ACE TEST SERIES 2017 DEPENDENCY PROBLEM

Question

WHICH OF THE FOLLOWING DEPENDENCY PROBLEM CAN BE ELIMINATED BY USING REGISTER RENAMING?

A)DATA DEPENDENCY

B)RESOURCE CONFLICT

C)STRUCTURAL DEPENDENCY

D)ANTI DATA DEPENDENCY

.we can remove structural dependency by renaming ...and war (anti ) waw(output) using register renaming ...what should be the answer ….anti data dependency alone or
BOTH C AND D
AND ONE DOUBT STRUCTURAL DEPENDENCY IS DUE TO RESOURCE CONFLICT SO B CAN BE ALSO?

Comments

well structural dependency can be eliminated by resource duplication but not completely. Here resource you are referring to is the cache or main memory. It is possible if you try to infer the same resource 2 or more times in the same cycle. For example think about IF stage and OL(operand load) stage. Here IF will fetch the instruction from let's say a cache and OL stage is loading data from the same cache. so it will lead to a conflict which can be avoided(not completely) by duplicating the cache(I-cache and D-cache).

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Structural Dependency is solved by "Renaming". Not "Register Renaming". There is a difference between the two.

In "Renaming" - you take the resource that is causing a structural dependency and divide it logically - and give each one a different name and treat them as separate resources in the pipeline.

"Register Renaming" is where you abstract logical registers from physical registers. This is used to help with WAR and WAW hazards in out-of-order processors.

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OK CLEARED