Increasing the block size

• As we have discussed, increasing the block size should reduce compulsory misses.
• The basic idea is to fetch a group of words, not just the word needed.
• A block of contiguous data will be fetched.
• Assume the block size is a power of two.
  • This will define the number of bits necessary to find the location of the item in the cache.
• So if we have a block size of 4, we will have 4 words in cache line.
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• The address now is broken even further
  • We will need two bits locate the item in the block (Block Offset or BO)
  • Plus the four index bits.
  • So we can take two bits out of the tag.
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  • And the associated pseudo circuit from the book.
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