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from abc import ABCMeta, abstractmethod

from ..boards.abstract_board import AbstractBoard

from m5.objects import SubSystem


class AbstractCacheHierarchy(SubSystem):
    __metaclass__ = ABCMeta

    def __init__(self):
        super().__init__()

    """
    A Cache Hierarchy incorporates any system components which manages
    communicaton between the processor and memory. E.g., Caches, the MemBus,
    MMU, and the MMU Cache.

    All Cache Hierarchies must have this as a base class.
    """

    @abstractmethod
    def incorporate_cache(self, board: AbstractBoard) -> None:
        """
        Incorporates the caches into a board.

        Each specific hierarchy needs to implement this function and will be
        unique for each setup.

        :param board: The board in which the cache heirarchy is to be
        incorporated.

        :type board: AbstractBoard
        """

        raise NotImplementedError

    @abstractmethod
    def is_ruby(self) -> bool:
        """
        Specifies whether this cache hierarchy is using the Ruby memory system
        or not.

        :returns: True if the cache hierarchy is ruby. Otherwise False.
        """
        raise NotImplementedError

    def _post_instantiate(self):
        """Called to set up anything needed after m5.instantiate"""
        pass