MdePkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / MdePkg / Library / BaseLib / HighBitSet64.c

/** @file\r
  Math worker functions.\r
\r
  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
  SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
\r
\r
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#include "BaseLibInternals.h"\r
\r
/**\r
  Returns the bit position of the highest bit set in a 64-bit value. Equivalent\r
  to log2(x).\r
\r
  This function computes the bit position of the highest bit set in the 64-bit\r
  value specified by Operand. If Operand is zero, then -1 is returned.\r
  Otherwise, a value between 0 and 63 is returned.\r
\r
  @param  Operand The 64-bit operand to evaluate.\r
\r
  @retval 0..63   Position of the highest bit set in Operand if found.\r
  @retval -1      Operand is zero.\r
\r
**/\r
INTN\r
EFIAPI\r
HighBitSet64 (\r
  IN      UINT64                    Operand\r
  )\r
{\r
  if (Operand == (UINT32)Operand) {\r
    //\r
    // Operand is just a 32-bit integer\r
    //\r
    return HighBitSet32 ((UINT32)Operand);\r
  }\r
\r
  //\r
  // Operand is really a 64-bit integer\r
  //\r
  if (sizeof (UINTN) == sizeof (UINT32)) {\r
    return HighBitSet32 (((UINT32*)&Operand)[1]) + 32;\r
  } else {\r
    return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;\r
  }\r
}\r