pcsx2/common/BitUtils.h

99 lines
2.6 KiB
C++

/* PCSX2 - PS2 Emulator for PCs
* Copyright (C) 2002-2023 PCSX2 Dev Team
*
* PCSX2 is free software: you can redistribute it and/or modify it under the terms
* of the GNU Lesser General Public License as published by the Free Software Found-
* ation, either version 3 of the License, or (at your option) any later version.
*
* PCSX2 is distributed in the hope that 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 PCSX2.
* If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include "common/Pcsx2Defs.h"
#include <bit>
#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
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)
{
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));
}
} // namespace Common