4. Suppose a computer using set associative cache has 2²¹ words of main memory and a cache of 64 blocks, where each cache block contains 4 words.

1. If this cache is 2-way set associative, what is the format of a memory address as seen by the cache, that is, what are the sizes of the tag, set, and word fields?
2. If this cache is 4-way set associative, what is the format of a memory address as seen by the cache?