common: Add basic bit manipulation utility function to Common

This commit is contained in:
Lioncash 2018-12-19 15:25:12 -05:00
parent e73dd39413
commit fc8da2d5e3
2 changed files with 62 additions and 0 deletions

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@ -44,6 +44,7 @@ add_library(common STATIC
detached_tasks.cpp
detached_tasks.h
bit_field.h
bit_util.h
cityhash.cpp
cityhash.h
color.h

61
src/common/bit_util.h Normal file
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@ -0,0 +1,61 @@
// 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
} // namespace Common