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| '''Direct Mapped Cache''' | == Direct Mapped Cache == |
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| '''Tags''' contain the address information required to identify if the information in a cache location coresponds to the data needed. These tags contain the upper bits: | '''Tags''' contain the address information required to identify if the information in a cache location coresponds to the data needed. These tags contain the upper bits of the memory address. '''NOTE:''' The ''byte offset'' is the number of bits required to specify bytes in a block. Since this example uses 4 byte (word) sized blocks the ''byte offset'' is 2 bits |
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| ||||||||||||||||||Upper bits||||||||||Lower bits|| ||7||||6||||5||||4||||3||||2||||1||||0|| |
https://www.scotnpatti.com/images/directmappedcache2.jpg |
Cache
Direct Mapped Cache
Cache's are directed mapped if each memory location is mapped to exactly one location in the cache. An example would be:
location = (Block Address) MOD (Number of cache blocks in the cache)
In this way we can map a memory location to a cache location.
Example: Suppose we have a cache with 8 slots 2^3. Then a word at 45 would be found at slot 5 in the cache.
https://www.scotnpatti.com/images/directmappedcache.jpg
Tags contain the address information required to identify if the information in a cache location coresponds to the data needed. These tags contain the upper bits of the memory address. NOTE: The byte offset is the number of bits required to specify bytes in a block. Since this example uses 4 byte (word) sized blocks the byte offset is 2 bits
