MdePkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / MdePkg / Library / BaseMemoryLib / CopyMem.c

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