Project ForgeComputer Organization & Architecture
Memory Hierarchy & Floating Point
GATE 2016
Hard
The width of the physical address on a machine is 40 bits. The width of the tag field in a 512 KB 8-way set associative cache (assuming the standard 32-byte block size) is ____ bits.
24
Explanation
Total blocks = 512KB/32B = 2¹⁴. Number of sets = 2¹⁴/8 = 2¹¹, needing 11 set-index bits. Block offset needs log₂32=5 bits. Tag = 40−11−5 = 24 bits.
Source: GATE CS 2016 (Session 2 / Set B) (2016)
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