CHANGELOG.md

Changelog for intx

Documentation of all notable changes to the intx project.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.15.0 — 2026-01-30

Added

• Add bit_width() helper. #356
• Add load() and store() helpers with std::span<uint8_t> parameters. #366
• Add support for 0X prefix to from_string(). #361
• Add constructor from builtin_uint128 to avoid truncation. #355
• Add constructor from std::span<uint64_t>. #362

Changed

• Git default branch changed to main.
• Optimize exp() by traversing exponent bits from the top. #357
• Change as_words() to return fixed-size std::span<uint64_t>. #364
• Add explicit implementations of assignment operators. #353
• Use std::span for division internals and helper procedures. #365

0.14.0 — 2025-11-14

Added

• Add ctz() (count trailing zeros). #350
• Add bit_test(). #351
• Add support for Conan package manager. #352

Fixed

• Fix udivrem dead branch causing static analysis failures #349

0.13.0 — 2025-05-14

Added

• Add support for C++20 spaceship operator <=>. #328

Fixed

• Build fixes for newer compilers and C++23:
  • Assume word counts out of div normalization are not negative. #340
  • Add missing C header #include. #337
  • Don't specify deprecated float_denorm_style. #336
  • Drop constexpr tests for division. #335
  • Remove whitespace in literal operator declarations. #334
  • Remove redundant inline specifiers. #330

0.12.1 — 2024-10-09

Fixed

• Fix MSVC build in preprocessor conformance mode #327

0.12.0 — 2024-09-03

Added

• Consequent type aliases and literal suffixes: #317
  • uint128, 1_u128
  • uint192, 1_u192
  • uint256, 1_u256
  • uint320, 1_u320
  • uint384, 1_u384
  • uint448, 1_u448
  • uint512, 1_u512

Changed

• Restructure of the code by using friend operator and if constexpr. #318 #319 #320 #321 #322 #324

0.11.0 — 2024-08-06

Added

• Support constexpr context execution for all arithmetic including division. #305 #311 #314

Changed

• Literal operators changed to consteval. #298
• Some C++20 modernization. #297 #308

Fixed

• Fixes to division for constexpr context. #309 #310

0.10.1 — 2023-07-17

Fixed

• Fixed buggy __builtin_subcll in Xcode 14.3.1 on arm64. 294

0.10.0 — 2023-04-25

Changed

• C++20 is now required to use intx. #287 #290

0.9.3 — 2023-07-17

Fixed

• Fixed buggy __builtin_subcll in Xcode 14.3.1 on arm64. 294

0.9.2 — 2023-03-11

Changed

• Increase tolerance to some compiler warnings (e.g. unknown pragma, unknown attribute) in case intx.hpp is used without CMake assistance. #286

0.9.1 — 2023-01-25

Fixed

• Fixed 32-bit Windows builds: the _umul128 intrinsic is not available there. #283

0.9.0 — 2022-12-13

Changed

• Optimizations for GCC compiler. #279 #281
• Required CMake version increased from 3.10 to 3.16 #276
• Simplification of many operators declarations by using friend inline functions. #270 #271
• Benchmarks updates and fixes. #274 #275 #277

0.8.0 — 2022-03-15

Added

• Added support for big-endian architectures. #257
• Extend endian-specific load/store helpers to work with builtin integer types. #265

Changed

• The addc() and subc() have been optimized with compiler's builtins if available. #250 #251 #253
• Fixed and enabled CI testing for architectures other than x86. #255
• Small multiplication optimization. #261
• Small division optimization. #263
• Small comparison operators optimization for the uint256 type. #264

0.7.1 — 2022-02-15

Fixed

• Added support for bswap() of small unsigned types: uint8_t, uint16_t and uint32_t. Previously arguments where promoted to uint64_t what produced invalid results. #247

0.7.0 — 2021-12-17

Changed

• The int128.hpp and intx.hpp header files have been merged. Now the whole library is included in single intx/intx.hpp file. #242
• The addmod() implementation has the optimized path for elliptic curve context. #206
• The implementation of operator== now explicitly performs XOR folding. #245

0.6.0 — 2021-06-25

Changed

• The internal representation of unsigned integers has been changed to be an array of 64-bit words. This provides types composed of any number of words (e.g. uint384). Previously only power-of-two numbers of words were allowed. This is a big change that affects implementation of many operators. #212 #213
• Subtraction has been slightly rewritten to make it easier for compilers to optimize it. The performance now matches the addition. #189
• Multiplication API has been cleaned up by using std::is_constant_evaluated-like helpers internally. #195 #205
• Shift API has been changed to use uint64_t as shift amount on the fundamental API level. #202

0.5.1 — 2020-12-14

Changed

• The utility macros (e.g. INTX_UNREACHABLE()) have been redefined. #182
• Test and benchmarks improvements. #175

0.5.0 — 2020-06-23

Added

• Support for using intx dependency as a CMake subproject (e.g. by git submodules or FetchContent). #160
• Support for building intx exceptions handling disabled (-fno-exceptions) and without RTTI (-fno-rtti). #164

Changed

• Converted to a header-only library. #155 #156
• Addition / subtraction optimizations. #115 #117 #130
• Division optimizations. #129 #131 #134 #141 #147 #171
• Exponentiation optimizations. #128 #146

Removed

• The unused builtins.h header has been deleted. #173

0.4.0 — 2019-08-21

Added

• Added the as_bytes() casting helper. #106

Changed

• The endian-specific API for converting intx types to/from bytes has been reworked. #107
• The clz() is now constexpr and produces correct answer for zero inputs. #108

0.3.0 — 2019-06-20

Added

• New addmod() and mulmod() procedures have been added for the uint256 type. #101

Changed

• Pedantic compiler warnings have been fixed. #98
• The performance of the division algorithm increased up to 40% when dividing 256-bit values by 128-bit and 64-bit ones. #99