Mapping Function 1.0

Hi~~ How are your guys?

Today, I want to show you what is Mapping Function.

First,

 Mapping function can be determine as 3 topic below:

a)Direct Mapping

b) Associative Mapping

c) Set Associative Mapping

For examples,

Cache of 64K Bytes,

Cache block of 4 Bytes.

That's mean cache is organized as

(64/4)KB Lines of 4 bytes each.

Or,

16 MBytes main memory,

Main memory consists of

(16/4)MB Lines of 4 bytes each.

From the solutions at above,

∴Lines is equal to capacity of cache/main memory divide by the capacity of cache block.

Direct Mapping

-Each block of main memory maps to ONLY one cache line.
-Address is in 2 parts.
-Least Significant 'w' bits identify unique word/byte within a block of main memory.
-Most Significant 's' bits specify one of 2 power of 's' memory block.








Direct Mapping Address Structure

Direct Mapping Cache Organization

Well...Let me do a summary for the direct mapping..

According to the all diagram above,

We can know that:

a)Address length = (s+w) bits.

b)Block size=Line size= 2^(w) words or bytes.

c)Number of blocks in main memory = 2^(s)

d)Number of lines in cache = m = 2^(r)

e)Size of tag = (s-r) bits

Direct Mapping is simple and inexpensive but its fixed location for given block.


Youtube:Direct mapped function


To be continues....

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