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Last change
on this file since 80924 was 80721, checked in by vboxsync, 6 years ago |
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Devices/EFI/FirmwareNew: Start upgrade process to edk2-stable201908 (compiles on Windows and works to some extent), bugref:4643
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| 1 | /** @file
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| 2 | Math worker functions.
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| 3 |
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| 4 | Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
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| 5 | SPDX-License-Identifier: BSD-2-Clause-Patent
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| 6 |
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| 7 | **/
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| 8 |
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| 9 |
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| 10 |
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| 11 |
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| 12 | #include "BaseLibInternals.h"
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| 13 |
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| 14 | /**
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| 15 | Returns the bit position of the highest bit set in a 32-bit value. Equivalent
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| 16 | to log2(x).
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| 17 |
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| 18 | This function computes the bit position of the highest bit set in the 32-bit
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| 19 | value specified by Operand. If Operand is zero, then -1 is returned.
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| 20 | Otherwise, a value between 0 and 31 is returned.
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| 21 |
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| 22 | @param Operand The 32-bit operand to evaluate.
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| 23 |
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| 24 | @retval 0..31 Position of the highest bit set in Operand if found.
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| 25 | @retval -1 Operand is zero.
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| 26 |
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| 27 | **/
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| 28 | INTN
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| 29 | EFIAPI
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| 30 | HighBitSet32 (
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| 31 | IN UINT32 Operand
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| 32 | )
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| 33 | {
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| 34 | INTN BitIndex;
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| 35 |
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| 36 | if (Operand == 0) {
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| 37 | return - 1;
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| 38 | }
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| 39 | for (BitIndex = 31; (INT32)Operand > 0; BitIndex--, Operand <<= 1);
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| 40 | return BitIndex;
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| 41 | }
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