core/MdePkg/Library/BaseMemoryLib/CopyMem.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseMemoryLib/CopyMem.c b/Core/MdePkg/Library/BaseMemoryLib/CopyMem.c new file mode 100644 index 0000000000..3db25ca851 --- /dev/null +++ b/Core/MdePkg/Library/BaseMemoryLib/CopyMem.c @@ -0,0 +1,154 @@ +/** @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>
+
+ 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"
+
+/**
+ 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;
+}
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