yuzu/src/common/bit_util.h
Lioncash 33db37e669 common/bit_util: Make CountLeading/CountTrailing functions have the same return types
Makes the return type consistently uniform (like the intrinsics we're
wrapping). This also conveniently silences a truncation warning within
the kernel multi_level_queue.
2019-04-05 15:29:40 -04:00

101 lines
1.8 KiB
C++

// 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 u32 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 static_cast<u32>(__builtin_clz(value));
}
inline u32 CountLeadingZeroes64(u64 value) {
if (value == 0) {
return 64;
}
return static_cast<u32>(__builtin_clzll(value));
}
#endif
#ifdef _MSC_VER
inline u32 CountTrailingZeroes32(u32 value) {
unsigned long trailing_zero = 0;
if (_BitScanForward(&trailing_zero, value) != 0) {
return trailing_zero;
}
return 32;
}
inline u32 CountTrailingZeroes64(u64 value) {
unsigned long trailing_zero = 0;
if (_BitScanForward64(&trailing_zero, value) != 0) {
return trailing_zero;
}
return 64;
}
#else
inline u32 CountTrailingZeroes32(u32 value) {
if (value == 0) {
return 32;
}
return static_cast<u32>(__builtin_ctz(value));
}
inline u32 CountTrailingZeroes64(u64 value) {
if (value == 0) {
return 64;
}
return static_cast<u32>(__builtin_ctzll(value));
}
#endif
} // namespace Common