Reading from Cache
Take the memory address (X) and find X mod 8 (= 3 least sig. bits of X) = I (index).
Find X div 8 (= 2 most sig. bits of X) = T (tag).
Look in cache entry I, and check the valid field. If this is 0 then there’s a miss.
Check the tag field, if this is not the same as T then there’s a miss.
Otherwise a hit and retrieve the data.