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36# Authors: Prakash Ramrakhyani
37
38from m5.params import *
39from m5.proxy import *
40from m5.objects.ClockedObject import ClockedObject
41from m5.objects.IndexingPolicies import *
42
43class BaseTags(ClockedObject):
44    type = 'BaseTags'
45    abstract = True
46    cxx_header = "mem/cache/tags/base.hh"
47
48    # Get system to which it belongs
49    system = Param.System(Parent.any, "System we belong to")
50
51    # Get the size from the parent (cache)
52    size = Param.MemorySize(Parent.size, "capacity in bytes")
53
54    # Get the block size from the parent (system)
55    block_size = Param.Int(Parent.cache_line_size, "block size in bytes")
56
57    # Get the tag lookup latency from the parent (cache)
58    tag_latency = Param.Cycles(Parent.tag_latency,
59                               "The tag lookup latency for this cache")
60
61    # Get the warmup percentage from the parent (cache)
62    warmup_percentage = Param.Percent(Parent.warmup_percentage,
63        "Percentage of tags to be touched to warm up the cache")
64
65    sequential_access = Param.Bool(Parent.sequential_access,
66        "Whether to access tags and data sequentially")
67
68    # Get indexing policy
69    indexing_policy = Param.BaseIndexingPolicy(SetAssociative(),
70        "Indexing policy")
71
72    # Set the indexing entry size as the block size
73    entry_size = Param.Int(Parent.cache_line_size,
74                           "Indexing entry size in bytes")
75
76class BaseSetAssoc(BaseTags):
77    type = 'BaseSetAssoc'
78    cxx_header = "mem/cache/tags/base_set_assoc.hh"
79
80    # Get the cache associativity
81    assoc = Param.Int(Parent.assoc, "associativity")
82
83    # Get replacement policy from the parent (cache)
84    replacement_policy = Param.BaseReplacementPolicy(
85        Parent.replacement_policy, "Replacement policy")
86
87class SectorTags(BaseTags):
88    type = 'SectorTags'
89    cxx_header = "mem/cache/tags/sector_tags.hh"
90
91    # Get the cache associativity
92    assoc = Param.Int(Parent.assoc, "associativity")
93
94    # Number of sub-sectors (data blocks) per sector
95    num_blocks_per_sector = Param.Int(1, "Number of sub-sectors per sector");
96
97    # The indexing entry now is a sector block
98    entry_size = Parent.cache_line_size * Self.num_blocks_per_sector
99
100    # Get replacement policy from the parent (cache)
101    replacement_policy = Param.BaseReplacementPolicy(
102        Parent.replacement_policy, "Replacement policy")
103
104class CompressedTags(SectorTags):
105    type = 'CompressedTags'
106    cxx_header = "mem/cache/tags/compressed_tags.hh"
107
108    # Maximum number of compressed blocks per tag
109    max_compression_ratio = Param.Int(2,
110        "Maximum number of compressed blocks per tag.")
111
112    # We simulate superblock as sector blocks
113    num_blocks_per_sector = Self.max_compression_ratio
114
115    # We virtually increase the number of data blocks per tag by multiplying
116    # the cache size by the compression ratio
117    size = Parent.size * Self.max_compression_ratio
118
119class FALRU(BaseTags):
120    type = 'FALRU'
121    cxx_class = 'FALRU'
122    cxx_header = "mem/cache/tags/fa_lru.hh"
123
124    min_tracked_cache_size = Param.MemorySize("128kB", "Minimum cache size for"
125                                              " which we track statistics")
126
127    # This tag uses its own embedded indexing
128    indexing_policy = NULL
129