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Last change
on this file 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 highest bit set in a 64-bit value. Equivalent
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| 13 | to log2(x).
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| 14 |
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| 15 | This function computes the bit position of the highest bit set in the 64-bit
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| 16 | value specified by Operand. If Operand is zero, then -1 is returned.
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| 17 | Otherwise, a value between 0 and 63 is returned.
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| 18 |
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| 19 | @param Operand The 64-bit operand to evaluate.
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| 20 |
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| 21 | @retval 0..63 Position of the highest bit set in Operand if found.
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| 22 | @retval -1 Operand is zero.
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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 | HighBitSet64 (
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| 28 | IN UINT64 Operand
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| 29 | )
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| 30 | {
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| 31 | if (Operand == (UINT32)Operand) {
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| 32 | //
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| 33 | // Operand is just a 32-bit integer
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| 34 | //
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| 35 | return HighBitSet32 ((UINT32)Operand);
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| 36 | }
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| 37 |
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| 38 | //
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| 39 | // Operand is really a 64-bit integer
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| 40 | //
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| 41 | if (sizeof (UINTN) == sizeof (UINT32)) {
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| 42 | return HighBitSet32 (((UINT32 *)&Operand)[1]) + 32;
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| 43 | } else {
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| 44 | return HighBitSet32 ((UINT32)RShiftU64 (Operand, 32)) + 32;
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| 45 | }
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| 46 | }
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