GATE 2013 CS (CS1) – Question 62
Virtual addresses are 46 bits, physical addresses 32 bits. A three-level page table has one-page T₁, entries of T₁ pointing to T₂ pages and T₂ entries pointing to T₃ pages. T₃ entries are 32-bit PTEs. The processor has a 1 MB, sixteen-way, virtually indexed physically tagged cache with 64-byte blocks. Find page size in KB.
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Correct answer: (C) 8
Explanation
Let page size be 2ᵖ bytes. A four-byte entry means each page-table page holds 2ᵖ⁻² entries. Three index fields of p−2 bits plus p offset bits total 46: 3(p−2)+p=46. Therefore p=13 and page size is 8192 bytes=8 KiB, C. The intermediate physical base addresses use the stated 32-bit width.