yuzu/src/common/bit_util.h

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// Copyright 2018 yuzu emulator team
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#pragma once
#include <climits>
#include <cstddef>
#ifdef _MSC_VER
#include <intrin.h>
#endif
#include "common/common_types.h"
namespace Common {
/// Gets the size of a specified type T in bits.
template <typename T>
constexpr std::size_t BitSize() {
return sizeof(T) * CHAR_BIT;
}
#ifdef _MSC_VER
inline u32 CountLeadingZeroes32(u32 value) {
unsigned long leading_zero = 0;
if (_BitScanReverse(&leading_zero, value) != 0) {
return 31 - leading_zero;
}
return 32;
}
inline u64 CountLeadingZeroes64(u64 value) {
unsigned long leading_zero = 0;
if (_BitScanReverse64(&leading_zero, value) != 0) {
return 63 - leading_zero;
}
return 64;
}
#else
inline u32 CountLeadingZeroes32(u32 value) {
if (value == 0) {
return 32;
}
return __builtin_clz(value);
}
inline u64 CountLeadingZeroes64(u64 value) {
if (value == 0) {
return 64;
}
return __builtin_clzll(value);
}
#endif
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inline u32 CountTrailingZeroes32(u32 value) {
u32 count = 0;
while (((value >> count) & 0xf) == 0 && count < 32)
count += 4;
while (((value >> count) & 1) == 0 && count < 32)
count++;
return count;
}
inline u64 CountTrailingZeroes64(u64 value) {
u64 count = 0;
while (((value >> count) & 0xf) == 0 && count < 64)
count += 4;
while (((value >> count) & 1) == 0 && count < 64)
count++;
return count;
}
} // namespace Common