mirror of
https://github.com/FEX-Emu/FEX.git
synced 2026-10-27 13:00:47 +01:00
Alyssa Rosenzweig
af21b8f3c7
It is not an external component, and it makes paths needlessly long. Ryan seemed amenable to this when we discussed on IRC earlier. Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
82 lines
2.6 KiB
C++
82 lines
2.6 KiB
C++
#pragma once
|
|
|
|
// Header for various utilities that operate on bits and bytes.
|
|
|
|
#include <bit>
|
|
#include <climits>
|
|
#include <cstddef>
|
|
#include <cstdint>
|
|
#include <cstring>
|
|
#include <type_traits>
|
|
|
|
namespace FEXCore {
|
|
|
|
// Determines the number of bits inside of a given type.
|
|
template <typename T>
|
|
[[nodiscard]] constexpr size_t BitSize() noexcept {
|
|
return sizeof(T) * CHAR_BIT;
|
|
}
|
|
|
|
// Swaps the bytes of a 16-bit unsigned value.
|
|
[[nodiscard]] inline uint16_t BSwap16(uint16_t value) noexcept {
|
|
#ifdef __GNUC__
|
|
return __builtin_bswap16(value);
|
|
#else
|
|
return (value >> 8) | (value << 8);
|
|
#endif
|
|
}
|
|
|
|
// Swaps the bytes of a 32-bit unsigned value.
|
|
[[nodiscard]] inline uint32_t BSwap32(uint32_t value) noexcept {
|
|
#ifdef __GNUC__
|
|
return __builtin_bswap32(value);
|
|
#else
|
|
return ((value & 0xFF000000U) >> 24) | ((value & 0x00FF0000U) >> 8) |
|
|
((value & 0x0000FF00U) << 8) | ((value & 0x000000FFU) << 24);
|
|
#endif
|
|
}
|
|
|
|
// Swaps the bytes of a 64-bit unsigned value.
|
|
[[nodiscard]] inline uint64_t BSwap64(uint64_t value) noexcept {
|
|
#ifdef __GNUC__
|
|
return __builtin_bswap64(value);
|
|
#else
|
|
return ((value & 0xFF00000000000000ULL) >> 56) | ((value & 0x00FF000000000000ULL) >> 40) |
|
|
((value & 0x0000FF0000000000ULL) >> 24) | ((value & 0x000000FF00000000ULL) >> 8) |
|
|
((value & 0x00000000FF000000ULL) << 8) | ((value & 0x0000000000FF0000ULL) << 24) |
|
|
((value & 0x000000000000FF00ULL) << 40) | ((value & 0x00000000000000FFULL) << 56);
|
|
#endif
|
|
}
|
|
|
|
// Finds the first least-significant set bit within a given value.
|
|
// Note that all returned indices are 1-based, not 0-based.
|
|
template <typename T>
|
|
[[nodiscard]] constexpr int FindFirstSetBit(T value) noexcept {
|
|
static_assert(std::is_unsigned_v<T>, "Type must be unsigned.");
|
|
|
|
if (value == 0) {
|
|
return 0;
|
|
}
|
|
|
|
const int trailing_zeroes = std::countr_zero(value);
|
|
return trailing_zeroes + 1;
|
|
}
|
|
|
|
// Stand-in for std::bit_cast until libc++ implements it.
|
|
template <typename To, typename From>
|
|
[[nodiscard]] inline To BitCast(const From& source) noexcept
|
|
{
|
|
static_assert(sizeof(From) == sizeof(To),
|
|
"BitCast source and destination types must be equal in size.");
|
|
static_assert(std::is_trivially_copyable_v<From>,
|
|
"BitCast source type must be trivially copyable.");
|
|
static_assert(std::is_trivially_copyable_v<To>,
|
|
"BitCast destination type must be trivially copyable.");
|
|
|
|
std::aligned_storage_t<sizeof(To), alignof(To)> storage;
|
|
std::memcpy(&storage, &source, sizeof(storage));
|
|
return reinterpret_cast<To&>(storage);
|
|
}
|
|
|
|
} // namespace FEXCore
|