mirror of
https://github.com/Atmosphere-NX/Atmosphere.git
synced 2024-11-26 22:02:15 +00:00
298 lines
11 KiB
C++
298 lines
11 KiB
C++
/*
|
|
* Copyright (c) Atmosphère-NX
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|
|
* more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#pragma once
|
|
#include <vapours/common.hpp>
|
|
#include <vapours/assert.hpp>
|
|
|
|
namespace ams::util {
|
|
|
|
namespace impl {
|
|
|
|
template<size_t N>
|
|
constexpr inline size_t Log2 = Log2<N / 2> + 1;
|
|
|
|
template<>
|
|
constexpr inline size_t Log2<1> = 0;
|
|
|
|
}
|
|
|
|
template <typename T> requires std::integral<T>
|
|
class BitsOf {
|
|
private:
|
|
static constexpr ALWAYS_INLINE int GetLsbPos(T v) {
|
|
return __builtin_ctzll(static_cast<u64>(v));
|
|
}
|
|
|
|
T m_value;
|
|
public:
|
|
/* Note: GCC has a bug in constant-folding here. Workaround: wrap entire caller with constexpr. */
|
|
constexpr ALWAYS_INLINE BitsOf(T value = T(0u)) : m_value(value) {
|
|
/* ... */
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE bool operator==(const BitsOf &other) const {
|
|
return m_value == other.m_value;
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE bool operator!=(const BitsOf &other) const {
|
|
return m_value != other.m_value;
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE int operator*() const {
|
|
return GetLsbPos(m_value);
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE BitsOf &operator++() {
|
|
m_value &= ~(T(1u) << GetLsbPos(m_value));
|
|
return *this;
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE BitsOf &operator++(int) {
|
|
BitsOf ret(m_value);
|
|
++(*this);
|
|
return ret;
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE BitsOf begin() const {
|
|
return *this;
|
|
}
|
|
|
|
constexpr ALWAYS_INLINE BitsOf end() const {
|
|
return BitsOf(T(0u));
|
|
}
|
|
};
|
|
|
|
template<typename T = u64, typename ...Args> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T CombineBits(Args... args) {
|
|
return (... | (T(1u) << args));
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T ResetLeastSignificantOneBit(T x) {
|
|
return x & (x - 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T SetLeastSignificantZeroBit(T x) {
|
|
return x | (x + 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T LeastSignificantOneBit(T x) {
|
|
return x & ~(x - 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T LeastSignificantZeroBit(T x) {
|
|
return ~x & (x + 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T ResetTrailingOnes(T x) {
|
|
return x & (x + 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T SetTrailingZeros(T x) {
|
|
return x | (x - 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T MaskTrailingZeros(T x) {
|
|
return (~x) & (x - 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T MaskTrailingOnes(T x) {
|
|
return ~((~x) | (x + 1));
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T MaskTrailingZerosAndLeastSignificantOneBit(T x) {
|
|
return x ^ (x - 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T MaskTrailingOnesAndLeastSignificantZeroBit(T x) {
|
|
return x ^ (x + 1);
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE int PopCount(T x) {
|
|
using U = typename std::make_unsigned<T>::type;
|
|
U u = static_cast<U>(x);
|
|
|
|
if (std::is_constant_evaluated()) {
|
|
/* https://en.wikipedia.org/wiki/Hamming_weight */
|
|
constexpr U m1 = U(-1) / 0x03;
|
|
constexpr U m2 = U(-1) / 0x05;
|
|
constexpr U m4 = U(-1) / 0x11;
|
|
|
|
u = static_cast<U>(u - ((u >> 1) & m1));
|
|
u = static_cast<U>((u & m2) + ((u >> 2) & m2));
|
|
u = static_cast<U>((u + (u >> 4)) & m4);
|
|
|
|
for (size_t i = 0; i < impl::Log2<sizeof(T)>; ++i) {
|
|
const size_t shift = (0x1 << i) * BITSIZEOF(u8);
|
|
u += u >> shift;
|
|
}
|
|
|
|
return static_cast<int>(u & 0x7Fu);
|
|
} else {
|
|
if constexpr (std::is_same<U, unsigned long long>::value) {
|
|
return __builtin_popcountll(u);
|
|
} else if constexpr (std::is_same<U, unsigned long>::value) {
|
|
return __builtin_popcountl(u);
|
|
} else {
|
|
static_assert(sizeof(U) <= sizeof(unsigned int));
|
|
return __builtin_popcount(static_cast<unsigned int>(u));
|
|
}
|
|
}
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE int CountLeadingZeros(T x) {
|
|
if (std::is_constant_evaluated()) {
|
|
for (size_t i = 0; i < impl::Log2<BITSIZEOF(T)>; ++i) {
|
|
const size_t shift = (0x1 << i);
|
|
x |= x >> shift;
|
|
}
|
|
return PopCount(static_cast<T>(~x));
|
|
} else {
|
|
using U = typename std::make_unsigned<T>::type;
|
|
const U u = static_cast<U>(x);
|
|
|
|
if (u != 0) {
|
|
if constexpr (std::is_same<U, unsigned long long>::value) {
|
|
return __builtin_clzll(u);
|
|
} else if constexpr (std::is_same<U, unsigned long>::value) {
|
|
return __builtin_clzl(u);
|
|
} else if constexpr(std::is_same<U, unsigned int>::value) {
|
|
return __builtin_clz(u);
|
|
} else {
|
|
static_assert(sizeof(U) < sizeof(unsigned int));
|
|
constexpr size_t BitDiff = BITSIZEOF(unsigned int) - BITSIZEOF(U);
|
|
return __builtin_clz(static_cast<unsigned int>(u)) - BitDiff;
|
|
}
|
|
} else {
|
|
return BITSIZEOF(U);
|
|
}
|
|
}
|
|
}
|
|
|
|
static_assert(CountLeadingZeros(~static_cast<u64>(0)) == 0);
|
|
static_assert(CountLeadingZeros(static_cast<u64>(1) << 5) == BITSIZEOF(u64) - 1 - 5);
|
|
static_assert(CountLeadingZeros(static_cast<u64>(0)) == BITSIZEOF(u64));
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE int CountTrailingZeros(T x) {
|
|
if (std::is_constant_evaluated()) {
|
|
auto count = 0;
|
|
for (size_t i = 0; i < BITSIZEOF(T) && (x & 1) == 0; ++i) {
|
|
x >>= 1;
|
|
++count;
|
|
}
|
|
return count;
|
|
} else {
|
|
using U = typename std::make_unsigned<T>::type;
|
|
const U u = static_cast<U>(x);
|
|
if (u != 0) {
|
|
if constexpr (std::is_same<U, unsigned long long>::value) {
|
|
return __builtin_ctzll(u);
|
|
} else if constexpr (std::is_same<U, unsigned long>::value) {
|
|
return __builtin_ctzl(u);
|
|
} else if constexpr(std::is_same<U, unsigned int>::value) {
|
|
return __builtin_ctz(u);
|
|
} else {
|
|
static_assert(sizeof(U) < sizeof(unsigned int));
|
|
return __builtin_ctz(static_cast<unsigned int>(u));
|
|
}
|
|
} else {
|
|
return BITSIZEOF(U);
|
|
}
|
|
}
|
|
}
|
|
|
|
static_assert(CountTrailingZeros(~static_cast<u64>(0)) == 0);
|
|
static_assert(CountTrailingZeros(static_cast<u64>(1) << 5) == 5);
|
|
static_assert(CountTrailingZeros(static_cast<u64>(0)) == BITSIZEOF(u64));
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE bool IsPowerOfTwo(T x) {
|
|
return x > 0 && ResetLeastSignificantOneBit(x) == 0;
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T CeilingPowerOfTwo(T x) {
|
|
AMS_ASSERT(x > 0);
|
|
return T(1) << (BITSIZEOF(T) - CountLeadingZeros(T(x - 1)));
|
|
}
|
|
|
|
template<typename T> requires std::integral<T>
|
|
constexpr ALWAYS_INLINE T FloorPowerOfTwo(T x) {
|
|
AMS_ASSERT(x > 0);
|
|
return T(1) << (BITSIZEOF(T) - CountLeadingZeros(x) - 1);
|
|
}
|
|
|
|
template<typename T, typename U>
|
|
constexpr ALWAYS_INLINE T DivideUp(T v, U d) {
|
|
using Unsigned = typename std::make_unsigned<U>::type;
|
|
const Unsigned add = static_cast<Unsigned>(d) - 1;
|
|
return static_cast<T>((v + add) / d);
|
|
}
|
|
|
|
template<typename T, T N, T D>
|
|
constexpr ALWAYS_INLINE T ScaleByConstantFactorUp(const T V) {
|
|
/* Multiplying and dividing by large numerator/denominator can cause error to be introduced. */
|
|
/* This algorithm multiples/divides in stages, so as to mitigate this (particularly with large denominator). */
|
|
|
|
/* Justification for the algorithm. */
|
|
/* Calculate: (V * N) / D */
|
|
/* = (Quot_V * D + Rem_V) * (Quot_N * D + Rem_N) / D */
|
|
/* = (D^2 * (Quot_V * Quot_N) + D * (Quot_V * Rem_N + Rem_V * Quot_N) + Rem_V * Rem_N) / D */
|
|
/* = (D * Quot_V * Quot_N) + (Quot_V * Rem_N) + (Rem_V * Quot_N) + ((Rem_V * Rem_N) / D) */
|
|
|
|
/* Calculate quotients/remainders. */
|
|
const T Quot_V = V / D;
|
|
const T Rem_V = V % D;
|
|
constexpr T Quot_N = N / D;
|
|
constexpr T Rem_N = N % D;
|
|
|
|
/* Calculate the remainder multiplication, rounding up. */
|
|
const T rem_mult = ((Rem_V * Rem_N) + (D - 1)) / D;
|
|
|
|
/* Calculate results. */
|
|
return (D * Quot_N * Quot_V) + (Quot_V * Rem_N) + (Rem_V * Quot_N) + rem_mult;
|
|
}
|
|
|
|
template<std::integral T>
|
|
constexpr ALWAYS_INLINE T RotateLeft(T v, int n) {
|
|
using Unsigned = typename std::make_unsigned<T>::type;
|
|
static_assert(sizeof(Unsigned) == sizeof(T));
|
|
|
|
return static_cast<T>(std::rotl<Unsigned>(static_cast<Unsigned>(v), n));
|
|
}
|
|
|
|
template<std::integral T>
|
|
constexpr ALWAYS_INLINE T RotateRight(T v, int n) {
|
|
using Unsigned = typename std::make_unsigned<T>::type;
|
|
static_assert(sizeof(Unsigned) == sizeof(T));
|
|
|
|
return static_cast<T>(std::rotr<Unsigned>(static_cast<Unsigned>(v), n));
|
|
}
|
|
|
|
}
|