96 lines
2.7 KiB
Python
96 lines
2.7 KiB
Python
from typing import TYPE_CHECKING, List
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import enum
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from ..utils import get_indexed_path
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if TYPE_CHECKING:
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from systemrdl.node import FieldNode
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from ..exporter import RegblockExporter
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class AssignmentPrecedence(enum.IntEnum):
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"""
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Enumeration of standard assignment precedence groups.
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Each value represents the precedence of a single conditional assignment
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category that determines a field's next state.
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Higher value denotes higher precedence
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Important: If inserting custom intermediate assignment rules, do not rely on the absolute
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value of the enumeration. Insert your rules relative to an existing precedence:
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FieldBuilder.add_hw_conditional(MyConditional, HW_WE + 1)
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"""
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# Software access assignment groups
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SW_ONREAD = 5000
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SW_ONWRITE = 4000
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# Hardware access assignment groups
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HW_WE = 3000
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HWSET = 2000
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HWCLR = 1000
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COUNTER_INCR_DECR = 0
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class SVLogic:
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"""
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Represents a SystemVerilog logic signal
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"""
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def __init__(self, name: str, width: int, default_assignment: str) -> None:
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self.name = name
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self.width = width
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self.default_assignment = default_assignment
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def __eq__(self, o: object) -> bool:
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if not isinstance(o, SVLogic):
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return False
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return (
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o.name == self.name
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and o.width == self.width
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and o.default_assignment == self.default_assignment
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)
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class NextStateConditional:
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"""
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Decribes a single conditional action that determines the next state of a field
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Provides information to generate the following content:
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if(<conditional>) begin
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<assignments>
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end
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"""
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def __init__(self, exporter:'RegblockExporter'):
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self.exporter = exporter
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def is_match(self, field: 'FieldNode') -> bool:
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"""
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Returns True if this conditional is relevant to the field. If so,
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it instructs the FieldBuider that Verilog for this conditional shall
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be emitted
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"""
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raise NotImplementedError
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def get_field_path(self, field:'FieldNode') -> str:
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return get_indexed_path(self.exporter.top_node, field)
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def get_conditional(self, field: 'FieldNode') -> str:
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"""
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Returns the rendered conditional text
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"""
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raise NotImplementedError
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def get_assignments(self, field: 'FieldNode') -> List[str]:
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"""
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Returns a list of rendered assignment strings
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This will basically always be two:
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<field>.next = <next value>
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<field>.load_next = '1;
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"""
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def get_extra_combo_signals(self, field: 'FieldNode') -> List[SVLogic]:
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return []
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