A two way set associative cache memory unit with a capacity of 16 KB is built…
2017
A two way set associative cache memory unit with a capacity of 16 KB is built using a block size of 8 words. The word length is 32 bits. The physical address space is 4 GB. The number of bits in the TAG, SET fields are
- A.
20, 7
- B.
19, 8
- C.
20, 8
- D.
21, 9
Attempted by 69 students.
Show answer & explanation
Correct answer: B
1. Word length = 32 bits = 4 bytes. Block size = 8 words * 4 bytes/word = 32 bytes.
2. Block offset bits = log2(32) = 5 bits. Cache capacity = 16 KB = 2^14 bytes.
3. Number of blocks = 2^14 / 32 = 2^9. Number of sets (2-way) = 2^9 / 2 = 2^8. Set index bits = log2(256) = 8 bits.
4. Physical address = 4 GB = 2^32 bytes (32 bits). Tag bits = 32 - 8 - 5 = 19 bits. Final Answer: TAG = 19 bits, SET = 8 bits.
A video solution is available for this question — log in and enroll to watch it.