mirror of https://github.com/acidanthera/audk.git
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
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/** @file
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Math worker functions.
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Copyright (c) 2006, Intel Corporation<BR>
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All rights reserved. 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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//
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// Include common header file for this module.
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//
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#include "CommonHeader.h"
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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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@return 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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