5fc3b5d6c8
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10683 6f19259b-4bc3-4df7-8a09-765794883524
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/** @file
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Math worker functions.
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Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
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This program and the accompanying materials
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are licensed and made available under the terms and conditions of the BSD License
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which accompanies this distribution. The full text of the license may be found at
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http://opensource.org/licenses/bsd-license.php.
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THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
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WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
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**/
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#include "BaseLibInternals.h"
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/**
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Returns the bit position of the highest bit set in a 32-bit value. Equivalent
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to log2(x).
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This function computes the bit position of the highest bit set in the 32-bit
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value specified by Operand. If Operand is zero, then -1 is returned.
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Otherwise, a value between 0 and 31 is returned.
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@param Operand The 32-bit operand to evaluate.
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@retval 0..31 Position of the highest bit set in Operand if found.
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@retval -1 Operand is zero.
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**/
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INTN
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EFIAPI
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HighBitSet32 (
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IN UINT32 Operand
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)
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{
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INTN BitIndex;
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if (Operand == 0) {
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return - 1;
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}
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for (BitIndex = 31; (INT32)Operand > 0; BitIndex--, Operand <<= 1);
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return BitIndex;
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}
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