GATE | GATE CS 2008 | Question 38

In an instruction execution pipeline, the earliest that the data TLB (Translation Lookaside Buffer) can be accessed is
(A) before effective address calculation has started
(B) during effective address calculation
(C) after effective address calculation has completed
(D) after data cache lookup has completed


Answer: (C)

Explanation: The Effective address is address after using adderssing mode.But this lead address is still a virtual address, the virtual address is not visible to the CPU and will only be provided by Memory Management Unit when it is assigned a corresponding address. Virtual address is provided for TLB lookup.

TLB -Translation Lookaside Buffer, here Lookaside means during address translation (from Virtual to Physical).

But the virtual address must be there before we can look at the TLB.

So (C) is correct option.

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