1// 2// Copyright 2017 The Abseil Authors. 3// 4// Licensed under the Apache License, Version 2.0 (the "License"); 5// you may not use this file except in compliance with the License. 6// You may obtain a copy of the License at 7// 8// https://www.apache.org/licenses/LICENSE-2.0 9// 10// Unless required by applicable law or agreed to in writing, software 11// distributed under the License is distributed on an "AS IS" BASIS, 12// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13// See the License for the specific language governing permissions and 14// limitations under the License. 15 16// This file contains :int128 implementation details that depend on internal 17// representation when ABSL_HAVE_INTRINSIC_INT128 is defined. This file is 18// included by int128.h and relies on ABSL_INTERNAL_WCHAR_T being defined. 19 20namespace int128_internal { 21 22// Casts from unsigned to signed while preserving the underlying binary 23// representation. 24constexpr __int128 BitCastToSigned(unsigned __int128 v) { 25 // Casting an unsigned integer to a signed integer of the same 26 // width is implementation defined behavior if the source value would not fit 27 // in the destination type. We step around it with a roundtrip bitwise not 28 // operation to make sure this function remains constexpr. Clang and GCC 29 // optimize this to a no-op on x86-64. 30 return v & (static_cast<unsigned __int128>(1) << 127) 31 ? ~static_cast<__int128>(~v) 32 : static_cast<__int128>(v); 33} 34 35} // namespace int128_internal 36 37inline int128& int128::operator=(__int128 v) { 38 v_ = v; 39 return *this; 40} 41 42constexpr uint64_t Int128Low64(int128 v) { 43 return static_cast<uint64_t>(v.v_ & ~uint64_t{0}); 44} 45 46constexpr int64_t Int128High64(int128 v) { 47 // Initially cast to unsigned to prevent a right shift on a negative value. 48 return int128_internal::BitCastToSigned( 49 static_cast<uint64_t>(static_cast<unsigned __int128>(v.v_) >> 64)); 50} 51 52constexpr int128::int128(int64_t high, uint64_t low) 53 // Initially cast to unsigned to prevent a left shift that overflows. 54 : v_(int128_internal::BitCastToSigned(static_cast<unsigned __int128>(high) 55 << 64) | 56 low) {} 57 58 59constexpr int128::int128(int v) : v_{v} {} 60 61constexpr int128::int128(long v) : v_{v} {} // NOLINT(runtime/int) 62 63constexpr int128::int128(long long v) : v_{v} {} // NOLINT(runtime/int) 64 65constexpr int128::int128(__int128 v) : v_{v} {} 66 67constexpr int128::int128(unsigned int v) : v_{v} {} 68 69constexpr int128::int128(unsigned long v) : v_{v} {} // NOLINT(runtime/int) 70 71// NOLINTNEXTLINE(runtime/int) 72constexpr int128::int128(unsigned long long v) : v_{v} {} 73 74constexpr int128::int128(unsigned __int128 v) : v_{static_cast<__int128>(v)} {} 75 76inline int128::int128(float v) { 77 v_ = static_cast<__int128>(v); 78} 79 80inline int128::int128(double v) { 81 v_ = static_cast<__int128>(v); 82} 83 84inline int128::int128(long double v) { 85 v_ = static_cast<__int128>(v); 86} 87 88constexpr int128::int128(uint128 v) : v_{static_cast<__int128>(v)} {} 89 90constexpr int128::operator bool() const { return static_cast<bool>(v_); } 91 92constexpr int128::operator char() const { return static_cast<char>(v_); } 93 94constexpr int128::operator signed char() const { 95 return static_cast<signed char>(v_); 96} 97 98constexpr int128::operator unsigned char() const { 99 return static_cast<unsigned char>(v_); 100} 101 102constexpr int128::operator char16_t() const { 103 return static_cast<char16_t>(v_); 104} 105 106constexpr int128::operator char32_t() const { 107 return static_cast<char32_t>(v_); 108} 109 110constexpr int128::operator ABSL_INTERNAL_WCHAR_T() const { 111 return static_cast<ABSL_INTERNAL_WCHAR_T>(v_); 112} 113 114constexpr int128::operator short() const { // NOLINT(runtime/int) 115 return static_cast<short>(v_); // NOLINT(runtime/int) 116} 117 118constexpr int128::operator unsigned short() const { // NOLINT(runtime/int) 119 return static_cast<unsigned short>(v_); // NOLINT(runtime/int) 120} 121 122constexpr int128::operator int() const { 123 return static_cast<int>(v_); 124} 125 126constexpr int128::operator unsigned int() const { 127 return static_cast<unsigned int>(v_); 128} 129 130constexpr int128::operator long() const { // NOLINT(runtime/int) 131 return static_cast<long>(v_); // NOLINT(runtime/int) 132} 133 134constexpr int128::operator unsigned long() const { // NOLINT(runtime/int) 135 return static_cast<unsigned long>(v_); // NOLINT(runtime/int) 136} 137 138constexpr int128::operator long long() const { // NOLINT(runtime/int) 139 return static_cast<long long>(v_); // NOLINT(runtime/int) 140} 141 142constexpr int128::operator unsigned long long() const { // NOLINT(runtime/int) 143 return static_cast<unsigned long long>(v_); // NOLINT(runtime/int) 144} 145 146constexpr int128::operator __int128() const { return v_; } 147 148constexpr int128::operator unsigned __int128() const { 149 return static_cast<unsigned __int128>(v_); 150} 151 152// Clang on PowerPC sometimes produces incorrect __int128 to floating point 153// conversions. In that case, we do the conversion with a similar implementation 154// to the conversion operators in int128_no_intrinsic.inc. 155#if defined(__clang__) && !defined(__ppc64__) 156inline int128::operator float() const { return static_cast<float>(v_); } 157 158inline int128::operator double() const { return static_cast<double>(v_); } 159 160inline int128::operator long double() const { 161 return static_cast<long double>(v_); 162} 163 164#else // Clang on PowerPC 165 166inline int128::operator float() const { 167 // We must convert the absolute value and then negate as needed, because 168 // floating point types are typically sign-magnitude. Otherwise, the 169 // difference between the high and low 64 bits when interpreted as two's 170 // complement overwhelms the precision of the mantissa. 171 // 172 // Also check to make sure we don't negate Int128Min() 173 constexpr float pow_2_64 = 18446744073709551616.0f; 174 return v_ < 0 && *this != Int128Min() 175 ? -static_cast<float>(-*this) 176 : static_cast<float>(Int128Low64(*this)) + 177 static_cast<float>(Int128High64(*this)) * pow_2_64; 178} 179 180inline int128::operator double() const { 181 // See comment in int128::operator float() above. 182 constexpr double pow_2_64 = 18446744073709551616.0; 183 return v_ < 0 && *this != Int128Min() 184 ? -static_cast<double>(-*this) 185 : static_cast<double>(Int128Low64(*this)) + 186 static_cast<double>(Int128High64(*this)) * pow_2_64; 187} 188 189inline int128::operator long double() const { 190 // See comment in int128::operator float() above. 191 constexpr long double pow_2_64 = 18446744073709551616.0L; 192 return v_ < 0 && *this != Int128Min() 193 ? -static_cast<long double>(-*this) 194 : static_cast<long double>(Int128Low64(*this)) + 195 static_cast<long double>(Int128High64(*this)) * pow_2_64; 196} 197#endif // Clang on PowerPC 198 199// Comparison operators. 200 201constexpr bool operator==(int128 lhs, int128 rhs) { 202 return static_cast<__int128>(lhs) == static_cast<__int128>(rhs); 203} 204 205constexpr bool operator!=(int128 lhs, int128 rhs) { 206 return static_cast<__int128>(lhs) != static_cast<__int128>(rhs); 207} 208 209constexpr bool operator<(int128 lhs, int128 rhs) { 210 return static_cast<__int128>(lhs) < static_cast<__int128>(rhs); 211} 212 213constexpr bool operator>(int128 lhs, int128 rhs) { 214 return static_cast<__int128>(lhs) > static_cast<__int128>(rhs); 215} 216 217constexpr bool operator<=(int128 lhs, int128 rhs) { 218 return static_cast<__int128>(lhs) <= static_cast<__int128>(rhs); 219} 220 221constexpr bool operator>=(int128 lhs, int128 rhs) { 222 return static_cast<__int128>(lhs) >= static_cast<__int128>(rhs); 223} 224 225#ifdef __cpp_impl_three_way_comparison 226constexpr absl::strong_ordering operator<=>(int128 lhs, int128 rhs) { 227 if (auto lhs_128 = static_cast<__int128>(lhs), 228 rhs_128 = static_cast<__int128>(rhs); 229 lhs_128 < rhs_128) { 230 return absl::strong_ordering::less; 231 } else if (lhs_128 > rhs_128) { 232 return absl::strong_ordering::greater; 233 } else { 234 return absl::strong_ordering::equal; 235 } 236} 237#endif 238 239// Unary operators. 240 241constexpr int128 operator-(int128 v) { return -static_cast<__int128>(v); } 242 243constexpr bool operator!(int128 v) { return !static_cast<__int128>(v); } 244 245constexpr int128 operator~(int128 val) { return ~static_cast<__int128>(val); } 246 247// Arithmetic operators. 248 249constexpr int128 operator+(int128 lhs, int128 rhs) { 250 return static_cast<__int128>(lhs) + static_cast<__int128>(rhs); 251} 252 253constexpr int128 operator-(int128 lhs, int128 rhs) { 254 return static_cast<__int128>(lhs) - static_cast<__int128>(rhs); 255} 256 257inline int128 operator*(int128 lhs, int128 rhs) { 258 return static_cast<__int128>(lhs) * static_cast<__int128>(rhs); 259} 260 261inline int128 operator/(int128 lhs, int128 rhs) { 262 return static_cast<__int128>(lhs) / static_cast<__int128>(rhs); 263} 264 265inline int128 operator%(int128 lhs, int128 rhs) { 266 return static_cast<__int128>(lhs) % static_cast<__int128>(rhs); 267} 268 269inline int128 int128::operator++(int) { 270 int128 tmp(*this); 271 ++v_; 272 return tmp; 273} 274 275inline int128 int128::operator--(int) { 276 int128 tmp(*this); 277 --v_; 278 return tmp; 279} 280 281inline int128& int128::operator++() { 282 ++v_; 283 return *this; 284} 285 286inline int128& int128::operator--() { 287 --v_; 288 return *this; 289} 290 291constexpr int128 operator|(int128 lhs, int128 rhs) { 292 return static_cast<__int128>(lhs) | static_cast<__int128>(rhs); 293} 294 295constexpr int128 operator&(int128 lhs, int128 rhs) { 296 return static_cast<__int128>(lhs) & static_cast<__int128>(rhs); 297} 298 299constexpr int128 operator^(int128 lhs, int128 rhs) { 300 return static_cast<__int128>(lhs) ^ static_cast<__int128>(rhs); 301} 302 303constexpr int128 operator<<(int128 lhs, int amount) { 304 return static_cast<__int128>(lhs) << amount; 305} 306 307constexpr int128 operator>>(int128 lhs, int amount) { 308 return static_cast<__int128>(lhs) >> amount; 309} 310