A machine has a byte-addressable main memory of 2¹⁶ bytes and a block size of 8 bytes. A direct-mapped cache with 32 lines is used. How many bits are in the tag, line and word fields of the address?

1. A8, 5, 3
2. B8, 6, 2
3. C7, 5, 4
4. D7, 6, 3

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Correct answer: A. 8, 5, 3

Explanation

Word = log₂ 8 = 3 bits; line = log₂ 32 = 5 bits; tag = 16 − 5 − 3 = 8 bits.