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amaranth/amaranth/hdl/_ast.py

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from abc import ABCMeta, abstractmethod
import warnings
import functools
import operator
from collections import OrderedDict
from collections.abc import Iterable, MutableMapping, MutableSet, MutableSequence
from enum import Enum, EnumMeta
from itertools import chain
from ._repr import *
from .. import tracer
from ..utils import *
from .._utils import *
from .._unused import *
__all__ = [
"Shape", "signed", "unsigned", "ShapeCastable", "ShapeLike",
"Value", "Const", "C", "AnyConst", "AnySeq", "Operator", "Mux", "Part", "Slice", "Cat",
"Array", "ArrayProxy",
"Signal", "ClockSignal", "ResetSignal",
"ValueCastable", "ValueLike",
"Initial",
"Statement", "Switch",
"Property", "Assign", "Assert", "Assume", "Cover",
"SignalKey", "SignalDict", "SignalSet",
]
class DUID:
"""Deterministic Unique IDentifier."""
__next_uid = 0
def __init__(self):
self.duid = DUID.__next_uid
DUID.__next_uid += 1
class Shape:
"""Bit width and signedness of a :class:`Value`.
A :class:`Shape` can be obtained by:
* constructing with explicit bit width and signedness;
* using the :func:`signed` and :func:`unsigned` aliases if the signedness is known upfront;
* casting from a variety of objects using the :meth:`cast` method.
Parameters
----------
width : int
The number of bits in the representation of a value. This includes the sign bit for signed
values. Cannot be zero if the value is signed.
signed : bool
Whether the value is signed. Signed values use the
`two's complement <https://en.wikipedia.org/wiki/Two's_complement>`_ representation.
"""
def __init__(self, width=1, signed=False):
if not isinstance(width, int):
raise TypeError(f"Width must be an integer, not {width!r}")
if not signed and width < 0:
raise TypeError(f"Width of an unsigned value must be zero or a positive integer, "
f"not {width}")
if signed and width <= 0:
raise TypeError(f"Width of a signed value must be a positive integer, not {width}")
self.width = width
self.signed = bool(signed)
# The algorithm for inferring shape for standard Python enumerations is factored out so that
# `Shape.cast()` and Amaranth's `EnumMeta.as_shape()` can both use it.
@staticmethod
def _cast_plain_enum(obj):
signed = False
width = 0
for member in obj:
try:
member_shape = Const.cast(member.value).shape()
except TypeError as e:
raise TypeError("Only enumerations whose members have constant-castable "
"values can be used in Amaranth code")
if not signed and member_shape.signed:
signed = True
width = max(width + 1, member_shape.width)
elif signed and not member_shape.signed:
width = max(width, member_shape.width + 1)
else:
width = max(width, member_shape.width)
return Shape(width, signed)
@staticmethod
def cast(obj, *, src_loc_at=0):
"""Cast :pc:`obj` to a shape.
Many :ref:`shape-like <lang-shapelike>` objects can be cast to a shape:
* a :class:`Shape`, where the result is itself;
* an :class:`int`, where the result is :func:`unsigned(obj) <unsigned>`;
* a :class:`range`, where the result has minimal width required to represent all elements
of the range, and is signed if any element of the range is signed;
* an :class:`enum.Enum` whose members are all :ref:`constant-castable <lang-constcasting>`
or :class:`enum.IntEnum`, where the result is wide enough to represent any member of
the enumeration, and is signed if any member of the enumeration is signed;
* a :class:`ShapeCastable` object, where the result is obtained by repeatedly calling
:meth:`obj.as_shape() <ShapeCastable.as_shape>`.
Raises
------
TypeError
If :pc:`obj` cannot be converted to a :class:`Shape`.
RecursionError
If :pc:`obj` is a :class:`ShapeCastable` object that casts to itself.
"""
while True:
if isinstance(obj, Shape):
return obj
elif isinstance(obj, ShapeCastable):
new_obj = obj.as_shape()
elif isinstance(obj, int):
return Shape(obj)
elif isinstance(obj, range):
if len(obj) == 0:
return Shape(0)
signed = obj[0] < 0 or obj[-1] < 0
width = max(bits_for(obj[0], signed),
bits_for(obj[-1], signed))
if obj[0] == obj[-1] == 0:
width = 0
return Shape(width, signed)
elif isinstance(obj, type) and issubclass(obj, Enum):
# For compatibility with third party enumerations, handle them as if they were
# defined as subclasses of lib.enum.Enum with no explicitly specified shape.
return Shape._cast_plain_enum(obj)
else:
raise TypeError(f"Object {obj!r} cannot be converted to an Amaranth shape")
if new_obj is obj:
raise RecursionError(f"Shape-castable object {obj!r} casts to itself")
obj = new_obj
def __repr__(self):
"""Python code that creates this shape.
Returns :pc:`f"signed({self.width})"` or :pc:`f"unsigned({self.width})"`.
"""
if self.signed:
return f"signed({self.width})"
else:
return f"unsigned({self.width})"
def __eq__(self, other):
return (isinstance(other, Shape) and
self.width == other.width and self.signed == other.signed)
def unsigned(width):
"""Returns :pc:`Shape(width, signed=False)`."""
return Shape(width, signed=False)
def signed(width):
"""Returns :pc:`Shape(width, signed=True)`."""
return Shape(width, signed=True)
class ShapeCastable:
"""Interface class for objects that can be cast to a :class:`Shape`.
Shapes of values in the Amaranth language are specified using :ref:`shape-like objects
<lang-shapelike>`. Inheriting a class from :class:`ShapeCastable` and implementing all of
the methods described below adds instances of that class to the list of shape-like objects
recognized by the :meth:`Shape.cast` method. This is a part of the mechanism for seamlessly
extending the Amaranth language in third-party code.
To illustrate their purpose, consider constructing a signal from a shape-castable object
:pc:`shape_castable`:
.. code::
value_like = Signal(shape_castable, reset=initializer)
The code above is equivalent to:
.. code::
value_like = shape_castable(Signal(
shape_castable.as_shape(),
reset=shape_castable.const(initializer)
))
Note that the :pc:`shape_castable(x)` syntax performs :pc:`shape_castable.__call__(x)`.
.. tip::
The source code of the :mod:`amaranth.lib.data` module can be used as a reference for
implementing a fully featured shape-castable object.
"""
def __init__(self, *args, **kwargs):
if type(self) is ShapeCastable:
raise TypeError("Can't instantiate abstract class ShapeCastable")
super().__init__(*args, **kwargs)
def __init_subclass__(cls, **kwargs):
if cls.as_shape is ShapeCastable.as_shape:
raise TypeError(f"Class '{cls.__name__}' deriving from 'ShapeCastable' must override "
f"the 'as_shape' method")
if cls.const is ShapeCastable.const:
raise TypeError(f"Class '{cls.__name__}' deriving from 'ShapeCastable' must override "
f"the 'const' method")
if cls.__call__ is ShapeCastable.__call__:
raise TypeError(f"Class '{cls.__name__}' deriving from 'ShapeCastable' must override "
f"the '__call__' method")
# The signatures and definitions of these methods are weird because they are present here for
# documentation (and error checking above) purpose only and should not affect control flow.
# This especially applies to `__call__`, where subclasses may call `super().__call__()` in
# creative ways.
def as_shape(self, *args, **kwargs):
"""as_shape()
Convert :pc:`self` to a :ref:`shape-like object <lang-shapelike>`.
This method is called by the Amaranth language to convert :pc:`self` to a concrete
:class:`Shape`. It will usually return a :class:`Shape` object, but it may also return
another shape-like object to delegate its functionality.
This method must be idempotent: when called twice on the same object, the result must be
exactly the same.
This method may also be called by code that is not a part of the Amaranth language.
Returns
-------
Any other object recognized by :meth:`Shape.cast`.
Raises
------
Exception
When the conversion cannot be done. This exception must be propagated by callers
(except when checking whether an object is shape-castable or not), either directly
or as a cause of another exception.
"""
return super().as_shape(*args, **kwargs) # :nocov:
def const(self, *args, **kwargs):
"""const(obj)
Convert a constant initializer :pc:`obj` to its value representation.
This method is called by the Amaranth language to convert :pc:`obj`, which may be an
arbitrary Python object, to a concrete :ref:`value-like object <lang-valuelike>`.
The object :pc:`obj` will usually be a Python literal that can conveniently represent
a constant value whose shape is described by :pc:`self`. While not constrained here,
the result will usually be an instance of the return type of :meth:`__call__`.
For any :pc:`obj`, the following condition must hold:
.. code::
Shape.cast(self) == Const.cast(self.const(obj)).shape()
This method may also be called by code that is not a part of the Amaranth language.
Returns
-------
A :ref:`value-like object <lang-valuelike>` that is :ref:`constant-castable <lang-constcasting>`.
Raises
------
Exception
When the conversion cannot be done. This exception must be propagated by callers,
either directly or as a cause of another exception. While not constrained here,
usually the exception class will be :exc:`TypeError` or :exc:`ValueError`.
"""
return super().const(*args, **kwargs) # :nocov:
def __call__(self, *args, **kwargs):
"""__call__(obj)
Lift a :ref:`value-like object <lang-valuelike>` to a higher-level representation.
This method is called by the Amaranth language to lift :pc:`obj`, which may be any
:ref:`value-like object <lang-valuelike>` whose shape equals :pc:`Shape.cast(self)`,
to a higher-level representation, which may be any value-like object with the same
shape. While not constrained here, usually a :class:`ShapeCastable` implementation will
be paired with a :class:`ValueCastable` implementation, and this method will return
an instance of the latter.
If :pc:`obj` is not as described above, this interface does not constrain the behavior
of this method. This may be used to implement another call-based protocol at the same
time.
For any compliant :pc:`obj`, the following condition must hold:
.. code::
Value.cast(self(obj)) == Value.cast(obj)
This method may also be called by code that is not a part of the Amaranth language.
Returns
-------
A :ref:`value-like object <lang-valuelike>`.
"""
return super().__call__(*args, **kwargs) # :nocov:
# TODO: write an RFC for turning this into a proper interface method
def _value_repr(self, value):
return (Repr(FormatInt(), value),)
class _ShapeLikeMeta(type):
def __subclasscheck__(cls, subclass):
return issubclass(subclass, (Shape, ShapeCastable, int, range, EnumMeta)) or subclass is ShapeLike
def __instancecheck__(cls, instance):
if isinstance(instance, (Shape, ShapeCastable, range)):
return True
if isinstance(instance, int):
return instance >= 0
if isinstance(instance, EnumMeta):
for member in instance:
if not isinstance(member.value, ValueLike):
return False
return True
return False
@final
class ShapeLike(metaclass=_ShapeLikeMeta):
"""Abstract class representing all objects that can be cast to a :class:`Shape`.
:pc:`issubclass(cls, ShapeLike)` returns :pc:`True` for:
* :class:`Shape`;
* :class:`ShapeCastable` and its subclasses;
* :class:`int` and its subclasses;
* :class:`range` and its subclasses;
* :class:`enum.EnumMeta` and its subclasses;
* :class:`ShapeLike` itself.
:pc:`isinstance(obj, ShapeLike)` returns :pc:`True` for:
* :class:`Shape` instances;
* :class:`ShapeCastable` instances;
* non-negative :class:`int` values;
* :class:`range` instances;
* :class:`enum.Enum` subclasses where all values are :ref:`value-like objects <lang-valuelike>`.
This class cannot be instantiated or subclassed. It can only be used for checking types of
objects.
"""
def __new__(cls, *args, **kwargs):
raise TypeError("ShapeLike is an abstract class and cannot be instantiated")
def _overridable_by_reflected(method_name):
"""Allow overriding the decorated method.
Allows :class:`ValueCastable` to override the decorated method by implementing
a reflected method named ``method_name``. Intended for operators, but
also usable for other methods that have a reflected counterpart.
"""
def decorator(f):
@functools.wraps(f)
def wrapper(self, other):
if isinstance(other, ValueCastable) and hasattr(other, method_name):
res = getattr(other, method_name)(self)
if res is not NotImplemented:
return res
return f(self, other)
return wrapper
return decorator
class Value(metaclass=ABCMeta):
"""Abstract representation of a bit pattern computed in a circuit.
The Amaranth language gives Python code the ability to create a circuit netlist by manipulating
objects representing the computations within that circuit. The :class:`Value` class represents
the bit pattern of a constant, or of a circuit input or output, or within a storage element; or
the result of an arithmetic, logical, or bit container operation.
Operations on this class interpret this bit pattern either as an integer, which can be signed
or unsigned depending on the value's :meth:`shape`, or as a bit container. In either case,
the semantics of operations that implement Python's syntax, like :pc:`+` (also known as
:meth:`__add__`), are identical to the corresponding operation on a Python :class:`int` (or on
a Python sequence container). The bitwise inversion :pc:`~` (also known as :meth:`__invert__`)
is the sole exception to this rule.
Data that is not conveniently representable by a single integer or a bit container can be
represented by wrapping a :class:`Value` in a :class:`ValueCastable` subclass that provides
domain-specific operations. It is possible to extend Amaranth in third-party code using
value-castable objects, and the Amaranth standard library provides several built-in ones:
* :mod:`amaranth.lib.enum` classes are a drop-in replacement for the standard Python
:class:`enum` classes that can be defined with an Amaranth shape;
* :mod:`amaranth.lib.data` classes allow defining complex data structures such as structures
and unions.
Operations on :class:`Value` instances return another :class:`Value` instance. Unless the exact
type and value of the result is explicitly specified below, it should be considered opaque, and
may change without notice between Amaranth releases as long as the semantics remains the same.
.. note::
In each of the descriptions below, you will see a line similar to:
**Return type:** :class:`Value`, :pc:`unsigned(1)`, :ref:`assignable <lang-assignable>`
The first part (:class:`Value`) indicates that the returned object's type is a subclass
of :class:`Value`. The second part (:pc:`unsigned(1)`) describes the shape of that value.
The third part, if present, indicates that the value is assignable if :pc:`self` is
assignable.
"""
@staticmethod
def cast(obj):
"""Cast :pc:`obj` to an Amaranth value.
Many :ref:`value-like <lang-valuelike>` objects can be cast to a value:
* a :class:`Value` instance, where the result is itself;
* a :class:`bool` or :class:`int` instance, where the result is :pc:`Const(obj)`;
* an :class:`enum.IntEnum` instance, or a :class:`enum.Enum` instance whose members are
all integers, where the result is a :class:`Const(obj, enum_shape)` where :pc:`enum_shape`
is a shape that can represent every member of the enumeration;
* a :class:`ValueCastable` instance, where the result is obtained by repeatedly calling
:meth:`obj.as_value() <ValueCastable.as_value>`.
Raises
------
TypeError
If :pc:`obj` cannot be converted to a :class:`Value`.
RecursionError
If :pc:`obj` is a :class:`ValueCastable` object that casts to itself.
"""
while True:
if isinstance(obj, Value):
return obj
elif isinstance(obj, ValueCastable):
new_obj = obj.as_value()
elif isinstance(obj, Enum):
return Const(obj.value, Shape.cast(type(obj)))
elif isinstance(obj, int):
return Const(obj)
else:
raise TypeError(f"Object {obj!r} cannot be converted to an Amaranth value")
if new_obj is obj:
raise RecursionError(f"Value-castable object {obj!r} casts to itself")
obj = new_obj
def __init__(self, *, src_loc_at=0):
super().__init__()
self.src_loc = tracer.get_src_loc(1 + src_loc_at)
@abstractmethod
def shape(self):
"""Shape of :pc:`self`.
Returns
-------
:ref:`shape-like object <lang-shapelike>`
"""
# TODO: while this is documented as returning a shape-like object, in practice we
# guarantee that this is a concrete Shape. it's unclear whether we will ever want to
# return a shape-catable object here, but there is not much harm in stating a relaxed
# contract, as it can always be tightened later, but not vice-versa
pass # :nocov:
def as_unsigned(self):
"""Reinterpretation as an unsigned value.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self))`, :ref:`assignable <lang-assignable>`
"""
return Operator("u", [self])
def as_signed(self):
"""Reinterpretation as a signed value.
Returns
-------
:class:`Value`, :pc:`signed(len(self))`, :ref:`assignable <lang-assignable>`
Raises
------
ValueError
If :pc:`len(self) == 0`.
"""
if len(self) == 0:
raise ValueError("Cannot create a 0-width signed value")
return Operator("s", [self])
def __bool__(self):
"""Forbidden conversion to boolean.
Python uses this operator for its built-in semantics, e.g. :pc:`if`, and requires it to
return a :class:`bool`. Since this is not possible for Amaranth values, this operator
always raises an exception.
Raises
------
:exc:`TypeError`
Always.
"""
raise TypeError("Attempted to convert Amaranth value to Python boolean")
def bool(self):
"""Conversion to boolean.
Performs the same operation as :meth:`any`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("b", [self])
def __pos__(self):
"""Unary position, :pc:`+self`.
Returns
-------
:class:`Value`, :pc:`self.shape()`
:pc:`self`
"""
return self
def __neg__(self):
"""Unary negation, :pc:`-self`.
..
>>> C(-1).value, C(-1).shape()
-1, signed(1)
>>> C(-(-1), signed(1)).value # overflows
-1
Returns
-------
:class:`Value`, :pc:`signed(len(self) + 1)`
"""
return Operator("-", [self])
@_overridable_by_reflected("__radd__")
def __add__(self, other):
"""Addition, :pc:`self + other`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(self.width(), other.width()) + 1)`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(max(self.width() + 1, other.width()) + 1)`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(max(self.width(), other.width() + 1) + 1)`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(max(self.width(), other.width()) + 1)`
If both :pc:`self` and :pc:`other` are unsigned.
"""
return Operator("+", [self, other], src_loc_at=1)
def __radd__(self, other):
"""Addition, :pc:`other + self` (reflected).
Like :meth:`__add__`, with operands swapped.
"""
return Operator("+", [other, self])
@_overridable_by_reflected("__rsub__")
def __sub__(self, other):
"""Subtraction, :pc:`self - other`.
Returns
-------
:class:`Value`, :pc:`signed(max(self.width(), other.width()) + 1)`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(max(self.width() + 1, other.width()) + 1)`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(max(self.width(), other.width() + 1) + 1)`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(max(self.width(), other.width()) + 1)`
If both :pc:`self` and :pc:`other` are unsigned.
Returns
-------
:class:`Value`
"""
return Operator("-", [self, other], src_loc_at=1)
def __rsub__(self, other):
"""Subtraction, :pc:`other - self` (reflected).
Like :meth:`__sub__`, with operands swapped.
"""
return Operator("-", [other, self])
@_overridable_by_reflected("__rmul__")
def __mul__(self, other):
"""Multiplication, :pc:`self * other`.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self) + len(other))`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(len(self) + len(other))`
If either :pc:`self` or :pc:`other` are signed.
"""
return Operator("*", [self, other], src_loc_at=1)
def __rmul__(self, other):
"""Multiplication, :pc:`other * self` (reflected).
Like :meth:`__mul__`, with operands swapped.
"""
return Operator("*", [other, self])
@_overridable_by_reflected("__rfloordiv__")
def __floordiv__(self, other):
"""Flooring division, :pc:`self // other`.
If :pc:`other` is zero, the result of this operation is zero.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self))`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(len(self) + 1)`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(len(self))`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(len(self) + 1)`
If both :pc:`self` and :pc:`other` are signed.
"""
return Operator("//", [self, other], src_loc_at=1)
def __rfloordiv__(self, other):
"""Flooring division, :pc:`other // self` (reflected).
If :pc:`self` is zero, the result of this operation is zero.
Like :meth:`__floordiv__`, with operands swapped.
"""
return Operator("//", [other, self])
@_overridable_by_reflected("__rmod__")
def __mod__(self, other):
"""Flooring modulo or remainder, :pc:`self % other`.
If :pc:`other` is zero, the result of this operation is zero.
Returns
-------
:class:`Value`, :pc:`other.shape()`
"""
return Operator("%", [self, other], src_loc_at=1)
def __rmod__(self, other):
"""Flooring modulo or remainder, :pc:`other % self` (reflected).
Like :meth:`__mod__`, with operands swapped.
"""
return Operator("%", [other, self])
@_overridable_by_reflected("__eq__")
def __eq__(self, other):
"""Equality comparison, :pc:`self == other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("==", [self, other], src_loc_at=1)
@_overridable_by_reflected("__ne__")
def __ne__(self, other):
"""Inequality comparison, :pc:`self != other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("!=", [self, other], src_loc_at=1)
@_overridable_by_reflected("__gt__")
def __lt__(self, other):
"""Less than comparison, :pc:`self < other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("<", [self, other], src_loc_at=1)
@_overridable_by_reflected("__ge__")
def __le__(self, other):
"""Less than or equals comparison, :pc:`self <= other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("<=", [self, other], src_loc_at=1)
@_overridable_by_reflected("__lt__")
def __gt__(self, other):
"""Greater than comparison, :pc:`self > other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator(">", [self, other], src_loc_at=1)
@_overridable_by_reflected("__le__")
def __ge__(self, other):
"""Greater than or equals comparison, :pc:`self >= other`.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator(">=", [self, other], src_loc_at=1)
def __abs__(self):
"""Absolute value, :pc:`abs(self)`.
..
>>> abs(C(-1)).shape()
unsigned(1)
>>> C(1).shape()
unsigned(1)
Return
------
:class:`Value`, :pc:`unsigned(len(self))`
"""
if self.shape().signed:
return Mux(self >= 0, self, -self)[:len(self)]
else:
return self
def __invert__(self):
"""Bitwise NOT, :pc:`~self`.
The shape of the result is the same as the shape of :pc:`self`, even for unsigned values.
.. important::
In Python, :pc:`~0` equals :pc:`-1`. In Amaranth, :pc:`~C(0)` equals :pc:`C(1)`.
This is the only case where an Amaranth operator deviates from the Python operator
with the same name.
This deviation is necessary because Python does not allow overriding the logical
:pc:`and`, :pc:`or`, and :pc:`not` operators. Amaranth uses :pc:`&`, :pc:`|`, and
:pc:`~` instead; if it wasn't the case that :pc:`~C(0) == C(1)`, that would have
been impossible.
Returns
-------
:class:`Value`, :pc:`self.shape()`
"""
return Operator("~", [self])
@_overridable_by_reflected("__rand__")
def __and__(self, other):
"""Bitwise AND, :pc:`self & other`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(max(self.width() + 1, other.width()))`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(max(self.width(), other.width() + 1))`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
"""
return Operator("&", [self, other], src_loc_at=1)
def __rand__(self, other):
"""Bitwise AND, :pc:`other & self`.
Like :meth:`__and__`, with operands swapped.
"""
return Operator("&", [other, self])
def all(self):
"""Reduction AND; are all bits :pc:`1`?
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("r&", [self])
@_overridable_by_reflected("__ror__")
def __or__(self, other):
"""Bitwise OR, :pc:`self | other`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(max(self.width() + 1, other.width()))`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(max(self.width(), other.width() + 1))`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
"""
return Operator("|", [self, other], src_loc_at=1)
def __ror__(self, other):
"""Bitwise OR, :pc:`other | self`.
Like :meth:`__or__`, with operands swapped.
"""
return Operator("|", [other, self])
def any(self):
"""Reduction OR; is any bit :pc:`1`?
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("r|", [self])
@_overridable_by_reflected("__rxor__")
def __xor__(self, other):
"""Bitwise XOR, :pc:`self ^ other`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
:class:`Value`, :pc:`signed(max(self.width() + 1, other.width()))`
If :pc:`self` is unsigned and :pc:`other` is signed.
:class:`Value`, :pc:`signed(max(self.width(), other.width() + 1))`
If :pc:`self` is signed and :pc:`other` is unsigned.
:class:`Value`, :pc:`signed(max(self.width(), other.width()))`
If both :pc:`self` and :pc:`other` are unsigned.
"""
return Operator("^", [self, other], src_loc_at=1)
def __rxor__(self, other):
"""Bitwise XOR, :pc:`other ^ self`.
Like :meth:`__xor__`, with operands swapped.
"""
return Operator("^", [other, self])
def xor(self):
"""Reduction XOR; are an odd amount of bits :pc:`1`?
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
return Operator("r^", [self])
def implies(self, conclusion):
# TODO: should we document or just deprecate this?
return ~self | conclusion
def __check_shamt(self):
if self.shape().signed:
# Neither Python nor HDLs implement shifts by negative values; prohibit any shifts
# by a signed value to make sure the shift amount can always be interpreted as
# an unsigned value.
raise TypeError("Shift amount must be unsigned")
@_overridable_by_reflected("__rlshift__")
def __lshift__(self, other):
"""Left shift by variable amount, :pc:`self << other`.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self) + 2 ** len(other) - 1)`
If :pc:`self` is unsigned.
:class:`Value`, :pc:`signed(len(self) + 2 ** len(other) - 1)`
If :pc:`self` is signed.
Raises
------
:exc:`TypeError`
If :pc:`other` is signed.
"""
other = Value.cast(other)
other.__check_shamt()
return Operator("<<", [self, other], src_loc_at=1)
def __rlshift__(self, other):
"""Left shift by variable amount, :pc:`other << self`.
Like :meth:`__lshift__`, with operands swapped.
"""
self.__check_shamt()
return Operator("<<", [other, self])
def shift_left(self, amount):
"""Left shift by constant amount.
If :pc:`amount < 0`, performs the same operation as :pc:`self.shift_right(-amount)`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(len(self) + amount, 0))`
If :pc:`self` is unsigned.
:class:`Value`, :pc:`signed(max(len(self) + amount, 1))`
If :pc:`self` is signed.
"""
if not isinstance(amount, int):
raise TypeError(f"Shift amount must be an integer, not {amount!r}")
if amount < 0:
return self.shift_right(-amount)
if self.shape().signed:
return Cat(Const(0, amount), self).as_signed()
else:
return Cat(Const(0, amount), self) # unsigned
def rotate_left(self, amount):
"""Left rotate by constant amount.
If :pc:`amount < 0`, performs the same operation as :pc:`self.rotate_right(-amount)`.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self))`, :ref:`assignable <lang-assignable>`
"""
if not isinstance(amount, int):
raise TypeError(f"Rotate amount must be an integer, not {amount!r}")
if len(self) != 0:
amount %= len(self)
return Cat(self[-amount:], self[:-amount]) # meow :3
@_overridable_by_reflected("__rrshift__")
def __rshift__(self, other):
"""Right shift by variable amount, :pc:`self >> other`.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self))`
If :pc:`self` is unsigned.
:class:`Value`, :pc:`signed(len(self))`
If :pc:`self` is signed.
Raises
------
:exc:`TypeError`
If :pc:`other` is signed.
"""
other = Value.cast(other)
other.__check_shamt()
return Operator(">>", [self, other], src_loc_at=1)
def __rrshift__(self, other):
"""Right shift by variable amount, :pc:`other >> self`.
Like :meth:`__rshift__`, with operands swapped.
"""
self.__check_shamt()
return Operator(">>", [other, self])
def shift_right(self, amount):
"""Right shift by constant amount.
If :pc:`amount < 0`, performs the same operation as :pc:`self.left_right(-amount)`.
Returns
-------
:class:`Value`, :pc:`unsigned(max(len(self) - amount, 0))`
If :pc:`self` is unsigned.
:class:`Value`, :pc:`signed(max(len(self) - amount, 1))`
If :pc:`self` is signed.
"""
if not isinstance(amount, int):
raise TypeError(f"Shift amount must be an integer, not {amount!r}")
if amount < 0:
return self.shift_left(-amount)
if self.shape().signed:
if amount >= len(self):
amount = len(self) - 1
return self[amount:].as_signed()
else:
return self[amount:] # unsigned
def rotate_right(self, amount):
"""Right rotate by constant amount.
If :pc:`amount < 0`, performs the same operation as :pc:`self.rotate_right(-amount)`.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self))`, :ref:`assignable <lang-assignable>`
"""
if not isinstance(amount, int):
raise TypeError(f"Rotate amount must be an integer, not {amount!r}")
if len(self) != 0:
amount %= len(self)
return Cat(self[amount:], self[:amount])
def __len__(self):
"""Bit width of :pc:`self`.
Returns
-------
:class:`int`
:pc:`self.shape().width`
"""
return self.shape().width
def __getitem__(self, key):
"""Bit slicing.
.. todo::
Describe this operation.
"""
n = len(self)
if isinstance(key, int):
if key not in range(-n, n):
raise IndexError(f"Index {key} is out of bounds for a {n}-bit value")
if key < 0:
key += n
return Slice(self, key, key + 1, src_loc_at=1)
elif isinstance(key, slice):
if isinstance(key.start, Value) or isinstance(key.stop, Value):
raise TypeError(f"Cannot slice value with a value; use Value.bit_select() or "
f"Value.word_select() instead")
start, stop, step = key.indices(n)
if step != 1:
return Cat(self[i] for i in range(start, stop, step))
return Slice(self, start, stop, src_loc_at=1)
elif isinstance(key, Value):
raise TypeError(f"Cannot index value with a value; use Value.bit_select() instead")
else:
raise TypeError(f"Cannot index value with {key!r}")
def __contains__(self, other):
"""Forbidden membership test operator.
Python requires this operator to return a :class:`bool`. Since this is not possible
for Amaranth values, this operator always raises an exception.
To check membership in a set of constant integer values, use :meth:`matches` instead.
Raises
------
:exc:`TypeError`
Always.
"""
raise TypeError("Cannot use 'in' with an Amaranth value")
def bit_select(self, offset, width):
"""Part-select with bit granularity.
Selects a constant width, variable offset part of :pc:`self`, where parts with successive
offsets overlap by :pc:`width - 1` bits. Bits above the most significant bit of :pc:`self`
may be selected; they are equal to zero if :pc:`self` is unsigned, to :pc:`self[-1]` if
:pc:`self` is signed, and assigning to them does nothing.
When :pc:`offset` is a constant integer and :pc:`offset + width <= len(self)`,
this operation is equivalent to :pc:`self[offset:offset + width]`.
Parameters
----------
offset: :ref:`value-like <lang-valuelike>`
Index of the first selected bit.
width: :class:`int`
Amount of bits to select.
Returns
-------
:class:`Value`, :pc:`unsigned(width)`, :ref:`assignable <lang-assignable>`
Raises
------
:exc:`TypeError`
If :pc:`offset` is signed.
:exc:`TypeError`
If :pc:`width` is negative.
"""
offset = Value.cast(offset)
if type(offset) is Const and isinstance(width, int):
return self[offset.value:offset.value + width]
return Part(self, offset, width, stride=1, src_loc_at=1)
def word_select(self, offset, width):
"""Part-select with word granularity.
Selects a constant width, variable offset part of :pc:`self`, where parts with successive
offsets are adjacent but do not overlap. Bits above the most significant bit of :pc:`self`
may be selected; they are equal to zero if :pc:`self` is unsigned, to :pc:`self[-1]` if
:pc:`self` is signed, and assigning to them does nothing.
When :pc:`offset` is a constant integer and :pc:`width:(offset + 1) * width <= len(self)`,
this operation is equivalent to :pc:`self[offset * width:(offset + 1) * width]`.
Parameters
----------
offset: :ref:`value-like <lang-valuelike>`
Index of the first selected word.
width: :class:`int`
Amount of bits to select.
Returns
-------
:class:`Value`, :pc:`unsigned(width)`, :ref:`assignable <lang-assignable>`
Raises
------
:exc:`TypeError`
If :pc:`offset` is signed.
:exc:`TypeError`
If :pc:`width` is negative.
"""
offset = Value.cast(offset)
if type(offset) is Const and isinstance(width, int):
return self[offset.value * width:(offset.value + 1) * width]
return Part(self, offset, width, stride=width, src_loc_at=1)
def replicate(self, count):
"""Replication.
Equivalent to :pc:`Cat(self for _ in range(count))`, but not assignable.
..
Technically assignable right now, but we don't want to commit to that.
Returns
-------
:class:`Value`, :pc:`unsigned(len(self) * count)`
Raises
------
:exc:`TypeError`
If :pc:`count` is negative.
"""
if not isinstance(count, int) or count < 0:
raise TypeError("Replication count must be a non-negative integer, not {!r}"
.format(count))
return Cat(self for _ in range(count))
def matches(self, *patterns):
"""Pattern matching.
Matches against a set of patterns, recognizing the same grammar as :pc:`with m.Case()`.
.. todo::
Describe the pattern language in detail.
Returns
-------
:class:`Value`, :pc:`unsigned(1)`
"""
matches = []
# This code should accept exactly the same patterns as `with m.Case(...):`.
for pattern in patterns:
if isinstance(pattern, str) and any(bit not in "01- \t" for bit in pattern):
raise SyntaxError("Match pattern '{}' must consist of 0, 1, and - (don't care) "
"bits, and may include whitespace"
.format(pattern))
if (isinstance(pattern, str) and
len("".join(pattern.split())) != len(self)):
raise SyntaxError("Match pattern '{}' must have the same width as match value "
"(which is {})"
.format(pattern, len(self)))
if isinstance(pattern, str):
pattern = "".join(pattern.split()) # remove whitespace
mask = int(pattern.replace("0", "1").replace("-", "0"), 2)
pattern = int(pattern.replace("-", "0"), 2)
matches.append((self & mask) == pattern)
else:
try:
orig_pattern, pattern = pattern, Const.cast(pattern)
except TypeError as e:
raise SyntaxError("Match pattern must be a string or a constant-castable "
"expression, not {!r}"
.format(pattern)) from e
pattern_len = bits_for(pattern.value)
if pattern_len > len(self):
warnings.warn("Match pattern '{!r}' ({}'{:b}) is wider than match value "
"(which has width {}); comparison will never be true"
.format(orig_pattern, pattern_len, pattern.value, len(self)),
SyntaxWarning, stacklevel=2)
continue
matches.append(self == pattern)
if not matches:
return Const(0)
elif len(matches) == 1:
return matches[0]
else:
return Cat(*matches).any()
def eq(self, value, *, src_loc_at=0):
""":ref:`Assignment <lang-assigns>`.
Once it is placed in a domain, an assignment changes the bit pattern of :pc:`self` to
equal :pc:`value`. If the bit width of :pc:`value` is less than that of :pc:`self`,
it is zero-extended (for unsigned :pc:`value`\\ s) or sign-extended (for signed
:pc:`value`\\ s). If the bit width of :pc:`value` is greater than that of :pc:`self`,
it is truncated.
Returns
-------
:class:`Statement`
"""
return Assign(self, value, src_loc_at=src_loc_at + 1)
#: Forbidden hashing.
#:
#: Python objects are :term:`python:hashable` if they provide a :pc:`__hash__` method
#: that returns an :class:`int` and an :pc:`__eq__` method that returns a :class:`bool`.
#: Amaranth values define :meth:`__eq__` to return a :class:`Value`, which precludes them
#: from being hashable.
#:
#: To use a :class:`Value` as a key in a :class:`dict`, use the following pattern:
#:
#: .. testcode::
#:
#: value = Signal()
#: assoc = {}
#: assoc[id(value)] = value, "a signal"
#: _, info = assoc[id(value)]
#: assert info == "a signal"
__hash__ = None # type: ignore
def _lhs_signals(self):
raise TypeError(f"Value {self!r} cannot be used in assignments")
@abstractmethod
def _rhs_signals(self):
raise NotImplementedError # :nocov:
class ValueCastable:
"""Interface class for objects that can be cast to a :class:`Value`.
Computations in the Amaranth language are described by combining :ref:`value-like objects
<lang-valuelike>`. Inheriting a class from :class:`ValueCastable` and implementing
all of the methods described below adds instances of that class to the list of
value-like objects recognized by the :meth:`Value.cast` method. This is a part of the mechanism
for seamlessly extending the Amaranth language in third-party code.
.. note::
All methods and operators defined by the :class:`Value` class will implicitly cast
a :class:`ValueCastable` object to a :class:`Value`, with the exception of arithmetic
operators, which will prefer calling a reflected arithmetic operation on
the :class:`ValueCastable` argument if it defines one.
For example, if :pc:`value_castable` implements :pc:`__radd__`, then
:pc:`C(1) + value_castable` will perform :pc:`value_castable.__radd__(C(1))`, and otherwise
it will perform :pc:`C(1).__add__(value_castable.as_value())`.
"""
def __init__(self, *args, **kwargs):
if type(self) is ValueCastable:
raise TypeError("Can't instantiate abstract class ValueCastable")
super().__init__(*args, **kwargs)
def __init_subclass__(cls, **kwargs):
if cls.as_value is ValueCastable.as_value:
raise TypeError(f"Class '{cls.__name__}' deriving from 'ValueCastable' must override "
"the 'as_value' method")
if cls.shape is ValueCastable.shape:
raise TypeError(f"Class '{cls.__name__}' deriving from 'ValueCastable' must override "
"the 'shape' method")
# The signatures and definitions of these methods are weird because they are present here for
# documentation (and error checking above) purpose only and should not affect control flow.
def as_value(self, *args, **kwargs):
"""as_value()
Convert :pc:`self` to a :ref:`value-like object <lang-valuelike>`.
This method is called by the Amaranth language to convert :pc:`self` to a concrete
:class:`Value`. It will usually return a :class:`Value` object, but it may also return
another value-like object to delegate its functionality.
This method must be idempotent: when called twice on the same object, the result must be
exactly the same.
This method may also be called by code that is not a part of the Amaranth language.
Returns
-------
Any other object recognized by :meth:`Value.cast`.
Raises
------
Exception
When the conversion cannot be done. This exception must be propagated by callers,
either directly or as a cause of another exception.
It is recommended that, in cases where this method raises an exception,
the :meth:`shape` method also raises an exception.
"""
return super().as_value(*args, **kwargs) # :nocov:
def shape(self, *args, **kwargs):
"""shape()
Compute the shape of :pc:`self`.
This method is not called by the Amaranth language itself; whenever it needs to discover
the shape of a value-castable object, it calls :class:`self.as_value().shape()`. However,
that method must return a :class:`Shape`, and :class:`ValueCastable` subclasses may have
a richer representation of their shape provided by an instance of a :class:`ShapeCastable`
subclass. This method may return such a representation.
This method must be idempotent: when called twice on the same object, the result must be
exactly the same.
The following condition must hold:
.. code::
Shape.cast(self.shape()) == Value.cast(self).shape()
Returns
-------
A :ref:`shape-like <lang-shapelike>` object.
Raises
------
Exception
When the conversion cannot be done. This exception must be propagated by callers,
either directly or as a cause of another exception.
It is recommended that, in cases where this method raises an exception,
the :meth:`as_value` method also raises an exception.
"""
return super().shape(*args, **kwargs) # :nocov:
# TODO(amaranth-0.6): remove
@staticmethod
@deprecated("`ValueCastable.lowermethod` is no longer required and will be removed in Amaranth 0.6")
def lowermethod(func):
@functools.wraps(func)
def wrapper_memoized(self, *args, **kwargs):
# Use `in self.__dict__` instead of `hasattr` to avoid interfering with custom
# `__getattr__` implementations.
if not "_ValueCastable__lowered_to" in self.__dict__:
self.__lowered_to = func(self, *args, **kwargs)
return self.__lowered_to
wrapper_memoized.__memoized = True
return wrapper_memoized
class _ValueLikeMeta(type):
def __subclasscheck__(cls, subclass):
if issubclass(subclass, (Value, ValueCastable, int)) or subclass is ValueLike:
return True
if issubclass(subclass, Enum):
return isinstance(subclass, ShapeLike)
return False
def __instancecheck__(cls, instance):
return issubclass(type(instance), cls)
@final
class ValueLike(metaclass=_ValueLikeMeta):
"""Abstract class representing all objects that can be cast to a :class:`Value`.
:pc:`issubclass(cls, ValueLike)` returns :pc:`True` for:
* :class:`Value`;
* :class:`ValueCastable` and its subclasses;
* :class:`int` and its subclasses (including :class:`bool`);
* :class:`enum.Enum` subclasses where all values are :ref:`value-like <lang-valuelike>`;
* :class:`ValueLike` itself.
:pc:`isinstance(obj, ValueLike)` returns the same value as
:pc:`issubclass(type(obj), ValueLike)`.
This class cannot be instantiated or subclassed. It can only be used for checking types of
objects.
.. note::
It is possible to define an enumeration with a member that is
:ref:`value-like <lang-valuelike>` but not :ref:`constant-castable <lang-constcasting>`,
meaning that :pc:`issubclass(BadEnum, ValueLike)` returns :pc:`True`, but
:pc:`Value.cast(BadEnum.MEMBER)` raises an exception.
The :mod:`amaranth.lib.enum` module prevents such enumerations from being defined when
the shape is specified explicitly. Using :mod:`amaranth.lib.enum` and specifying the shape
ensures that all of your enumeration members are constant-castable and fit in the provided
shape.
"""
def __new__(cls, *args, **kwargs):
raise TypeError("ValueLike is an abstract class and cannot be constructed")
class _ConstMeta(ABCMeta):
def __call__(cls, value, shape=None, src_loc_at=0, **kwargs):
if isinstance(shape, ShapeCastable):
return shape.const(value)
return super().__call__(value, shape, **kwargs, src_loc_at=src_loc_at + 1)
@final
class Const(Value, metaclass=_ConstMeta):
"""A constant, literal integer value.
Parameters
----------
value : int
shape : int or tuple or None
Either an integer ``width`` or a tuple ``(width, signed)`` specifying the number of bits
in this constant and whether it is signed (can represent negative values).
``shape`` defaults to the minimum possible width and signedness of ``value``.
Attributes
----------
width : int
signed : bool
"""
src_loc = None
@staticmethod
def cast(obj):
"""Converts ``obj`` to an Amaranth constant.
First, ``obj`` is converted to a value using :meth:`Value.cast`. If it is a constant, it
is returned. If it is a constant-castable expression, it is evaluated and returned.
Otherwise, :exn:`TypeError` is raised.
"""
obj = Value.cast(obj)
if type(obj) is Const:
return obj
elif type(obj) is Cat:
value = 0
width = 0
for part in obj.parts:
const = Const.cast(part)
part_value = Const(const.value, unsigned(const.width)).value
value |= part_value << width
width += len(const)
return Const(value, width)
elif type(obj) is Slice:
value = Const.cast(obj.value)
return Const(value.value >> obj.start, unsigned(obj.stop - obj.start))
else:
raise TypeError(f"Value {obj!r} cannot be converted to an Amaranth constant")
def __init__(self, value, shape=None, *, src_loc_at=0):
# We deliberately do not call Value.__init__ here.
self.value = int(operator.index(value))
if shape is None:
shape = Shape(bits_for(self.value), signed=self.value < 0)
elif isinstance(shape, int):
shape = Shape(shape, signed=self.value < 0)
else:
if isinstance(shape, range) and self.value == shape.stop:
warnings.warn(
message="Value {!r} equals the non-inclusive end of the constant "
"shape {!r}; this is likely an off-by-one error"
.format(self.value, shape),
category=SyntaxWarning,
stacklevel=3)
shape = Shape.cast(shape, src_loc_at=1 + src_loc_at)
self.width = shape.width
self.signed = shape.signed
if self.signed and self.value >> (self.width - 1) & 1:
self.value |= -(1 << self.width)
else:
self.value &= (1 << self.width) - 1
def shape(self):
return Shape(self.width, self.signed)
def _rhs_signals(self):
return SignalSet()
def __repr__(self):
return "(const {}'{}d{})".format(self.width, "s" if self.signed else "", self.value)
C = Const # shorthand
@final
class Operator(Value):
def __init__(self, operator, operands, *, src_loc_at=0):
super().__init__(src_loc_at=1 + src_loc_at)
self.operator = operator
self.operands = [Value.cast(op) for op in operands]
def shape(self):
def _bitwise_binary_shape(a_shape, b_shape):
if not a_shape.signed and not b_shape.signed:
# both operands unsigned
return unsigned(max(a_shape.width, b_shape.width))
elif a_shape.signed and b_shape.signed:
# both operands signed
return signed(max(a_shape.width, b_shape.width))
elif not a_shape.signed and b_shape.signed:
# first operand unsigned (add sign bit), second operand signed
return signed(max(a_shape.width + 1, b_shape.width))
else:
# first signed, second operand unsigned (add sign bit)
return signed(max(a_shape.width, b_shape.width + 1))
op_shapes = list(map(lambda x: x.shape(), self.operands))
if len(op_shapes) == 1:
a_shape, = op_shapes
if self.operator in ("+", "~"):
return Shape(a_shape.width, a_shape.signed)
if self.operator == "-":
return Shape(a_shape.width + 1, True)
if self.operator in ("b", "r|", "r&", "r^"):
return Shape(1, False)
if self.operator == "u":
return Shape(a_shape.width, False)
if self.operator == "s":
return Shape(a_shape.width, True)
elif len(op_shapes) == 2:
a_shape, b_shape = op_shapes
if self.operator == "+":
o_shape = _bitwise_binary_shape(*op_shapes)
return Shape(o_shape.width + 1, o_shape.signed)
if self.operator == "-":
o_shape = _bitwise_binary_shape(*op_shapes)
return Shape(o_shape.width + 1, True)
if self.operator == "*":
return Shape(a_shape.width + b_shape.width, a_shape.signed or b_shape.signed)
if self.operator == "//":
return Shape(a_shape.width + b_shape.signed, a_shape.signed or b_shape.signed)
if self.operator == "%":
return Shape(b_shape.width, b_shape.signed)
if self.operator in ("<", "<=", "==", "!=", ">", ">="):
return Shape(1, False)
if self.operator in ("&", "|", "^"):
return _bitwise_binary_shape(*op_shapes)
if self.operator == "<<":
assert not b_shape.signed
return Shape(a_shape.width + 2 ** b_shape.width - 1, a_shape.signed)
if self.operator == ">>":
assert not b_shape.signed
return Shape(a_shape.width, a_shape.signed)
elif len(op_shapes) == 3:
if self.operator == "m":
s_shape, a_shape, b_shape = op_shapes
return _bitwise_binary_shape(a_shape, b_shape)
raise NotImplementedError # :nocov:
def _lhs_signals(self):
if self.operator in ("u", "s"):
return union(op._lhs_signals() for op in self.operands)
return super()._lhs_signals()
def _rhs_signals(self):
return union(op._rhs_signals() for op in self.operands)
def __repr__(self):
return "({} {})".format(self.operator, " ".join(map(repr, self.operands)))
def Mux(sel, val1, val0):
"""Choose between two values.
Parameters
----------
sel : Value, in
Selector.
val1 : Value, in
val0 : Value, in
Input values.
Returns
-------
Value, out
Output ``Value``. If ``sel`` is asserted, the Mux returns ``val1``, else ``val0``.
"""
return Operator("m", [sel, val1, val0])
@final
class Slice(Value):
def __init__(self, value, start, stop, *, src_loc_at=0):
if not isinstance(start, int):
raise TypeError(f"Slice start must be an integer, not {start!r}")
if not isinstance(stop, int):
raise TypeError(f"Slice stop must be an integer, not {stop!r}")
value = Value.cast(value)
n = len(value)
if start not in range(-n, n+1):
raise IndexError(f"Cannot start slice {start} bits into {n}-bit value")
if start < 0:
start += n
if stop not in range(-n, n+1):
raise IndexError(f"Cannot stop slice {stop} bits into {n}-bit value")
if stop < 0:
stop += n
if start > stop:
raise IndexError(f"Slice start {start} must be less than slice stop {stop}")
super().__init__(src_loc_at=src_loc_at)
self.value = value
self.start = int(operator.index(start))
self.stop = int(operator.index(stop))
def shape(self):
return Shape(self.stop - self.start)
def _lhs_signals(self):
return self.value._lhs_signals()
def _rhs_signals(self):
return self.value._rhs_signals()
def __repr__(self):
return f"(slice {self.value!r} {self.start}:{self.stop})"
@final
class Part(Value):
def __init__(self, value, offset, width, stride=1, *, src_loc_at=0):
if not isinstance(width, int) or width < 0:
raise TypeError(f"Part width must be a non-negative integer, not {width!r}")
if not isinstance(stride, int) or stride <= 0:
raise TypeError(f"Part stride must be a positive integer, not {stride!r}")
value = Value.cast(value)
offset = Value.cast(offset)
if offset.shape().signed:
raise TypeError("Part offset must be unsigned")
super().__init__(src_loc_at=src_loc_at)
self.value = value
self.offset = offset
self.width = width
self.stride = stride
def shape(self):
return Shape(self.width)
def _lhs_signals(self):
return self.value._lhs_signals()
def _rhs_signals(self):
return self.value._rhs_signals() | self.offset._rhs_signals()
def __repr__(self):
return "(part {} {} {} {})".format(repr(self.value), repr(self.offset),
self.width, self.stride)
@final
class Cat(Value):
"""Concatenate values.
Form a compound ``Value`` from several smaller ones by concatenation.
The first argument occupies the lower bits of the result.
The return value can be used on either side of an assignment, that
is, the concatenated value can be used as an argument on the RHS or
as a target on the LHS. If it is used on the LHS, it must solely
consist of ``Signal`` s, slices of ``Signal`` s, and other concatenations
meeting these properties. The bit length of the return value is the sum of
the bit lengths of the arguments::
len(Cat(args)) == sum(len(arg) for arg in args)
Parameters
----------
*args : Values or iterables of Values, inout
``Value`` s to be concatenated.
Returns
-------
Value, inout
Resulting ``Value`` obtained by concatenation.
"""
def __init__(self, *args, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
self.parts = []
for index, arg in enumerate(flatten(args)):
if isinstance(arg, Enum) and (not isinstance(type(arg), ShapeCastable) or
not hasattr(arg, "_amaranth_shape_")):
warnings.warn("Argument #{} of Cat() is an enumerated value {!r} without "
"a defined shape used in bit vector context; define the enumeration "
"by inheriting from the class in amaranth.lib.enum and specifying "
"the 'shape=' keyword argument"
.format(index + 1, arg),
SyntaxWarning, stacklevel=2 + src_loc_at)
if isinstance(arg, int) and not isinstance(arg, Enum) and arg not in [0, 1]:
warnings.warn("Argument #{} of Cat() is a bare integer {} used in bit vector "
"context; specify the width explicitly using C({}, {})"
.format(index + 1, arg, arg, bits_for(arg)),
SyntaxWarning, stacklevel=2 + src_loc_at)
self.parts.append(Value.cast(arg))
def shape(self):
return Shape(sum(len(part) for part in self.parts))
def _lhs_signals(self):
return union((part._lhs_signals() for part in self.parts), start=SignalSet())
def _rhs_signals(self):
return union((part._rhs_signals() for part in self.parts), start=SignalSet())
def __repr__(self):
return "(cat {})".format(" ".join(map(repr, self.parts)))
class _SignalMeta(ABCMeta):
def __call__(cls, shape=None, src_loc_at=0, **kwargs):
signal = super().__call__(shape, **kwargs, src_loc_at=src_loc_at + 1)
if isinstance(shape, ShapeCastable):
return shape(signal)
return signal
@final
class Signal(Value, DUID, metaclass=_SignalMeta):
"""A varying integer value.
Parameters
----------
shape : ``Shape``-castable object or None
Specification for the number of bits in this ``Signal`` and its signedness (whether it
can represent negative values). See ``Shape.cast`` for details.
If not specified, ``shape`` defaults to 1-bit and non-signed.
name : str
Name hint for this signal. If ``None`` (default) the name is inferred from the variable
name this ``Signal`` is assigned to.
reset : int or integral Enum
Reset (synchronous) or default (combinatorial) value.
When this ``Signal`` is assigned to in synchronous context and the corresponding clock
domain is reset, the ``Signal`` assumes the given value. When this ``Signal`` is unassigned
in combinatorial context (due to conditional assignments not being taken), the ``Signal``
assumes its ``reset`` value. Defaults to 0.
reset_less : bool
If ``True``, do not generate reset logic for this ``Signal`` in synchronous statements.
The ``reset`` value is only used as a combinatorial default or as the initial value.
Defaults to ``False``.
attrs : dict
Dictionary of synthesis attributes.
decoder : function or Enum
A function converting integer signal values to human-readable strings (e.g. FSM state
names). If an ``Enum`` subclass is passed, it is concisely decoded using format string
``"{0.name:}/{0.value:}"``, or a number if the signal value is not a member of
the enumeration.
Attributes
----------
width : int
signed : bool
name : str
reset : int
reset_less : bool
attrs : dict
decoder : function
"""
def __init__(self, shape=None, *, name=None, reset=None, reset_less=False,
attrs=None, decoder=None, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
if name is not None and not isinstance(name, str):
raise TypeError(f"Name must be a string, not {name!r}")
self.name = name or tracer.get_var_name(depth=2 + src_loc_at, default="$signal")
orig_shape = shape
if shape is None:
shape = unsigned(1)
else:
shape = Shape.cast(shape, src_loc_at=1 + src_loc_at)
self.width = shape.width
self.signed = shape.signed
orig_reset = reset
if isinstance(orig_shape, ShapeCastable):
try:
reset = Const.cast(orig_shape.const(reset))
except Exception:
raise TypeError("Reset value must be a constant initializer of {!r}"
.format(orig_shape))
if reset.shape() != Shape.cast(orig_shape):
raise ValueError("Constant returned by {!r}.const() must have the shape that "
"it casts to, {!r}, and not {!r}"
.format(orig_shape, Shape.cast(orig_shape),
reset.shape()))
else:
if reset is None:
reset = 0
try:
reset = Const.cast(reset)
except TypeError:
raise TypeError("Reset value must be a constant-castable expression, not {!r}"
.format(orig_reset))
# Avoid false positives for all-zeroes and all-ones
if orig_reset is not None and not (isinstance(orig_reset, int) and orig_reset in (0, -1)):
if reset.shape().signed and not self.signed:
warnings.warn(
message="Reset value {!r} is signed, but the signal shape is {!r}"
.format(orig_reset, shape),
category=SyntaxWarning,
stacklevel=2)
elif (reset.shape().width > self.width or
reset.shape().width == self.width and
self.signed and not reset.shape().signed):
warnings.warn(
message="Reset value {!r} will be truncated to the signal shape {!r}"
.format(orig_reset, shape),
category=SyntaxWarning,
stacklevel=2)
self.reset = reset.value
self.reset_less = bool(reset_less)
if isinstance(orig_shape, range) and orig_reset is not None and orig_reset not in orig_shape:
if orig_reset == orig_shape.stop:
raise SyntaxError(
f"Reset value {orig_reset!r} equals the non-inclusive end of the signal "
f"shape {orig_shape!r}; this is likely an off-by-one error")
else:
raise SyntaxError(
f"Reset value {orig_reset!r} is not within the signal shape {orig_shape!r}")
self.attrs = OrderedDict(() if attrs is None else attrs)
if decoder is not None:
# The value representation is specified explicitly. Since we do not expose `hdl._repr`,
# this is the only way to add a custom filter to the signal right now. The setter sets
# `self._value_repr` as well as the compatibility `self.decoder`.
self.decoder = decoder
else:
# If it's an enum, expose it via `self.decoder` for compatibility, whether it's a Python
# enum or an Amaranth enum. This also sets the value representation, even for custom
# shape-castables that implement their own `_value_repr`.
if isinstance(orig_shape, type) and issubclass(orig_shape, Enum):
self.decoder = orig_shape
else:
self.decoder = None
# The value representation is specified implicitly in the shape of the signal.
if isinstance(orig_shape, ShapeCastable):
# A custom shape-castable always has a `_value_repr`, at least the default one.
self._value_repr = tuple(orig_shape._value_repr(self))
elif isinstance(orig_shape, type) and issubclass(orig_shape, Enum):
# A non-Amaranth enum needs a value repr constructed for it.
self._value_repr = (Repr(FormatEnum(orig_shape), self),)
else:
# Any other case is formatted as a plain integer.
self._value_repr = (Repr(FormatInt(), self),)
@property
def decoder(self):
return self._decoder
@decoder.setter
def decoder(self, decoder):
# Compute the value representation that will be used by Amaranth.
if decoder is None:
self._value_repr = (Repr(FormatInt(), self),)
self._decoder = None
elif not (isinstance(decoder, type) and issubclass(decoder, Enum)):
self._value_repr = (Repr(FormatCustom(decoder), self),)
self._decoder = decoder
else: # Violence. In the name of backwards compatibility!
self._value_repr = (Repr(FormatEnum(decoder), self),)
def enum_decoder(value):
try:
return "{0.name:}/{0.value:}".format(decoder(value))
except ValueError:
return str(value)
self._decoder = enum_decoder
@classmethod
def like(cls, other, *, name=None, name_suffix=None, src_loc_at=0, **kwargs):
"""Create Signal based on another.
Parameters
----------
other : Value
Object to base this Signal on.
"""
if name is not None:
new_name = str(name)
elif name_suffix is not None:
new_name = other.name + str(name_suffix)
else:
new_name = tracer.get_var_name(depth=2 + src_loc_at, default="$like")
if isinstance(other, ValueCastable):
shape = other.shape()
else:
shape = Value.cast(other).shape()
kw = dict(shape=shape, name=new_name)
if isinstance(other, Signal):
kw.update(reset=other.reset, reset_less=other.reset_less,
attrs=other.attrs, decoder=other.decoder)
kw.update(kwargs)
return cls(**kw, src_loc_at=1 + src_loc_at)
def shape(self):
return Shape(self.width, self.signed)
def _lhs_signals(self):
return SignalSet((self,))
def _rhs_signals(self):
return SignalSet((self,))
def __repr__(self):
return f"(sig {self.name})"
@final
class ClockSignal(Value):
"""Clock signal for a clock domain.
Any ``ClockSignal`` is equivalent to ``cd.clk`` for a clock domain with the corresponding name.
All of these signals ultimately refer to the same signal, but they can be manipulated
independently of the clock domain, even before the clock domain is created.
Parameters
----------
domain : str
Clock domain to obtain a clock signal for. Defaults to ``"sync"``.
"""
def __init__(self, domain="sync", *, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
if not isinstance(domain, str):
raise TypeError(f"Clock domain name must be a string, not {domain!r}")
if domain == "comb":
raise ValueError(f"Domain '{domain}' does not have a clock")
self.domain = domain
def shape(self):
return Shape(1)
def _lhs_signals(self):
return SignalSet((self,))
def _rhs_signals(self):
raise NotImplementedError("ClockSignal must be lowered to a concrete signal") # :nocov:
def __repr__(self):
return f"(clk {self.domain})"
@final
class ResetSignal(Value):
"""Reset signal for a clock domain.
Any ``ResetSignal`` is equivalent to ``cd.rst`` for a clock domain with the corresponding name.
All of these signals ultimately refer to the same signal, but they can be manipulated
independently of the clock domain, even before the clock domain is created.
Parameters
----------
domain : str
Clock domain to obtain a reset signal for. Defaults to ``"sync"``.
allow_reset_less : bool
If the clock domain is reset-less, act as a constant ``0`` instead of reporting an error.
"""
def __init__(self, domain="sync", allow_reset_less=False, *, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
if not isinstance(domain, str):
raise TypeError(f"Clock domain name must be a string, not {domain!r}")
if domain == "comb":
raise ValueError(f"Domain '{domain}' does not have a reset")
self.domain = domain
self.allow_reset_less = allow_reset_less
def shape(self):
return Shape(1)
def _lhs_signals(self):
return SignalSet((self,))
def _rhs_signals(self):
raise NotImplementedError("ResetSignal must be lowered to a concrete signal") # :nocov:
def __repr__(self):
return f"(rst {self.domain})"
@final
class AnyValue(Value, DUID):
class Kind(Enum):
AnyConst = "anyconst"
AnySeq = "anyseq"
def __init__(self, kind, shape, *, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
self.kind = self.Kind(kind)
shape = Shape.cast(shape, src_loc_at=1 + src_loc_at)
self.width = shape.width
self.signed = shape.signed
def shape(self):
return Shape(self.width, self.signed)
def _rhs_signals(self):
return SignalSet()
def __repr__(self):
return "({} {}'{})".format(self.kind.value, self.width, "s" if self.signed else "")
def AnyConst(shape, *, src_loc_at=0):
return AnyValue("anyconst", shape, src_loc_at=src_loc_at+1)
def AnySeq(shape, *, src_loc_at=0):
return AnyValue("anyseq", shape, src_loc_at=src_loc_at+1)
class Array(MutableSequence):
"""Addressable multiplexer.
An array is similar to a ``list`` that can also be indexed by ``Value``s; indexing by an integer
or a slice works the same as for Python lists, but indexing by a ``Value`` results in a proxy.
The array proxy can be used as an ordinary ``Value``, i.e. participate in calculations and
assignments, provided that all elements of the array are values. The array proxy also supports
attribute access and further indexing, each returning another array proxy; this means that
the results of indexing into arrays, arrays of records, and arrays of arrays can all
be used as first-class values.
It is an error to change an array or any of its elements after an array proxy was created.
Changing the array directly will raise an exception. However, it is not possible to detect
the elements being modified; if an element's attribute or element is modified after the proxy
for it has been created, the proxy will refer to stale data.
Examples
--------
Simple array::
gpios = Array(Signal() for _ in range(10))
with m.If(bus.we):
m.d.sync += gpios[bus.addr].eq(bus.w_data)
with m.Else():
m.d.sync += bus.r_data.eq(gpios[bus.addr])
Multidimensional array::
mult = Array(Array(x * y for y in range(10)) for x in range(10))
a = Signal.range(10)
b = Signal.range(10)
r = Signal(8)
m.d.comb += r.eq(mult[a][b])
Array of records::
layout = [
("r_data", 16),
("r_en", 1),
]
buses = Array(Record(layout) for busno in range(4))
master = Record(layout)
m.d.comb += [
buses[sel].r_en.eq(master.r_en),
master.r_data.eq(buses[sel].r_data),
]
"""
def __init__(self, iterable=()):
self._inner = list(iterable)
self._proxy_at = None
self._mutable = True
def __getitem__(self, index):
if isinstance(index, ValueCastable):
index = Value.cast(index)
if isinstance(index, Value):
if self._mutable:
self._proxy_at = tracer.get_src_loc()
self._mutable = False
return ArrayProxy(self, index)
else:
return self._inner[index]
def __len__(self):
return len(self._inner)
def _check_mutability(self):
if not self._mutable:
raise ValueError("Array can no longer be mutated after it was indexed with a value "
"at {}:{}".format(*self._proxy_at))
def __setitem__(self, index, value):
self._check_mutability()
self._inner[index] = value
def __delitem__(self, index):
self._check_mutability()
del self._inner[index]
def insert(self, index, value):
self._check_mutability()
self._inner.insert(index, value)
def __repr__(self):
return "(array{} [{}])".format(" mutable" if self._mutable else "",
", ".join(map(repr, self._inner)))
@final
class ArrayProxy(Value):
def __init__(self, elems, index, *, src_loc_at=0):
super().__init__(src_loc_at=1 + src_loc_at)
self.elems = elems
self.index = Value.cast(index)
def __getattr__(self, attr):
return ArrayProxy([getattr(elem, attr) for elem in self.elems], self.index)
def __getitem__(self, index):
return ArrayProxy([ elem[index] for elem in self.elems], self.index)
def _iter_as_values(self):
return (Value.cast(elem) for elem in self.elems)
def shape(self):
unsigned_width = signed_width = 0
has_unsigned = has_signed = False
for elem_shape in (elem.shape() for elem in self._iter_as_values()):
if elem_shape.signed:
has_signed = True
signed_width = max(signed_width, elem_shape.width)
else:
has_unsigned = True
unsigned_width = max(unsigned_width, elem_shape.width)
# The shape of the proxy must be such that it preserves the mathematical value of the array
# elements. I.e., shape-wise, an array proxy must be identical to an equivalent mux tree.
# To ensure this holds, if the array contains both signed and unsigned values, make sure
# that every unsigned value is zero-extended by at least one bit.
if has_signed and has_unsigned and unsigned_width >= signed_width:
# Array contains both signed and unsigned values, and at least one of the unsigned
# values won't be zero-extended otherwise.
return signed(unsigned_width + 1)
else:
# Array contains values of the same signedness, or else all of the unsigned values
# are zero-extended.
return Shape(max(unsigned_width, signed_width), has_signed)
def _lhs_signals(self):
signals = union((elem._lhs_signals() for elem in self._iter_as_values()),
start=SignalSet())
return signals
def _rhs_signals(self):
signals = union((elem._rhs_signals() for elem in self._iter_as_values()),
start=SignalSet())
return self.index._rhs_signals() | signals
def __repr__(self):
return "(proxy (array [{}]) {!r})".format(", ".join(map(repr, self.elems)), self.index)
@final
class Initial(Value):
"""Start indicator, for model checking.
An ``Initial`` signal is ``1`` at the first cycle of model checking, and ``0`` at any other.
"""
def __init__(self, *, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
def shape(self):
return Shape(1)
def _rhs_signals(self):
return SignalSet()
def __repr__(self):
return "(initial)"
class _StatementList(list):
def __repr__(self):
return "({})".format(" ".join(map(repr, self)))
def _lhs_signals(self):
return union((s._lhs_signals() for s in self), start=SignalSet())
def _rhs_signals(self):
return union((s._rhs_signals() for s in self), start=SignalSet())
class Statement:
def __init__(self, *, src_loc_at=0):
self.src_loc = tracer.get_src_loc(1 + src_loc_at)
@staticmethod
def cast(obj):
if isinstance(obj, Iterable):
return _StatementList(list(chain.from_iterable(map(Statement.cast, obj))))
else:
if isinstance(obj, Statement):
return _StatementList([obj])
else:
raise TypeError(f"Object {obj!r} is not an Amaranth statement")
@final
class Assign(Statement):
def __init__(self, lhs, rhs, *, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
self.lhs = Value.cast(lhs)
self.rhs = Value.cast(rhs)
def _lhs_signals(self):
return self.lhs._lhs_signals()
def _rhs_signals(self):
return self.lhs._rhs_signals() | self.rhs._rhs_signals()
def __repr__(self):
return f"(eq {self.lhs!r} {self.rhs!r})"
class UnusedProperty(UnusedMustUse):
pass
@final
class Property(Statement, MustUse):
_MustUse__warning = UnusedProperty
class Kind(Enum):
Assert = "assert"
Assume = "assume"
Cover = "cover"
def __init__(self, kind, test, *, name=None, src_loc_at=0):
super().__init__(src_loc_at=src_loc_at)
self.kind = self.Kind(kind)
self.test = Value.cast(test)
self.name = name
if not isinstance(self.name, str) and self.name is not None:
raise TypeError("Property name must be a string or None, not {!r}"
.format(self.name))
def _lhs_signals(self):
return set()
def _rhs_signals(self):
return self.test._rhs_signals()
def __repr__(self):
if self.name is not None:
return f"({self.name}: {self.kind.value} {self.test!r})"
return f"({self.kind.value} {self.test!r})"
def Assert(test, *, name=None, src_loc_at=0):
return Property("assert", test, name=name, src_loc_at=src_loc_at+1)
def Assume(test, *, name=None, src_loc_at=0):
return Property("assume", test, name=name, src_loc_at=src_loc_at+1)
def Cover(test, *, name=None, src_loc_at=0):
return Property("cover", test, name=name, src_loc_at=src_loc_at+1)
@final
class Switch(Statement):
def __init__(self, test, cases, *, src_loc=None, src_loc_at=0, case_src_locs={}):
if src_loc is None:
super().__init__(src_loc_at=src_loc_at)
else:
# Switch is a bit special in terms of location tracking because it is usually created
# long after the control has left the statement that directly caused its creation.
self.src_loc = src_loc
# Switch is also a bit special in that its parts also have location information. It can't
# be automatically traced, so whatever constructs a Switch may optionally provide it.
self.case_src_locs = {}
self.test = Value.cast(test)
self.cases = OrderedDict()
for orig_keys, stmts in cases.items():
# Map: None -> (); key -> (key,); (key...) -> (key...)
keys = orig_keys
if keys is None:
keys = ()
if not isinstance(keys, tuple):
keys = (keys,)
# Map: 2 -> "0010"; "0010" -> "0010"
new_keys = ()
key_mask = (1 << len(self.test)) - 1
for key in keys:
if isinstance(key, str):
key = "".join(key.split()) # remove whitespace
elif isinstance(key, int):
key = format(key & key_mask, "b").rjust(len(self.test), "0")
elif isinstance(key, Enum):
key = format(key.value & key_mask, "b").rjust(len(self.test), "0")
else:
raise TypeError("Object {!r} cannot be used as a switch key"
.format(key))
assert len(key) == len(self.test)
new_keys = (*new_keys, key)
if not isinstance(stmts, Iterable):
stmts = [stmts]
self.cases[new_keys] = Statement.cast(stmts)
if orig_keys in case_src_locs:
self.case_src_locs[new_keys] = case_src_locs[orig_keys]
def _lhs_signals(self):
return union((s._lhs_signals() for s in self.cases.values()), start=SignalSet())
def _rhs_signals(self):
signals = union((s._rhs_signals() for s in self.cases.values()), start=SignalSet())
return self.test._rhs_signals() | signals
def __repr__(self):
def case_repr(keys, stmts):
stmts_repr = " ".join(map(repr, stmts))
if keys == ():
return f"(default {stmts_repr})"
elif len(keys) == 1:
return f"(case {keys[0]} {stmts_repr})"
else:
return "(case ({}) {})".format(" ".join(keys), stmts_repr)
case_reprs = [case_repr(keys, stmts) for keys, stmts in self.cases.items()]
return "(switch {!r} {})".format(self.test, " ".join(case_reprs))
class _MappedKeyCollection(metaclass=ABCMeta):
@abstractmethod
def _map_key(self, key):
pass # :nocov:
@abstractmethod
def _unmap_key(self, key):
pass # :nocov:
class _MappedKeyDict(MutableMapping, _MappedKeyCollection):
def __init__(self, pairs=()):
self._storage = OrderedDict()
for key, value in pairs:
self[key] = value
def __getitem__(self, key):
key = None if key is None else self._map_key(key)
return self._storage[key]
def __setitem__(self, key, value):
key = None if key is None else self._map_key(key)
self._storage[key] = value
def __delitem__(self, key):
key = None if key is None else self._map_key(key)
del self._storage[key]
def __iter__(self):
for key in self._storage:
if key is None:
yield None
else:
yield self._unmap_key(key)
def __eq__(self, other):
if not isinstance(other, type(self)):
return False
if len(self) != len(other):
return False
for ak, bk in zip(sorted(self._storage), sorted(other._storage)):
if ak != bk:
return False
if self._storage[ak] != other._storage[bk]:
return False
return True
def __len__(self):
return len(self._storage)
def __repr__(self):
pairs = [f"({k!r}, {v!r})" for k, v in self.items()]
return "{}.{}([{}])".format(type(self).__module__, type(self).__name__,
", ".join(pairs))
class _MappedKeySet(MutableSet, _MappedKeyCollection):
def __init__(self, elements=()):
self._storage = OrderedDict()
for elem in elements:
self.add(elem)
def add(self, value):
self._storage[self._map_key(value)] = None
def update(self, values):
for value in values:
self.add(value)
def discard(self, value):
if value in self:
del self._storage[self._map_key(value)]
def __contains__(self, value):
return self._map_key(value) in self._storage
def __iter__(self):
for key in [k for k in self._storage]:
yield self._unmap_key(key)
def __len__(self):
return len(self._storage)
def __repr__(self):
return "{}.{}({})".format(type(self).__module__, type(self).__name__,
", ".join(repr(x) for x in self))
class SignalKey:
def __init__(self, signal):
self.signal = signal
if isinstance(signal, Signal):
self._intern = (0, signal.duid)
elif type(signal) is ClockSignal:
self._intern = (1, signal.domain)
elif type(signal) is ResetSignal:
self._intern = (2, signal.domain)
else:
raise TypeError(f"Object {signal!r} is not an Amaranth signal")
def __hash__(self):
return hash(self._intern)
def __eq__(self, other):
if type(other) is not SignalKey:
return False
return self._intern == other._intern
def __lt__(self, other):
if type(other) is not SignalKey:
raise TypeError(f"Object {other!r} cannot be compared to a SignalKey")
return self._intern < other._intern
def __repr__(self):
return f"<{__name__}.SignalKey {self.signal!r}>"
class SignalDict(_MappedKeyDict):
_map_key = SignalKey
_unmap_key = lambda self, key: key.signal
class SignalSet(_MappedKeySet):
_map_key = SignalKey
_unmap_key = lambda self, key: key.signal
from ._repr import *
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