pcsx2/common/BitUtils.h

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// SPDX-FileCopyrightText: 2002-2024 PCSX2 Dev Team
// SPDX-License-Identifier: GPL-3.0+
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#pragma once
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#include "common/Pcsx2Defs.h"
#include <bit>
#include <cstring>
#ifdef _MSC_VER
#include <intrin.h>
#else
static inline int _BitScanReverse(unsigned long* const Index, const unsigned long Mask)
{
if (Mask == 0)
return 0;
// For some reason, clang won't emit bsr if we use std::countl_zeros()...
*Index = 31 - __builtin_clz(Mask);
return 1;
}
#endif
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namespace Common
{
template <typename T>
static constexpr __fi bool IsAligned(T value, unsigned int alignment)
{
return (value % static_cast<T>(alignment)) == 0;
}
template <typename T>
static constexpr __fi T AlignUp(T value, unsigned int alignment)
{
return (value + static_cast<T>(alignment - 1)) / static_cast<T>(alignment) * static_cast<T>(alignment);
}
template <typename T>
static constexpr __fi T AlignDown(T value, unsigned int alignment)
{
return value / static_cast<T>(alignment) * static_cast<T>(alignment);
}
template <typename T>
static constexpr __fi bool IsAlignedPow2(T value, unsigned int alignment)
{
return (value & static_cast<T>(alignment - 1)) == 0;
}
template <typename T>
static constexpr __fi T AlignUpPow2(T value, unsigned int alignment)
{
return (value + static_cast<T>(alignment - 1)) & static_cast<T>(~static_cast<T>(alignment - 1));
}
template <typename T>
static constexpr __fi T AlignDownPow2(T value, unsigned int alignment)
{
return value & static_cast<T>(~static_cast<T>(alignment - 1));
}
template <typename T>
static constexpr T PageAlign(T size)
{
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static_assert(std::has_single_bit(__pagesize), "Page size is a power of 2");
return Common::AlignUpPow2(size, __pagesize);
}
__fi static u32 CountLeadingSignBits(s32 n)
{
// If the sign bit is 1, we invert the bits to 0 for count-leading-zero.
if (n < 0)
n = ~n;
// If BSR is used directly, it would have an undefined value for 0.
if (n == 0)
return 32;
// Perform our count leading zero.
return std::countl_zero(static_cast<u32>(n));
}
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} // namespace Common
template <typename T>
[[maybe_unused]] __fi static T GetBufferT(const u8* buffer, u32 offset)
{
T value;
std::memcpy(&value, buffer + offset, sizeof(value));
return value;
}
[[maybe_unused]] __fi static u8 GetBufferU8(const u8* buffer, u32 offset) { return GetBufferT<u8>(buffer, offset); }
[[maybe_unused]] __fi static u16 GetBufferU16(const u8* buffer, u32 offset) { return GetBufferT<u16>(buffer, offset); }
[[maybe_unused]] __fi static u32 GetBufferU32(const u8* buffer, u32 offset) { return GetBufferT<u32>(buffer, offset); }
[[maybe_unused]] __fi static u64 GetBufferU64(const u8* buffer, u32 offset) { return GetBufferT<u64>(buffer, offset); }