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from ..boards.mem_mode import MemMode
from ..boards.abstract_board import AbstractBoard
from ..processors.simple_core import SimpleCore
from ..processors.cpu_types import CPUTypes, get_mem_mode
from .switchable_processor import SwitchableProcessor
from ...isas import ISA
from m5.util import warn

from ...utils.override import *

from typing import Optional


class SimpleSwitchableProcessor(SwitchableProcessor):
    """
    A Simplified implementation of SwitchableProcessor where there is one
    processor at the start of the simuation, and another that can be switched
    to via the "switch" function later in the simulation. This is good for
    fast/detailed CPU setups.
    """

    def __init__(
        self,
        starting_core_type: CPUTypes,
        switch_core_type: CPUTypes,
        num_cores: int,
        isa: Optional[ISA] = None,
    ) -> None:
        """
        :param starting_core_type: The CPU type for each type in the processor
        to start with (i.e., when the simulation has just started).

        :param switch_core_types: The CPU type for each core, to be switched
        to..

        :param isa: The ISA of the processor. This argument is optional. If not
        set the `runtime.get_runtime_isa` is used to determine the ISA at
        runtime. **WARNING**: This functionality is deprecated. It is
        recommended you explicitly set your ISA via SimpleSwitchableProcessor
        construction.
        """

        if not isa:
            warn(
                "An ISA for the SimpleSwitchableProcessor was not set. This "
                "will result in usage of `runtime.get_runtime_isa` to obtain "
                "the ISA. This function is deprecated and will be removed in "
                "future releases of gem5. Please explicitly state the ISA "
                "via the processor constructor."
            )

        if num_cores <= 0:
            raise AssertionError("Number of cores must be a positive integer!")

        self._start_key = "start"
        self._switch_key = "switch"
        self._current_is_start = True

        self._mem_mode = get_mem_mode(starting_core_type)

        switchable_cores = {
            self._start_key: [
                SimpleCore(cpu_type=starting_core_type, core_id=i, isa=isa)
                for i in range(num_cores)
            ],
            self._switch_key: [
                SimpleCore(cpu_type=switch_core_type, core_id=i, isa=isa)
                for i in range(num_cores)
            ],
        }

        super().__init__(
            switchable_cores=switchable_cores, starting_cores=self._start_key
        )

    @overrides(SwitchableProcessor)
    def incorporate_processor(self, board: AbstractBoard) -> None:
        super().incorporate_processor(board=board)

        board.set_mem_mode(self._mem_mode)

    def switch(self):
        """Switches to the "switched out" cores."""
        if self._current_is_start:
            self.switch_to_processor(self._switch_key)
        else:
            self.switch_to_processor(self._start_key)

        self._current_is_start = not self._current_is_start