50 lines
1.2 KiB
C
50 lines
1.2 KiB
C
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// SPDX-License-Identifier: AGPL-1.0-only
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// Copyright (C) 2018 Ludvig Strigeus <info@tunsafe.com>. All Rights Reserved.
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#pragma once
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#include "tunsafe_types.h"
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#include "tunsafe_endian.h"
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#if !defined(ARCH_CPU_X86_64) && defined(COMPILER_MSVC)
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static inline int _BitScanReverse64(unsigned long *index, uint64 x) {
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if (_BitScanReverse(index, x >> 32)) {
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(*index) += 32;
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return true;
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}
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return _BitScanReverse(index, (uint32)x);
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}
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#endif
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#if !defined(COMPILER_MSVC)
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static inline int _BitScanReverse64(unsigned long *index, uint64 x) {
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*index = 63 - __builtin_clzll(x);
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return (x != 0);
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}
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static inline int _BitScanReverse(unsigned long *index, uint32 x) {
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*index = 31 - __builtin_clz(x);
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return (x != 0);
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}
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#endif
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static inline int FindHighestSetBit32(uint32 x) {
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unsigned long index;
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return _BitScanReverse(&index, x) ? (int)(index + 1) : 0;
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}
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static inline int FindLastSetBit32(uint32 x) {
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unsigned long index;
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_BitScanReverse(&index, x);
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return index;
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}
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static inline int FindHighestSetBit64(uint64 x) {
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unsigned long index;
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return _BitScanReverse64(&index, x) ? (int)(index + 1) : 0;
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}
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static inline int FindHighestSetBit128(uint64 hi, uint64 lo) {
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return hi ? 64 + FindHighestSetBit64(hi) : FindHighestSetBit64(lo);
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}
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