Initial import.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@3 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseLib/GetPowerOfTwo64.c

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+/** @file
+  Math worker functions.
+
+  Copyright (c) 2006, Intel Corporation<BR>
+  All rights reserved. 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 "BaseLibInternals.h"
+
+/**
+  Returns the value of the highest bit set in a 64-bit value. Equivalent to
+  1 << HighBitSet64(x).
+
+  This function computes the value of the highest bit set in the 64-bit value
+  specified by Operand. If Operand is zero, then zero is returned.
+
+  @param  Operand The 64-bit operand to evaluate.
+
+  @return 1 << HighBitSet64(Operand)
+  @retval 0 Operand is zero.
+
+**/
+UINT64
+EFIAPI
+GetPowerOfTwo64 (
+  IN      UINT64                    Operand
+  )
+{
+  INTN                              BitPos;
+
+  return (BitPos = HighBitSet64 (Operand)) > 0 ? LShiftU64 (1, BitPos) : 0;
+}