The Sun UltraSPARC processor has multiple register sets. Describe what
happens when a context switch occurs if the new context is already
loaded into one of the register sets. What happens if the new context is
in memory rather than in a register set and all the register sets are in
use?
Answer:
The CPU current-register-set pointer is changed to point to the set
containing the new context, which takes very little time. If the context is
in memory, one of the contexts in a register set must be chosen and be
moved to memory, and the new context must be loaded from memory
into the set. This process takes a little more time than on systems with
one set of registers, depending on how a replacement victim is selected.
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