This document describes changes to the public interfaces in the Amaranth language and standard library. It does not include most bug fixes or implementation changes.
Support for enumerations has been extended. A shape for enumeration members can be provided for an enumeration class, as defined in `RFC 3`_.
The language includes several new extension points for integration with :class:`Value` based data structures defined outside of the core language. In particular, ``Signal(shape)`` may now return a :class:`Signal` object wrapped in another if ``shape`` implements the call protocol, as defined in `RFC 15`_.
Several issues with shape inference have been resolved. Notably, ``a - b`` where both ``a`` and ``b`` are unsigned now returns a signed value.
Support for Python 3.6 has been removed, and support for Python 3.11 and 3.12 has been added.
Features deprecated in version 0.3 have been removed. In particular, the ``nmigen.*`` namespace is not provided, ``# nmigen:`` annotations are not recognized, and ``NMIGEN_*`` envronment variables are not used.
* Changed: creating a :class:`Signal` with a shape that is a :class:`ShapeCastable` implementing :meth:`ShapeCastable.__call__` wraps the returned object using that method. (`RFC 15`_)
* Changed: :meth:`Value.cast` treats instances of classes derived from both :class:`enum.Enum` and :class:`int` (including :class:`enum.IntEnum`) as enumerations rather than integers.
* Changed: :meth:`Value.matches` with an empty list of patterns returns ``Const(1)`` rather than ``Const(0)``, to match the behavior of ``with m.Case():``.
* Deprecated: use of mixed-case toolchain environment variable names, such as ``NMIGEN_ENV_Diamond`` or ``AMARANTH_ENV_Diamond``; use upper-case environment variable names, such as ``AMARANTH_ENV_DIAMOND``.
* Removed: (deprecated in 0.3) :meth:`sim.Simulator.step`.
* Removed: (deprecated in 0.3) :mod:`back.pysim`.
* Removed: (deprecated in 0.3) support for invoking :func:`back.rtlil.convert()` and :func:`back.verilog.convert()` without an explicit `ports=` argument.
The project has been renamed from nMigen to Amaranth.
Features deprecated in version 0.2 have been removed.
Migrating from version 0.2
--------------------------
..currentmodule:: amaranth
Apply the following changes to code written against nMigen 0.2 to migrate it to Amaranth 0.3:
* Update ``import nmigen as nm``:ref:`explicit prelude imports <lang-prelude>` to be ``import amaranth as am``, and adjust the code to use the ``am.*`` namespace.
* Update ``import nmigen.*`` imports to be ``import amaranth.*``.
* Update ``import nmigen_boards.*`` imports to be ``import amaranth_boards.*``.
* Update board definitions using :class:`vendor.lattice_machxo2.LatticeMachXO2Platform` to use :class:`vendor.lattice_machxo_2_3l.LatticeMachXO2Platform`.
* Update board definitions using :class:`vendor.xilinx_spartan_3_6.XilinxSpartan3APlatform`, :class:`vendor.xilinx_spartan_3_6.XilinxSpartan6Platform`, :class:`vendor.xilinx_7series.Xilinx7SeriesPlatform`, :class:`vendor.xilinx_ultrascale.XilinxUltrascalePlatform` to use :class:`vendor.xilinx.XilinxPlatform`.
* Switch uses of :class:`hdl.ast.UserValue` to :class:`ValueCastable`; note that :class:`ValueCastable` does not inherit from :class:`Value`, and inheriting from :class:`Value` is not supported.
* Added: If a compatible Yosys version is not installed, :mod:`back.verilog` will fall back to the `amaranth-yosys <https://github.com/amaranth-lang/amaranth-yosys>`_ PyPI package. The package can be :ref:`installed <install>` as ``amaranth[builtin-yosys]`` to ensure this dependency is available.
* Added: Symbiflow toolchain support for :class:`xilinx_7series.Xilinx7SeriesPlatform`.
* Added: :class:`lattice_machxo_2_3l.LatticeMachXO2Or3LPlatform` generates separate Flash and SRAM SVF programming vectors, ``{{name}}_flash.svf`` and ``{{name}}_sram.svf``.
* Deprecated: :class:`lattice_machxo_2_3l.LatticeMachXO2Or3LPlatform` SVF programming vector ``{{name}}.svf``; use ``{{name}}_flash.svf`` instead.
* Added: :class:`quicklogic.QuicklogicPlatform`.
* Added: ``cyclonev_oscillator`` as ``default_clk`` clock source in :class:`intel.IntelPlatform`.
* Added: ``add_settings`` and ``add_constraints`` overrides in :class:`intel.IntelPlatform`.
* Added: :class:`xilinx.XilinxPlatform`.
* Deprecated: :class:`xilinx_spartan_3_6.XilinxSpartan3APlatform`, :class:`xilinx_spartan_3_6.XilinxSpartan6Platform`, :class:`xilinx_7series.Xilinx7SeriesPlatform`, :class:`xilinx_ultrascale.XilinxUltrascalePlatform`; use :class:`xilinx.XilinxPlatform` instead.
* Added: Mistral toolchain support for :class:`intel.IntelPlatform`.
* Added: ``synth_design_opts`` override in :class:`xilinx.XilinxPlatform`.
Versions 0.1, 0.2
=================
No changelog is provided for these versions.
The PyPI packages were published under the ``nmigen`` namespace, rather than ``amaranth``.
