df72480395
Now that clang-format makes [[nodiscard]] attributes format sensibly, we can apply them to several functions within the common library to allow the compiler to complain about any misuses of the functions.
144 lines
3.1 KiB
C++
144 lines
3.1 KiB
C++
// Copyright 2018 yuzu emulator team
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// Licensed under GPLv2 or any later version
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// Refer to the license.txt file included.
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#pragma once
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#include <climits>
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#include <cstddef>
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#ifdef _MSC_VER
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#include <intrin.h>
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#endif
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#include "common/common_types.h"
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namespace Common {
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/// Gets the size of a specified type T in bits.
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template <typename T>
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[[nodiscard]] constexpr std::size_t BitSize() {
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return sizeof(T) * CHAR_BIT;
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}
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#ifdef _MSC_VER
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[[nodiscard]] inline u32 CountLeadingZeroes32(u32 value) {
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unsigned long leading_zero = 0;
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if (_BitScanReverse(&leading_zero, value) != 0) {
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return 31 - leading_zero;
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}
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return 32;
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}
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[[nodiscard]] inline u32 CountLeadingZeroes64(u64 value) {
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unsigned long leading_zero = 0;
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if (_BitScanReverse64(&leading_zero, value) != 0) {
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return 63 - leading_zero;
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}
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return 64;
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}
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#else
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[[nodiscard]] inline u32 CountLeadingZeroes32(u32 value) {
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if (value == 0) {
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return 32;
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}
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return static_cast<u32>(__builtin_clz(value));
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}
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[[nodiscard]] inline u32 CountLeadingZeroes64(u64 value) {
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if (value == 0) {
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return 64;
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}
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return static_cast<u32>(__builtin_clzll(value));
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}
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#endif
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#ifdef _MSC_VER
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[[nodiscard]] inline u32 CountTrailingZeroes32(u32 value) {
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unsigned long trailing_zero = 0;
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if (_BitScanForward(&trailing_zero, value) != 0) {
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return trailing_zero;
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}
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return 32;
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}
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[[nodiscard]] inline u32 CountTrailingZeroes64(u64 value) {
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unsigned long trailing_zero = 0;
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if (_BitScanForward64(&trailing_zero, value) != 0) {
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return trailing_zero;
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}
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return 64;
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}
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#else
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[[nodiscard]] inline u32 CountTrailingZeroes32(u32 value) {
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if (value == 0) {
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return 32;
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}
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return static_cast<u32>(__builtin_ctz(value));
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}
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[[nodiscard]] inline u32 CountTrailingZeroes64(u64 value) {
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if (value == 0) {
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return 64;
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}
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return static_cast<u32>(__builtin_ctzll(value));
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}
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#endif
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#ifdef _MSC_VER
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[[nodiscard]] inline u32 MostSignificantBit32(const u32 value) {
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unsigned long result;
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_BitScanReverse(&result, value);
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return static_cast<u32>(result);
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}
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[[nodiscard]] inline u32 MostSignificantBit64(const u64 value) {
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unsigned long result;
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_BitScanReverse64(&result, value);
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return static_cast<u32>(result);
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}
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#else
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[[nodiscard]] inline u32 MostSignificantBit32(const u32 value) {
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return 31U - static_cast<u32>(__builtin_clz(value));
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}
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[[nodiscard]] inline u32 MostSignificantBit64(const u64 value) {
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return 63U - static_cast<u32>(__builtin_clzll(value));
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}
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#endif
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[[nodiscard]] inline u32 Log2Floor32(const u32 value) {
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return MostSignificantBit32(value);
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}
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[[nodiscard]] inline u32 Log2Ceil32(const u32 value) {
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const u32 log2_f = Log2Floor32(value);
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return log2_f + ((value ^ (1U << log2_f)) != 0U);
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}
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[[nodiscard]] inline u32 Log2Floor64(const u64 value) {
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return MostSignificantBit64(value);
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}
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[[nodiscard]] inline u32 Log2Ceil64(const u64 value) {
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const u64 log2_f = static_cast<u64>(Log2Floor64(value));
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return static_cast<u32>(log2_f + ((value ^ (1ULL << log2_f)) != 0ULL));
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}
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} // namespace Common
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