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"""
A run script for a very simple Syscall-Execution running simple binaries.
The system has no cache heirarchy and is as "bare-bones" as you can get in
gem5 while still being functinal.
"""

import m5
from m5.objects import Root

import os
import sys

# This is a lame hack to get the imports working correctly.
# TODO: This needs fixed.
sys.path.append(
    os.path.join(
        os.path.dirname(os.path.abspath(__file__)),
        os.pardir,
        os.pardir,
        os.pardir,
    )
)

from components_library.resources.resource import Resource
from components_library.boards.simple_board import SimpleBoard
from components_library.cachehierarchies.classic.no_cache import NoCache
from components_library.memory.single_channel import SingleChannelDDR3_1600
from components_library.processors.simple_processor import SimpleProcessor
from components_library.processors.cpu_types import CPUTypes

import argparse

parser = argparse.ArgumentParser(
    description="A script to run the gem5 boot test. This test boots the "
    "linux kernel."
)

parser.add_argument(
    "resource",
    type=str,
    help="The gem5 resource binary to run.",
)

parser.add_argument(
    "cpu",
    type=str,
    choices=("kvm", "timing", "atomic", "o3"),
    help="The CPU type used.",
)

parser.add_argument(
    "-r",
    "--resource-directory",
    type=str,
    required=False,
    help="The directory in which resources will be downloaded or exist.",
)

parser.add_argument(
    "-o",
    "--override-download",
    action="store_true",
    help="Override a local resource if the hashes do not match.",
)

args = parser.parse_args()

def input_to_cputype(input: str) -> CPUTypes:
    if input == "kvm":
        return CPUTypes.KVM
    elif input == "timing":
        return CPUTypes.TIMING
    elif input == "atomic":
        return CPUTypes.ATOMIC
    elif input == "o3":
        return CPUTypes.O3
    else:
        raise NotADirectoryError("Unknown CPU type '{}'.".format(input))

# Setup the system.
cache_hierarchy = NoCache()
memory = SingleChannelDDR3_1600()
processor = SimpleProcessor(cpu_type=input_to_cputype(args.cpu), num_cores=1)

motherboard = SimpleBoard(
    clk_freq="3GHz",
    processor=processor,
    memory=memory,
    cache_hierarchy=cache_hierarchy,
)

motherboard.connect_things()

# Set the workload
binary = Resource(args.resource,
        resource_directory=args.resource_directory,
        override=args.override_download)
motherboard.set_workload(binary)

root = Root(full_system=False, system=motherboard)

if args.cpu == "kvm":
    # TODO: This of annoying. Is there a way to fix this to happen
    # automatically when running KVM?
    root.sim_quantum = int(1e9)

m5.instantiate()

exit_event = m5.simulate()
print(
    "Exiting @ tick {} because {}.".format(m5.curTick(), exit_event.getCause())
)