A 16-bit-wide data bus is used to read a 128-bit instruction. How many bus…
2021
A 16-bit-wide data bus is used to read a 128-bit instruction. How many bus accesses are required?
Answer: C. 8 — ConceptA data bus transfers a number of bits equal to its width in each access. When the instruction size is an exact multiple of the bus width, the required…
- A.
2
- B.
4
- C.
8
- D.
7
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Show answer & explanation
Correct answer: C
Concept
A data bus transfers a number of bits equal to its width in each access.
When the instruction size is an exact multiple of the bus width, the required number of accesses is instruction size divided by bits transferred per access.
Application
Instruction size = 128 bits; bus width = 16 bits per access.
Number of accesses = 128 bits ÷ 16 bits per access = 8.
Therefore, reading the complete instruction requires 8 bus accesses.
Cross-check
8 accesses × 16 bits per access = 128 bits, which exactly equals the instruction size.