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Last change
on this file since 109247 was 99404, checked in by vboxsync, 2 years ago |
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Devices/EFI/FirmwareNew: Update to edk2-stable202302 and make it build, 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 | #include "BaseLibInternals.h"
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| 10 |
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| 11 | /**
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| 12 | Returns the bit position of the lowest bit set in a 64-bit value.
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| 13 |
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| 14 | This function computes the bit position of the lowest bit set in the 64-bit
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| 15 | value specified by Operand. If Operand is zero, then -1 is returned.
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| 16 | Otherwise, a value between 0 and 63 is returned.
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| 17 |
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| 18 | @param Operand The 64-bit operand to evaluate.
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| 19 |
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| 20 | @retval 0..63 The lowest bit set in Operand was found.
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| 21 | @retval -1 Operand is zero.
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| 22 |
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| 23 |
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| 24 | **/
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| 25 | INTN
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| 26 | EFIAPI
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| 27 | LowBitSet64 (
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| 28 | IN UINT64 Operand
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| 29 | )
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| 30 | {
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| 31 | INTN BitIndex;
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| 32 |
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| 33 | if (Operand == 0) {
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| 34 | return -1;
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| 35 | }
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| 36 |
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| 37 | for (BitIndex = 0;
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| 38 | (Operand & 1) == 0;
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| 39 | BitIndex++, Operand = RShiftU64 (Operand, 1))
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| 40 | {
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| 41 | }
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| 42 |
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| 43 | return BitIndex;
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| 44 | }
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