Suppose we have a byte addressable memory of size 4GB (2 32 bytes) with a cache of size 256KB (2^18 bytes), not including tag bits. Also suppose the cache block size is 32 bytes. For each of the following cache organizations, compute the length in number of bits for the tag, index and offset fields of the 32-bit memory address (show your calculations), and justify your answer. i. direct mapped
ii. 2-way set associative
iii. 8-way set associative
iv. fully associative