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from m5.params import *
from m5.proxy import *
from m5.SimObject import *

from m5.objects.IndexingPolicies import *
from m5.objects.ReplacementPolicies import *


class BaseCacheCompressor(SimObject):
    type = "BaseCacheCompressor"
    abstract = True
    cxx_class = "gem5::compression::Base"
    cxx_header = "mem/cache/compressors/base.hh"

    block_size = Param.Int(Parent.cache_line_size, "Block size in bytes")
    chunk_size_bits = Param.Unsigned(
        32, "Size of a parsing data chunk (in bits)"
    )
    size_threshold_percentage = Param.Percent(
        50,
        "Minimum percentage of the block size, a compressed block must "
        "achieve to be stored in compressed format",
    )

    comp_chunks_per_cycle = Param.Unsigned(
        1, "Number of chunks that can be compressed in parallel per cycle."
    )
    comp_extra_latency = Param.Cycles(
        1,
        "Number of extra cycles required "
        "to finish compression (e.g., due to shifting and packaging).",
    )
    decomp_chunks_per_cycle = Param.Unsigned(
        1, "Number of chunks that can be decompressed in parallel per cycle."
    )
    decomp_extra_latency = Param.Cycles(
        1,
        "Number of extra cycles required "
        "to finish decompression (e.g., due to shifting and packaging).",
    )


class BaseDictionaryCompressor(BaseCacheCompressor):
    type = "BaseDictionaryCompressor"
    abstract = True
    cxx_class = "gem5::compression::BaseDictionaryCompressor"
    cxx_header = "mem/cache/compressors/dictionary_compressor.hh"

    dictionary_size = Param.Int(
        Parent.cache_line_size, "Number of dictionary entries"
    )


class Base64Delta8(BaseDictionaryCompressor):
    type = "Base64Delta8"
    cxx_class = "gem5::compression::Base64Delta8"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 64

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class Base64Delta16(BaseDictionaryCompressor):
    type = "Base64Delta16"
    cxx_class = "gem5::compression::Base64Delta16"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 64

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class Base64Delta32(BaseDictionaryCompressor):
    type = "Base64Delta32"
    cxx_class = "gem5::compression::Base64Delta32"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 64

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class Base32Delta8(BaseDictionaryCompressor):
    type = "Base32Delta8"
    cxx_class = "gem5::compression::Base32Delta8"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 32

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class Base32Delta16(BaseDictionaryCompressor):
    type = "Base32Delta16"
    cxx_class = "gem5::compression::Base32Delta16"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 32

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class Base16Delta8(BaseDictionaryCompressor):
    type = "Base16Delta8"
    cxx_class = "gem5::compression::Base16Delta8"
    cxx_header = "mem/cache/compressors/base_delta.hh"

    chunk_size_bits = 16

    # Base-delta compressors achieve 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class CPack(BaseDictionaryCompressor):
    type = "CPack"
    cxx_class = "gem5::compression::CPack"
    cxx_header = "mem/cache/compressors/cpack.hh"

    comp_chunks_per_cycle = 2
    # Accounts for pattern matching, length generation, packaging and shifting
    comp_extra_latency = 5
    decomp_chunks_per_cycle = 2
    decomp_extra_latency = 1


class FPC(BaseDictionaryCompressor):
    type = "FPC"
    cxx_class = "gem5::compression::FPC"
    cxx_header = "mem/cache/compressors/fpc.hh"

    comp_chunks_per_cycle = 8
    comp_extra_latency = 1
    decomp_chunks_per_cycle = 4
    decomp_extra_latency = 1

    # Dummy dictionary size, since FPC has no dictionary
    dictionary_size = 1

    zero_run_bits = Param.Int(3, "Number of bits of the zero run bit field")


class FPCD(BaseDictionaryCompressor):
    type = "FPCD"
    cxx_class = "gem5::compression::FPCD"
    cxx_header = "mem/cache/compressors/fpcd.hh"

    # Accounts for checking all patterns, selecting patterns, and shifting
    # The original claim of a decompression latency of 2 cycles would likely
    # generate an unrealistically complex circuit
    comp_chunks_per_cycle = 4
    comp_extra_latency = 1
    decomp_chunks_per_cycle = 4
    decomp_extra_latency = 0

    dictionary_size = 2


class FrequentValuesCompressor(BaseCacheCompressor):
    type = "FrequentValuesCompressor"
    cxx_class = "gem5::compression::FrequentValues"
    cxx_header = "mem/cache/compressors/frequent_values.hh"

    chunk_size_bits = 32
    code_generation_ticks = Param.Unsigned(
        10000,
        "Number of elapsed "
        "ticks until the samples are analyzed and their codes are generated.",
    )
    # @todo The width of a counter width is determined by the maximum
    # number of times a given value appears in the cache - i.e.,
    # log2(cache_size/chunk_size_bits))".
    counter_bits = Param.Unsigned(18, "Number of bits per frequency counter.")
    max_code_length = Param.Unsigned(
        18,
        "Maximum number of bits in a "
        "codeword. If 0, table indices are not encoded.",
    )
    num_samples = Param.Unsigned(
        100000,
        "Number of samples that must be "
        "taken before compression is effectively used.",
    )
    check_saturation = Param.Bool(
        False,
        "Whether the counters should be " "manipulated in case of saturation.",
    )

    vft_assoc = Param.Int(16, "Associativity of the VFT.")
    vft_entries = Param.MemorySize("1024", "Number of entries of the VFT.")
    vft_indexing_policy = Param.BaseIndexingPolicy(
        SetAssociative(
            entry_size=1, assoc=Parent.vft_assoc, size=Parent.vft_entries
        ),
        "Indexing policy of the VFT.",
    )
    vft_replacement_policy = Param.BaseReplacementPolicy(
        LFURP(), "Replacement policy of the VFT."
    )

    comp_chunks_per_cycle = 1
    comp_extra_latency = 1
    decomp_chunks_per_cycle = 1
    decomp_extra_latency = 0


class MultiCompressor(BaseCacheCompressor):
    type = "MultiCompressor"
    cxx_class = "gem5::compression::Multi"
    cxx_header = "mem/cache/compressors/multi.hh"

    # Dummy default compressor list. This might not be an optimal choice,
    # since these compressors have many overlapping patterns
    compressors = VectorParam.BaseCacheCompressor(
        [CPack(), FPCD()], "Array of compressors"
    )
    encoding_in_tags = Param.Bool(
        False,
        "If set the bits to inform which "
        "sub-compressor compressed some data are added to its corresponding "
        "tag entry.",
    )

    # Use the sub-compressors' latencies
    comp_chunks_per_cycle = 0
    decomp_chunks_per_cycle = 0

    # Assume extra 1 cycle to select the results of the winning sub-compressor
    comp_extra_latency = 1

    # Multi-compressors may need a couple of extra cycles to the select
    # which sub-compressor should be used to decompress the data
    decomp_extra_latency = 1


class PerfectCompressor(BaseCacheCompressor):
    type = "PerfectCompressor"
    cxx_class = "gem5::compression::Perfect"
    cxx_header = "mem/cache/compressors/perfect.hh"

    chunk_size_bits = 64

    max_compression_ratio = Param.Int("Maximum compression ratio allowed")

    # In a perfect world compression and decompression happen in 1 cycle
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class RepeatedQwordsCompressor(BaseDictionaryCompressor):
    type = "RepeatedQwordsCompressor"
    cxx_class = "gem5::compression::RepeatedQwords"
    cxx_header = "mem/cache/compressors/repeated_qwords.hh"

    chunk_size_bits = 64

    # Assume 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class ZeroCompressor(BaseDictionaryCompressor):
    type = "ZeroCompressor"
    cxx_class = "gem5::compression::Zero"
    cxx_header = "mem/cache/compressors/zero.hh"

    chunk_size_bits = 64

    # Assume 1-cycle latencies
    comp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    comp_extra_latency = 0
    decomp_chunks_per_cycle = 8 * Self.block_size / Self.chunk_size_bits
    decomp_extra_latency = 0


class BDI(MultiCompressor):
    compressors = [
        ZeroCompressor(size_threshold_percentage=99),
        RepeatedQwordsCompressor(size_threshold_percentage=99),
        Base64Delta8(size_threshold_percentage=99),
        Base64Delta16(size_threshold_percentage=99),
        Base64Delta32(size_threshold_percentage=99),
        Base32Delta8(size_threshold_percentage=99),
        Base32Delta16(size_threshold_percentage=99),
        Base16Delta8(size_threshold_percentage=99),
    ]

    # By default assume that the encoding is stored in the tags, and is
    # retrieved and decoded while (and ends before) the data is being read.
    decomp_extra_latency = 0
    encoding_in_tags = True